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Old 07-18-2002, 07:34 PM   #1
Yellow Rex
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Exclamation Link ECU, Unichip, stock ECU?????

Hi people!

I've been thinking about the best way to do engine management. So far, the only solutions that seem to be complete are the stand alone ECU replacements like the LINK or MOTEC.

I'm seriously considering upgrading to one of those from the TXS Unichip II. I would like to hear from people who actually have a Link or Motec and how they like them, etc.

What are the disadvantages of such a system?

how easy or hard is the installation?

what about driveability?

I've also spoken to some who have quite a few mods including turbo-back exhaust, up-pipe, EBC and even bigger turbos and are using the stock ECU. What's the story here? Why are some of us buying things like Unichips, S-AFCs, or even Links or Motecs if the OEM ECU will do the job??

I'm more than a bit confused here.... Please educate me, if the stock ECU can handle serious mods like the ones I've heard about, how come more folks don't do it like that? I'd love to hear from actual, hands-on, personal experience folks. Please do not just give me some great theory or hypothesis. I've read a lot of articles, posts, etc. about engine management but I want to hear about people who've actually done it.

I've got a big sign over my desk that says:

"There is nothing so tragic as a beautiful theory murdered by a gang of brutal facts!"

As an engineer, I've experienced the truth of the above saying more than once Theories are fine and good but nothing beats real world experience and empirical knowlege. I sure would like to hear the un-varnished truth [b]
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Old 07-18-2002, 08:16 PM   #2
davidm_sh
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Default Turned out to be really long :)

I am in the SAME BOAT you are!!! and I am also an engineer [heh]. Here is what I have experienced and my thought process on the subject so far.

First my setup and dilema:

-VF22 @ 17.5psi
-STi injectors
-GSS342 fuel pump
-air-to-water intercooler
-AEM CAI
-uppipe
-MRT 3" turbo back
-lightened pullies
-blitz DSBC for boost
-unichip CUSTOM tuned by Cobb Tuning! (yes I made the trek for the tune)

With this on 91 pump gas I dynoed at 265whp and 231wtq... not too bad eh! It was even good enough to run a 13.3@101 @6000ft. above sea level

NOw for the dilema:

My situation now is I currently ordered a DeltaDash to do some datalogging to see what my A/F (via front wideband), timing, and knock. With this I plan on gathering a LOT of data at the same time of day and on the same exact route at 25-50mile increments after a ECU reset to see what and how the ECU does over time/restarts/and miles.

THEN I will send all that to Trey at Cobb and hopefully he can give me a "tweaked" map. Maybe take some timing out... maybe I am running lean... personally I "think" I am experiencing BOTH!! But need the DeltaDash to confirm.

Then if Cobb can get me a map that brings things more in line (if there even in need of such tuning) all will be great. I then will do the fuel rail upgrade (parrallel fuel rails and an ADJUSTABLE FPR) to add a little more tweaking capability to my setup for A/F across the board for hotter days or colder days!!

Here are some of my thoughts and theories:

I REALLY hope between getting a "tweaked" unichip map, having control over boost (currently have), and having a bit of control over fueling I will beable to compensate for bad gas, REALLY extreme temp days and/or track events. I have heard you can even take out 0-5 degrees of timing, across the board, with JUST the delta dash software - yet another bit of adjustability.

Now you maybe asking yourself as SO DO I LATELY. Why not just scrap the stock ECU, unichip, FPR, piggyback crap and just get a standalone like the Link. Personally MOTEC is FAR out of my price range and tuning/experience capability. I feel that I have a very good grasp of where the timing/fuel/boost maps should be just there isn't a very good All-in-one solution yet.

The MAIN reason I want to try and stick with the stock ECU + all the piggy back crap is for the following reasons:
1) Everything is ALREADY done for you!!! - idle, hot start, cold start, elevation correction, etc... bottom line is stock ECU is a LOT MORE REFINED, for lack of a better expression, then say the Link.
2) I do a LOT of road tripping and don't need my car unexpectedly acting up on the road
3) I just plain don't like the way the Link handles certain things:
-Not very good open/closed loop control
-only see MAF air temp and not after turbo or intercooler
-DOES NOT USE front wideband!! relies on crappy rear 0-1V O2 sensor... that's a biggie
-And a bunch of little things that aren't as good even compared to somthing like the AEM ECU.

