Looking for what the exhaust gas temp should be at for my 2002 mxzx 440? I am running a Avenger 2.

Skidoo's race book claims detonation occurs at about 1330 deg. with the probes placed 100mm from the piston skirt. 1250 deg. SHOULD be safe, but depends on the placement accuracy of probes. You really should calibrate YOUR sled by also using plug readings and piston wash. EGT's are NOT the tell tail.

My experience.

Pete, I concur. :)

Many people have taken the time to "Study" piston wash on different days.
It is simple to take a bendalite with you to read the piston. I'll mention from lots of experience and experiences from other sled owners that on days you ride where one day the temperature is cold, the wash will be different, on days where the temp is warm, the wash will be slightly different than previous examination...

...But the most difference you will see is where you drive your sled and how you drive it. You may be jetted fat to run across a lake and will show lots of wash having a clean piston top to even seeing the machine marks on top and the numbers, but with say that same main jet and you are running 90% of your day with 1/2 throttle to 3/4 throttle going midrange speeds, if your jetting is slightly lean, you will start to cover the piston with carbon and show beauty wash.
Most of the top of the piston will get covered in carbon but the areas at the intake port openings will show the carbon is washed-away and you get those little thumbnail or fingernail sizes areas where there is no carbon.

Now you gage your EGT's to this wash that you will be happy with. The thing is that one person's probe will show 1200 and another person's probe will show 1300....
...Who's temperature do you believe? Or better yet, whose temperature are you NOT afraid of??

Here is a page out of my 440 & 800 clutch kit manual. I get many people asking the same question about egt's, so I supplied this page in the manual.


EGT Comments:

One should be wary of exhaust gauge temperatures...
Clutching a sled to make it shift hard, working the engine to make the combustion chamber heat go up...this requires altering jetting to agree with the demand needed and power to match the need.

Setting up clutching with higher engagements and/or shallow cams allow the engine to flash to peak rpms requires less work from the engine because the torque load isn't as high.
The heat will not build quickly inside the combustion chamber.
Gauges will be slow to react than what you may hope for.
However, your ignition retard is "quicker than clutching" taking heat away from the chamber...or rather not allowing it to build as quickly. What would your exh temp gauge tell you?


Quoting Freddie Klies "SUPERTUNER" www.easterncycleperf.com
Advancing or retarding ignition-timing moves around whatever heat your engine is capable of making.
An engine is a heat pump. If you run advanced ignition timing you put heat in the combustion chamber where it is needed to make power.
Retarding the timing puts the heat out in the pipe.* Think of an exaggerated relative position of the piston and crank orientation between what you think of advance and retard timing.* Think of where the spark fires the fuel.
This is why you could see EGT's go up on a dyno and power go down.
Some engine tuners rarely use EGT for tuning and would rather check piston wash.
The advanced ignition timing that most race engines responds to, put the heat in the chamber where it needs to be but by the time it gets to the EGT probe in the pipe it has already begun to cool.* On a dyno, most people think something is wrong on the dyno when 900 degrees is the peak exh temp, yet the power is up.

You want EGT of > 1100 degrees? Retard your timing, but be happy with the loss of power.
You want EGT of < 1100 degrees? Advance your timing, and watch the piston wash.


Your results may not match theories.
Gain an experience and learn to read the piston...then EGT gauge; Then gage your piston wash to the EGT gauge.
Believe in the exercise you just performed. You can always know the theory but when you now have an experience, you can make a quality decision on what jet to use for piston wash you want...EGT you want.

DJ,

An in-depth description as always. :)

Elevation also has a lot to do with the "Correct" wash, temp, plug color ect... as well as atmospheric conditions.

This is kinda like the circle track racing I used to do.

Everytime out was a different experience due to the changing track and atmospheric conditions. Always looking for that "ultimate" set-up.

It&#39;s never ending...