Stock ECU & 10 psi........... Myth??????
Cheese
Joined: May 2001
Posts: 452
Likes: 0
From: Australia
Originally Posted by Marshall
All this talk of AFRs is absolutely pointless without knowing the timing maps on the stock ECU. If you have too much timing at peak torque (usually where the spike is on a sequential setup), it hardly matters if you're running 10.x AFRs, you'll still ping. I'd rather run 12.0 AFRs with conservative timing than 10.0 with aggressive timing.
just for reference i run 10-8-10psi (controlled via AVCR) with downpipe, gutted cat, cat back, opened up air box with k&n filter. I have had no problems running it at sprint days or on the street. i'd be the 1st to admit i'm foolish for not having AFRs checked but just pointing out the stock ECU seems to cope
Cheese
Joined: Aug 2004
Posts: 769
Likes: 0
From: Lynnwood, WA
Also, you will want to take into account the injectors themselves. I just got mine back from RC Engineering, and at only 60k miles on them, they had lost about 4-5% of their flow, and one was dripping instead of spraying. If you are running higher mileage, or had dirty gas, whatever, youll have a less efficient injector, and thatll mean that less fuel is reaching the combustion chamber than is supposed to. Also, if it doesnt have good atomization, it wont burn as good as it should. IMO anyway.
Also, if you port your wastegate, and get a MBC, you should be able to safely run more than 3 mods...assuming it is infact based on PSI. I plan to try anyway, call it a test
Also, if you port your wastegate, and get a MBC, you should be able to safely run more than 3 mods...assuming it is infact based on PSI. I plan to try anyway, call it a test
Eats, Sleeps, Dreams Rotary
Joined: May 2003
Posts: 3,639
Likes: 0
From: MIA
Isn't it possible that this theory may have started in Cali where the **** fuel is from? Cause I ran DP, gutted cat, stock cat back, and intakes, at 11psi and ran hard and never any break up or stutter or detonation. I lost my motor duel to coolant seals.
WWFSMD
Joined: Jun 2001
Posts: 5,035
Likes: 4
From: SoCal
The same CFM at different temps and boost pressures gives different lbs/hr. Lbs/hr should correlate better with power than CFM does.
Defeating the fuel cut on the stock ECU is accomplished by tweaking the MAP signal to make the ECU think you are running less boost than you really are. So it doesn't really matter if there are higher-boost maps in the stock ECU because if you are running higher boost (and tell the stock ECU about it), you'll get the fuel cut. This is what the PFS PMC does, which is why you need to add more fuel to run more boost. For instance, you might need to add 15% fuel to run 13 psi (which the stock ECU will think is X psi) and add 20% fuel to run 15 psi (since the stock ECU will still think you are running X psi). X psi is some number below the stock fuel cut.
-Max
Defeating the fuel cut on the stock ECU is accomplished by tweaking the MAP signal to make the ECU think you are running less boost than you really are. So it doesn't really matter if there are higher-boost maps in the stock ECU because if you are running higher boost (and tell the stock ECU about it), you'll get the fuel cut. This is what the PFS PMC does, which is why you need to add more fuel to run more boost. For instance, you might need to add 15% fuel to run 13 psi (which the stock ECU will think is X psi) and add 20% fuel to run 15 psi (since the stock ECU will still think you are running X psi). X psi is some number below the stock fuel cut.
-Max
Last edited by maxcooper; Jan 13, 2005 at 02:12 AM.
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