So for now I am going to make a go at getting the unichip tweaked along with adding a FPR for some extra tuning capablity. I figure if I do decide to go standalone I can sell the unichip and Delta Dash software for some money anyway. Plus this also gives me time to wait and see what TurboXS's or Jorges' or ANYEONE's "big secret" will be in the next couple of months. Maybe the Link will keep getting better?

But bottom line to me is I think the stock ECU is more than capable of supporting moderate-decent hp (350hp and under at the flywheel) which is all I really want. You just have to have some knobs to turn and tweak things, even with the unichip. IMO All you really want to control is the timing, fuel and boost. I think the most important two are boost and fuel personally. Becuase the stock ECU is very dynamic and can take up the slack in the timing area.

Ok I have babbled on enough. If you have any insight or comments yourself or anyone I would love to hear them.

Last edited by davidm_sh; 07-18-2002 at 08:27 PM.
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Old 07-18-2002, 09:01 PM   #3
JenisonWRX
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Quote:
1) Everything is ALREADY done for you!!! - idle, hot start, cold start, elevation correction, etc... bottom line is stock ECU is a LOT MORE REFINED, for lack of a better expression, then say the Link.
when you give up control you gain ease of use ... period. Links interface is great. The only probelm is lack of tools to analyze data. But the tools I'm talking about are just bells and whistles.

Quote:
-only see MAF air temp and not after turbo or intercooler
and your stock/unichip setup does? Remember the Link is developed to be a direct replacement for the stock ecu. No more ... no less. Where the ECU's like the tec upgarde other sensors so it can perform. The link is not the greatest ecu on the planet. But its a good median between Uber ecus and stock.

Quote:
-DOES NOT USE front wideband!! relies on crappy rear 0-1V O2 sensor... that's a biggie
man...we have a true wideband in our cars? well why would anyone buy that greddy or any other wideband system? have you seen how wide that 'wideband' is compared to the back? IIRC - 1.2v?

The key for the wideband if I recall was gaining accuracy as it aproched that perfect burn and above so you could see the 15 - 16 to 1's.

I would NEVER EVER would use an auto tune on a Link or ANY ecu. Why...cause its just guessing. Hell if were that easy, Shiv, Trey and all the other tuners would be out of business.

Link is great...and I've said this before...i would buy it again, and there is only ONE aftermarket ecu I would replace it with.

The only issue I've had with my link was the MAP limit issue. Which was resolved with a new update in software. Otherwise ... the car runs friggin great. Hell I havent had any reason to change ANYTHING in a while now.

If you don't want to mess with anyting...and get good results...Unichip. They have proven to be effective. Link is a great start for those of us who didnt want the complexity of say a Tec. I felt it was a good middle ground in complexity and cost! I wanted a tec for the longest time yet didn't feel I was ready for the demand that it takes to know how to tune it.

would _I_ consider a unichip....no. I'm a control freak. thats why. I like spending my time thinkgina bout fuel and timing.
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Old 07-18-2002, 09:21 PM   #4
JaMa
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Default a Gang of Facts

Yes, I too am an engineer, tragically, but a very practical one. I believe in nothing I see on paper until the model is built. A scientist much see what he sees and all that he sees, then adjust the theory for reality then test test test to make reality part of the the theoretical study.

Anyway, about the Link. I am getting to be a veteran of the Link at this point just because I have uncovered SO many of its problems. I notice the slightest differences in the performance of my car and the Link has helped me iron out some of the not so desirable features.

Let me address some of the Link issues:

1. IDLE - This is my number one issue with the Link. Yes, it is capable of sustaining a -decent- idle, but not really on par with the stock electronics. Frankly, I think the stock unit just plain has a better microprocessor with more power and is able to control the idle mechanism in the Subaru better than the Link.
2. VOLTAGE - Voltage is never consistent within the Link, and I have had to make quite a few new grounding points in the car to get voltage regulated to a decent steady level.
3. DOCUMENTATION: Links documentation, what they ship with the unit, is dreadful. It leaves things out, dosent explain many more, and just plain mistates the facts on many subjects.

