I've been thinking about this one more and more lately and have come up with some conclusions that I hope you all will critcize so we can discuss.

Now I know the programmable ECU gives you more precise control, but what does it really entail? Owning a laptop and spending hours figure out what you're looking at before you can get values right?

With piggybacks like the ITC, S-AFC, J&S, and boost controller you can dial things in, but possibly not as acurately.

Now in comparison the programmable ECU is a decent way to go, but also a pain to program... you have to drag out the laptop (if you even own one, which I don't) and then drive around and analyze numbers (until you've figured them all out, that is). Now with piggybacks if you're having problems you just reach over and turn a knob or hit a few buttons and you get them dialed in fine.

Now the other trick in the two systems... boost control. If you turn down the boost on a programmable ECU system, the ECU may compensate, then again it may not. Though with the piggybacks you're almost assured that they will not compensate, correct?

---------------------------------------------

Now to the personal part of it all... Since I don't have a laptop, would the piggybacks be the easier way to go for me? I also plan on changing my boost levels fairly often (ie. maybe once or twice every 2-3 days depending on the driving situation).

Now I only plan on running an ITC, S-AFC, & boost controller if I get into it (who needs the J&S when you can listen for it by ear and actually LET OFF when something happens?) OR if I get a line on a decent & easily programmable ECU for about the same amount, I'll go with that.

Anyone with more knowledge on the topic want to help a confused soul? http://www.i-club.com/ubb-files/smile.gif

I don't believe the Wolf EMS needs a laptop. Supposedly you just give it the base map on your home PC then the fine tuning is done in the car through the interface.

Tony

8, you can get away with not owning a laptop. How? (a) borrow someone else's (work?), (b) run a power inverter and use your desktop.

Sure, it's a pain, but it works.

Also, run the numbers on the cost. Piggybacks will only save you a few hundred, but they really limit what you can do. There's no limit to what you can do safely with a programmable system.

The programmable ECU always takes into account your boost level if you set it up properly. The correct method is to start mapping your engine at the wastegate spring setting (usually 5 psi). Then you re-map the engine slowly turning up the boost with the programmable ECU's boost controller. At each step, you'd make whatever adjustments are necessary to the map before increasing boost. And at each boost level, you save a correct map. Presto! Perfectly safe map for every condition, provided you don't rush things.

It's going to be a pain to program, but once you're done you're done. Shiv's now running 12psi of T03/04 boost on his MY99 with 1500F EGTs with the injectors at 85% duty cycle. Not that I'm experienced with such things, but I bet you if it's even possible to do that with piggybacks, it'd be more difficult, not less. (And I'm not sure you could get over the maxed out injector issue).

<A HREF="http://members.home.net/gopspin/"><IMG SRC="http://216.242.153.40/MembersList/UserPics/158/tiny2.gif" HEIGHT=53 WIDTH=82 ALT="My car" BORDER=0></A>

[This message has been edited by R Diamond (edited October 10, 2000).]

The stock injectors reach 100 duty cycle at 1-2psi of boost. Above that, you're just running lean. Hence, the 1650 degree EGTs at 7psi with stock 280cc njectors and 1500 degree EGTs at 12 with TEC-II and 550cc injectors. Not only is the latter configuration 50% more powerful, it's also a lot safer in the long run.

shiv

Shiv-- is that number on the stock injectors assuming you keep stock fuel pressure?

Wouldn't it be fair to assume one of the piggybacks is a boost-referenced fuel pressure riser?

I assumed the subject title, "piggy back electronics" only refers to electronics, not fuel pressure regulators http://www.i-club.com/ubb-files/smile.gif

With 80psi of fuel pressure at 10psi of boost, you will get 27% more fuel flow. Essentially turning the 280cc injectors into 355cc injectors. Still only considered ideal for 210-240hp. Either way, injectors don't like to go static.

Shiv

(who needs the J&S when you can listen for it by ear and actually LET OFF when something happens?)The trick with the J&S is to get it to cut back on the timing BEFORE there is any detonation.

8-

I have done both. First I had the ITC, S-AFC, and AVC-R (timing, fuel, and boost). Now, I have the TEC-II doing all three.

Personally, I will NEVER go back to the piggyback method. Not for the RS. Do the piggybacks work? Yes. Is it safe? I think so...looking at Adam and Richard (as well as man others), it seems to work just fine. Is it more stressful on the engine than the TEC-II setup? Yes.

After experiencing the TEC-II, it's the obvious choice for engine control. Sometimes I wish I never looked at the TEC-II...I'd be $3000 richer http://www.i-club.com/ubb-files/smile.gif

Maybe you should just never experience the TEC-II...then you could just go with the piggybacks and be perfectly happy http://www.i-club.com/ubb-files/smile.gif

One last thing - I thought that I wanted to change boost levels often like you say you do. In the end, I realized that I don't want this. I want to pick a boost level and stick with it. Lowering the boost for daily driving SUCKS! http://www.i-club.com/ubb-files/smile.gif After driving around at 8psi, then switching back to 3psi, the car feels like a golf cart.

Sean

8- the wolf3d runs about $1250.00

and yes mine is a Wolf3D

it does require a laptop to make the initial base curve but after a basic map is made it can be modified with the led console without an laptop. unless you want nice datalogging and pretty graphs the laptop isn't necassary

Tony - I've taken a look at that before, but I haven't heard of anyone using one or even developing one. Do you have any clue who sells/installs/uses them?

R Diamond - You're correct about the saving of maps, but I'm talking cranking it up during an autocross (or to play on the street) and turning it down for normal driving. This can only be done with the laptop though, correct? I mean if I want to change it for 20 minutes, thats a helluva hassle, right?

Oh and about running the desktop in the car... my monitor is a 20incher so there is NO WAY I'm even considering that one. I could probably get a cheap pI system for like $200, but thats just added costs. *shrug*

You're right about the duty cycle and running out of injector abilities, though. IIRC it was at 10psi when you absolutely needed to upgrade them, right? I think at 8psi you just needed to upgrade the fuel pump & regulator.

