cup air box mod= 4 RWHP I did the dyno work 2 years ago with Geoffery on Dyno Pac dyno.
bob

 

Bob

Could you please provide a few more details of the test. What was the spec of the car? Did it have any DME mods etc.

I have always suspected that to get the maximum benefit from breathing mods you need to do both sides of the equation and that it is one of those occasions that 2+2 equals more than 4.

 

Simon, M64-01 engine, euro rs DME, stock headers, Fabspeed euro pre muffler, secondary and primary bypasses.
no other mods. Bob

 

I have a drilled airbox but, inspired by this thread, I have now cut the whole thing out. I'm pleased to confirm that the car sounds great. In fact, identically great to how it did before. Thought it would be useful to share this!

 

That was the case when I did the identicle thing on a Supra, Dyno'd it after each step.

Intake gave me 6hp, cat back gave me 8hp, both gave me 17.

 

Here's the one I did for my 993. Doubtful if there is a detectable power increase, but it sure sounds nice at WOT.

 

I wonder if you would have seen the same increase if you hadn't done stuff to the exhaust side of the equation......

 

Yes, but how do you get a nice rumble at idle?

 

To get a nice rumble at idle, bypass the secondary muffler.

 

Has anyone got the cat bypass, cup pipe AND g pipe? Would it be too loud and what would the potential hp gains be?