BTW - I have only a 2.6 " downpipe on my car - IMHO 3" is not required in the down pipe unless you are trying to make 2 or 3 extra whp

 

Nope, Dave uses slip fit connections instead of flanged connections. You could get a muffler shop that is good with SS weld on a flang for you though.

Keith

 

per dave in the 1st post: The downpipe uses a 3/8" 304 laser cut stainless steel flange on each end.

I interpret this to mean YES. He also mentions that it allows you to use the stock cat.

 

On the 2.5" downpipe you are correct....but Jason8 asked about the 3" system.

Keith

 

Right, I want to know about the 3'. :-)

Jason

 

The 3" buschur downpipe is not designed for the stock cat. I talked to David himself, and it's designed to work with his catback and not stand alone. It is designed for the buschur test pipe or high flow cat, and that's it.

 

That's right, our 3" downpipe has no flange on the back, it is designed to slip fit into a 3" highflow cat or offroad pipe.

David Buschur
www.buschurracing.com

 

size on stock downpipe ,anyone? i got 2.5 ultimate racing downpipe and it seems like there is not much difference in size between thoese two... i should ve gone with 3''

 

Wow, this is an old topic brought back. Our 3" downpipe does have a flange on both ends now, as a side note.

The stock downpipe is closer to 2.25" than 2.5" The 2.5" downpipe you have will do you just fine up to about 400 whp. The 3" will make more power though all over the powerband.

David Buschur
www.buschurracing.com

 

i wish someone got dyno results on 2.5'' and 3'' turbo back

anyone willing to do those comparison test ?

i just cant believe 2.5''could handle up tp 400whp

 

David dyno'd the 2.5" vs 3" in one of his development threads. There is a slight power gain with the 3" but nothing you can really feel imo with your butt dyno. Also someone mentioned HKS said 2.5" is good to 400hp. You might want to contact HKS if you want to check.

 

dynoflash suggest to go with 3'' all the way even at 350whp
i dont know whos right

 

I suggest using the 3" too. We do make a 2.5" for those people that want it. The power difference on a 320 whp EVO was small going from 2.5" to 3" but was there.

David Buschur
www.buschurracing.com

 

thnakz david! but i ll just stay with 2.5'' unless 3''outlet o2 housingis available ,

 

Just to re-clarify. ALL of our EVO downpipes are flanged at both ends and will work with any other manufacturers offroad pipe/cats.

We are now porting the stock 02 housings and while 3" is not really feasible to port them to we are getting them up to about 2-3/4". This does nothing without the approriate downpipe flange which we have also developed. This is a fairly hard core swap as there is no gasket between the two and the factory lip on the 02 housing is eliminated. Power increase, yes, slight leak at the connection, yes.

David Buschur
www.buschurracing.com