who's tried the fat cat pipe?

mechanickid · #1 (**permalink**) 10-07-2009, 12:21 AM

I was wondering if anyone has tried this expansion pipe and what they're experience with it was?

thanks

Fat Cat Chrome Expansion Chamber - $49.99

azbill · #2 (**permalink**) 10-07-2009, 12:43 AM

that is the grubee expansion chamber that spookytooth, and a few others sell as well

bairdco · #3 (**permalink**) 10-07-2009, 12:45 AM

i think everyone who's said they've gone over 40mph with a stock kit has tried the "fat cat pipe."

mechanickid · #4 (**permalink**) 10-07-2009, 12:48 AM

does it produce a power band like a dirt bike has? thats what im trying to achieve. it seems the sbp pipe is differently set up, i know nothing about these things but i know its important how long the thing is.

Foximus · #5 (**permalink**) 10-07-2009, 01:20 AM

That thing will produce an incredibly peaky and narrow powerband, obviously designed by someone who doesnt know 2 stroke theory very well. Dont bother. Your much better off with the SBC ones.

xlite · #6 (**permalink**) 10-08-2009, 10:58 AM

Quote:

Originally Posted by Foximus

That thing will produce an incredibly peaky and narrow powerband, obviously designed by someone who doesnt know 2 stroke theory very well.

What is the reasoning behind that statement?

Foximus · #7 (**permalink**) 10-08-2009, 01:14 PM

1) the chamber is tiny
2) there is basically no headpipe
3)the baffle cone is not steep enough
4)The baffle cone ends in an abrubt wall, then goes to the stinger
5)there is basically no stinger.

freewheeling frank · #8 (**permalink**) 10-08-2009, 01:20 PM

it doesnt clear the front tire on either of my 2 strokes

xlite · #9 (**permalink**) 10-09-2009, 06:06 AM

Quote:

Originally Posted by Foximus

1) the chamber is tiny
2) there is basically no headpipe
3)the baffle cone is not steep enough
4)The baffle cone ends in an abrubt wall, then goes to the stinger
5)there is basically no stinger.

Thanks Foxie. I'm pondering modifying pocket pipes/scratch build vs hitting up SBP again. Your list pretty much sums up the Big Picture. A couple of these occurred to me when I saw the photo.

I'm also wondering how much the smooth curves effect performance vs a simple can which would be easier to construct.

Foximus · #10 (**permalink**) 10-09-2009, 10:20 AM

curves and turns effect the pipe in absolutely no way. You can have three 180 degree bends in a row, and as long as your not actually crimping the pipe to impede the flow, the sonic resonance will happily follow the path. You can even have angled bends, that go in 20* segments or whatever.

Important things are keeping the cones and chambers cylindrical, and not flattened or ovaled in any way. Thats far more importatnt than placing bends in the pipe.

edit...

if your going to try to make your own pipe, the one piece that is absolutely critical is to make sure you have a straight, clean and smooth entry from the head pipe (which idealy should have a 2-3* taper of its own) into the diffuser cone. So when you weld the head pipe to the diffuser cone, go back with a die grinder and smooth the joint on the inside, make sure its all flush.