Right now I have two downpipes, exiting somewhere near where a stock manifold would exit(or attach to a factory cats/h pipe). The guy I am having make my charge pipes, is going to make me an exhaust system, 3". I was planing on him making me an X pipe,...then back into there own tailpipes.

My question is,...is the X pipe a good idea for a twin turbo setup? I don't personally see why it would make a difference but, someone has just planted it into my head that it would.

Insight?

 

Pointless.

 

I'd think it may quiet it down a bit, no?

 

Do you already have one or are you going to buy one? I don't think its worth rushing out and buying one. But, I would think yes it could help. Scientifically, the main benefit of the x-pipe is to create a suction effect from the opposing banks firing...creating a scavenging effect to increase the exhaust gas velocity. BUT with a turbo in the middle of the exhaust pulses, that gets kinda thrown off I would think. I bet it wouldn't hurt though. Just make sure you run a adequate one, like a 3". Bigger the better to get that backpressure gone. It'll help quiet it a db or 2 maybe also.

 

yeah agreed... the turbos will throw it off some ..but the benefit of scavenging will also benifit a turbo setup whether it be an x pipe or stepped up exhaust.as long as its a big pipe with little backpressure

 

K.

I was running a 3" offroad X with my blower setup...which I have sold. I would have to have one custom made,...with my new exhaust. I was thinking it would help with velocity but...wasn't sure if it would effect or hinder setup. I'm not going to run mufflers soo,...the x might be the option.

Would love to hear more input on this if anyone has more.

Thanks for the replies.

 

do not go with an x pipe if you are doing a rear setup. even if the turbo is before the x it will not scavenge, since the flow of air is no longer pulsing. It will hurt your top end big time.

 

I have a twin turbo c5 with an x pipe before the turbos.................although I dont think its hurting the top end.

 

Have you tested it with and without an x? or are we just biased towards our setup like everyone else?

If you are smashing two exhaust flows into eachother, it isnt scavenging, then you are hurting airflow. Seems like simple physics to me?

 

I have a front/top mount turbo setup.

Thanks for the replies guys.... although I don't think anybody has the "correct" response here.

I'll do the X. I'll even have some pipes made up and i'll test the "theory" myself. Even though I believe the X will help with velocity/exit.

peace

 

any results? I know the 300zx twin turbo guys are convinced the xpipe is the way to go with turbos also. would like to see real results tho on the fbody side.

 

anybody have any definitive testing regarding this? it would seem that straight pipes or maybe an h-pipe would be the best route. searched this site and the net and could not find a good answer for a v8 engine with twin turbos.

 

I tried a balance pipe on my old RV8TT. Cant comment on performance, as dont really think it made any difference, but it certainly quietened things down a bit. Much smoother sound too. ( previously totally seperate pipes )

The idea of the gases colliding may be valid. But only one cylinder fires at a time, so in theory only one set of gases is exiting.... go from a 3" single pipe, into an open X with 2 x 3" outlets.....

Well, that should flow better than sticking to a single 3". I assume thats part of the theory.

Id love to know more myself though, as I currently have a DIY X-pipe on my setup, and would like to know how different styles perform, or indeed if no X-pipe might be better.

I made mine fully open using 2 90deg bends cut and welded together. The only other one Ive seen is a DiFillipo for a friends Monaro, and it had 2 x 90's back to back, but with only a single 1" diameter home linking the X together. So it was more like to full 3" bends, with a small link between them.

 

No x-pipe. Yeah the x-pipe helps balance and increase scavange, but only on a NA setup. Think about it, if in order to make boost you have to build exhaust pressure, then the exhaust is coming out of the turbo under pressure and you want as little restriction as possible. An x_pipe will be more of a restriction more than anything else unless you want it to quiet it down a little. IMO

 

If the X is downstream of the turbo, how would it impose an increased restriction?

 

no X pipes, it helps N/A, but it will hurt on a busted set up.

 

Less back pressure after can decrease spool time, that is why many people run a 3inch downpipe for 6inches then goes to 4inch. Do a search and you can find some examples.

 

I see some people use a hooker y pipe to connect to the catback. On APS's dynosheet they use dual 3 inch pipes. Does a turbo quieten down the exhaust compared to a N/A setup? Would there be any difference between the single exhaust setup and dual 3inch?

Thank you.

 

Yes, turbo's do quieten an exhaust a considerable amount.

 

Yah, unless you got a rearmount then its loud in a whole other way.