I just ordered my Wolf EMS
!! http://www.i-club.com/ubb-files/smile.gif http://www.i-club.com/ubb-files/smile.gif http://www.i-club.com/ubb-files/smile.gif http://www.i-club.com/ubb-files/smile.gif !!
should be here in 2 weeks.
its very simple to use compared to an Motec or something else. they even have an subaru harness with it..

Byron uses a wolf computer and some other Rx7 people but i don't really know anybody else.

doripreza - How much did the Wolf EMS run you? And was it the Wolf 3D?

Or is it Wolfenstein? http://www.i-club.com/ubb-files/biggrin.gif

Hey 8-
Depending upon what is needed for the laptop, check out e-Bay and get yourself an old laptop for like $100. Just a thought...

-Rez
http://smilecwm.tripod.com/net6/scrambles.gif

[This message has been edited by Rez (edited October 11, 2000).]

doripreza - Cool sounds like it's not too bad of a system.

Rez - Yeah, I've been checking out the <a href="http://www.pricewatch.com/1/247/2491-1.htm" target="_blank">refurbished notebooks</a> at www.pricewatch.com (http://www.pricewatch.com) lately to see what they've got. Not too bad of deals, either.

what about for a stage I what would you need?

doripreza (or anyone else), would you mind elaborating more about the Wolf3D (are you sure you are not talking about Wolfenstein 3D?)

-who resells it
-website, if any
-what it comes with - I like the fact that the Vishnu TECII replaces many of the sensors.

thanks...

8, if you need a cheap lap top let me know.i manage a major electronic store in the schaumburg area,should be no problem getting you a cheap reliable laptop under a warrenty. let me know,im local to you....

TR-
About the Wolf EMS.

I got mine through byron who i think is the only reseller out right now that i know of..
http://www.b-specusa.com
(dispite all the rumors he still sells dope parts)
anyway you can find out about the computer at http://www.wolfems.com/Products/EMS/Wolf_3D/wolf_3d.html
hope that helps some

[This message has been edited by doripreza (edited October 11, 2000).]

Well on the EFI system I got you can swap maps with a switch. The ecu has two memory "locations" that may or may not be different chips. When the switch is open the ECU runs map 1, shorted it runs map 2. Then it also has the ability to have a 10K ohm pot wired in which will allow a 0-10 degrees of ignition timing to be removed. You could in theory make a switch to cut the 10 degrees of out and have a valet mode w/o using the second map.

As far as laptops go, I got mine for free, but its a old 486Sx33 w 4MB of ram. Not critical as the efi tuning software will run on a 286.

Also while it is not as powerful as the TecII and does not include the coils, it was only $630+ shipping when I bought it.

yeah, the piggybacks work. Is it idea? Nope, but its easier IMHO. The choice on my car was simple..I have aTEC2 on another car, and while it was the sinlge biggest improvement I ever made to it (its o my ZX Turbo), I wanted to do this one abit differently...I am happy with th piggyback method.

No info on the Wolf, but I don't think its widely used here in the states. At the time I got my TEC, I looked at a bunch of others (Motech, Haltech, DFI, SDS), but the TEC wsa the best bet. And for a 4 cylinder, its downright inexpensive (on a cost basis at least, not sure what the resellers charge...something my wallet thankfully didn't have to confront)

Adam,

Has you ZX ever bent a rod?

Shiv

I'm still drawn between the two, though I have to admit that the entire problem is the price difference. I would go with the TEC-II setup if it was $1000 less, but $2500 for what I can spend around $1200 on just doesn't seem right (300 ITC, 300 S-AFC, 200 boost controller, 500 injectors - ok I left off knock detection, but there is a stock sensor and my ears work fairly well too).

So get a haltech E6K! Trey will sell you one without coils and with whatever crank trigger you want.

8-

But how do you control larger injectors with the stock ECU?

Sean

8complex look here.
www.perfectpower.com (http://www.perfectpower.com)

I got the Mic3. Its dirt cheap, and decent in features. the only real problem I see is needing to make the crank trigger(s), but at least for me it wasn't that bad once I got around to doing it.

Colin - You got a good point... I haven't asked Trey about that HalTech setup lately. Gonna hafta give him a call and get filled in on it.

Sean McElderly - Errrr... ummmm... damnit, I fergot about that different impedence thing, didn't I?

XT6Wagon - I'll take a look. Thanks. http://www.i-club.com/ubb-files/smile.gif

[This message has been edited by 8Complex (edited October 11, 2000).]

Not only different impedence, but the duty cycles required to match fuel delivery across the operating range will be WAY off. The S-AFC can only do so much.

IMO, even if you could get the impedence of the injectors to match, you'd have a helluva time getting it to idle properly and drive like stock with piggybacks.

This, BTW, is the exact reason I decided to go with a programmable ECU. I couldn't resolve the larger injector problem easily with piggyback electronics.

Sean

So I guess my question now would be, why doesn't someone design a high-impedence injector whose output is say 150% of stock instead of 200% like the TEC-II ones? Could probably be much more easily adjusted with the S-AFC...

Damn that price difference... I've got about $1100 on one hand and $2500 on the other. As much as I want to go programmable, I think I'm going to have to go piggyback until I can afford to drop the cash on the programmable system. I guess it's not like I can't get back most of my money on the piggybacks, right? http://www.i-club.com/ubb-files/smile.gif

8-

High impedance injectors that flow 150% more than stock might work under driving conditions, but your idle will probably be way off. You'll be running either really rich (REALLY rich) or have to have an idle above 1000rpm. Tuning the idle is one of the hardest things, IMO.

Sean

$1100 is fairly cheap...and if you go that route first, you'll know all about piggybacks, right? That knowledge can't hurt.

Sean

Well with the S-AFC you'd need to lean out the idle mixture a LOT, but I suppose it wouldn't be impossible. I think the only problem with a turbo is that you need a curve for between normal acceleration and WOT and idle because of the variable boost levels since you can take it easy with your foot or you can peg it to the floor and get different boost levels at different RPM's (or this may have just been true with my old 2.1L Volvo with th T3 in it).

Knowing all about the piggybacks and such would be very good knowledge. I've played with the ITC and S-AFC before on an N/A car and they were both very easy to manipulate, even just basing it off of butt dyno runs and an A/F meter readings.

