artic cat 600efi mountain cat - Snowmobile Forum: Your #1 Snowmobile Forum

dkotschevar · 11-23-2004, 11:49 AM

I bought this sled 3 years ago for my son. He has now grown quite a bit and I would like to add some more power to it. A friend told me to cut open the exhaust can, gut it and weld it back together. So I did, now another friend tells me if I run hard the machine won't have any backpressure and it will burn up my engine. So anybody out there have any advice before we run this sled.

dano · 11-23-2004, 12:37 PM

well, the concept behind what you did was to decrease the back presure in order to increase peak horse power. as you may know 2-strokes NEED back pressure or the internal temp will get too high and the engine will burn up. When you buy aftermarket pipes they are testes for the specific sled so the back pressure is decreased but not to the point of hurting the engine (for the most part). I wont do this to my new sled untill the warranty runs out because if i burn the engine the factory may say that the burn down was caused by the aftermarket pipe and thus no warranty.

Now for the most part, aftermarket pipes are great. they save weight and increase horsepower (awesome for the mountains) But i am not sure about gutting a pipe yourself. My mind says that it is the same as a aftermarket pipe but i wonder to what extent. my concern is you may have decreased the back pressure too much. To be safe i would double check with a dealer but i would just buy an aftermarket pipe for that sled. then there is no question.

anyone else have a better idea? just my thoughts

BC_Dan · 11-23-2004, 03:07 PM

The can mostly silences the engine, most of the back pressure that is needed by the 2-stroke comes from the shape of the pipe and the location of the restricted area.

You may get better performance benefits by making sure your clutches are clean and adjusted than by gutting the can.. plus, overly loud sleds are not very well received by others...

**smallengineguy** · 11-23-2004, 05:33 PM

Quote:

Originally posted by dano
When you buy aftermarket pipes they are testes for the specific sled so the back pressure is decreased but not to the point of hurting the engine (for the most part).

Um...testes?? Dano, do you know something the rest of us don't???

Sled engines are specifically designed to work with the exhausts that are bolted to them or a similar aftermarket design, not a gutted pipe. Your performance will suffer in the long run, and you can indeed burn the pistons....

**Administrator** · 11-23-2004, 06:22 PM

I agree with SmallEngineGuy and Dano (except for the conceptual "testes" upgrade... which I have not heard about). I'd definately go ask a dealer about the specifics of gutting the silencer.... I wouldn't do it to my 600. Burning up an engine is too much risk for only a few horsepower increase.

Maybe you should look into buying an aftermarket pipe and silencer.

dano · 11-23-2004, 06:39 PM

Quote:

Originally posted by smallengineguy
Um...testes?? Dano, do you know something the rest of us don't??? Sled engines are specifically designed to work with the exhausts that are bolted to them or a similar aftermarket design, not a gutted pipe. Your performance will suffer in the long run, and you can indeed burn the pistons....

LOL!!! i just read my own mesage. I meant to say tested

silly dano. i thought he was talking about the pipe. the can is another story, i would be less worried about the can than the actuall pipe or testes as i so affectionally called them

i could have edited that post but its to funny to get rid of.

need an f9 · 11-23-2004, 08:33 PM

[quote]Originally posted by dano
[b]
testes

HAHAHAHA, I wondered if anyone else was going to catch that

**smallengineguy** · 11-24-2004, 02:50 PM

Who said your sled doesn't have balls now!!!!