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Saturday Night Racer >> RACE TECH >> excessive exhuast temp
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Message started by Prostock5j on 04/19/09 at 2:24am

Title: excessive exhuast temp
Post by Prostock5j on 04/19/09 at 2:24am

would a cam that is running at its max rpm range cause excessive exhuast heat muffler was glowing red after 8 lap heat race? Thanks for any input need all the help i can get on this one

Title: Re: excessive exhuast temp
Post by lm26p on 04/19/09 at 8:04am

sounds like a lean condition,do a plug reading.

Title: Re: excessive exhuast temp
Post by Prostock5j on 04/19/09 at 11:37am

we are definately on the rich side with fuel thats why i was asking about the cam being to small for the engine. the engine stops pulling about half way down the stright away

Title: Re: excessive exhuast temp
Post by Andrew on 04/19/09 at 11:42am

Timing can cause exhaust heat too. Too far advanced, I think, will make headers and mufflers glow red.

Title: Re: excessive exhuast temp
Post by Prostock5j on 04/19/09 at 1:04pm

we are at 32 degrees on timing

Title: Re: excessive exhuast temp
Post by hogracer3d on 04/22/09 at 6:58am

Contrary to popular belief, glowing red headers are generally caused from a rich condition, not a lean one.

Look for a plugged air bleed, all it takes is a piece of lint in either the high or low speed air bleed.

one side or both, high or low speed?

Title: Re: excessive exhuast temp
Post by dirtfan21 on 04/22/09 at 10:55am

i agree, unburned fuel is usually the cause of a glowing exaust

Title: Re: excessive exhuast temp
Post by sj_valley_dave on 04/22/09 at 12:53pm

Absolutely agree with the too rich condition....if you have a lean problem, you'll lose pistons before you'll get the headers to glow...LOL!

Title: Re: excessive exhuast temp
Post by Prostock5j on 04/22/09 at 3:41pm

The high temp was at high speed the exhuast crosses over into 1 muffler running the hugh howe muffler and exhuast system. Thank you to all who replyed i also contacted jr motorsports their thoughts were way to rich running 74 jets at 4200 ft elevation was too much fuel and they suggested to bump timing from 32 to 36. Thanks again to all

Title: Re: excessive exhuast temp
Post by sj_valley_dave on 04/22/09 at 4:30pm

Are you running a 4412? We rana similiar exhaust, 3 1/2" collector into 3" pipe into a 4" Y and a $' in and out muffler. Most of the time at an adjusted altitude between 500-1500 fett we had 72's in it. As the adjusted altitude went up we would go down to 70's or even 69's. When we went tp Pahrump with the 4 bbl, we went down 2 sizes front and rear and that was from being very close down in the San Joaquin valley. Unless you have a "Fast Burn" head, 32* is not enough timing . go with the recommended 35-36*

Title: Re: excessive exhuast temp
Post by Prostock5j on 04/22/09 at 11:33pm

Yes running a 4412. Heads are oem with a little port work more of a clean up than enlarging anything. This si my first year racing up here so trying to be on the careful side with the engine. I was also told to go down slow with the jets taking several plug checks but not to be surprised if i end up around 68 on the jets. By the way bottom end is a 383 oem parts nothing fancy with this engine trying to work in the car then add the horsepower