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Discussion Starter #1
I am brand new to Turbo cars. I have been building, racing v8 camaro's for years and admittedly know NOTHING about turbo cars.
First of all, I must admit, I just bought an 04 STI and this car is unbelieveable, I will never make fun of big wings again, lol.
Now, my question. On the stock turbo guage, the highest I see the gauge rise to is +10. Is this 10 pounds of boost?? I understand the STI is supposed to put out 14.5 pounds?
I was told a stock STI turbo is capable of putting out up to 17-18?
What steps can I take to increase boost without getting in to big dollar mods??
Thanks again for all the help!!!
 

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AZ:JDM Sti Version 7 CAMS & BUCKETS, Mint!

first of all, the "stock" boost gauge reads in Mpa, so +10 isn't 10 pounds of boost.

i don't think anybody has a good handle on how much boost the stock turbo can take. it's pretty small so i'd be a bit leery of running 17 psi. try a little bit more and work from there.

if you want to increase boost without spending lots of mony get yourself an mbc and go from there.

don't balme anyone but yourself when you blow up your motor. tuning turbos is nothing like tuning pushrod v8s, trust me, i know.
 

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Discussion Starter #3
Thank you for the input. I appreciate the help. I will take it very slow, but I have a lot to learn. WHat is a MBC? A boost controller? What is involved in installing one? What brand do you recommend? Thanks again
 

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Re: Auto Sprayer ?

Its not the turbo itself that is of concern when raising boost as it is a variety of other factors. If you are from the V8 world, you will certainly understand air/fuel ratios. Well, consider what is happening when you force induction and consider how the ECU needs to correct the a/f ratio based on boost pressure and then throw in variable valve timing for added confusion. I'm not saying I understand it all.....I just understand what is involved.
So, an MBC is a manual boost controller.
The conservative approach to tuning an STi is to WAIT for engine management. I'm not even sure that the stock ECU would have the ability to compensate the a/f ratio with more fuel if you used an MBC, or if you would just run lean.
There is a conversion for Mpa to PSI, but my suggestion is to get rid of that factory boost gauge and get one that reads in PSI or Bar.
 

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Many mods to increase boost: inlet hose, intake, downpipe, TBE, exhaust, ~headers (maybe), boost controller, etc. Make sure to NOT go over 17.2 psi OR .12 MPa (on stock gauge) as you will hit boost cut, as I have, and its not fun. Feels like running into a brick wall. I cant wait for some engine management :) ... Also remember... each gear has a different load so make sure to set your boost in like 4th or 5th gear... otherwise your increased load will make the boost rise and you could hit boost cut(example: setting 16-17 psi in 3rd... 4th would be ~17.X 5th ~17.X 6th 18.X) ? Good luck and Im glad you love the car.

Robert~

installing a mbc (manual boost controller) takes about 5 minutes. A very good mod, but Im going to sell mine (if you want it let me know) and get an electronic boost controller. You will spool MUCH faster and will obviously have control over your boost settings.
 

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Discussion Starter #7
Thanks a lot for all the info!! I am beginning to see there is much more to tuning/modifying turbo cars than I expected.
I do not autoX or really get too involved in the twisties, however, I love speed, mostly straight line, so I am not really too worried about modifying anything about the car except improving acceleration/1/4 mile performance.

Can you give me an idea of where I should start (mods) to improve my acceleration/power. I am really looking forward kicking the as*** of a few guys around here with Transams and camaros.

I belong to a F-body club with over 150 members and they have no idea of what these cars can do, lol...

Thanks again for the help
 

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Well to be honest with you, since the ECU is so complex and confusing no one knows if the mods we are all doing (intakes, BOVs, etc) will make our cars run too rich/lean or if the ECU will compensate for it and such. So it would be smarter to wait til december for a UTEC Ecu or some kind of ecu upgrade/tuning. Otherwise here are some great mods for acceleration: Boost controller, downpipe, exhaust, and stuff like that. I am not doing the big 3" TBE and such yet as I only have an 1/8 mile track around here and I dont need the extra lag from them. The boost controller and downpipe will rasie PSI and cause faster spool up so that is good for us who dont have a full 1/4 track. Learn how to launch. Its not very hard once you get the hang of it (i did today ;) hehe). DO NOT use auto on the DCCD, use the first or second triangle and dump (somewhat) from 4.5-5k rpm. As long as you dont get much bog and dont burn the clutch there isnt a negative effect too this approach. - VERY fun and good lord is an AWD a serious pull, feels like space shot or something only forward. This will drop your 0-60 1/4 considerably. I would love to keep rambling, but I have to get ready for church so, if you have anymore questions feel free to ask via pm or email or these guys can help as well.

Robert~
 

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Discussion Starter #9
Robert, thank you for all the help!!!

In reference to a boost controller, What do you recommend, A Manual Boost Controller or an electronic boost controller?? Brand??

Another thing I dont understand, If you order, for example, A turboXS turbo back exhaust, this would include the downpipe with it, correct??

Any Turbo Back exhaust includes the down pipe, right??

When you speak of correcting the A/F ratios, and waiting for a computer management system, why wouldn't one of those APEX a/f controllers work? I guess what I am asking is... I do a lot of tuning on V8 cars and with a software setup like Autotap and a wideband O2 sensor, I can log my O2 readings in MV.
I understand, and correct me if I am wrong, but the Apex A/F controller intercepts the signal from the MAF sensor and corrects it before it reaches the PCM.
If you were able to log GOOD A/F info, you could adjust your settings via the Apex and thus control the ECM that way??
I know I am mumbling, but this is basically what we do with V8 cars, we determine our 02 readings, intercept the signal from the MAF and change it with a computer, similar to APEX called a MAF translator, which then sends the corrected signal to the PCM(ECM).
If I am way off base, please teach me something, just a thought.

