Need Help: An analysis of boost control methods

[smiles]

So I am tossing around ideas - Unichip, SBC-id, AVC-r, Link, back and forth and going insane.

Here are the conclusion I have come to from research. Feel free to comment as I would like this to be an open discussion. I am by no means an expert on turbo cars.

Unichip - Seems to be reliable. Some CEL issues and EGT issues. No real in cockpit user control. Not sure I am entirely comfortable with leaning out the fuel mixture. From the number I looked at with the factory fuel mixture it seemed good to run on the safe side for forced induction.

SBC-id - nice to have the in cockpit adjustment. Also apparently these do limit part throttle boost to control EGT temps (is this true??)

MBC - uh....no thanks

Stnadalone system - big willy style for crazy mods. not really what I have planned.

I am leaning towards the SBC-id. I want to be able to keep boost down to stock levels and just crank it up for some fun (say to 16 or so PSI). Concerns are:
1.) any EGT issues with the SBD-id?
2.) how to hide this from the dealer? I need to tap into wires etc unless there is plug and play harness??
3.) what happens in the event of a vacuum leak in the line leading to SBC (or the line comes undone)....this could be interesting. If the SBC doesn't read boost pressure does it keep the wastegate stay closed? Just some food for thought.

Appreciate any help on this. Researching these options has been quite an experience. Phew...I think I have a headache

Thanks!
Scott

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[smiles]

Wow...i guess there is no best way to do this. Thanks for all the replies. Maybe its they crappy title. Guess I will figure it out on my own....
Scott

[Fubaru]

Good luck!
I'm in the process of trying out some of those things myself.
I've got both the unichip & the SBC-iD installed in my WRX,
and have got the AVC-R sitting around in the garage waiting for me to find time to install it. For the time being I've disconnected the SBC-iD solenoid and am letting the unichip control boost. Just deferring to the unichip is probably the easiest aftermarket boost control method of all (short of an MBC valve). I'm pretty happy with the Turboxs setup with no real complaints.
The SBC-iD does a great job but won't let you tailor boost versus RPM or TPS, so you can't deliberately taper boost @ RPM>5000. It succeeds at reaching your desired boost with minimal spiking, and is super easy to install & tune. The boost graph & replay modes are both very nice. Makes monitoring boost easy (an excellent but extremely expensive boost gauge).

The AVC-R is much more feature-rich than the SBC-iD, thereby way more complicated to set-up. Installing it is also relatively painful since you need to splice some ECU wires. I plan to splice into the unichip piggyback wiring to allow clean removal. This will keep things truly plug n' play. At some point I'll have to decide between the SBC-iD and AVC-r and get rid of one of them.

As for your question about what the controller does in the event of a MAP sensor failure... not sure how the controller would respond. Hopefully it's smart enough to prevent a broken loop death spiral letting boost skyrocket trying to hit the setpoint. In any case I prefer the Apexi sensor because it uses an electronic sending unit which you can position very close to the source, and it's an "absolute" reading meaning that it corrects MAP according to outside atmospheric pressure variation.

[snookem]

Scott

Your not the only one who is going crazy.

Unichip is a major problem in cold weather. In most of australia it doesn't get below freezing and the altitude is mostly below 3000ft so unichip works fine down there. I,m an Aussie. That's why problems are developing here as temperature changes and altitude are greater. Seems it is a good thing to go with a ebc with unichip here.

Have talked at length with link ecu distributor here in Calgary. He is turbo expert with very good connection to link manufacturing. There has been a problem with link ignition and tumble valve for US wrx that has only very recently been fixed. Now this link distributor has shown me windows based tuning setup for ecu and wrx. If you give him cars vin number the link factory in New Zealand can pre tune for your mods and is very accurate as the only tuning required when it is put in is its own self tuning which learns for its self. He as a turbo expert also suggested I should use a ebc to turn down boost and only turn up for fun on those occassions.

Talked with Dale at Teagues auto(great guy). He has put mods on his car like exhaust,uppipe, samco intercooler hoses etc and NO ecu upgrade as he is waiting on link ecu and at the moment he believes his car is getting crank hp around 265. We also discussed putting on a vf 23/29 turbo without ecu mods as there is enough fuel in the stock system but as yet the only person to recommend this is Dominic Rigoli in Australia which he said just add vf23. Dominic also said to run a fuel bleed on the car with an air/fuel ratio meter. He said you don't need ecu upgrading till 350 hp, just exhaust, intake, ebc and bleed the fuel down to lean out the extra rich mixture or put on the vf23 without the fuel bleed.

So the only thing at the moment that all these people agree on is an ebc. The rest of the ecu stuff has become very easy for me. WAIT till spring, by then Dale at teagues auto, shiv and others will have setup etc on link. The unichip cold problems will all come out and a fix might too. Others by then will have tried vf23 without upgrading ecu or fuel bleed.