The Haltech is an ok way to go....alot more involved tuning wise than the TEC2 is though. Remember though, Shiv's TEC2 comes with various extras, and has a much better initial software setup in it than any other ec will. The actual TEC portion of the package (minus the injectors, etc.)is very inexpensive.

Shiv - the great thing about those datsuns is they are incredibly strong. The Skyline motor is an outgrowth of it, albeit a bit smalle displacement. I have never had a rod issue on that car. My initial set up (which netted low 12's) consisted of my original normally aspirated motor (with 120k on it) which we turbocharged. It never blew up, but the rings did begin to let go. I then swapped the blcok for a '81 Turbo block, and eventually played around with te hydraulic-lifter head (mine was a good one, which is tough to find!), which we ran 11's with...all internally stock, no cams, head work, etc. Just ARP studs, HKS headgasket, and lots of careful work on the turbo side to ensure we had the right one on there. My new setu uses "super special Z1 only stuff" http://www.i-club.com/ubb-files/smile.gif hahaha, but I will say this...the rods in my new motor (which dynoed a bit over 630 on the engine dyno bfore we instaled it in my car) is still using stock zx turbo rods. The head has ben thoroughly worked now, as have pistons, cams, etc...and nother special turbo. Great thing about these motors is, like a Supra TT motor, they are very much over-engineered by Nissan so they are very, very strong.

8-

Yes, you'd have to lean the mixture at idle, but you'll run into the problem of high impedence injectors. They might not be able to go as lean as you need them to go. They have a minimum on-time, and if you try to go below that minimum on-time (by leaning them out), bad things will happen. You car will idle very poorly and probably stall. So you're kinda stuck with a rich idle...and probably a high idle as well.

Sean

But then again...many people have run high boost on the stock injectors. Richard, Adam, TMR (??), etc. Seems to have worked fine for them.

Sean

I thought that the stock injectors maxed out around 8-10psi.

Hey Adam, were you actually running that 17psi through stock injectors? Must have had one HELL of a fuel pump in there...

The stock injectors max out with any amount of boost (even 1psi, IIRC). This is speaking of just duty cycle.

By raising the fuel pressure, you can flow more fuel through the injectors while they're statically open. This will require a RRFPR.

To contrast, with the TEC-II, my injectors (550cc/min) are at 75% duty cycle with the stock fuel pressure at 8psi of boost at redline.

Yes, Adam was running the stock injectors...amazing, huh? http://www.i-club.com/ubb-files/smile.gif

8, you have a MY00, right? The S-AFC won't do you any good, IMO. Get a RRFPR instead. Otherwise, you'll be stuck with 3psi of boost. The stock ECU doesn't like MAP voltages about 3psi of boost...so it enters fuel cut mode. You need a mechanical device like a RRFPR to get around this. And with that, you don't get the control that you would have with an S-AFC or similar device.

Sean

Yeah I know. In my MY00 there is another consideration... that damn MAP problem. I'd need to run a voltage clip and RRFPR and then tweak tweak tweak tweak until it is in line.

Hmmmmm... maybe I should get one of the fuel pumps that the Supra TT guys upgrade to instead of hteir stock ones... lol.

The worst part is that I'm going through all these nutty thoughts and I still want a supercharger instead of a turbo (and I've already priced a turbo kit too). http://www.i-club.com/ubb-files/frown.gif

8-

What are your reasons for wanting a SC instead of TC? I think both are awesome...but I'm just curious as to why the SC route is more appealing to you.

Sean

Well the main reason for wanted an SC over TC is because of the immediate boost. I autocross a lot and plan on sitting myself in SMod next year and I just don't want to have to deal with any lag at all.

Granted that T28/T3 hybrid unit that JCS sells is probably real close to lagless, that is the only one I'm really considering since the Minnam/Vishnu kit is just WAY oversized for the regular driver. Yeah you can push 20psi out of it, but your average Joe doesn't want to blow their engine and trans and clutch and rear diff like that. You're looking at another $10k in driveline parts just to keep the car running. 10psi is about the level I'm looking at and as hard as I am on cars, I somehow manage not to brake them like everyone else does so I'm hoping (at least for a while) not to replace any driveline components (though I believe my dealership will do *one* warantee tranny replacement for me since I know them well enough).

That and you're looking at a lot more parts to be screwed up in a turbo kit. I am notoriously bad with exhaust systems so I'm not looking forward to that part of the turbo kit. A SC is really just an interruption in the intake tract if you think about it. http://www.i-club.com/ubb-files/smile.gif

yes - stock injectors, upgraded pump (Supra TT, which is a hell of a unit!), and a Magnetti Mareli 2:1 AFPR...running about 82-82 psi of pressure at WOT, with 18 psi. although i expected them, I had no leaks from the injector seal, etc., and yes, idle was a bit rich (fuel pressure was 46 at idle), but no visible black smoke, etc. like My ZX has

8-

Cool. Well, good luck with all your endeavors. Sounds like you've got quite a bit of work ahead of you http://www.i-club.com/ubb-files/smile.gif

Sean

Adam - Sweet, well at least I know I've got a good pump coming my way. http://www.i-club.com/ubb-files/smile.gif

I had heard something about the XT6 FPR being able to drop the idle fuel pressure down to the stock 34psi, IIRC. I'd suggest it to you but last I heard you were going full-swap. Speaking of which, how is that project coming along?

Sean - Oh yeah... tons and TONS of work. http://www.i-club.com/ubb-files/eek.gif http://www.i-club.com/ubb-files/smile.gif

[This message has been edited by 8Complex (edited October 12, 2000).]

Heh.. I just saw a P1 - 75mhz compaq laptop on ebay for like $50. Chalk it up to tuning costs http://www.i-club.com/ubb-files/wink.gif

8,

What is your typical use for your car? Is it a daily driver? Daily driver and weekend autocrosser? Is it strictly your "toy" with little daily driving and as autocrossing 'till your ears bleed? (I wish)

Reason I ask is that the ol' saying of "Speed costs money how fast do you want to go" is pretty much a universal truth in the car performance industry. I too am sometimes frustrated at the lack of options available to us Subie fanatics but then I remeber how relatively rare our cars are on this continent. I am then thankfull that we have a guy like Shiv sharing pretty much ALL of his finding with us here on the board. Do you realise that in any other place in the world, people would pay $$ to glean that info from his skull which he shares freely here? All things being equal, I think you may want to reconsider the gift that we have in his participation in this lil' ol' community of ours.

