Nixon1

Ok, I've been debating this forever now, and can't find a clear-cut answer. I keep hearing from V8 buildups that peak horsepower numbers were increased when the fuel mixture was richened. But then I read in other magazines...mostly forced induction stuff....that peak power was boosted when the mixture was leaned out.

So which makes the most PEAK, not broad horsepower....rich, or lean? I've got a dyno run coming up soon and I want to come as close as possible to my current goal of 280, so I need to know!

Thanks.

dankhound

Generally speaking youll want to start out rich and then lean it out untill you hit you peak numbers. The reason you want to do it that way is because being to lean can damage your engine while being to rich will do little harm. Generally your low tech v8 will make its best power more toward the rich side than the lean side. What you were reading about was probably some newer engine that was designed to make its peak power with a lean mixture in order to reduce emmisions and increase fuel milage. That however doesnt apply to your motor so you can just ignore it.

DSmith

A Ford guy asking Chevy guys how to make power.
Thats a GOOD ONE. LOL!!!!!!!!!!!!!!!!!!!!!!!
Anyway, this is how I understand it.
Torque gets you there Horsepower keeps you there.
Add fuel to speed up, when you get to top rpm lean it out to make more power. Thats the way we did our pro mod outlaw car to run 4.5 sec. 1/8's

dimented24x7

iTrader: (2)

Ive been shooting for AFRs of high 12's around the areas of peak torque. Seems to work well. The other areas at high rpms and low rpms are set to be slightly leaner. Cant really truly verify it untill I get a WB-O2. With the stock O2 its just a ball-park estimate at best.

Nixon1

Well there's no exhaust sniffer here, and this isn't a dyno tune....just a plain dyno test. All I've got is an AFPR...so I'm just deciding whether to bump up or bump down. Stock is 40 psi with vacuum, I've always run 42 psi with vacuum. I tried 44/45 once, but it seemed to run pig rich. Stunk up real bad and started acting up...it was trying to foul the plugs.

And hey...I used to be a Chevy guy, until I got the Mustang last resort and saw what these little 302's can do. They're pretty amazing for their size. I got a buddy with a 302, .030 over...Victor heads, a cam with like .612 lift, race block etc etc and a 125 shot of nitrous, that runs 10.30's at 133 mph. Not bad eh?

Thanks for the help guys. Looks like my best bet will probably be to leave it right where it's at....about 42.