Have any of you guys messed around on the dyon to see how much hp can be gained by completely removing the exhaust from the header back? Might be going to the track this weekend and was thinking of unbolting my rear section. Thanks in advance.

 

With the following mods: intake through highbeam, Comptech foam filter, JDM Honda 4-1, Chris dyno'd at:

173 WHP with stock muffler, b-pipe and test pipe
174 WHP with stock b-pipe and test pipe
176 WHP with just the test pipe.

Torque figure was unchanged. Bring earplugs if you go ahead with the last setup.

*edit*changed description*edit*


[Modified by Bob#497, 11:21 PM 10/24/2001]

 

On one of my 235 WHP all motor jobs, you could lose as much as 15 HP from a restricting cat.

And 20 WHP with a stock Type-R muffler. Even running the straight pipe..

Jeff

 

Here's another can of worms.

While Bob did see an increase I believe he did since the stock cat/exhaust is so restrictive due to the bottle necks. But I would say he could have picked up a little more with a tuned length tailpipe attached to the header. RStoR LOST 2-3whp when he went from a test pipe and full 2-1/2" exhaust to an open header.

 

It was actually my car. I had no CAT that day... It was all with the test pipe, and officially, I unhooked the B pipe from the test pipe for that last run, so it TECHNICALLY wasnt RIGHT out of the header...

 

So if I'm going from stock Cat to no cat I should expect around 6whp gain or so? If going from test pipe to no cat nets 3 whp I would expect to gain alot more having the stock cat in place.

 

Cant compare me to having a CAT...cause in all those runs I didnt have one! I would expect going from FULL STOCK exhaust to NO exhaust..maybe 8-10WHP PEAK max.