I was part of the fmax groupbuy and should be getting the kit pretty soon. I also just ordered a 3" carsound cat and 3" thermal exhaust from Ben. Does anyone know how big the downpipe is that comes with the fmax kit? Their website says it will mate up with the factory cat, so what kind of modifications will be needed to hook the downpipe up to the 3" cat

 

dunno how to answer your question...but where did u get the carsound cat?

 

did you buy your cat with flanges welded on already? if so, it'll be too large. the fmax kit for an integra comes with a puny 2" downpipe with flanges so that it can bolt up to the stock cat.

Just take everything to a muffler shop and have them weld it together for $10

Tom

 

I got it from Ben at importparts

 

Does the 2" downpipe hurt performace a lot? If I remember correctly, the larger size is more important further down the line, and having a larger downpipe isn't as important. Is this correct?

 

how much boost do you plan to run? usually if you are running less than 10 pounds a 2-2.5 inch dp should be good enough...

 

Yes it does. Im only running 7.35psi and I gained 10whp and 10ft/lbs on a 104deg. day by upgrading my downpipe from 2.5-3". My final numbers were 277whp 200ft/lbs.

art

 

i believe its a 2.5" downpipe. Although to connect to the stock honda cat they have to downsize it to 2.25" (cuz the honda cat is lame small).

So all ya do is cut off the end of the f-max downpipe, and connect that to your 3" cat and 3" cat back. it will be perfect.

Most people like 2.5" downpipe to a 3" exhaust.

liam

 

Actually fmax does come with either a 2.25" or 2", but I know its not 2.5".

art

 

from the picture..it looks like the piping doesnt change size...so most likely its 2.25". My bad.



liam

 

i had mine made to 2.25" it is normally 2" which is what the stock cat is.
a good stainless exhaust guy made a ball joint swivel flared to 3" to go to my carsound/thermal exhaust. it then bolts with a standard 2 bolt flange to my fmax dp.