A/F Question for you boost junkies

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01-03-2009, 05:51 AM

#11

mygt500

Multi-Tasking Moderator!

Join Date: Nov 2006

Location: Detroit Rock City!

Posts: 15,618

Quote:

Originally Posted by Simon1

11.0-11.5 is just fine. If you want to run on the ragged edge you push it closer to 12.0.

My motor is built so it may run slightly different.

Just on a side note:

I'm currently doing some tuning on my car and it's on the rich side with a 100 oct tune at around 10.4 on WOT in 4th. It makes around 14 psi and spins the DRs in 1st, 2nd, 3rd and 4th sometimes. Talking to the tuner, he said when he leanes it out to the 11.8ish range I will gain another 50+ hp. Wow. I can't imagine. The difference in 100 and 91 is dramatic. I make 200 rwhp more at around 3500 rpms compared to the 91. For those who go to the track and have access to a good tuner it's money well spent.

Thanks for the tip Simon! I will have to see what my race tune (100 octane) is set at as far a A/F ratio numbers and dyno numbers too.

01-03-2009, 09:18 AM

#12

Simon1

5th Gear Member

Join Date: Dec 2006

Location: Redding, CA

Posts: 4,552

Quote:

Originally Posted by mygt500

Thanks for the tip Simon! I will have to see what my race tune (100 octane) is set at as far a A/F ratio numbers and dyno numbers too.

You're welcome. It's rather inexpensive to switch over to the 100 oct fuel. You need a minumum of 4 gallons to go play around with. When I'm all done I just let hook an adapter to the fuel rail and let the pumps pump out the rest of the tank.

I'm sure I've posted it before but look at the difference in the graphs. Not the peak numbers but down low.