Also, Robert, when launching the car, you said take it out of DCCD and set the diff at the first or second triangle, do you mean from the bottom or the top?? The top says LOCK, I was unsure which setting you were using.

Thanks again for everything, I will understand these cars yet, lol...

P.S. Please explain to me the change a large Downpipe/exhaust has on a turbo car? You make it sound like the larger the DP/exhaust, the more power you will make, however, the more lag you will get, is this correct??
 

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Man, you are asking some sweet questions...basically the same ones i have been having. Bravo!
 

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I use an electronic since it gives me a nice digital boost gauge with peak hold for me to monitor and will trigger a warning light as well as cut boost if I go over the preset limit. Keeps me from ever hitting the boost cut. Manual will work but stay away from the cheapie ones like the Joe P. They are aweful. Go for a nice Turbo XS HPBC instead. It is what we were using for testing. YOu can not use the boost controller to raise boost really but it will help with consistency and response dramatically.
 

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I shoudl also add that yes you can raise boost but you need to add fuel accordingly. We hit over 300 whp on the stock turbo which is 53 whp increase over stock by increasing boost 2 PSI and adding a downpipe, intake and the boost controller. Nothing else was done but it was knocking at that level at midrange RPM so fuel tuning becomes a necessity. The AF curves were getting a bit lean also although not critically so. The E-Manage can be used to adjust both timing and fuel easily which timing is probably more critical than fuel at this stage of the game.
 

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chadar15 said:
Robert, thank you for all the help!!!

In reference to a boost controller, What do you recommend, A Manual Boost Controller or an electronic boost controller?? Brand??

I'd either wait for engine managment (ECU or something) or get an electronic one, as they are the most efficient, safe, and such. Blitz SBC-ID seems ot be one of the best. Profec B spec I was a good easy controller too. Blitz seems to be the most stable, have the most features, and support a lot of boost (for the future upgraded turbos and such ;)).

Another thing I dont understand, If you order, for example, A turboXS turbo back exhaust, this would include the downpipe with it, correct??

In short... Turbo Back Exhaust system means, from the turbo back. Downpipe, mid pipe, exhaust. Full exhaust from the exhaust turbine back. Cat-Back systems mean, I believe, right after the last cat (the end of the downpipe) so I assume mid pipe and exhaust.

Any Turbo Back exhaust includes the down pipe, right??

Yes :)

When you speak of correcting the A/F ratios, and waiting for a computer management system, why wouldn't one of those APEX a/f controllers work? I guess what I am asking is... I do a lot of tuning on V8 cars and with a software setup like Autotap and a wideband O2 sensor, I can log my O2 readings in MV.
I understand, and correct me if I am wrong, but the Apex A/F controller intercepts the signal from the MAF sensor and corrects it before it reaches the PCM.
If you were able to log GOOD A/F info, you could adjust your settings via the Apex and thus control the ECM that way??
I know I am mumbling, but this is basically what we do with V8 cars, we determine our 02 readings, intercept the signal from the MAF and change it with a computer, similar to APEX called a MAF translator, which then sends the corrected signal to the PCM(ECM).
If I am way off base, please teach me something, just a thought.

you are right, you can use anything. Apexi AFC / AFC-2, Greddy Emanage, etc... problem is, is that means splicing your ecu which isnt good for most of us. Thats why we just wait for UTEC or an engine management. That will come with everything in one big PLUG AND PLAY package. No splicing, cutting, etc... unhook stock pieces, plug in new ones and done. That and as sweet as the new UTEC is sounding (better then the standard WRX version) Im really hoping it will have some nice tuning options.

Also, Robert, when launching the car, you said take it out of DCCD and set the diff at the first or second triangle, do you mean from the bottom or the top?? The top says LOCK, I was unsure which setting you were using.

Im sorry I should have specified.... From the bottom (Its always good to be in the Green triangles). Also to correct myself, 4500-6000 should be good. As today I did it from ~5300-6000 and my launch was much better. A TAD more spin on the tires, but no bog - which is very good - and when my tires caught I was at perfect peak torque ~4000-4500 and took off like a rocket. Trust me, once you do it once really well, you will LOVE it and be addicted to AWD hehe.

Thanks again for everything, I will understand these cars yet, lol...

P.S. Please explain to me the change a large Downpipe/exhaust has on a turbo car? You make it sound like the larger the DP/exhaust, the more power you will make, however, the more lag you will get, is this correct??
Yes I believe the bigger the piping = more hp, but with a loss in low end. I wish I had the cash to try both the 2.5" TBE and 3" TBE as the 3" would probably win in the end, but for a short track like the 1/8th I wouldnt think the 3" would be best, but either way you shouldnt go wrong and Im sure the 3" is fine (as hummer, among others) have had great results and LOTS of hp from them (~30awhp). Good luck and keep safe!

Robert~[/b]
 

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Discussion Starter #14
thanks everyone for all the help!! Robert, thank yu especially for taking the time to explain these things to me!!!

Well, I guess it's time to start making some purchases and see what happens, lol.

Again, thank you !!!!!
 

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Actually that is not true. 2.5 inch will not improve low end on a turbo car. Always go for 3 or 3.5 inch. It wil be more power overall.
 

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how so? I know you might not get as much TQ out of the deal, but I figured low end RESPONSE would be better? Sorry for giving incorrect info then if Im wrong.

Robert~
 
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