However, all these complaints in hand and given all the issues the Link has, I challenge anyone to find anything better for the price. The Link gives you 100% control over every programmable aspect of your car. Not many systems for $1200-1400 range that can do that, and its sure as hell better than the UniChip, what a joke.

It is possible to tune the Link yourself if you have the right tools, and for my dollar you must have the following tools:

1. Wideband O2 sensor and gauge: Because Link left Lambda out of the WRXlink(its there but dosent use the stock lambda sensor) get a wideband and gauge and tune your air fuel ratio from there. It is absolutely bulletproof and will help you get the most power from the car.
2. EGT gauge: obviously
3. Water and Oil temp: obviously

Now, I am keeping my Link even though a week ago I was considering getting a Fuel Cut defender and a super AFC. Why? More consistent results is why. The Link is a standalone, which means it is going to do what YOU tell it to, not what some pencil neck Subaru engineer halfway across the world told it to do. My car, as many others here, is far beyond the state of tune the factory ECU is desinged to handle and thats bad. You just cannot tune a 227hp ecu beyond a certain delta of change and expect it to function correctly. Get enough boost under the wing of that engine and the stock ECU will significantly retard timing on you and destroy all the power you are making by going higher boost and higher fuel. Plus, as you build your engine and your car further, YOU have complete control to go back in to reprogram the ECU, not TurboXS or Shiv or Cobb or Whomever. You can also raise your redline to your liking and do any number of other things in the comfort of your garage.

The biggest advantage to having the Link to me at this point is the large community of installed WRX users. There are many people who have this system and there is a lot of knowledge out there. I am not sure why, but it seems like a lot of the community never have any problems with their computers and that is puzzling to me. I have had all kinds of very obvious issues with mine and have eventually solved every single one of them.

Is the Link perfect? Hell no - its a disaster and a learning experience. But, when its solid its solid and all it takes is some time to learn it and its all good after that.

My 38c

JaMa
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Old 07-18-2002, 09:22 PM   #5
davidm_sh
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Quote:
Originally posted by JenisonWRX



man...we have a true wideband in our cars? well why would anyone buy that greddy or any other wideband system? have you seen how wide that 'wideband' is compared to the back? IIRC - 1.2v?

The key for the wideband if I recall was gaining accuracy as it aproched that perfect burn and above so you could see the 15 - 16 to 1's.
I should have quantified with not-quite-wideband ... BUT a lot better than the rear o2 sensor

Quote:
Originally posted by JenisonWRX

I would NEVER EVER would use an auto tune on a Link or ANY ecu. Why...cause its just guessing. Hell if were that easy, Shiv, Trey and all the other tuners would be out of business.
Just curious how did you tune your Link then? Do you have a wideband? Did you use someone elses base map? Did you just tune off of EGT and knock? I am actually very curious.

I am actually a bit of a control freak myself. Like I said I was in the same boat as Yellow Rex and I just plain can't decide on which way to go. Sooner or later I will make a decision though ... well since I already have the unichip I should say sooner or later I will probably get the Link and decide for myself but for now I guess I am just going to ring out the possibilities of the unichip .

Oh and as far as the Link goes can you answer me a few experience type questions please ?

So you NEVER run in closed loop right? So there is enough automation in the temp input changing, altitude, etc... so the ECU will adapt to different kinds of weather, considering it's basically in open loop all the time then? Have you had it through a winter and a full summer yet? Maybe I am confused on how it works but as far as my understanding of it goes like this: You can run in closed loop/lambda learning mode and it will "automagically" adjust while you drive. OR you can drive in open loop and it just uses the maps as they are and makes minute adjustments based off of temp outside and I guess altitude differences are inherent with the MAP based loading of the system anyway as far as fueling goes.

Just trying to figure out the link some more is all .

Thanks
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Old 07-18-2002, 11:52 PM   #6
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Old 07-19-2002, 12:17 AM   #7
JenisonWRX
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david - great questions. sorry if I seemed harsh. I always do yet never mean it like that. ... anyway ...

to answer your questions ...

