toddk911

+1

I have 3" with no cat, Flowmaster and wg dump. Normal driving/idle is a little deeper/throaty that stock but when on revs/full boost on highway it has a throaty scream, if that makes sence.

Andial951

No I was serious......really.....in fact I copy and pasted just the beginning of what Dave from LR said to me about it.

"Andial,

I'm building a 5" exhaust because I think it will make more power and probably
sound like nothing else. We shall see. "

porshhhh951

Click the link in my sig and find a run titled me and JD or JD and porshh something to that effect. You get some great WOT behind the car shots and sounds.

If you wanna know what it sounds like rolling down the road that is.

toddk911

I am sure 5" will sound awesome, but the jury is still out on more power being made on 4" much less 5".

Comparison: 6+ L diesel trucks(20-30psi) use 4" exhaust. 18 wheelers use 5" exhaust

toddk911

"194lbs lost-last update 4/4/07 "

Dude!!!!!!! You've lost more than the avg. guy weighs!!!!!

And just in time for bikini season!!! LOL

ausgeflippt951

That new beetle is one quick mother @#$&er...oh wait too bad it's a beetle...

RogueM3

I doubt it will sound much, if any, different than the current 4" or 3" before that....

Geneqco

I think the rationale is that, whilst substantially reduced with the 4", significant exhaust backpressure is still present which they hope to eliminate with the 5".

The DareDevil

I think they should just go for broke and skip the 5" system. 6" is definitely the answer.

porshhhh951

Thanks its actually -196lbs now. muahaha

RogueM3

That is assuming there is "significant exhaust backpressure" with the 4" system. Considering the outlet of the turbos you guys are running likely isnt larger than 3", is an exhaust 2" larger than that really worthwhile?

I have seen 4" exhausts handle in excess of 1000whp in the BMW world. Here is a 4" exhaust on a 328 putting down 882whp. The car is currently making 996whp and doesnt show any negative effects of the 4" exhaust (no drop-off up top): www.bmwturbo328.com/newbuild/tunning1.wmv

I think looking at a 5" exhaust tip would be amusing, however..

Geneqco

Apparently the backpressure is something they have actually measured on the 4" exhaust. Whilst I think the point you make about turbo outlet is probably correct, some other factors would be the overall length of the exhaust, engine speed & boost, and the number and type of bends.

RKD in OKC

From a comment Dave Lindsey made...

"Even with the 4 inch we've measured back pressure from where the wastegate dump rejoins the exhaust. I would like to build a 5 inch making it bigger where the wategate dump joins to see if it makes any more power."

From that comment the 5 inch idea is not that the 4 inch is not big enough for the turbo outliet, it's about the wastegate line re-joining the exhuast.

Also, they already have 5 inch tips for after the muffler.

The DareDevil

Oh... You weren't joking

BlacknRedGT

I have a sound clip of the 4 inch exhaust with 3 inch downpipe on google.. Once dan (sharky47) is done I will take some clips of my car actually moving.