CA18DET - GT2554 (GT25R) @ 14psi - late boost

[MartinS]

Hi,

My current engine spec is:

Freeflow intakefreeflow 2.5'' Exhaust (2.5'' R-S-K Cat back exhaust, stock cat - stock down pipe - 2.5'' Turbo knee)GT25R @ 14psi - HKS WastegateHorsham Stage 1 chipWabro 255l/h fuel pumpDenso spark plugs (1 step colder)

My problem is now, that boost is hitting full boost at arount 4000 - 4300 psi, usually I saw cars with T28 hitting fullboost there. There is no leak in the piping, triple checked it. Last weekend I disasembled half the engine bay. I did check the cam timing, and it was good, so no off timing there. Took today the spark plugs off and realized that they were a bit white, like it would be running bit lean, but stage 1 is made for GT25R on 14psi. Was really desperate that afternoon and checked the turbocharger; it IS a GT25R.

Can anyone help me? I'm going to burn the car or kill myself

Regards Martin

[wynnEZ]

Could possibly be your tune, were did you get it from?

[MartinS]

I've got a HH Stage 1:

http://www.h-dev.co.uk/product...47dcf

Checkout the dyno.

[MartinS]

Spark plugs

[wynnEZ]

Wow your running really lean, usually people are having troubles running rich, what plugs are you running.

[MartinS]

Denso IQ24.

Usually the HH Stage 1 isn't that lean, but why am I so lean?

Regards Martin

[wynnEZ]

Hmm im kinda stumped now, ill try to get some mods in here and see what they think.

[mbmbmb23]

Denso IQ24.

Usually the HH Stage 1 isn't that lean, but why am I so lean?

Regards Martin

Have you checked your timing? Maybe the belt is a tooth off. Do you have cam gears or stock gears?...because Ive heard aftermarket gears arent always marked correctly...so what looks like its set might actually be off. What fuel pressure regulator are you using?
Modified by mbmbmb23 at 8:35 PM 11/10/2008

[bentvalves]

do you have a stock ECU?

[iliketocrash]

i would definitely check your fuel pressure if you haven't already. i know you have a new pump but it's more of a reason you should check the pressure.

[mbmbmb23]

do you have a stock ECU?

He has a chipped ECU with a "stage 1" tune.

[bentvalves]

yea well he might want to switch back to the stock ecu and run 8-10 psi and see how it feels.

[float_6969]

I was just going to suggest this. If you can switch back to the stock ecu and see how it runs, that would help. Also, late boost is usually caused by an exhaust leak before the turbo, bad wastegate actuator, or VERY advanced timing, or a hole in the hose going to the wastegate actuator.

Check all of these things and get back to us.

[MartinS]

Haphazardly, we had to unmount the front strut-brace to make the pictures of the plugs. I realized that the intake mainfold was rubbing on the strutbrace so we decided to after assembling everything to keep it outside the car. The result was, that the the car was going like a rocket from low RPM (ca. 2500). At 3400 - 3600 I had full boost and it was a great plesure to drive. .

Next steps for this winter:- FMIC- Exhaust header- Custom Mapping @ 1.2bar

Has anyone suggestions for cams? Would it be usefull to get a good overall-powerband by taking HKS Step1 256/256 combo?

Thanks for the help guys.

Regards Martin

[mbmbmb23]

Haphazardly, we had to unmount the front strut-brace to make the pictures of the plugs. I realized that the intake mainfold was rubbing on the strutbrace so we decided to after assembling everything to keep it outside the car. The result was, that the the car was going like a rocket from low RPM (ca. 2500). At 3400 - 3600 I had full boost and it was a great plesure to drive. .

Next steps for this winter:- FMIC- Exhaust header- Custom Mapping @ 1.2bar

Has anyone suggestions for cams? Would it be usefull to get a good overall-powerband by taking HKS Step1 256/256 combo?

Thanks for the help guys.

Regards Martin

So you removed the strut tower bar and the spool came back? Maybe the rotational movement of the engine torquing toward the exhaust side caused a boost leak somewhere on the intake side? That's all it can be really.

Cams...I dont think HKS cams are still in production....someone correct me if Im wrong. You could get Tomei Poncams (256/8.5), they are pre indexed so you dont need cam gears to dial them in. That would be my next upgrade.

-m

[MartinS]

Yeah, the strut bar was pushing on the Intake mani. So there was a leak arount the Intake-to-head gasket. Glad I found that fault.

[float_6969]

You could get Tomei Poncams (256/8.5), they are pre indexed so you dont need cam gears to dial them in. That would be my next upgrade.