Furthermore, yes, the kit is pricey, but as Shiv has stated on numerous occasions, the kit is a full turn key affair (except catback exhaust & fuel pump). The injectors are custom made and calibrated, so is the fuel rail, so are the Magnetocore wires, etc. etc. etc. Sure you may be able to find the parts for cheaper, but will they have been selected to work well together as a system? Have the bugs been worked out of them? Will they be as good a quality or provide you with the opportunity to upgrade to more power in the future?

I also ask the question..."Is the Vishnu kit worth the expense?" My ansewer to myself..."If the system is overkill and I get a hugely reliable 5-8psi of boost for my daily driver that has to last me at least 150,000miles, I'll pay the extra few bucks because it will be cheaper than a rebuild everytime."

Food for thought.

Peace,
MB

PS Not trying to poo-poo on anyones parade here, but I do appreciate that some people are asking tough questions and are open mineded enough to listen to opinions of others.

BTW, It's still "tomorrow" http://www.i-club.com/ubb-files/wink.gif http://www.i-club.com/ubb-files/wink.gif

8Complex,
Please re-read my post. I talked about holding hp equal, not boost level. The T3/T04 will move more mass airflow than the T28 at any given useful pressure ratio. Not only does this mean more power for each additional pound of boost. It also means cooler aircharge and less exhaust back pressure once hp levels reach and exceed the ~240hp mark. Less exhaust back pressure and less charge head means a greater resistance to detonation, cooler EGTs and a longer-runing, less stressed engine.

At 20psi, Adam Bloom was running his turbo into compressor surge. Not only does this potentially damage the turbo through overspeeding, it also places huge stresses on the engine. Both from excessive exhaust backpressure and sky-high intake charges. Running 108 octane race gas and only 12-13 seconds at a time, these stresses can be kept at bay. Until, of course, the engine knocks itself to death or bends a rod through excessive cylinder pressure. Both caused by inadequate spark timing/control.

The key to reliable high output performance is system optimization. Proper turbo matching and proper engine management. Without a moderately optimized system, it is simply impossible to draw conclusions about the innate "goodness" of any individual component. It's like driving a Porsche with Big O tires or a Geo Metro with SO-2s and wondering why neither car handles very well.

Shiv

[This message has been edited by shiv (edited October 12, 2000).]

This is to noone in particular:

I know it has been said before, but any relative newbie to the turbo world might benefit from reading Maximum Boost by Corky Bell.

I have read it a couple times now in the last week (just checked it out from the library) and it is very useful for the novice in the turbo world. It gives formulas to calculate what sized turbo would be best for the PSI and cfm of a particular engine, and all other kind of goodies.

It isn't the end all of turbo books, but it is a good read, and easy to understand for a non-engineer type, like myself. I feel I better understand what is involved in designing, choosing, or installing a turbo kit. Now I just need a turbo kit to practice with http://www.i-club.com/ubb-files/wink.gif

Aaron

8Complex writes...
Granted that T28/T3 hybrid unit that JCS sells is probably real close to lagless, that is the only one I'm really considering since the Minnam/Vishnu kit is just WAY oversized for the regular driver. Yeah you can push 20psi out of it, but your average Joe doesn't want to blow their engine and trans and clutch and rear diff like that.

You should do your homework before making statements like this. Holding hp equal, a smaller turbo will generate more torque in the midrange. They also tend to overboost since shaft speeds are so great. It will also spool up quicker between shifts. All these characteristics will create sharper torque spikes. And since trannys only care about torque and not hp, one could conclude that smaller turbos can be more hurtful to transmissions than larger turbos.

As for the Minnam configured T3/04 being able to support 20psi on a EJ25, that's also untrue. It is properly sized for 10-12psi of boost. At that pressure ratio, on that turbo, on the EJ25, hp would be in the 300-320hp range providing proper fuel and spark control. Of course, all this is acedemic if you don't have proper engine management. If this is the case, stay with a T28, keep boost levels below 8psi and be happy with 240-250hp. Just get an ITC, a fuel pump, a knock sensor, a rising rate fuel pressure regulator and watch your EGTs.

Shiv

[This message has been edited by shiv (edited October 12, 2000).]

just how critical is the ITC is the piggyback world? shouldnt just the knock sensor be enough for low level boost applications i.e. under 9 lbs?
thanks

I agree with Shiv in regards to the turbo sizing. Torque is the main killer to all drivetrain components.

In regards to Datsun/Nissan L6 Engines...I have some experience. http://www.i-club.com/ubb-files/smile.gif

I'm currently on my 3rd engine in the 240Z, and my 2nd engine threw a rod. My second engine was a home-built high-compression N/A L28. However, the rod itself did not break. The rod bolt was the culprit in this case. As we all know, a broken rod bolt sends parts flying, so this engine was a total writeoff. The reason this engine blew was due to myself. I had missed a shift the day prior to this and accidentally overreved the engine. This was prior to my MSD-6AL which has a rev-limiter. I'm convinced the overrev is what fatigued the bolt. My bad.

Based on my experience, and what I have read and heard from others, the weak point in L-series Datsun engines is not the rod itself, but rather the rod bolt. The early L24 engines actually had 8mm rod bolts, which were quickly increased to 9mm later in the production run. The quick fix to this is to obviously use bigger/stronger bolts. Chevy bolts actually fit quite well. Once properly prepped and polished, stock L series rods are VERY strong, as is the rest of the bottom-end. If properly built, these engines rarely fail.

Dave
'00 Subaru 2.5RS Sedan
'00 VW Passat GLS 4Motion
'72 Datsun 240Z w/new 3.0L engine due to previous rod issue.

Shiv - Yes one could conclude that, but one would also have to conclude that the owner of the larger turbo is still running the same boost levels as the one with the small turbo. http://www.i-club.com/ubb-files/smile.gif

My mistake about the 20psi comment... I had thought that Adam Bloom was running a Minnam stg.2 kit whereas I just checked his page and it seems to be a pieced together kit.

