exhaust temperature in water jacketed headers
 

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

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.

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?

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

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

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?

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.

on the Dino mine had ~ 1400 farenheit each port !

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.

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

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

why?

I am working on figuring what RPM my exhaust timing and header lengths are tuned to and sizing my tail pipe diameter.

I don't know how much cooling of the exhaust gases takes place throughout the system.

I don't know if you can use automotive guidelines because of the potential for cooler exhaust gases.

It seems from the replies above that that the water jacket has little impact; but I would like to measure at the collector to be sure.

I've build a wedge/spacer installed between the collector of my EMIs and my tail pipes which I've installed my egt probes. I have 4 SS Competition sytems installed, one in each bank.

I can't tell you any results on the motors yet as they sit on the shop floor ready to drop in at this time. (waiting on flood waters to drop so I can get my boat out)

Is your wedge/spacer like a nitrous plate? but with the EGT bung?

That sounds great. Good luck with the flood, watch out for debris.
http://www.google.com/search?q=house+floating+off+japan

Any advice on brand, installation, lessons learned is greatly appreciated.

Lessons that I have learned from EGT's. I will only use EGT's as a reference tool and only with a tune from an AFR. You can run an EGT and see temps from 1200*F - 1400*F depending on the placement of probe from the piston. (my experience I have the pistons to prove it :) ) And this is on the same tune. If I do not have an AFR I just run it a little fat.
Innovate LM1 or LM2

Like a nitrous plate I made to angle the risers down to match the transom holes. I drilled and tapped them for the probes. I could email you a pic.

I have an Innovate AFR but no place to mount the sensor. My spacers are only 1/2" thick. I use it on bikes on the dyno and shove it up the tail pipe. No water in them tho... I'd like to figure it out for setting up jetting.

I really need to do a set up like this for my lightnings, where can I get a probe in on those for EGT's ? thanks Rob