Maf over run?

[pianoman]

90 tsi awd 3inch turbo back, stock 14b, intake pipe, 255hp, 510cc 2.5 dejon tool uicp. I know I know, I don't have a afpr, but I don't believe it would help in my situation. did a pull last night @17psi.


This is what my car is doing. Fuel trims are at
100% with the low at 98-99%. WOT from 3500 to 4900 is fine, the 02 is
reading a tad low at .70-.72, Knock got as high as 8 counts, and
timing was in the 16-18 degrees. My log goes from 4900 to 5300, so at
5300 things get FUBAR. Knock is at 26 counts, timing is at 15*, 02 is
at a very lean .66. The mafs is reading 1427.8Hz

RPM-5593 Knock-26 Timing-12* o2-.68 INJD- 64% Mafs-1553.6Hz

RPM-5937 Knock-35 Timing-16* o2-.60 INJD-69.5% Mafs-1427.8Hz

RPM-6062 Knock-43 Timing-14* o2-.62 INJD-71% mafs-1490.7Hz

3RD Gear

RPM-4343 Knock-15 Timing-17* o2-.74 INJD-66.4% Mafs-1553.36Hz

RPM-4531 Knock-22 Timing-14* o2-.70 INJD-67.1% Mafs-1566.2Hz

RPM-4718 Knock-21 Timing-11* o2-.72 INJD-66.4% Mafs-1490.7Hz

RPM-5031 Knock-20 Timing-10* o2-.70 INJD-73.4% Mafs-1603.9Hz

RPM-5500 Knock-36 Timing-8* o2-.70 INJD-80.4% Mafs-1603.9Hz

RPM-5937 Knock-43 Timing-13* o2-.27 INJD-74.2% Mafs-1308.3Hz

Mind you my buddy was watching the logger and obviously I would of stopped had I saw the knock and 02. Im gonna test for boost leaks tomorrow. Im thinking a bad 02 sensor? Mas over run? Its a 1g mas with the free mods done and the lower honeycomb removed. I would think i'd be running pig rich, with the 255hp and 510's with no afpr. What do you guys think. The vaccum is 20hg at idle, and it holds boost stong. Time for a Maf-t?

 

[5150DSM]

I really think an AFPR would help you. You are leaning out under boost, at peak torque, due to the stock FPR being overran and skewing the fuel curve. When the stock FPR is overran, unregulated amounts of fuel are spitting into the rail causing uneven pressure and leaning individual cylinders.
Install an AFPR and set your base pressure, reset the ECU, log the results; I would expect to see a large improvement, also, you may want to consider some sort of fuel tuning device if you don't already have one. MAF-T might be a good idea, it solves a lot of problems on the intake side.
Aloha

 

[pianoman]

What about the maf numbers? I had this same setup on my gsx, only I had a big 1g and my 02s never dropped below.89. I had a 3000gt vr4 fuel pump before the 255 and although I didn't have a datalogger at the time, the car felt the same way. Anything over 14psi and it studders at the higher rpm's, as we can see why.

 

[diambo4life]

Is your MAF hacked? If so, how much?

 

[pianoman]

Lower honey comb and sliencer. Just the free mods.

And to clear up the post up above this one, I had a vr4 in my current tsi with 450s and car drove like it did in my first post. Which is why I don't think an afpr would help. Im going to get one nonetheless, but haveing a 185lph or 190lph I don't think is enough to over run the stock fpr.

 

[pianoman]

?? anythoughts on what it can be besides either boost leaks and/or a bad 02? the ecu is good, just had steve clean it up and replace the caps.