When to reset ECU on race gas?

[Enraged78]

Hey all,

You have all offered a great amount of information in the past, and I hope that you'll be able to do it again. I've got my car to a point where it's running very well on my current setup. (see mod list for details). I'm getting 21 degrees of timing at WOT in third. My O2's are at .94 @7K in third( a little rich, but safe...), and I would like to run 116 Octane race gas the next time I go to the track. I'm currently running 17PSI, and would like to run 20. I have been told that 21 is the max safe limit for the mods that I have on race gas, so I will run 20. In order to have the ECU get the most timing out of the setup, when should I reset it? Right before I run? In other words, how long does the ECU take to re-learn parameters before it performs at maximum? I would like to stagger and tune as I go (eg. run 18Psi and log it, 19, and so fourth).

Thanks,
Matt.

 

[Nomad666]

I would also like to know the answer to this quetion. Sorry^^^^

 

[BoostinAWD]

Why would you want to reset it?
Keep your knock down and nothing will change. The ecu doesnt know the difference between c16 and pump gas. Neither does it know the difference between 10 and 20 psi.

All it does it base timing from your knock counts, and airflow.

 

[Enraged78]

Well, my timing varies depening on whether I can find 94 octance or not. From logging the car, I found that I was getting around 21 degrees of advance in third, WOT at 7K RPM with the Sunoco 94 octane. With the Texaco 93, it seems to drop to around 19 or so. Either way, the computer keeps the timing, short fuel, and long fuel trims in memory, right? And the trims effect the amount of fuel that the ECU gives out. So, wouldn't it make sense to reset it at some time?

Matt.

 

[BoostinAWD]

Why when it will rebuild them exactly the same?

 

[T6Rocket]

Resetting the ECU was the single biggest gain I made on the dyno, like 18 HP! Not even worth trying to figure why it helps or what it does exactly, just that it helps, sometimes a lot! Just reset it after you put the gas in and then you will start with the maximum timing possible.

Al

 

[Enraged78]

Originally posted by T6Rocket
Resetting the ECU was the single biggest gain I made on the dyno, like 18 HP! Not even worth trying to figure why it helps or what it does exactly, just that it helps, sometimes a lot! Just reset it after you put the gas in and then you will start with the maximum timing possible.

Al

Thank you, this was exactly the answer I was looking for. Next time I hit the track, I'll do this.

Thanks,
Matt.

 

[Defiant]

We're glad you found an answer you like, now let's hope it's more correct than the one you didn't.

I'd balk at ECU resets. Ah, but I balk at drag racing street cars, so good luck to you.

 

[Enraged78]

Originally posted by Defiant

We're glad you found an answer you like, now let's hope it's more correct than the one you didn't.

I'd balk at ECU resets. Ah, but I balk at drag racing street cars, so good luck to you.

I think that's one of the general rules of being an engineer. If you get an answer you don't like, ask someone else.

Why do you balk at ECU Resets? Is there something that you've seen that makes this a bad thing?

Thanks,
Matt.