Hey guys,

I have my EVO 8 at the shop on the dyno trying to tune it and we are having trouble with the stock ECU thinking that the engine is overboosting at only about 12 PSI.

So, assuming I do not have a boost leak, can I be maxing out my MAF with the following mods:

- Agency Power intake
- Agency Power BOV
- TurboXS FMIC
- Custom Upper FMIC pipes (Stock LICP)
- HKS 272 Cams
- Hallman MBC

I think that accounts for everything that could possibly be affecting this. If I didn't mention something, then it is stock. Thanks in advance for your help!

 

no not even close. Since your tuning it why not set the boost cut way later? Regardless though you still shouldnt be hitting boost cut near 12 psi

 

I am not physically doing the tuning so I cannot say for sure because I don't know enough about the tuning aspect. I will check though and thanks for your help. By the way, I wanted to mention that I am obviously running the stock turbo.

 

Does everyone else agree with kreionic?

 

definitely not maxing out the MAF. People are running 35r's on race gas and not maxing out the MAF. Might be a boost leak.

 

nah, I'm sitting at 500+awhp on 93 octane @ 30psi with the HTA 35R with the stock MAS

 

Stock MAF apparently only runs out of range above 450HP on the Crank...

So its highly unlikely that it can me maxxed out on the stock Turbo

You would need at least a GT3076R or bigger to start worring

.

 

I was just doing some tweaking on a guys car here in Virginia and the only mods he has is Walbro, an exhaust, intake and test pipe, with the test pipe installed he was hitting boost cut at 3500 rpm's. I just increased his boost cut threshold and logged it a couple times for him and all was good! Once he gets his wideband and installs it I am going to do a full tune for him.

Josh

 

where did you come up with that figure ? I'm seeing ~ 340kpa loads in the logs and I've seen as high at 380kpa when I let the boost spike beyone 30psi for a split second. 30psi has me at 500awhp, I think it'll do 550+ awhp with the stock mas without any problems.

 

Ck the vacuum line that goes the the Diverter/BOV.

My line had a small leak and car would only boost up to 12 PSI.

 

Thanks everyone for your help. It sounds like there may be a boost leak somewhere.

 

BiFfMaN,

I am a little confused. Are you referring to the vacuum line that goes to the top of the BOV?

 

Its the one thats Circled.



I have seen Dyno's take that line off at that location to hook up there boost guage. I knew about it because on one of my dyno runs the guy left the hose lying on my manifold..melted the hose..and my car would only then boost to 12 psi.

I looked back at the other evo guys there and laughed...well at least the boost taper is gone.

 

The car should run around 18psi stock.. how would 12psi be overboosting the MAF? How come it's only running 12psi? Did someone remove the stock boost lines / solenoid? The car might not run great at 12psi since it's tuned for 18psi from the factory.