Lastly, get the exhaust,uppipe and panel filter samco hoses and an ebc for fun moments. and wait till all this sorts itself out

[gtguy]

I've been searching on this, and there appears to be no evidence that an MBC set to factory boost levels is at all harmful to our cars. I know that people were having problems with boost levels of 16 psi or higher, but I wonder about setting it at 15 psi (factory peak according to my Subaru gauge...what I get, anyhow).

Anyone?

Kevin

[smiles]

Great!! Thanks for the replies guys! This is good info and the stuff I was looking for. I kinda drew the conclusion about the EBC after hours and hours of research.

Fubaru, would you be interested in selling your SBC-id? It should never come down to this, but I like the looks and size better.

snookem, from your input I think I have decided on:

With an EBC, upipe, downpipe, and the aforementioned hoses can I get 1/4 mile in the low 13's?
Thanks,
Scott

[smiles]

gtguy,
The problem can arise when you disconnect the factory boost solenoid. The turbo can actually spool to 14psi at part throttle (normally Subaru limits this to ~8-9 psi). This can cause the EGT to increase (some people but now all have reported this problem).

Many people have changed their driving style style to compensate for this. I on the other hand, want to tune this out with the proper tools (albeit at a reasonable price). Because I want to be able to turn up boost for fun to 16psi, and down for the street, I need an adjustable BC. MBC's don't allow enough tuning.

I am thinking if I do a proper RPM map and overboost control, I can satisfy the req without going to a Link (which is over kill for what I want). The factory full map runs rich, so I am hoping I can find a happy median with boost and the fuel mixture.
Scott

[smiles]

Anyone use the HKS EVC Pro? This would be ideal. It allows boost per throttle position in 5 places at 1% increments.

I am not sure why Apexi doesn't support this feature (boost by throttle position) as they read throttle position.

Does the Blitz SBC-id support boost by TPS (with teh addition of the Power Meter id)?

Scott

[zmw]

the SBC-ID does not support boost by TPS under any circumstances, even with the power meter. However with the PM it does gain the ability to adjust boost by RPM and speed.

I was unaware the HKS boost controller would control by throttle position and that in my opinion is by FAR the best method of controlling boost and prevents all the other issues related to BC's like the high EGTs and what not.

-Z

[zmw]

wow the HKS EVC pro seems to be the most kick a$$ boost controller ever invented

http://www.hksusa.com/products/more.asp?id=673

Unfortunately it's a $1600 boost controller, but man it sure does rock, as an atmospheric pressure meter to adjust the boost map accordingly...

Rock on!... is there any less expensive boost controller that can do all these same feature?

-Z

[smiles]

That's the 64k question!! Any boost controller that does TPS boost that doesn't require a piggyback ECU?? (and hopefully has a comapct design smaller than the HKS unit
Scott

[Fubaru]

The apex'i does use TPS to trigger boost... I think it uses TPS threshholds for max boost & self-learn mode. Something like 50% and 90%. Smiles... I am planning to sell the SBC-iD... let me know if you're interested.

[smiles]

Fubaru,
PM'd ya on the SBC-id.

As far as the AVC-R goes, you said it does use throttle threshold? I was looking at the doco for the box and saw it can do Gear/RPM/or Manual. I know it take in throttle input. Is it safe to say you can adjust boost by TPS then?? Can you explain what the "atuo learn mode" is??

I like the EVC Pro, but it is costly, and Fuzzy Logic is not fun to deal with.

Thanks,
Scott

[smiles]

Well, I just got off the phone with the guy from HKS and he is saying that they have "several WRX's there and haven't seen this problem". I suggested he come here to search and market his product In any case, he suggested I use the standard EVC IV because the cost of the Pro is through the roof. Nice to see someone in a company not trying to gouge you! And they were much more responsive than ApexI.

Dan from Godspeed also said he hadn't seen high EGT's with the SBC-id, so maybe I will just go with that.

Anyone care to comment on High EGT's with a EBC?

Scott

[02WRX_BLUE]

With my limited knoweledge!

PRODRIVE tuned ECU is the way to go IMHO! I have posted a thread requesting more info from one who has it installed.

Unless you are planning on boosting beyond 16 psi, I like the idea of programming/utilizing ECU with newer timing retard, fuel curve, & increasing boost. I believe PRODRIVE tuned ECU has backup route programmed to tune back to stock level of boost if anything goes wrong~

Just my 2 cents.

Dan.

[snookem]

Smiles
mid 13's at best unless you can lean out the mixture of the stock system. I will be talking again with Dominic on Monday about fuel bleed as I'm still interested in exactly what he uses to lean out fuel for just those fun time 1/4 mile traffic light runs and maybe a bit of a fang thru some corners.
Will also get info again on just putting on vf23/29 with no ecu upgrade.

[smiles]

snookem,
any news on your phone call?? interested to hear how the mod questions went.
Thanks,
Scott