Visit The Dirt Forum for More Information

Author Topic:   Lean or Rich?
Dirt Maniac

Total posts: 174
posted April 02, 2002 12:29 PM
OK guys, I've always understood that you want to run your engine on the lean but still safe side for maximum power. We take the weather into account and jet for that textbook tan color on the plugs at all times and have been successful, however in higher forms of racing you hear of richening the mixture for maximum power. I know there's a world of difference between a Street Stock and a CART car, but I would think the principles of internal combustion would be similar. My engines run great, but am I leaving something on the table by not running a little fatter?

Dirt Freak

Total posts: 230
posted April 02, 2002 03:03 PM
Turbos, and alky are not like what you have. Those things you hear about apply to much different injection systems than a gas carb engine has.

Dirt Maniac

Total posts: 174
posted April 02, 2002 04:59 PM
That's kind of what I thought, but when I heard or read something like that I wondered if I have been missing something. We'll continue with what's working. Thanks.

Dirt Full Roller

Total posts: 35
posted April 02, 2002 08:29 PM
in lower forms of racing (125 shifter karts on gas and modified briggs on methanol I always ran extemely rich compared to the other guys and always had alot of succes.) The plugs on my shifter always came out jet black, I will probably try this on my MW Mod also, lean makes RPM but fuel make HP just an opinion

Dirt Forum Racer

Total posts: 90
posted April 04, 2002 10:24 AM
Some of the technical books/articles that I have read/studied explained the advantages of running "heavy/rich" verse a lean mixture. Calculated numbers (dino) have shown that there is up to a 15% power loss if the engine gets to the point of being to lean. On the flip side, the tests showed you only lose up to about 5% running on the rich side. Since reading that info, I've been running all my stuff on the rich side. Cheap insurance w/horepower, especially when mid-summer hits, etc. Just my couple cents.

Dirt Full Roller

Total posts: 53
posted April 04, 2002 05:41 PM
i made my alky mod a little richer last weekend and it seemed like it didnt have the response and all that it had the week before so i changed them back for this week, when i ran alky in go karts i always ran them as lean as possible. in a 5 hosre briggs it seemed like being to rich hurt it alot.

Back to the Archives