[AS4EX]

Are there any DP's on the market that are a true, full 3inch from flange to flange?

[Torgus]

No. Have to be custom made. Many taper right at the last inch or two. No real gains from full 3". Feel free to have them made.

[Velocity26]

As Torgus stated, the factory exhaust flange is smaller than 3", so any DP designed to connect the the factory exhaust (all of them) tapers before the mounting flange.

If you wanted a full 3", you could cut the DP just before it tapers and then attach your custom exhaust there. Unless you plan to run 3" all the way out of the car, I doubt that you would have any potential benefit.

[AS4EX]

Figured that. Reason I ask is because I'm considering the idea of a full, dual 3 inch exhaust. Gains may not increase substantially (or they might..I think there would) but it's hard to believe an engine making around 500whp wouldn't like the extra breathing room. Plus I also would like to do it to have something a little more.. "one-off"?, not to mention in it for the exhaust sounds as well. Maybe scare me some old ladies...

[Torgus]

Originally Posted by E90Ryan

Figured that. Reason I ask is because I'm considering the idea of a full, dual 3 inch exhaust. Gains may not increase substantially (or they might..I think there would) but it's hard to believe an engine making around 500whp wouldn't like the extra breathing room. Plus I also would like to do it to have something a little more.. "one-off"?, not to mention in it for the exhaust sounds as well. Maybe scare me some old ladies...

FWIW people run 700whp single turbos with the stock exhuast. It flows really well considering.

A dual 3" is really going to be about sound at the end of the day vs. Performance especially with stock frames.

There was a nice mandrel bent dual 3" exhuast with MagnaFlow mufflers for sale a while back. So it is possible to fit it. But as the for sale thread said it's silly loud.

As said above if you want 3" you would be best cutting off before the taper and then connect it to whatever exhuast you want and or make vs having full 3" downpipes made. You would be wasting money.

[08njSTEP]

Dual 3" exhaust is LOUD!!!! Have it on my Chevelle and it always causes issues. Even when I tell people it's loud, they still aren't prepared.

[TrollToll]

If I was going to drop that kind of money, I would do a 3 inch single instead of duals. Have you seen the thread by ucsbwsr? Search for it. That thing sounds amazing.

[autoart]

Look at this video, it makes me think a 3in exhaust would help in high hp cars.
https://search.yahoo.com/yhs/search?...&hsimp=yhs-002

[vitan]

Like to see on stage 2+ and stage 3 turbos...

[Velocity26]

The famous HPF exhaust was a single 3.5" pipe that split into 2 pipes at the rear bumper. It was damn loud too.

[BSM n54iS]

Originally Posted by E90Ryan

Maybe scare me some old ladies...

I just go to the old folks home and flash them ~1 a month to get that outta my system

[Sered]

Originally Posted by Velocity26

The famous HPF exhaust was a single 3.5" pipe that split into 2 pipes at the rear bumper. It was damn loud too.

To be fair, it used a small resonator as a muffler, and that was it. My 4" single isn't as loud as the HPF 3.5" was (though being ST makes it quieter too)

[Tiago@VRSF]

We have guys running 850whp with our 3" downpipes and our single 3.5" exhaust.

A dual 3" exhaust will be significantly heavier, more expensive without any benefits over a single 3.5".

[Torgus]

Originally Posted by Tiago@VRSF

We have guys running 850whp with our 3" downpipes and our single 3.5" exhaust.

A dual 3" exhaust will be significantly heavier, more expensive without any benefits over a single 3.5".

Is the new version of the 3.5 available yet?

[Island Road]

Originally Posted by E90Ryan

Are there any DP's on the market that are a true, full 3inch from flange to flange?

We had a custom 3.5" exhaust made for our wagon. The tapered flanges were cut off and vbands added . It can be loud but sounds a lot better then HPF and more refined for sure. There is also a straight pipe option we added when we wanted to go louder remove the muffler (less than 10min swap). Sounds amazing but its typically not for every day if your running straight pipe.

[Tiago@VRSF]

Originally Posted by Torgus

Is the new version of the 3.5 available yet?

The new version has been out for a while now

http://www.vr-speed.com/vrsf-3-5-str...35i-335xi.html

[nitehawk]

Its been done before, custom work:

http://www.e90post.com/forums/showthread.php?t=367906

[vitan]

Originally Posted by Tiago@VRSF

We have guys running 850whp with our 3" downpipes and our single 3.5" exhaust.

A dual 3" exhaust will be significantly heavier, more expensive without any benefits over a single 3.5".

Which twins made 850whp?

[Jeff@TopGearSolutions]

Dual 3" exhaust is over kill for sure but it would need to be custom.

[Velocity26]

Originally Posted by vitan

Which twins made 850whp?

I would guess Vargas GC twins or their Stage 3 twins.

[Tiago@VRSF]

Originally Posted by vitan

Which twins made 850whp?

Single turbo

[AS4EX]

Originally Posted by nitehawk

Its been done before, custom work:

http://www.e90post.com/forums/showthread.php?t=367906

I like this tapering idea, this is probably best case scenario if I want to go through with this.

What about 2.75 in. piping? Little more realistic and will have a little more wiggle room under there. Looking on the bright side, say, going bigger than 2.5 does little as far as performance goes, but there must be other smaller benefits to be had. I may gain only a couple or few HP (if that but who really knows until it's tried and tested), but letting it exhale better should at least improve efficiency; remember we're talking about a turbo'd car, and as far as I know, they want to breathe.

Then also there could be weight savings, but this would ultimately be determined by what kind of material was used. I have a guy who can do all this with your run of the mill steel, to the hardcore titanium (yeah, definitely don't have deep enough pockets for that). But in my case, this HKS rep isn't lightweight by any means and I wouldn't be surprised if it weighed more than the factory unit, and I would definitely choose to use a lighter weight metal than what is on there now - as much as I could afford.

So even if I don't gain much in power, I should be able to gain in other areas, not to mention I do want to hear some different and potentially louder exhaust sounds. I guess you can say I just want something that isn't quite found on any of the aftermarket parts shelves'.