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T88 YOU
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3,567 Posts
Discussion Starter #1
this is my first turbo car and i read alot about you guys turning up and down the boost. i know in my supercharged truck, everytime i want to change the boost i HAVE to get it retuned, is it not the same for supras? can i just throw in some racegas and turn the boost up without having to get it tuned with some sort of piggyback fuel controller or what? i guess what i am asking is what do you guys do when you turn the boost up to compensate for the extra air being put into the motor? i want to turn my boost up and need to know what else i need to do with increasing boost.
 

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If you're still on stock twins, the stock fuel system has plenty in it to compensate for any increase of boost over stock. With 550cc stock injectors, the stock fuel system has been known to handle up to ~500whp. Given that, the stock ECU will beable to read how much air is coming in and compensate for the increase in boost and supply the correct fuel. Basicly what i'm saying is that you dont have to worry about leaning out on stock twins with a healthy fuel system/healthy car unless your car is OBD I and you're boosting over 20psi, then you may experience the dreaded OBD I Lean spot, but this is a whole different subject on itself. If you do a search, you'll find lots of info on it.

A fuel controller will definately help, but when turning up the boost, i would worry about octane first as i believe the stock ecu runs pretty rich at bpu levels.
 

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T88 YOU
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3,567 Posts
Discussion Starter #3
wow, thanks! so i can just get a boost controller and turn it up to whatever boost i want (obviously not exceeding about 18psi on pump) and be good, no kind of tuning whatsoever? i guess i will be getting a boost controller and be good to go. also, if i put 100 octane in it, can i just pull the wastegate hose, not permanately, but just to see what it feels like one time?
 

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Let me just ask, what other mods do you have? Or is your car stock? If so, I would get a downpipe also in conjuntion with a purchase of a boost controller. A downpipe is probably the best , most hp gaining mod you can do on a stock mkiv.

But to answer you question, yes you can just get a boost controller and turn up the boost to whatever you want, given you have enough octane for that boost level. Personally I would only run 16psi on pump gas, but I run a mix of 110 and 93 only now, so my low boost setting is set at 18psi on my boost controller.

A fuel controller and tuning will definately help to optimize your power curve.

Take a walk over to www.mkiv.com if you havent yet and theres endless information over there for new mkiv guys who are looking to start the modding process. Good luck.



-Phu
 

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T88 YOU
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3,567 Posts
Discussion Starter #5
yeah, i have a custom 3.5" downpipe off my friends old car and also an intake and BOV. exhaust will be here next week (HKS Ti). thanks for the help.
 

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T88 YOU
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3,567 Posts
Discussion Starter #7
yea, i have one on the way, but thanks for the input.
 
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