|07-13-2004, 04:05 AM||#1|
Join Date: Oct 2003
Location: S. CaliforniaVehicle:
Dyno Results and Implications on CA 2004 WRX ECU Programming
I have a feeling this is going to be a catalyst for a bunch of discussion about WRX ECUs and learned/unlearned/Vishnu reset behavior. Before I start, please note my car is BONE stock. The only thing that could help its numbers would be 12-lb SSR wheels and a very ginger break-in period that lasted close to 2K miles.
I went to Harman today, and did 5 runs. I want you all to pay close attention to the blue versus the red run. The blue run is how I drove it in, with whatever learned data the ECU had in it since the last reset, say 500 miles worth. The red run represents an ECU reset, whereby I disconnected the negative battery cable, purged the remaining electrons through tapping the brake pedal, and then waited for 10 minutes, just to be on the safe side.
POINTS OF INTEREST:
1. I gained 13 whp with an ECU reset proving that a knock event or some other data point can "stick" the ECU in a severely retarded timing mode.
2. I made more whp than another other bone stock WRX on this particular dyno.
3. Check out the differences in the A/F ratio between the blue and the red. It's huge! Look how lean it stays in the red versus the blue.
4. Subaru is running these cars WAY lean when they're putting out the power they're supposed to. If you multiply 186 by 1.22, you get 227 horsepower, right where it should be.
5. The reality of the situation is that I believe most or much of the time none of us using CA gas are actually getting full power out of our cars. In fact, we're actually being cheated, due to safety precautions the ECU is taking.
6. The ECU doesn't seem to rebound quickly after a KE to bring our timing back. In essence, it gets stuck, and nothing but a hard reset seems to help it get back to where it should be.
1. Resetting your ECU if you feel that your car is sluggish has good odds of remedying the situation.
2. Subaru is running the cars too close to the knock threshold for CA 91 octane gas.
3. The ECUs, once they encounter knock, don't return timing advance the way they should.
4. Tuners such as Cobb, Vishnu, and others will all have problems with ideal maps until SOA implements some new ECU programming.
5. Perhaps both my learned and reset runs are a few hp higher than normal due to my break in and my lightweight wheels, but that can be argued.
6. Our cars should have consistent performance running 91 octane CA gas, and we need to be vigilant about this. There's no excuse for pinging in a stock car.
Now for the DYNO GRAPH!
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|07-13-2004, 03:46 PM||#2|
Join Date: Sep 2001
Location: Seattle, WAVehicle:
'02 OBS 2-tone!
'95 Montego Miata
Whups! Looks like you meant to post this to the "Engine Management & Tuning" Forum -- mods?
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