d1mbu1b

Can anyone tell me the nominal temperature or temperature gradient of the exhaust gases at both ends of a water jacketed header on a naturally aspirated gas engine.

Also, please let me know any contributing factors to the exhaust temperature.

any info or pointers are appreciated.
thanks in advance

MILD THUNDER

iTrader: (3)

The water jackets are there not to cool the exhaust gas, but to cool the outer pipes, so they dont get hot like a car does. High exhaust temps can be from a lean fuel mixture, or retarded timing.

d1mbu1b

Thank you.
Ignition timing or vavle timing?

I am trying to get a rough order on the actual measured temperatures.
I just have no idea what practical exhaust temperatures are and figured the water jacket may be influencing the temperature at the collector and slowing down the slugs and the pulses.
Basically, for argument sake, if a normal auto exhaust is 700 degrees C at the collector would a water jacketed exhaust be closer to 500 or 700?

kubelwagonman

you should be able to lay your hands on the manifold without getting burned.....

tcelano

I think the question is what an egt probe will read. How much lower should an egt measured just after the collector on a CMI header vs an automotive header.

Also, how much heat would be lost between reading an egt right in the runner vs after the collector? Thanks

d1mbu1b

Exactly, thank you.
How and where do you install an EGT sensor on a jacketed header?
Is there a way you can snake a probe up the exhaust to measure?

PatriYacht

I don't think it would be any cooler than car exhaust. You are running under higher loads and throttle openings in a boat. That would more than make up for any cooling from the manifold.

Rockfish71

I'm running a egt right at the head #7 cylinder I have it tuned to see 700-725 @ idle cruising about 850-950 wot 1350- 1400 @ wot is about 12.5 afr That was how i did a close tune. I did a safe tune on it 2 years ago . I will be tuning with the dual channel lm2 meter this year tuning by a temp will prevent melt downs it is the closest to afr reading for a safe tune.

d1mbu1b

Thank you. Do you have any advise on purchasing or installing the EGT sender?

RunninHotRacing163.1

1400 degree EGTs seems to be the norm and a shot of meth brings her down to 1200 degrees