V
vegasviper
Guest
Thanks
OP
OP
vegasviper
Guest
Is 12.0 ok?
OP
OP
vegasviper
Guest
Its for my SC Viper. the higher the # the richer?
OP
OP
vegasviper
Guest
Thanks
Every where I've read 14.7 parts air to 1 part fuel is ideal. When you increase the parts of air by turbo or SC you are leaning it out. Take away the air by a plugged air filter and it's too rich. When you supercharge you have to give it more fuel to get back to 14.7/1 ratio. Hope this puts it in perspective. 
KenH
Enthusiast
You want around 14.7 at idle and part throttle operation. With your setup and running the water/methanol injection, the ideal for power at WOT is about 12.0-12.2, but many people tune a little richer at around 11.5 to provide some safety margin since it is safer to run too rich than too lean, especially when boosted.
Joseph Dell
Enthusiast
more on what KenH said. WOT is different than part throttle which is different than on decelleration. and NOS has differnet targets from SC from TT.
At WOT, here are some guidelines: SC 11.5:1 , NOS, 10.5:1, TT: 11.0:1
on race gas, you can go higher. add .5:1 to the above for SC and TT... not for NOS. with WM, optimal WOT burn happens around 12.0-12.2.
N/A is 14.7:1.
Now part throttle is a whole different ballgame. and Decel is normal to see 18.0:1.... or leaner.
exciting stuff, eh?
At WOT, here are some guidelines: SC 11.5:1 , NOS, 10.5:1, TT: 11.0:1
on race gas, you can go higher. add .5:1 to the above for SC and TT... not for NOS. with WM, optimal WOT burn happens around 12.0-12.2.
N/A is 14.7:1.
Now part throttle is a whole different ballgame. and Decel is normal to see 18.0:1.... or leaner.
exciting stuff, eh?
With an NA car the max hp is achieved at 12.8, max torque at 12.6. It will vary a bit, but, those numbers apply to all cars. Contrary to belief, our cars even like it a bit leaner than the norm.
JD:
I have to slightly disagree with you on the nitrous a/f. The 10.5 you mentioned can also cause problems, excess fuel in the ring lands can cause as many problems as being too lean. I belong to many nitrous forums and the over-rich issue shows up quite often.
JD:
I have to slightly disagree with you on the nitrous a/f. The 10.5 you mentioned can also cause problems, excess fuel in the ring lands can cause as many problems as being too lean. I belong to many nitrous forums and the over-rich issue shows up quite often.
Joseph Dell
Enthusiast
Jack -
Thanks for correcting me. I was multi-tasking when i wrote the above. it should say that N/A is 12.7:1-13.0:1 is target N/A.
And RE: the NOS - what A/F have you noticed as being a good target for NOS? I've always tuned for a 10.5:1 target, but if there is a more optimal one then what should I/we be targeting?
thanks!
JD
Thanks for correcting me. I was multi-tasking when i wrote the above. it should say that N/A is 12.7:1-13.0:1 is target N/A.
And RE: the NOS - what A/F have you noticed as being a good target for NOS? I've always tuned for a 10.5:1 target, but if there is a more optimal one then what should I/we be targeting?
thanks!
JD
JD:
Ideal for hp and ideal for safety are far different. In a perfect world, 12.2 is where nitrous derives the most power, but, virtually everyone tries for 10:5 to 11.0 for reliability, no different than the SC crowd trying to stay rich.
The 10:5 scares me because of the issues with fuel accumulation between rings. The reason is, most nitrous cars run richer near the end of the quarter due to the bottle pressure dropping, therefore, a car that starts at 10.5 ends up with an a/f in the 9's. This is more pronounced as the shot size increases. It may not be a big issue on a 150-200 shot, but, at 250-300 it is a big problem.
I wonder how many failures have been due to over-rich a/f when on nitrous. As stated previously, virtually every nitrous forum has case examples of over-rich causing that issue, on the other hand there are more examples of problems when running lean. I guess you have to walk the line and shoot for an average of 11.0.
Ideal for hp and ideal for safety are far different. In a perfect world, 12.2 is where nitrous derives the most power, but, virtually everyone tries for 10:5 to 11.0 for reliability, no different than the SC crowd trying to stay rich.
The 10:5 scares me because of the issues with fuel accumulation between rings. The reason is, most nitrous cars run richer near the end of the quarter due to the bottle pressure dropping, therefore, a car that starts at 10.5 ends up with an a/f in the 9's. This is more pronounced as the shot size increases. It may not be a big issue on a 150-200 shot, but, at 250-300 it is a big problem.
I wonder how many failures have been due to over-rich a/f when on nitrous. As stated previously, virtually every nitrous forum has case examples of over-rich causing that issue, on the other hand there are more examples of problems when running lean. I guess you have to walk the line and shoot for an average of 11.0.
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