A/F ratios
 

How lean can one go and still not get into detanation in a N/A engine on methanol? For instance in my sbc 406 about 4.75/1 is as lean as i have tried. I still get quite a bit of oil dilution, so i assume I am still pretty rich, but I am afraid to go much leaner for fear of burning a hole in a piston. does anyone know if I can go, say 5/1 or maybe a little more 5.25/1 and still be safe, and maybe solve some of the dilution or at least cut back on it some.

I don't really know about a/f ratios, but, if it were mine. I'd tune it to run the best and quit worrying about it...

4.75/1 was its best E.T. and speed to date, and I would like to try it leaner, but I am worried about burning my engine down. However, I still appreciate your input, thanks.

Where did you get these #'s from?, you need to run an EGT and keep the #'s around 1100 degrees on topend. if you go leaner than that you will burn something down.

JMO

Zip.

Don't be afraid to lean it out. You'd have to go really, REALLY lean to hurt it unless you're running nitrous or some sort of forced induction with a lot of boost....

Another thought, if you're injected, the oil delution could be the barrel valve adjustment, or running the engine too cold w/carb or injection...

Like ZIP said you need an EGT.

Where can I get an EGT?

Also here for duel setup $300.00

Zip.

http://www.exhaustgas.com/ProductDet...ID=sub2&RepID=

I'm sure MANY will disagree with this statement, but egt's aren't of much use until you know what your combo likes. Probe location, tube diameter & length, port design etc will effect the egt numbers. No one can say " x degrees is perfect". Once you tune your combo for max performance, whatever egt you have then is yours. Until then, the numbers don't mean much....JMO

EXACTLY!!!!!! EGT's are just a reference point and NO two vehicles or Combo's will be the same. Tune for max Performance and see where the EGT's are.

I was a Diehard EGT man, gave the O2 a shot and love it! The EGT will read different from header to header and the O2 stays the same.

5/1 AFR is still on the fat side. FWIW mine likes 5.6/1 on Motor and 5.9/1 when i spray it. When I spray I enrich with Race Gas though.
Your best tool of all is you Plugs, reading them will tell you exactly where your at.
.........................Tyster