BTW, there is not a single good resource that you can do reading on around about turboing our RS's that isn't aimed toward one kit or another. No offense intended, but the only coverage I see is of the Vishnu package, which I don't understand the price of. I could probably get the JCS/TEC-II combo for almost $1000 less then the Vishnu kit and still run 10psi and have more of that midrange torque. Midrange torque is very important to me since I'm mainly doing it for autocrossing.

Anyway, back on subject and hopefully I didn't offend you with the above, but for about $1300 I could have an ITC, S-AFC, fuel pump, J&S knock sensor, and a RRFPR. I'll still have to spend about the same on guages and whatnot as well. Though I wouldn't have to get a laptop... *shrug*

Chuck - Yeah, this is true. I think I found a friend of mine with a 486 laptop I thought had gone under that I could get from them for like $50 or so, so I might just be set there...

markus - I drive it everywhere. It is my transportation, my toy, my race car, basically my everything.

Oddly enough, what you said has sunk in pretty well... chalk a few marks up for the TEC kit.

BTW, I tried going over to Webster the other day... they had security throw me out! Imagine, someone trying to correct them and they throw me out! http://www.i-club.com/ubb-files/wink.gif

shiv - Ever since I found out that HP was a fake number, I've tried not to think of it, but you're right about the backpressure etc, I did forget to think about that (which I imagine woulda been real bad had I gone twin-turbo).

Oh but I bet that Metro with the SO-2's would actually handle pretty good. http://www.i-club.com/ubb-files/smile.gif

AaronB - I may have to go down to the local library and see if they have it (damn well better considering their size), but I'm one of those people with ADD when it comes to reading so hopefully I'll be able to shove it down. Thanks for the tip. http://www.i-club.com/ubb-files/smile.gif

8-
Sport Compact Car's October edition covers their opinions on this kind of thing. It may be helpful.
They removed their piggyback units from their ECU and installed a programmable engine mgmt system. ("Project Subaru Impreza 2.5 RS Part XI: Wiring the Tec -II"). They had the same concern about piggyback accuracy and tunability.

EDIT: SPELLING LIKE USUAL!

[This message has been edited by Subi Chick (edited October 13, 2000).]

Subi Chick-- those are good articles, aren't they? The "shiv" posting in this thread is the one and the same who wrote the articles. There is a Vishnu Performance forum hosted here as well, that's his company.

There is a conflict of interest in my opinion, but I'm not sure I would subscribe to SCC if Shiv weren't contributing to it.

Didn't know that!

8Complex,

Why do you consider horsepower a "fake" number. I don't understand...

shiv

Shiv - Actually I re-thought that word on my way to work this morning... I meant it in more along the lines of "generated" since it doesn't matter too much for our cars. Horsepower numbers aren't nearly as important as torque since they are generated mainly above 5252RPM and for more driving that last 1000RPM isn't as importants as the RPM's below when you can really push. *shrug* I'm sure you can prove me wrong one way or another, but I'm just kinda focused on torque lately.

Because he can http://www.i-club.com/ubb-files/biggrin.gif

That makes no sense, hehe. He has a 2.5L high compression motor running 18psi that has 0 problems and he is switching to a 2.0L low compression motor running 14 psi. Am I missing something?

http://www.i-club.com/ubb-files/biggrin.gif http://www.i-club.com/ubb-files/biggrin.gif http://www.i-club.com/ubb-files/biggrin.gif

Alex..

People ask why I rebuilt a pefectly good engine..

Mine was fine... no problems.. but yet I pulled it to bits... and changed everything..

Why ?

Cos I wanted to http://www.i-club.com/ubb-files/smile.gif

J.

ps - I still have all the original parts to prove there wasnt anything wrong http://www.i-club.com/ubb-files/smile.gif

Adam,

I heard that you bent a rod. So this isn't true? As for compressor surge, at 18psi at 4000rpm, I assure you that you had it. I ran my stock IHI RBH52 turbo into surge all the time (in my Miata). Lasted years before the shaft broke in half. But what it did to performance was terrible. Tons of midrange torque, but it hit a hp brick wall at 225 at the wheels due to backpressure and flow restrictions. Couldn't make any more power than that... regardless of boost pressures. It also heated the charge so severely that I had to retard huge amounts of timing at higher rpm. As a result, it only made big power on race gas. But under sustained load, the engine would experience terrible thermal loads. Very nasty. But okay for 1/4 mile times when race gas was the choice beverage.

Shiv

[This message has been edited by shiv (edited October 13, 2000).]

Why does everyone give Adam such a hard time around here? Because he has the fastest time slips http://www.i-club.com/ubb-files/rolleyes.gif?

I never heard Adam mention that he was going to run a modest 14 psi on a low compression built WRX motor. In fact, I would be very suprised if he isn't running twice that after he some tuning time under his belt.

Shiv, are you comparing the IHI RHB-52 that I know and love to Adam's T3/T4? I know the RS has more displacement than the Miata, but a much lower rev limit... a T3/T4 has gotta to be more suited to providing 18 psi on an EJ25 than an IHI RHB-52 providing the same amount on a Miata motor.

[This message has been edited by Tim Prudence (edited October 13, 2000).]

Tim,

I don't know where you get your numbers. The IHI was capable of supporting 8-10psi on a 9:1CR 1.8L Miata motor with good efficiency. Above 10psi, it's lack of efficiency started to show. In fact, by the 7000rpm redline, it was only capable of supporting 11psi. Couldn't go any higher that that regardless of wastegate setting. And even that boost level, the engine was crippled with backpressure. The T-bird compressor upgrade helped by slowing the shaft down a bit and cooled things off slightly. With it, it was capable of holding 13psi at redline. But again, we're talking marginal efficiencies and gobs of knock-inducing backpressure. Max. hp with the stock IHI (on pump gas) was 230 Dynojet HP @ 5900rpm. Max hp with the upgraded IHI (on pump gas) was 260 wheel hp @ 5900rpm. And this is with four 550cc/min injectors and a TEC-II. The car needed race gas (and another 10 degrees of sprark advance) to make the big numbers.

Shiv

Hi there..

Are we just talking about surge.. or effeciency..

