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Help with tuning issue.


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Posted (edited)

Hello all, I am having trouble finding the cause of my current issue.

I rebuilt my 05 OBXT last summer and had an uneventful break-in period. I then began tuning the car with the guys over at cryo and without making that much power we were maxing out the MAF on the stock air box. I thought this was strange because almost every post I have read on the forum states that the stock air box is capable of 300ish hp. The logs were not putting up much more than stock boost. Fast forward and I changed the air box to the Cobb intake with enclosure and now were back with the same issue just with more boost and it has begun to lean out at the high end causing knock. I have double check all connections, smoke tested it, and it looks to be getting good vacuum numbers so I don't think it has anything to do with that.  I installed a new MAF during the rebuild and have cleaned it a few times since with out any change. I have zero issues with normal driving, but generally keep it out of boost.  


To summarize current issues are: 

1. MAF sensor maxing out  (looking at the tune it has been scaled up 13%)

 2. leaning out at higher RPM 

3. and the knock around 3800



Here is the short list of relevant mods:

RA short block

Rebuilt stock B25 heads

all new vacuum lines and in bay fuel lines 

new in tank fuel filter 



DW 750cc injectors 

Tomei FPR set to 3 bar

DW 65c pump



stock manifold with phenolic spacers 

and TGV flap delete 

Grimmspeed top mount intercooler 

Kinugawa 16g  

Mishimoto turbo inlet 

Cobb intake 

Grimmspeed BCS


Stock headers with Grimmspeed cross over 

some aftermarket catless uppipe

Grimmspeed down pipe 

and custom catback exhaust 


Here is the last log after I made sure everything was tight. I probably wont make another pull until I find an issue.

Any help is appreciated!



R2 3rd gear pull after fix.xlsx

Edited by Taropatch
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I can see my fuel pressure while idling but i am unable to see real time. I can get a sensor and gauge in the cabin, but Im unsure if RR is capable of logging more than one additional signal.

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