Mellon Racing

iTrader: (38)

the temp difference could cause a boost spike, are you seeing more than 21psi now?

correct, not enough fuel supply can be due to the fuel pump or injectors being too small for the amount of power you're trying to make. IDC's over 100% mean the injectors are completely maxed out and when boost is increased it cannot supply any more fuel for the added air, this causes the lean condition. It might not be his issue, just a hunch.

check the boost, turn it back down to 21psi peak and log again to see if the AFR drops from the 12's to the 11's again.

mitsuevo803

iTrader: (3)

im running 26-27psi (weather depending) and im on stock injectors. they are usually between 98%-103% (again depending on weather) when i log the car and it causes knock up top. i was thinkig about picking up a set of used 680 injectors until i get my 880s (or maybe ill just go buy 880s now?) so i can solve this 100%+ IDC problem. would i have to get completely retuned for a set of new injectors or could i just adjust my fuel trims and injector scaling for the bigger injectors?

also would i be okay running 880s until FP red in the summer?

RSMike

iTrader: (1)

fully open 100% is about 120% on evoscan isn't it?
i've heard it reads a little differently and 100% IDC isn't actually 100% real.

Mellon Racing

iTrader: (38)

yes you would need to setup the new injectors scale and latency and probably tweak the fuel map as well.


about 110%+ is where I usually notice I'm adding fuel and the AFR is no longer getting richer which forced the IDC up even further.

speifer

+1

Make sure if you have your cat on the wideband sensor is upstream (downpipe for example) Otherwise the data is garbage.

zedevo

iTrader: (1)

is the AFR at 12's in 21PSI ?

Mellon Racing

iTrader: (38)

yep, he lowered the boost to 20 and the AFR dropped to 12.5 and it's not out of IDC. I'm not sure why it's doing this, I had him check the FPR hose etc...and everything was fine. I'm adding some fuel in the tune to see if we get an improvement or just more IDC

zedevo

iTrader: (1)

Go Mellon .... Ur the MANNNNN .... I wish if im living in us :'( ...

BoostWhore

iTrader: (42)

Check your vacum line on your fuel pressure regulator

Mellon Racing

iTrader: (38)

I already asked him to check that an any hoses that "T" into it, he said it's good.

mitsuevo803

iTrader: (3)

im stuck at 12.08 at the track (averaging 1.69-1.75 60 footers, stock turbo, 93 octane, 26psi). would it be so horrible to turn up the boost to say 28ish just at the track for a few runs to break 11's? would turning the boost up cause so much knock to cause the ecu to pull enough timing to end up slower and less hp than i was at 26/tuned (if that sentence made sense)? sorry off topic

Mellon Racing

iTrader: (38)

raising the boost will likely do several things:

1 - lean out the AFR due to inadequate injectors
2 - move you into a different fuel and timing column that the car wasn't tuned for potentially causing further issues

the short answer is that it's a very bad idea.