As Shiv knows.. they are different.. you can destroy a turbo without going into surge.. its where you need to know the compressor maps..and the exhaust spec..

The turbo is an air flowing device... and has its limitations.


When people talk about max boost.. and what rev range ? at what effeciency are people talking about ?

The T4 (depending on spec) flows more than the stock vf-22.. but like I said depends on the wheel/spec. But your engine is 25% bigger... *simplistically put* http://www.i-club.com/ubb-files/smile.gif

J.

Hello,

I think Adam gets a hard time because he runs a stock block with very poor engine management at levels of boost that are only sustainable because of the high-octane race gas that he uses for 13 seconds at a time. That's all fine and dandy, but then Adam uses that setup to justify that anyone can run all sorts of boost off mickey-mouse systems.

In actuality, if you were to run anything close to what Adam is running, but on street gas, your engine would blow up like a grenade. http://www.i-club.com/ubb-files/smile.gif

And I think, though I never did share, the animosity towards what Adam says all started when every time someone would post something about their system, as if to respond to that post, Adam would change something or come up with some result to show that his was better.

I DO NOT MEAN TO STIR ANYTHING UP WITH THIS, I AM JUST EXPLAINING WHAT I HAVE OBSERVED.

For example, Adam ran a 13.x that many people witnessed. Shane ran a 12.9 that many people witnessed. The next week, Adam "ran" a 12.8 that very few, if any, people witnessed. I AM NOT SAYING HE DIDN'T DO IT.

Another example was that Adam was running 10 pounds of boost. Shiv announced that he was able to run 12 pounds of boost after much careful system tuning. The next day, Adam reported he was running 14 pounds of boost, with no system tuning. When Shiv posted an answer to someone elses post about the limits of boost the 2.5 is capable of handling, Adam jumped in saying that the 2.5 could handle 16 pounds just fine.

Adam soon after posted the 12.6 or whatever his current fast-time is (or his mechanic did) at 17 or 18 psi, on race gas, with whatever other mods he did, and now is posting about the viability of piggyback systems.

Quite simply, sure, piggy back systems will allow you to go much further than a TEC will. If you use race gas with the piggybacks and normal gas with the TEC or MoTeC or Haltech or whatever, on a daily basis. For those of you who want to spend $4-$5 per gallon, sure, piggybacks are perfectly viable (heck, our european friends pay that much for normal gas) for just as much or more power...

Anyway, I don't want this to degrade into a piss-match. I DO BELIEVE THAT ADAM HAS RUN A 12.6 or whatever that number was. I just don't think it's fair of Adam to continuously talk about how far the 2.5 can go as if to encourage others to try the same thing when the discussion is about daily driving, not 12-13 second spurts on $5 gas.

And then of course, there's the whole issue of Adam having moved on from the 2.5. Seems the piggybacks were too much of a limitation since he was no where near the limits of the 2.5 engine itself...

Joel

Jay, I was asking him why EJ25 -> EJ20. I know why YOU are rebuilding your motor, hehe.

I'm just screwed in the head! http://www.i-club.com/ubb-files/wink.gif

J.

wow what happened?
i thought this was a discussion about the viability of an piggyback setup versus an independent ECU last week. Now i see the same thing that happens on most other boards with a good topic. A complete argument over personal preferences erupted from a good converstation.. I mean what people decide to do with there car is up to them reliable or not but this slamming people left and right is kind harsh isn't it? Modifing cars in any way is a roll of the dice no matter what you do. You can have the greatest setup ever and its still a modified car and never as reliable as your stock counterpart.
I just posted this because the thread was heading off on a pretty bad tangent.
As far as the surge stuff goes, i don't know much about anybodys setup but i do know that there is practically 100+ different variations of an T3/T04 type turbo just saying that they all hit surge at 20psi or whatever psi isn't acurate at all. At least state the A/R of the turbo or what kind of turbine is being used i mean there are ALLOT of turbine alterations that can be made and the boost curve of one T3/T04 can be completly altered with totally different surge points when compaired with another.
...EJ25 rods bend and pistons shatter ***** happens...
thats my 2 cents

Shiv,

I got my numbers from your post, I misread what you wrote. You said, "As for compressor surge, at 18psi at 4000rpm, I assure you that you had it. I ran my stock IHI RBH52 turbo into surge all the time (in my Miata)." I thought you were saying that running 18 psi at 4000 rpm on an IHI in your Miata, you had compressor surge, so Adam must have experienced it with his setup. I thought you were making a comparison of the IHI on a Miata to the T3/T4 on an EJ25. Guess I should no better than to think you would make such a ridiculous claim...

I think I am going to get that T-bird compressor upgrade... I wish the IHI could sustain 11 psi at redline on EJ25. 7 psi is all it can hold at redline in the RS.

Hello,

I didn't mean to move us down that tangent. I meant to refute some of what Adam and others have said.

That being said, here's my opinion on Piggyback versus Real ECU. If you want real power, you have to pay for it. Get a real ECU. If you want more power than stock, but not a huge amount of power, then skip the real ECU. IF you plan on getting 5 different piggy back components in order to support the power levels you want, you're asking for more power than you should be asking for, on a stock ecu, regardless of what's assisting that ECU.

Make sense? If you're worried about whether the alphabet soup will save your car (ie, an AFC, ITC, FPR, RRFPR, etc), then you're too close to the edge and your car will not be reliable. If, instead, you're running in a way that the stock ecu COULD drive the car, but you're using the various acronyms to make the system more safe, then you will have a reliable car.

In other words, a piggyback setup is just perfect for the guy who never ever ever will go above 8 psi. Done correctly, your engine will last probably almost as long as a stock engine.

IF you plan on running more pressure than that, your engine will blow up, your mechanic will spend more time working on (or driving) your car than you! If you want to avoid that, you'll need a real ECU.

Joel

8complex - my setup was a Minnam stage 2, I just listed its components on my page for those not familiar with the "Minnam" name.

Aaron - mayb you had a slightly less than optimal motor to start of with? Not quite sure why yours failed, but my mechanic has had several high compresion (11:1) Z motors (not ZX) where compresion was bumped by shaving the head (this ws the older days of playing!), hich are still alive and running today. My nw motor uses ARP hardware throughout, top to bottom.

