2 replies to this topic

[Flyntgr]

I have a 1.6 and want to know what Air/fuel ratio works best for this engine. Some use 13.4 to 13.5, while others go much richer. What do you find works best for Torqueand what works best for H.P. in your 1.6 SM?

[Mtaylor]

Leaner more higher end power

Richer more low end torqure




This is from 5xracings website:



dialing in more fuel equals a richer mixture of air and fuel, which will benefit low rpm torque and horsepower for tracks that are tight and have low speed corners. Dialing in less fuel will lean your mixture of air and fuel, which will benefit high rpm horsepower for tracks that are 3rd gear through 5th gear tracks and do not have tight turns.

I am in the process of testing the same to see what a happens but I think the dyno is your best bet here,
my current dyno show afr falls off as torque and hp increases but my max hp/tq gains show high 12s, none of the max hq or hp numbers are above 13, when you cross 5250 rpm., and this were most of the tq and hp starts to be generated.

not sure if you are asking for idle afr.

[Flyntgr]

Thanks for your reply. Our track has lots of twists and turns, only one in 2nd gear, 7 in 3rd gear and 6 in 4th gear. One of my friends runs his SM between 12.7 and 12.9 at 5,000 rpms and higher. I've been running at 13.5 for a couple of months, but I learned that torque likes richer settings, and torque wins races-not h.p. So, running at 38 psi at idle should run slower than a richer setting of 40 psi, which returns 13.4 to 12.8 afr at higher rpms? Even if the plugs are black with rich burn? Thanks!

Leaner more higher end power

Richer more low end torqure




This is from 5xracings website:



dialing in more fuel equals a richer mixture of air and fuel, which will benefit low rpm torque and horsepower for tracks that are tight and have low speed corners. Dialing in less fuel will lean your mixture of air and fuel, which will benefit high rpm horsepower for tracks that are 3rd gear through 5th gear tracks and do not have tight turns.

I am in the process of testing the same to see what a happens but I think the dyno is your best bet here,
my current dyno show afr falls off as torque and hp increases but my max hp/tq gains show high 12s, none of the max hq or hp numbers are above 13, when you cross 5250 rpm., and this were most of the tq and hp starts to be generated.

not sure if you are asking for idle afr.