Average muffler temperature?


#1

Hey everyone,



Just wondering if anyone can tell me what the average running temperature of an average muffler is? I’m guessing there would be fluctuations but a max at some point?



Just curious…



Thanks,

Jad


#2

Hot but less hot than a catalytic converter.

Why do you ask?


#3

Airplanes often have exhaust temperature gauges to help the pilot set the fuel/air mix. 1250 to 1400 degrees F is typical. It probably cools off a bit before it reaches the muffler though.


#4

I’m planning a little exhaust project, replacing mufflers and will need to put in a 45 degree angle pipe to the new mufflers and on top of the pipe clamps, wanted to seal the connections with QuikSteel…it has a heat rating of up to 260 C (500 F). Want to make sure it won’t melt off…

I always thought by the time the gases hit the muffler they are much cooler?


#5

Is the 1250-1400 for a car or airplanes? I’m only concerned with car mufflers here.


#6

If the muffler is at the back of the car, I think you’ll have no problem with the 500*F temperature rating.


#7

It’s for gasoline burning piston four-stroke engines. It’s probably the same for piston four-stroke gasoline engines used in cars, boats, tractors, generators, and even airplanes.
It’s the temperature coming right out of exhuat port. It probably cools a bit before it reaches the muffler.


#8

I believe the sensors for those systems are right in the exhaust manifolds. The temp goes down quickly as the gases move downstream.


#9

Yes they are almost at the rear bumper…thanks NYBo!


#10

My guess is that 500F will be OK at the muffler, the exhaust gas temperature at the engine is probably closer to 1000F but it will cool of pretty quickly. If you put your hand behind the tail pipe, it is no where near that hot.


#11

260 C (500F) is pretty darn hot - I don’t think you’ll get that kind of temp at the muffler - the cat converter may get that hot, but that is not all from the exaust temp - it’s the catalytic reaction heat. I would be more concerned about it cracking under the mechanical stress of trying to hold an exaust pipe (flexing and vibration). Is QuickSteel indended for structural use? How much elasticity does it have?


#12

Good point Craig…I guess that would be bad if it did get that hot all the way back there.


#13

Vogel, I’ll be using clamps to hopefully take most of the stress…here’s a QuikSteel website for some info:

http://www.dual-star.com/index2/Service/quiksteel_epoxy_putty.htm

Here are some excerpts, doesn’t really talk about elasticity, but it does talk about strength and hardness:

"STRONG: There are two ways strength is measured. One is on the horizontal plane – this is called “shear strength” – and the other is on the vertical plane and is called “tensile strength.”

Shear strength – When cured (one-hour drying time) QUIKSTEEL has a shear strength of 740 pounds per square inch. This means that when two pieces of material are bonded together with a one-inch bond of QUIKSTEEL, it would take a pressure greater than 740 pounds to break the bond. That would be the equivalent to the weight of four to five strong men. For comparison, pine lumber has a shear strength of 400 pounds per square inch. QUIKSTEEL is almost twice as strong as pine.

Tensile strength – QUIKSTEEL has as tensile strength of 6,200 pounds per square inch. This would mean that a piece of QUIKSTEEL one-inch in diameter could lift the weight of three automobiles.

HARD: QUIKSTEEL is a very hard material. Technically it is rated at D-87. “D” is the highest hardness rating in the Shore rating system. QUIKSTEEL, when cured, can be compared to ABS plastic (material used to manufacture automobiles) or the fiber epoxy wings on the B2 bomber.

When cured, QUIKSTEEL, can be processed in any way that you can process steel or wood. It can be turned on a lathe, machined, drilled, tapped, milled, sanded, sawed, routed, primed, and painted."

What do you think?


#14

Plus an airplane engine is usually running at or near WOT. Car engines usually run at fractions of full power, which doesn’t heat the exhaust up nearly as much.


#15

My experience with these kinds of epoxies is that they are very strong and hard, but to a fault. As soon as the QuickSteel encounters the inevitable vibrations of your exhaust system, it will break its bond loose from the pipe/muffler.


#16

Epoxy resins lose strength at high temperatures too. An old trick for ungluing stuff bonded with epoxy is to use a paint removing heat gun and warm up the glue joint to about 400~450 F and the glue softens and lets go.


#17

It has been a long time ago, but I have used some stuff I believe was called muffler patch or something like that. It came with a cloth like stuff to wrap around and some gunk to spread over and into the cloth. It worked for me. Of course that was back in the 60’s.


#18

The clamps should do the trick - the joint will be subject to both shear and tensile stresses - the shear stress (and tensile stress) during a vibration can peak at a very high value for a short time (similar to a voltage spike) and I would expect them to easily exceed 740 Lbs. Being a “very Hard” material I interpret as not very elastic (in ither words - brittle) - although I’m not sure. It should be fairly easy to look up D-87 and find out.

I think the use of clamps will provide you what you need - the quicksteel probably won’t make a good air seal, but I don’t think you need one - the clamps should do a good enough job of that as well.


#19

Ok thanks Vogel…I think based on your comments and others, I’ll just stick with some good clamps and see how it goes. I could always try the QuikSteel later if I ended up needing it.


#20

I used muffler patch on a cat converter rot hole once and it held up beautifully until I got a chance to put a new converter in…a few months later.

If my memory serves me correctly, cat converters need to get beyond 400 degrees F to be effective, and typically operate well above that, somewhere in the 600 F to 800 F range.