Hi guys...it may be a noob question, but can someone please explain the difference between a regular downpipe and a widemouth downpipe and what are the pros/cons of these two?


Regular Downpipe


Widemouth Downpipe

 

Both of these designs are for the stock frame/ internal waste gate turbos. The lager pipe on the "regular" downpipe is the turbine exhaust and the smaller is the wastegate dump tube. On the "wide mouth" down pipe the two exits have been merged with a larger single exit which is more like the factory housing. The wide mouth design will allow more flow, but possibly have more turbulence. When I was on the stock turbo, I used a wide mouth downpipe.

 

So, are you saying a divorced downpipe would flow a little less overall, but be smoother? I don't know if the extra smoothness would even be noticeable, or cause the turbo to spool any faster.

 

They're all 3" so the flow limits will be about the same. If anything, additional turbulence will reduce the flow.

 

thanks for the info. So for the stock turbo, which one would be better?

there is another thing, as my car is RHD, i am limited to options with the downpipe. Ultimate Racing has one for the RHD model but thats not widemouth.

 

The folks at UR convinced me to go with their O2housing/DP combo single piece. See what they have for RHD X's -- I absolutely love my exhaust and the performance bump it gave me. It all starts at that o2 housing, it's SO throaty and torquey now.

 

i think you have this one: http://www.ultimate-racing.com/Produ...ousingDP.shtml

i need this one: http://www.ultimate-racing.com/Produ...ngDP-RHD.shtml


i think they are the same but bends slightly different to clear the RHD steering rack

i am planning to use the UR downpipe to an ETS test pipe and then the ETS V2 quiet catback. also planning for the ETS UICP. with about 24psi boost on the stock turbo and some ecu tuning i think 60-70whp gain is quite expected

 

A 'regular' downpipe divides the turbine outlet and wastegate outlet into two separate paths, which then merge further down the pipe. A 'widemouth' downpipe merges the turbine and wastegate outlets immediately out of the turbo into a single pipe.

The widemouth will be simpler and more compact, while the divided outlet will have better flow and less turbulence. If you're worried about getting every last horsepower out of your setup, go with a divided outlet downpipe. If you're looking for something that will still make good power but is probably a bit less expensive, get yourself a widemouth downpipe.

 

Dark check out Tomei new turbo downpipe very nice way better than all others good price also,,my in order

 

ya, saw the one from Tomei. But thats a widemouth. According to ScottSpeed21 here, using a divorced downpipe would be better, and the UR downpipe is divided

 

why dont buy AMS DP? I have AMS for RHD EVO X. However you need to bend the steering rack a lil bit.

 

wait your from Cali and how do you have RHD EVO X??

 

^ +1

 

Can I warn you still before it's too late? Yes, you'll get those gains, I loved that. BUT unless you want to do this twice or keep your baby over-pampered, get something else.

I blew my UR DP apart at the weld this past week. I'd run it for a few miles and a few track weekends and the weld blew in my third session. Granted, the sessions were 1/2 hour with 1/2 in btwn. But it really broke during the second session. Weather was a non-factor.

I have heard others will guarantee theirs. Try one but not a UR. I'd heard about this failure from UR before, so I'm honestly glad to have had it fail and be done with that risk exposure once and for all. Granted, it sucks having to buy a DP twice, but the AMS one is what the big boys use who really race for money.

EDIT: After it blew, I really realized some perforance gains. OMG, I think I'm going to look into adding some cut-outs, manual and basic, to my setup for track events. SHEEZE, 120mph and it still had pull/acceleration!?? I want MORE of that feeling. Just not everyday, not worth the wear and tear.

 

My opinion is that you wouldn't notice a difference between the two. You will be happy with either one. Most of us have AMS because the name makes us wet.