How do I tune -

EGT and Knock and looking at the plugs. While i'm not an expert at reading plugs ... i think that by looking at the amt of 'black' thats on a plug can tell you how things are going in the chamber.

Knock I try to keep consistant #'s at WOT. In other words ... no spiky lines. If its consistant then you can say its noise. However, those jumps knock value are what you want to look out for.

EGTs at cruse I've kept between 1300 and 1350. It was HUMID as a marsh outside tonight and my egts at cruise were lower then ever! 1200!!!!

My egts rise to 1600 at wot as I get to redline. I do have an aftermarket egt gauge tapped on the #2 cyl.

I also take into account the OXY value. And here is my reasoning...and how I look at it. When we had our MAP limit issue ... and I was looking at the logs. On the line where you saw the FF% (fuel flow) go to 0 ... the very next line the oxy dropped down to nothing. Thats a pretty quick response IMO. The link does about 7 - 10 samples a second.

Now I think we can all agree that once an O2 sensor sees something its already out of date. Again...what I look for is a base #. what is the number that I'm seeing and how is it changing. Is it going up down? what. At WOT I look at the # and just see thats its staying consistant. That nothing crazy is going on....like values dropping to 0 or something.

Is a true wideband better....yeah. and its on my list. I really want to know my ratio for leaner condtions so I can get some friggin gas mileage again.

The Link looks at ambient temps. However you have to give it a base # to look at. I think mine is at 80 right now. Well tonight we cool-er then its been but humid as hell. Car still ran really good. I have some logs that I'm gonna pour over in a sec because i raised the boost to 16 now. I was 15.

OH I almost forgot ... yes. You can tell it NOT to do anything with the lambda values. If you turn it on....it will then try to tune itself.
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Old 07-19-2002, 12:46 AM   #8
Yellow Rex
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Thumbs up great input!

I must admit that I was thinking nobody was going to post on this thread. I'm extremely gratified to see such good, straightforward posts.

Thank you gentlemen, this is exactly what I've been looking for. I do not claim to be a tuner or anything of the sort. While it is true that I'm an engineer and design machines, I really do not delve deeply into the car business. To me the cars are more of a hobby where I enjoy the driving and owning them. I really like to do things to improve the performance and all but I do not really have the time, facilities or inclination to do a lot of the tuning and tech work. I have installed such things as suspensions, headers, exhaust, CAIs and piggyback electronics in my cars before, but I always left the mayor things like turbos, superchargers, etc to my local techs.

Now I've started down the slippery slope of engine management and I find once again that nothing is really simple or cut and dried. I did get my TXS stage II Unichip to go with my 3" turbo-back exhaust. While I really liked the extra power and speed I got, I did encounter a few issues such as the hesitation. While it's a fairly minor thing, it is an annoyance and what is worse is that I cannot solve it

Now that I get more into the thing, I begin to see the limitations I have as far as "tuning" this system. Now, I read and see all this stuff about the Link, Motec and other stand-alone solutions and naturally, I'm very tempted to just whip out the old credit card and zap! buy it!

Problem is, I have to stop and ask questions, here is where you guys come in. I really appreciate the no-punches-pulled information. It's very important to have clear idea of the pros and cons of any modification to the cars. I appreciate honest appraisals and accurate reports. I love to see this simple and straightforward posts. I think this is much more helpful than some technical discussion about details of that soon gets into splitting hairs about which method of measuring is better or more accurate, or what parameters are more appropriate for tuning the car.

To me what I like to see is simply, how did the thing work out? was it as expected? was it simple to install and use? did the driveability remain adequate? was it a cluster***k? did it live up to the marketing hype? And last but not least, what's the next thing coming down the pike?

Thanks again,

Manuel
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Old 07-19-2002, 02:13 AM   #9
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JenisonWRX - Thanks for the response however harsh it was . Your information COMPLETELY agrees with the information and knowledge I have been accumulating. The "auto-tune" option I came to find out tonight actually only applies to NON-WOT tuning even with it on. At least that was explained to me by a link owner. He said he uses the auto-tune for about a week or so and then turns it off with those values "locked in". And he DOES NOT use it at all at WOT which I don't even think is an option.

