trd_corolla

hi...

I have recently install the greddy turbo kit on my car. The car now accelerate faster than before.. but one problem. The turbo spools up around 2400-2500rpm. The power of the car gain from around 2400 - 5000rpm. Right after 5000rpm the car instally slows down, is like something blocking the exhaust. Does anyone experience a similar problem??

I have put..

HKS SSQV BOV
custom 2 1/4 exhaust (no cat)
no intercooler
stock emanage setting

can it be emanage setting problem?????

please let me know thx

fusionscion

you should get a wideband...

this way u can keep track of the afr's...
my car did a similar thing, except it bogged down around 45000rpms... it was because the spark plugs needed to be changed to a step colder...

if that isnt a fix, u need to retune the car to dump more fuel at higher rpms, or vise versa..

fusionscion

id invest in the intercooler option as well.... cold air can only help

trd_corolla

thx for the info i will try to get it fix and post again

xBtenchu

does it feel like the car just shuts off? Like, if you were to let off the gas feeling? Might be a fuel cut. I dunno how turbo-scions work but I know I had that problem with my Civic till I chipped the ECU

xoBkcalb

Have you changed your fuel injectors?

8psiXA

my guess is the colder plugs should do the trick like fusion said.. but definatly get a wideband.. better safe than sorry ;)

trd_corolla

I havent change the injectors.. but the celica GTS one seem to work since everyone saying it is going to fit..??? but how can you make the adjustment on idle once the injector changed??

Guest

It's because you already hit peak boost at 5000 rpm. Depend on the type of turbo, the spooling characteristic is different. GReddy uses a 14G turbo, which is plenty for a 1.5L xB motor. The spooling characteristic of this turbo is ideal for daily driving. You get most of the power during normal rpm. If you switch this out to let say a 16G or 18G turbo, than you basically shift the power band curve to a higher rpm range.

trd_corolla

thx all of your info. I change the spark plug to NGK #6 now the power does go a bit smoother and I also monitor it with a wideband. There are a few problems still..

1. If crusing @ around 1/4 throttle then suddenly goes to W.O.T. The car will bog. and the wideband shows 10 A/F mixture. then the mixture will go a bit leaner 11 then 12 then 13. once i see the A/F around 12 the car will goes back to life.

2. The turbo is overboosting on my car. donno if this is a problem that i dont have a cat. The turbo w/factory actuator rod length it goes to 0.6 bar @ around 4000 rpm then continue goes up.. @ around 6500rpm I had one time go up to 0.8bar. A/F mixture goes from 3k to 5500 rpm keeps w/ 13.5 A/F but after 5500rpm mixture goes to 14.5 and leaner if higher the rpm goes

3. I had the actuator re-adjust to the longest length just barely close the wastegate inside the turbo. Now I think i adjust the rod too long and it is leaking even w/no pressure on the actuator hose. The turbo now takes longer to spool up cuz of the leaking wastegate hahaha but the over boosting still havent fix. @ around 6000 rpm w/ 3 gear i had one time 0.75bar.

I still havent put in intercooler and injectors and the emanage still in factory setting.

Anyone have these similar problem?? and where i can find a softer spring actuator

UV7

It sounds as though you have a problem with the wastegate not functioning properly. This would explain why your AFR and boost continue to spike as the RPMs increase. As the RPMs go up, the turbo spins faster, creating more boost pressure. If the wastegate does not function properly, the boost pressure will continue to rise to the turbo's point of choke. This continuous rise will continue to lean out the AFR mix to the point of detonation. This is BAD NEWS!
Where have you tapped the vacuum for the wastegate? Are you sure you do not have a vacuum leak somewhere before the wastegate?
Also, once you have your wastegate problem fixed, you really should get the setup tuned rather than sticking with the factory settings. Your AFR ideally should be running a bit more on the rich side, like upper 11's to VERY low 12.