Shiv - Imn theory I understand what you are saying about boost and engine size, etc., but I had no comprssor surge I was aware of. After over 30k miles, the shaft on the turbo had zero lay, the fins were all still as-new (no bends), and the car used virtually no oil. When I went to Japan last yr. with Turbo, one of the guys there was from Turbonetics....he told me the unit I had was sized to be happy at about 18 psi, which was basially the reason I chose to run that much when I retunred from the trip in January. As for the motor, you should see what mine loks like all disassembled....I swaer it's as-new!

Adam, why are you doing an engine swap then?

Kevin, it's not that hard -- but probably someone experienced with both systems is better suited to addressing that point.

The TEC engine explosion you're referring to was a result of a lousy shop trying to tune a Subaru with a TEC from scratch. You're not going to blow up your engine with the nice baseline map provided by Shiv.

Aside from the issue of how easy/hard it is to tune, consider the safety benefits of the TEC system:<UL> Precisely controlled boost (no spikes!)
Big injectors mean they stay at the optimum duty cycle
Various unsafe engine conditions generate an engine-saving fuel cut
A killer-informative tuning forum that will answer any question you can think of.
Most of all, the ignition, fuel, and boost subsystems all talk to each other.[/list] Going fast is expensive, there's no way around that -- except with NoS! http://www.i-club.com/ubb-files/smile.gif

<A HREF="http://members.home.net/gopspin/"><IMG SRC="http://216.242.153.40/MembersList/UserPics/158/tiny2.gif" HEIGHT=53 WIDTH=82 ALT="My car" BORDER=0></A>

Hey guys,

JC Sports includes a 4-wire harness mod-chip with their MY00 turbo kits that fixes the 3 psi problem. It hooks up to the ECU, and I have it documented in the "turbo install instructions" that we are going to release as a PDF file soon. Mine is running 7 psi right now, athough the JC kit will come set for 5 psi I hear (to protect the buyers?).

Also, I agree you should get a RRFPR since the AFC can only compensate so much and no more. I have turned up fuel pressure to 45psi with a fuel presure regulator, until I got my RRFPR in next week. If I go to any pressure, like 50-60 psi, it runs well at full boost up to 6,000 rpm, but bogs down at low rpm - and if I use the AFC to lean it out near idle it triggers an eroneous "low manifold pressure" check engine light. I am using a 255lpm fuel pump that comes with the kit, and it will support 85 psi at boost.

Also, it seems to me that the TECII is getting more tuning support than the others, and I looked over the Wolf3d site and didn't see anywhere anything about boost control like the TECII. Boost control and Subaru specific tech support are important if you are gonna spend money and time tuning a programable ECU for a turbo.

Lastly, I rode in a JC Sports tuned 15psi low compression 2.2L wagon with two extra 480cc injectors mounted in the water-to-air intercooler right near the throttle body, and a seperate boost regulated injector controller - and it rocked. John Cox had just finished installing a new rear diff since the old one blew at 85,000 miles, and took me on the post install test run. First he took me on a 7 psi run, then upped the boost to 10 psi and is was much much better, then went to a full 15 psi and it took my breath away! At 6000 feet it did a 14.0 sec qtr mile at Bandimere Speedway today, which is like a low 13 second run at sea-level (cars up here run like they have 3 psi less boost, no matter what anyone tells you)...

So, 8Complex, are you getting a JC kit?

Larry www.ImprezaRS.com (http://www.ImprezaRS.com)

Joel,

Not everyone knows how to program an aftermarket ECU. Even people who do can miss important variables and blow up your engine. An aftermarket ECU is only as good as the person who is programming it. Just because you have all the ingredients to the recipe doesn't mean the food is going to come out right.

In either case, you are going to have to be careful on how you or someone else tunes your engine. Case in point: Didn't someone here awhile back had their car in a shop and the shop tried to 'tune' their aftermarket ECU setup and screwed up their engine? That may be a bad example because the shop wasn't asked to mess with the setup but the end result was still bad.

In any case, just be careful with whatever setup you have.

Questions: With injectors going static and all at boost pressures, has anyone here had any injector failures? I thought your stock fuel injectors are suppose to go bad after awhile of going static but I haven't heard of anyone's injector failing here. What is the normal lifespan of our injectors? What lifespan can we expect with boosted pressures and stock injectors? Is there a way a shop or dealership can check to see if you injectors are in fact failing?

I don't know where I fall in this equation with Turbo/Nos but the car has been running great.

wow, where did all tis come from?

Joel - I have never ever advocated anyone else to go as far as I did with my setup. All I have tried to present is that there are other options out there which work remarkably well, and produce reliable power. As for my boost evels, etc., lets not forget mine IS a street car, not a drag car at all....42k miles on it, and I have really only had it at the track maybe a dozen times in its life.

In no way do I want to diminish what Shiv and others have accomplished. Hell if ever I go to a TEC on the new motor, I may purchase some of his offerings....its just that sometimes, there are other viable answers that merit consideration/viability. And just becuase one works for an admittedly well-respected, well-prepared magazine does not mean that they have the only worthy solution.

Alex - why did I go for the swap? Plain and simple..I always wanted the V5. When it was released, I tried my ass off to get one into the country, but came up short due to various restrictions (it was to be a street car, not race, but race-only, i.e. not registered, was all I was able to obtain). At that point, I decided that the 2.5 was the route I would go, and I would just build my own V5. I happen to just plain like the 2.0 motor, if for nothing else than its lineage in the WRC. I also got to the point where I wanted to try something different with my car....different at least in terms of what other 2.5 owners had done. Initially, that meant turboing the EJ25. Now, that's more and more common, and I thought it was time to go a different route. So for me, the swap was a logical choice. As for 14 psi, not sure where you got that from....I absolutely plan on running as much as I can with the car, within the confines of its abilities. Plus, with the EJ20 now nearly upon us, I felt it was the way to go in terms of the platform to receive the most aftermarket support. Remember Alex, I already have a project car.....I do not want another. I now also have other financial priorities in my life, and have reached the conclusion that I like the tuning process far less the end result itself. I want to get in, drive, and have it be quick, in accordance with my definition of quick. I am not saying I won't play with the new motor, because I absolutely will. But, I don't care anymore if my car is exceeded by 100 other Impreza owners out there. If this were the only car which I modded, then I may feel differently. But this tuning thing is an expensive venture, and with what essentially boils down to 5 toys in my driveway (inasmuch as none of my cars are stock), I don't have the willingness to contribute the time or resources to getting the last ounce of hp out of the car. Plus, with me in the process of adding yet another car to the stable by next spring, at some point, I needed to decide that I have put enough into one particular car.