Yes tune for EGT's and knock when nary a wideband can be found .

Yellow Rex - Now on to the interesting thing. Phast on the board here has a Link unit and I spent a few hours with him tonight tuning and driving to get an impression of how the Link actually performs. In short I have to say I AM SOLD!! Here are some reasons why.

First off we hooked up my knocklink so I could get a correlation of the numbers the Link unit produced and the LED's on the knocklink. Here is what I found out: THe knocklink WORKS!! It only detected a full set of LEDS/knock about 1-2 times out of 5 knock events that the Link didn't pick up and phast said that might be becuase his knock threshold is a little on the aggressive side. Here is the COOL thing though. So we do about 5-6 3rd gear pulls and see some knock activity in certain rpm ranges. So we simply go in and add a bit of fuel or adjust the timing. Yes it's JUST THAT easy. You look at the log and see what rpm and what MAP reading was and you go right to it in the map and adjust away. Each time we made a change we would do another pull and bingo problem area cured!!

Then I got in and did some off-boost partial throttle driving and I will admit that there was a "slight" hesitation/stumble upon tip-in but phast explained to me there are 4 different rpm ranges where tip-in fuel can be adjusted. The idle was just fine. He said it idled at about 800rpm but on the tack it looked like it was between 900-1000rpm but pretty smooth... just a hint of lope. Then I hit the A/C on and still good idle. We started and stopped the car a few times and each time it pretty much fired up.

The only area I see where his map needed work, and he admited it as well, was I got into the boost in the curves and I that involves QUITE a bit of partial throttle activity and the knocklink lit up a couple of times. But honestly I don't really drive my car like that all that often and I am sure it is adjustable with the 4 different levels of fuel tip-in settings.

Overall I think it is a VERY good thing. By the end of the night we weren't getting ANY counts of knock, the knocklink was only lighting in the "normal" and the occasional single "caution" LED but that was related more to simple linear engine noise. It was really cool doing runs and I would see the KL light up and I would have an idea of what rpm it was and they I would scan the log and sure enough the knock was a spike to the 90-110 range so we would tune and it would go away.

All I have to say is I am SERIOUSLY considering one right now. Depending on the availability and price my will power might not beable to hold out [heh].

JenisonWRX - Just curious. When we were cruising around I was looking at his maps and the timing seemed nice and advanced at almost all vacuum areas BUT his fuel settings seemed VERY rich in a LOT of areas. Is this normal? I mean I saw some values in the 100-110 range when under almost full boost there were some areas where the fuel was the same. What general numbers do you go for in the partial throttle/off boost areas? I would assume this is where your road-trip milage is made or broken.
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Old 07-19-2002, 02:47 AM   #10
JenisonWRX
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JenisonWRX - Just curious. When we were cruising around I was looking at his maps and the timing seemed nice and advanced at almost all vacuum areas BUT his fuel settings seemed VERY rich in a LOT of areas. Is this normal? I mean I saw some values in the 100-110 range when under almost full boost there were some areas where the fuel was the same. What general numbers do you go for in the partial throttle/off boost areas? I would assume this is where your road-trip milage is made or broken.
100 - 110 is not bad. Its really dependent on the master fuel setting. So 110 with a master fuel value of 90 is not equal to a master fuel value of 80 with a 110 value in a zone. Master fuel value effects the ENTIRE scope of the fuel map...and even your settings (ACCEL X and other enrichment values)

I like it cause its a quick way to richen or lean out your entire map. Obviously you don't want ot go crazy...but a value here and there can help as the weather changes.

3k at -10psi...in other words 5th gear on the highway at cruse control. These zones are where you need to look at your fuel consumption. It would take at least 2 trips to get something. 1 to get a base #...and then modify those values and go again. See what yoru MPG is. THIS is where you want to run leaner to get better MPG. THIS is where a wideband would really help because your outside of the sensors range.

Unfortuneately I'm at a master value of 90 ... and my FF% is nearing the safety limit.
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