what is a good AFR to aim for in the evo?
Jan 13, 2005, 07:13 PM
#16
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Originally Posted by EVOTEXAS
So with that said, all this conversation can really accomplish is relating "rules of thumb." In reality, no specific information recieved on the Internet regarding tuning is going to work the same on two cars. Rules of thumb like richer is safer and leaner is more powerful, turbo cars run richer than naturally aspirated cars, etc. So with that, I guess there really isn't too much more to say! All the dyno graphs you post also only mean something to people who also dyno at Pruven in the same time of year, etc. They mean nothing to me here. Anyways....
The art of tuning is to find the happy medium of balance which achieves a decent power level while maintaining relaibility and a smooth, useful power band. There is more than one way to get to the same result and many people approach the subject from different angles which can all lead to the same result.
Also important to note is that differenet a/f ratio meters read differently and will also read differently depending on where you place the sesnor in the exhaust system
Most of my tuning is done on actual roads and the cars are tested using a rich and lean a/f to see where that particuar car runs smoother.
Of course the Dyno Flash must operate within the confines of the stock
knock controll calibration which I have chosen to leave fully functional for relaibility and saftey measures. Other systems such as the AEM or UTEC can be run slighly leaner without running afoul of the very senstive stock ecu.Also, cars with larger turbos and head work can generally be run leaner and pushed harder becuase they have less back pressure.
Finally, water injection also has a significant effect on these calculatuions.
Jan 13, 2005, 07:19 PM
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Just to offer another example, my car runs faster at ~10.8:1 than it does at 11.2:1. I've logged 40-80mph pulls at various A/F ratios and the fastest ones are always slightly below 11:1.
-Paul
-Paul
Jan 13, 2005, 07:38 PM
#19
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BTW - I hate it when I am wrong but someone reminded me of this dyno sheet that I did a long, long time ago when I was running the Dyno Flash on my own car - 535 whp but with a 30 shot of nos . Obviously, even when trying to set dyno records, I erred on the super rich and safe side with my own car.
I have done enough dyno pulls on Evos to burn out my lungs and wear out the parts on the dyno.
I have done enough dyno pulls on Evos to burn out my lungs and wear out the parts on the dyno.
Jan 13, 2005, 07:41 PM
#20
Originally Posted by PVD04
Just to offer another example, my car runs faster at ~10.8:1 than it does at 11.2:1. I've logged 40-80mph pulls at various A/F ratios and the fastest ones are always slightly below 11:1.
-Paul
-Paul
Jan 13, 2005, 08:36 PM
#22
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Originally Posted by umiami80
I'd figure anything under 12.0:1 on pump, I always run 94 octane, never get any timing pull that I can feel.
Jan 13, 2005, 10:42 PM
#23
These are the threads what makes the internet a useful tool. I always want to see and hear everyones theory of tuning. It seems that everyone has a little different angle on how to tune. I was very skeptical of Dynoflash the first time he came to Chicago. I sat in a few cars while he was tuning and actually described on what he was doing and why he was doing it. That shows me he knows what he is doing. Then came my car and half way through BAM i was hooked on Dynoflash. Now that it seems I am doing a mod a week I can't have down time in my car so thats why I purchased a UTEC. Great job and I'll see you next time you come to Chicago AL.
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