Visit The Dirt Forum for More Information

Author Topic:   Carb change differences
scanner
Dirt Roller

Total posts: 16
posted September 23, 2005 09:27 AM  
How much difference would we notice in power if we were to go from a 500cfm 2brl.4412, to a modified 2brl 4412 that was dynode at 710 cfm? We are going to a b-mod special next week that has an open 4412 rule, & was thinking about running the bigger carb, but don't know if it's worth making the change. Any opinions?

PS. We are running a stock rod 355 with a good set of double hump heads that has had quite abit of port work done to them. The motor runs pretty good with the old carb, just looking for more if they allow us to run a bigger carb. Thanks.

KPLugnut
Dirt Forum Champ
Total posts: 1019
posted September 23, 2005 07:14 PM  
Normal HP gains in that situation average about 35hp or so. Depends really who built each carb and a lot on the whole rest of the package whether or not the driver would "notice" a difference.
But if it's allowed, it'd be silly NOT to use the bigger carb.

And even the proverbial "890" 2bbls barely flow in the low 700's on the 2bbl scale, but anybody's modified 2bbl is always gonna wake up a motor noticeably over a stock dimension 4412 as long as the carb is adjusted properly.

Hope that helps,
KP

Back to the Archives