What should the ideal exhiast temp be on a carbed SBC?

BamaZ28
07-24-2004, 05:12 PM
I have a variant exhaust temps from 140-350* on my newly built SBC (carbed)

Just wondering what the IDEAL tempp should be.........thanks

BamaZ28

Mindgame
07-24-2004, 05:58 PM
There is no ideal exhaust temp per se. Take 10 engines in optimum tune and you'll find 10 different avg. exhaust gas temperatures. Just depends on compression ratio and alot of other factors.

Your variance in temps. Which intake manifold are you using and list the cylinders and temps.

Thanks.

-Mindgame

BamaZ28
07-24-2004, 09:10 PM
I am using the Performer RPM intake with new Dart Pro-1's 2.05/1.6

They were using one of those pyrometer's with a laser beam and it was showing 350* and less, I can't get the individual number til Monday.

The pistons should be about 9:1 with my 64cc heads

Injuneer
07-25-2004, 11:03 AM
It appears all you are doing is measuring the individual header primary tube metal temperatures at idle? Not sure that is going to tell you much of anything, unless you are looking for cylinders that aren't firing. When people talk about EGT's, generally they are looking at WOT/max load numbers, not idle. The IR non-contact sensors are susceptible to variations in the emissivity of the particular spot you happened to focus on, and have limited value in that respect as well.

BamaZ28
07-25-2004, 02:29 PM
hmmm, maybe that is why he said they should be ~220*, do you think that sounds right for a mild 350 at idle-2500

Yes, this would also let us know which cylinders are firing........

Mindgame
07-25-2004, 03:43 PM
I thought you were talking EGT's. I'm with Fred in that I don't know if a non-contact temp is going to help you much at all.

Generally speaking, a temp variation of 200ºF is not out of the ordinary with a carb setup. With EGT's you can spot air/fuel distribution problems easily and work towards improving the condition. In that respect, EGT's provide valuable data. I don't think you're too interested in improving distribution (manifold modifications) so I'd just work the tuning.... timing, jetting, etc.. Best to do this at the track.

Good luck.

-Mindgame

BamaZ28
07-25-2004, 06:22 PM
Yes, but I am having a sever missing problem, that I have yet to figure out. I have tried everything, they are resetting the rockers and hopefully that fixes the problem.

97WS6SCharged
07-30-2004, 02:54 AM
I always thought idle EGTs should be around 1000* F. At cruise, my 97 is running about 1300* and around 1200* at WOT. Yeah, it's rich. :)

1racerdude
07-30-2004, 08:32 PM
1300-1400* is about normal at WOT,depending on what risk's you want to take.Lean is mean (to a point).Measuring EGT at idle tells you nothing.You can pull the plug wire's one at a time to see which ones are missing.I would check valve adj,after ckecking the plugs.(plug may not tell you much)Are the plug wires and opti OK?