As for the fastest RS, I honestly could care less at this point, but as far as I have discovered, I do have the fastest timelsip for the car....including Byron. The fastest Byron lip I have seen was a 12.8-something (I don't recall the trap speed). I could be wrong though, and if so, congrats to whomever beat me. If no-one has yet, then I certainly welcome the challenge.

I think this board as a whole has gone on some wild tangent in recent months, and as such, I think I am going to follow in the footsteps of some others that at one time contributed with more frequency, and sit back and watch, and just do my thing with as much anonymity as possible. I certainly remain as open to offer whatever suggestions/answers I can to those who care to inquire.

And yes, as for me bending a rod, it is true, I did. It was a little while after my good timelsips. Also, by the time it happened, I was already financially committed to the new motor, so it was really no big deal to me. I got more out of my stock motor, both in terms of pure enjoyment and quick times, as well as longevity, than I ever expected. I was among the initial crop to turbo the RS, and I swear, I was nervous about it. I mean, a bolt on kit,for a big boxy 4 cylinder, from a company in Canada that was not a major player, but just some Subaru fans in search of more speed? I didn't expect big things. Needless to say, the kit meet and beat my expectations

Larry - Maybe... trying to decide whether to go to SMod next year or not. While it'd be interesting (noone in that class around here has an aftermarket turbo, just misc. dumb stuff or motor swaps), I fear what could happen.

See, if the Impreza isn't kicked out of Touring this year, I can stay in it. If it is kicked out, it's off to SMod I go. If the Impreza doesn't get kicked out of Touring and I go turbo and into SMod, then if I start losing that class, I can't really go back without a lot of work and lost money.

It's such a toss up, I'm not sure what I'm doing. Maybe I'll wait for Cobb's SC kit & HalTEC setup... not sure.

greetings all,
i haven't been on this page in quite a long while...today i signed on just for ****s and giggles and to my discontent everyone keeps bashin one another. i don't think the debate is whether which tuning method (piggybacks or programable comps.) are better because that is simply an issue of point of view. the focus should be on what WORKS...the tecs and haltechs work and work extremely well...the piggybacks however are a little simpler and less expensive when purchased one at a time albeit you lose a lot in the range of potential adjustability. both routes WORK and to debate what works better based on what EACH individual has is like fighting like four year olds do about whether chocolate chip cookies taste better than oatmeal cookies...basically you don't realize how retarded you all sound and how pointless your arguments are regardless of how much sleep you lose thinking about all this crap. i believe the saying "to each his own" is the best end to the argument.
so what is the goal fellas...ultimately to help one another in building and tuning the RS by sharing what WORKS...even though it may differ from your building philosophy.
i remember goin to the dealer with adam to initially look at the car...he kept ranting about how much he wanted an STI V5 but couldn't import one...now with the V5 engine swap to complete the tranny and suspension conversions he HAS a V5...in other words he has what he wanted from the get go. using the minnam kit was merely a way for the american car to RESEMBLE the original japanese car in terms of performance. and lets be honest, although the kits work and i never thought he car would go so fast, they certainly are not the cat's meow...they more or less give you piping that doesn't fit in all cases and "bob's turbo" (I.E. a cheapo no frills nothin fancy 'bout this turbo) it may not have been the real thinig, the kit may have fit poorly and utilized cheap components but it WORKED. anyone noticing a pattern yet??
personally, i don't quite get all the adam bashing...i guess i'm biased cuz he's my brother but aside from him I have had the most seat time in the car and i KNOW he was the guinea pig on this board in terms of boosting the turbo WAY beyond recommended stats to find what approaches real world limits of this setup...he bent a rod after 30,000 turbocharged miles of daily driving under 17-18 psi using 94 octane sunoco pump gas and maybe 10 drag race events. i think that is an accomplishment when using such an off the shelf kit pushed beyond recommended limits. thanks to contributions from adam you guys have a better idea of what WORKS and what DOESN'T.
i'm sure shiv's car is fast...with all the mods and time he put into the car it must be http://www.i-club.com/ubb-files/smile.gif but if you guys are after a rivalry put your money where your mouth is and show a timeslip...i know where adam's is...i know what he ran, i WAS there and he always BLEW away my Galant VR4 even though i was running deep 13's with an estimated 350 hp by road race engineerings standards on a stage 3 16G turbo and the rest of my mods.
so which method is better...the whole point of this rambling is to establish that it is open to interpretation of YOUR personal tuning philosophy because the answer is certainly NOT written in stone.
Jon
'92 GVR4
'FC RX-7

[This message has been edited by RotaryB (edited October 24, 2000).]

Thats a good explanation, Adam. I agree that if you just want "to drive" your V5 STi motor is a good choice.

Now let me talk about my opinion on the Piggyback vs. Standalone and EJ20 vs. EJ25.

I have to say that standalone is a better way to go for a turbo Impreza here in the US no matter what. I also think that EJ20 + it's ECU + piggybacks would work better than EJ25 + it's ECU + piggybacks + turbo. I also think that most of us will not really any big difference between say Wolf and Haltec. Of course they are different, but they do the same thing using their own interface, configureation, equipment, ect.

On the subject of EJ20 vs. EJ25, I am in the middle. That is why I am using my EJ25 and using many engine parts from the WRX including the actual turbo and miscellaneous exhaust and other parts. I think both motors have big potential but .5l on EJ25 keeps me from buying a STi motor. Afterall, well built EJ25 can be a true monster and we have proof of that thanks to JUN.

I don't think that anyone is bashing anyone here. I think it is just a sensative subject for some of us. http://www.i-club.com/ubb-files/wink.gif

[This message has been edited by Imprezer (edited October 24, 2000).]