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Pipe Differences

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Does anyone know what the actual differences are between the Fatty and Gnarly pipes? Measurements... ?

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You didn't ask for a specific bike, so the general answer is that the Fatty is a higher rpm pipe than the Gnarly, which is designed to build power sooner for off-road apps, and is also made of a heavier gauge of steel to make it tougher against denting. Generally, the Fatty will be shorter (both overall and at each of the four major measurement points) and have a larger mid section than the Gnarly, which will be longer and slightly slimmer through the center.

Some classic material from the late Gordon Jennings:

www.bridgestonemotorcycle.com/documents/do_you_really6.pdf

http://www.chuckbunnell.com/kart/jennings/jennings.html

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You didn't ask for a specific bike, so the general answer is that the Fatty is a higher rpm pipe than the Gnarly, which is designed to build power sooner for off-road apps, and is also made of a heavier gauge of steel to make it tougher against denting. Generally, the Fatty will be shorter (both overall and at each of the four major measurement points) and have a larger mid section than the Gnarly, which will be longer and slightly slimmer through the center.

I'm sorry, thought I did, but obviously hadn't... Its for a '98 cr250r.

I'm planning on buying a Gnarly, hoping to find a used one, would hate to buy a new one and not like it.

Just started wondering... You can buy pipe spacers to add more low end torque, which made me assume that the gnarly was longer (like you mentioned), but not sure how much longer. Or, what the other differences are. I would assume that the gnarly will probably have a smaller diameter end? (heh is that the stinger?)

I have some extra Fatty's, that I can play around with... would just be nice to know the measurements of the Gnarly (IF) I do play around with the Fatty's. I wouldn't bother to change the mid-section (don't want to put that much time into it), but it would be relatively fast to change the exit diameter or length, and the same on the front section...

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Your assumption on stinger diameter is reversed, but stinger diameter has a lot less to do with power range bias than other aspects of the pipe. Read Jennings on this. Also, simply changing the overall length of the pipe at any single point will yield less than optimal results, as virtually every element of the pipe's geometry will change with any adjustment to the targeted range. Again, read the linked info.

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Holy crap this stuff is cool..just what I was looking for. thanks gray racer:thumbsup:

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