Autocross and Road Racing Technique There is more to life than a straight line

AFR tuning

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Old Jul 11, 2004 | 01:59 AM
  #1  
Highlander's Avatar
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From: San Juan PR
AFR tuning

Hello guys...
I was wondering what AFR you tune for when doing hard autox or similar...

What would be lean and rich... 1/4 miles is a different ball game.

THanks
Old Jul 11, 2004 | 03:19 PM
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I tried to stay just on the rich side of 13:1. And make sure the rest of your fuel system is up to snuff if you make a lot of power. Just because your fuel pump holds up just fine on the dyno, doesn't mean it can keep up all day at the track. Ask me how I know....
Old Jul 11, 2004 | 04:08 PM
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YES PLEASE DO because i tuned a z06 13:1 and it broke after the 5th turn./
Old Jul 11, 2004 | 08:03 PM
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Why would the ideal AFR be any different for a different style of racing? I always heard you should tune for ~12.7:1 on a dynojet since it doesn't factor in the correct load
Old Jul 11, 2004 | 08:24 PM
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because you are pumping more power more time nad it will tend to overheat the engine and you need the cooling effect of the fuel to bring down temps....

I did it for 13.05:1 and it was at night... so on the track it should have been close to that during the day at full speed.
Old Jul 11, 2004 | 08:52 PM
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So how rich without giving up a lot of HP? I'm getting some new dynojet pulls on my rebuilt engine tomorrow. I'd like to what AFR's to strive for once I know what it's at now. I don't drag race at all - it's 100% daily driver & autox right now, but maybe some RR in the future as well.
Old Jul 11, 2004 | 09:10 PM
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Well that what i was trying to find out... you will lose about 3-5hp from 13.0:1 to 12.8:1. I targeted 13.0:1 on the dyno at night so I would have around the same during the day with 100mph winds...

For the next engine and/or race i will use 12.0:1 just to be sure, no matter if i loose 10rwhp, which i will.
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