how hot should my exhaust be???

[Augustus]

I am runing a 302 Q-jet'd motor with Duff's ceramic coated headers and dually exhaust.

How hot should the exhaust pipes be?

I noticed on it's maiden voyage to work this morning that the pipe after the mufflers is blue-ing.

Am I running hot?

 

[yellowbilly]

Is it chrome?

I wouldn't worry too much about it. As long as you are where you need to be in coolant temperature you should be ok. Look at your headers, if there seems to be 1 or a few cylinders that are getting hotter than the rest you may have a problem. The reason being that if only one or two cylinders are getting hot in may not have a significant inpact on the over all cooling and cause a problem. Listen for pinging, that is the best way to detect any heat issues in cylinders.

To answer your question...beats the pi$$ out of me ;D

If you are really concerned go out and by one of those cool little laser spotted, infared temp sensors. You just put the laser dot on the object and it tells you the temp. Again you are looking for temp variences between cylinders.

Sorry for being long winded...again :-

 

[Skuzzlebutt]

I don't know too! Normaly bluing that far down the line would indicate something wrong but with ceramic coatings, all that heat has to go somewhere. How much hotter should the pipes get? Who knows.
Make sure your timing is not too far advanced, or retarded. Make sure your cooling system's working right. And then... have your exhaust sniffed to make sure you're not running too lean. Then forget about it. It's probably nothing.

 

[Lttrbox]

I watched some show this weekend where they were dynoing an engine. I happen to see the computer monitor and exhaust temps. The temp numbers I saw were around 1000F. This was just after the head. This temperature will drop very quickly as it progresses down the header tubes. Further down, I have no idea.

 

[carnage351]

On my 85 Bronco with a 351 and single exhaust, It would get hot enough to boil snow at the exhaust tip. It is the only vehicle that I have ever seen do this. I always thought it was due to the restrictive single exhaust.

The truck made it to 170 thousand before I rebuilt the motor.

whether your truck is running to hot or something, I can't say. You may have something restricting the exhaust flow causing the heat to build up. Maybe to tight of turn in the pipe. Something to concider.

 

[76Broncofromhell]

Do you have an Air-Pump on your engine? You know the air mixing in with the hot exhaust gasses causes them to get even hotter, it's like a blow torch. The thermactor pump is the main cause of warping on exhaust manifolds and headers because of the heat. To give you an answer, my pipes are almost to the touching point ( about 225 degrees and I have no air-pump) and from what I remember steel goes yellow, brown, purple, blue when it tempers. Yellow starts at about 300-something and blue is 600ish. These are all from memory in high school metal shop so my numbers could be off. I would say as long as pipes are warping under the heat, don't worry about it.

 

[EricLar80]

I know that if you run your engine without enough timing (too retarded), then you will not be burning all the fuel and it will burn up in the pipes instead and cause higher exhaust temps. But for the most part, that will happen in the headers and make them run EXTREMELY hot. First time I started an engine one time this happened and it was melting wires from about 10 inches away, and you could feel the heat just by standing there, and that was basically right after I started it up. I couldn't imagine what it would be like while driving. I advanced the ignition to about 10 degrees base (yeah, it started on 0 degrees), and it was perfect after.
-Eric

 

[sheneeda]

Check your plugs . They are good at telling you if too fat or lean. ;D ;D

If your running too lean those cylinders will heat up good.