# 1.8T why do i have boost spike? what causes it?



## jetta8vwolfsburg (Jul 2, 2001)

ok am an 8v and 16v and never had a boost spike since it was always hitting the same boost everytime
now i got a 1.8T 20v and i noticed i have boost spikes, how can this problem be controlled? thanks

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## Rac_337 (Sep 24, 2004)

*Re: 1.8T why do i have boost spike? what causes it? (jetta8vwolfsburg)*

mbc and a diode


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## slowonder (Sep 26, 2005)

*Re: 1.8T why do i have boost spike? what causes it? (Rac_337)*


_Quote, originally posted by *Rac_337* »_mbc and a diode








 yes i took out my N75 cause i didnt like the spikes it caused and did the mbc and diode and no spikes anymore just boosts to 18 and holds then tappers off at redline...


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## Pimpovic (Jan 2, 2002)

*Re: 1.8T why do i have boost spike? what causes it? (slowonder)*

The boost spikes can be attributed to how much load is on the engine, and the ECU reacting to the interpretaion of the data it receives. Try this: in third gear at 4000 rpm floor it, and then try to floor it at 2000 rpm. At 2000 rpm the car knows it needs to get itself moving so it will request extra boost to do so. At 4k the car is moving well enough that it doesn't need that extra boost. You will notice the difference on your boost guage. It's a characteristic of our ecu tuning. It's not bad, that's just the way our cars are.


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## jetta8vwolfsburg (Jul 2, 2001)

*Re: 1.8T why do i have boost spike? what causes it? (Pimpovic)*

well the mods are the following
prog 1 APR 93 oct
prog 2 APR 104 oct
prog 3 APR 110 oct
**adjustable fuel pressure regulator
**580cc injectors
**i think its a t3/t4 but for sure .48 exhaust side with a 50 cold side turbo
**35mm tial wastegate
**3" full downpipe and exhaust
** greddy type s BOV
** 4" air flow mass sensor with stock air box
** ngk r7e spark plugs gapped at .028
** the typical crappy atp exhaust manifold that takes 8hrs to take off
**unorthodox pulleys
**vr6 tranny and stage 3 clutch
unplugged the air flow mass sensor because it wouldnt really idle right with it so i thought it was bad. then i put a new one in and hooked it up and saw that the new one did the same thing so i left it unplugged and the car ran better
i believe that is all the mods on the engine that its got
oh and actually it was pushing 24 psi but it was leaning out so i added a boost controller before the n75 valve but it did nothing so i routed the boost controller like this so it controls the boost and so i could lower the boost


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## QuickK03Crap (Oct 5, 2004)

*Re: 1.8T why do i have boost spike? what causes it? (jetta8vwolfsburg)*

There is no APR 110 octane file is there? Did you buy this car "pre built"? Any way to log boost to describe your problem a lilttle better?


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## jetta8vwolfsburg (Jul 2, 2001)

*Re: 1.8T why do i have boost spike? what causes it? (QuickK03Crap)*

what do you mean log boost? yes i got the car pre build


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## T-Boy (Jul 16, 2003)

*Re: 1.8T why do i have boost spike? what causes it? (jetta8vwolfsburg)*

And i thought only the stage 3 and 3+ had 104 programs.......








you sure the person you bought the car from is trust worthy?


_Modified by T-Boy at 11:43 AM 6-12-2006_


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## QuickK03Crap (Oct 5, 2004)

*Re: 1.8T why do i have boost spike? what causes it? (T-Boy)*

Exactly, sounds like he was a little off on specs he told you. lol


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## jetta8vwolfsburg (Jul 2, 2001)

*Re: 1.8T why do i have boost spike? what causes it? (QuickK03Crap)*

i dont know, i think he would be. anways, is there a way to find out what software the car has?


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