I pulled up this great article on "KFX/Z-400 Exhaust Shootout" from Dirt Wheels March 2003 - http://www.ctracing.com/ltz400%20pip...t%20mag%20.htm

I am deciding between the HMF and the CT pipes. The HMF cranks out .7HP more at 4000rpms and the CT is .8HP more at peak rpm. The HMF package (pipe, header, jet and filter) is about a little less than $100 than the CT package - I've done my own research. My question is: are these "minute" differences actually felt on the bike? I'm a newbie, will it make much of a difference? Thanks for you opinions.

 

What you need to look at is the TOTAL area under the curve in the graph of HP vs. RPM if you can get one from the pipe manufacturer, not just the peak maximum HP number unless you are running your quad at WOT all the time.

 

Hayashi makes a great point. You want the pipes that make the most power through out the entire powerband. Not just the one with the highest peak. Dont let the peak HP be your selling point.

 

here's the link to the dyno testings. what can you make out of it?
http://www.ctracing.com/z400-pipe-shootout-4.jpg

 

I would go with the HMF after looking at the charts. I think it has a pretty good gain throughout the entire powerband. My bro has a set of HMFs and they are a quality product and sound sweet. I am no expert so that is just my opinion.

 

Go with the HMF. Looks like the only deciding factor between the 2 setups is price. Unless you count the fact that the CT needs a smaller jet size which helps on fuel comsumption.
I seriously doubt you will tell the .7 or .8 hp difference. If you think you will then lose 5-10lbs and that should even it out.

 

$449 for complete exhaust system, jet kit and a foam filter at ebay. http://cgi.ebay.com/ebaymotors/ws/eB...5868499&rd=1,1
I'd call that a good deal. Thanks guys. It looks like it's going to be the HMF pipe. Luv the color too.