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H-Pipe Setup May Trump X-Pipe on the V6

9K views 24 replies 9 participants last post by  Christojesus 
#1 · (Edited)
Hey Guys and Gals,

Not sure if you guys saw this over in the Exhaust forum so I wanted to post it here as well. I know unless I need something specifically exhaust related I dont usually read over there.
Anyways I had an opportunity to ask Summit Racing what their opinion was on the X-Pipe vs. H-Pipe debate for the G8 V6 and below is what they said. This solidifies my decision to go with an H-Pipe. I have always leaned that way. Planning on doing it around Christmas time. I would love to hear some feedback on this.
Do any V6ers have an H-Pipe?


""Due to the small CID of your engine, an H-pipe setup likely will perform better than an X-pipe setup. It's hard to say for sure though how the vehicle will react to either due to it's small size engine and in a lot of cases conventional V8 ideas on making power do not equate to more power in V6 applications."

"Installing the H-pipe setup in place of the mid mufflers will increase the flow capabilities of the system greatly but also will likely greatly increase exhaust drone quite a bit at lower cruise rpm's. Making this change will likely also make the exhaust tone deeper. "

 
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#2 ·
That's pretty good info/feedback...they're generalizing but accurate at the same time (hmm that's contradictory? lol)

It's a speculation game...X-pipes are proven to produce better exhaust gas scavenging effects than H-pipes BUT then the exhaust system must be tuned and flow in such a way for a scavenging effect to take place under high RPM.

For most street cars in the 350-400ci range, running modest cams, catalysts, mufflers, you don't see X-pipes yielding HUGE gains over H-pipes...from all my research/experience on the subject the difference in say, for example the LS3, between an H-pipe and a (properly tuned) X-pipe system might be up to ~7-10whp (prob closer to 5 IMO)...I'm painting some broad strokes here but really in most ppl's applications the difference is fairly small.

Start adding boost, cams, entering the world of big-block displacement then, yeah, an X-pipe is the way to go all day long...

That being said, in a V8 application, to me there is NO comparison in sound - a properly located H-pipe sounds WAAAAYYYYY better than an X-pipe, and to me/some I'd rather leave (an arguable) 3-5whp on the table and not sound like a ricey/raspy foreign V8...

Now, as for V6s - I do agree an equalizing H-pipe would give a V6 a noticeably deeper tone but could contribute to increased 'drone' depending on a number of other factors (muffler type, pipe size, crossover location, etc...). But if you're looking for that, and understand it's not going to sound like a V8 no matter what, an H-pipe would likely yield the most tone change (deeper)...depending on muffler selection of course.


My $0.02.
 
#3 ·
They are probably recommending the H for the low end torque benefits.

For the record, I put a resonated X pipe on my 3.5 liter G35 sedan. It went in on a Borla catback that didn't have a H or a X. The X cut out alot of the drone and picked up some torque down low. How a H would have done in that situation? I dont' know. My main objective is to rid myself of the drone and gain some torque/hp/sound. Which it did
 
#4 ·
I am in the market for low torque gains. I am happy enough with my peak hp. I just want to improve my 60' mainly. I gained 2 mph with my mufflers and intake but lost a tad off the line .05 ave. If I could gain low end torque and not lose any peak hp I would be thrilled. That's exactly what I want.
 
#6 ·
Thanks for the feed back. I am assuming you have the V6? Do you have any other mods?

How is the drone and sound?

Could your estimation of high end power loss just be that extra low end torque isnt carried through the whole power band and just isnt more than it was before?

Do you have and performance apps on your phone etc? Wondering if you have a performance compare. Just makes me wonder more with the limitted information out there on H pipes and exhaust mods on our cars in general.

I know I gained HP with my super turbos (quarter mile runs dont lie). Seems like a complete crap shoot on whether there are any gains to be made by modifying the stock exhaust any further on the V6 (X-Pipe or H-Pipe)....
 
#9 ·
First setup was no resi, no mid muff,stait pipes and stock axle backs(very little drone)second was no resi,x-pipe and stock axle backs(little to no drone). Third was no resi, x-pipe and custom solo axle backs(worst drone i ever had). Fourth was no resi, flowmaster mid muff and custom solo axle backs(drone still pretty bad but a littler better). Fifth was no resi, flowmaster mid muff and regular solo axle backs(drone is still there but alot better). Sixth was no resi, h-pipe and reg solo axle backs(drone got a little worse). Oh and forgot to tell you that i have solo QR resi on there now to help with the drone and they do.
 
#10 ·
First setup was no resi, no mid muff,stait pipes and stock axle backs(very little drone)second was no resi,x-pipe and stock axle backs(little to no drone). Third was no resi, x-pipe and custom solo axle backs(worst drone i ever had). Fourth was no resi, flowmaster mid muff and custom solo axle backs(drone still pretty bad but a littler better). Fifth was no resi, flowmaster mid muff and regular solo axle backs(drone is still there but alot better). Sixth was no resi, h-pipe and reg solo axle backs(drone got a little worse). Oh and forgot to tell you that i have solo QR resi on there now to help with the drone and they do.
Thanks for your input. I do have a question about your first setup (no resi, no mid muff,stait pipes and stock axle backs).... How did it perform compared to the stock setup? How much louder was the exhaust and what kind of tone change did you notice. Did you like the sound at all? If I went this route I would keep the resonators. I just dont want to add an H pipe and have a drone like a B@#$%. My setup now is noticable but tame with little to no drone.

I always have given this setup some consideration as well because it would be dirt cheap and since its a V6 you may be able to get by without a cross over.

Thanks!!
 
#11 ·
IDK guys Hot Rod magazine did back to back dyno tests years ago when "X" pipes started coming out. They tested straight duel exhaust, "H" pipe's, and "X" pipe's and they found that the "H" pipe added around 5 to 7 hp and 7 to 10 lbft of tq and an "X" pipe added 8 to 10hp and 12 to 15 lbft of tq.

They used an other wise bone stock 5.0 Mustang as the test mule, now I know you V6 guys don't have as much displacement but the results should be the same regardless of engine size.

Now those numbers are from memory so I may be off a hp here of a lbft there but that was those were the general findings that Hot Rod had come up with that an "X" pipe is the best. Summit is a great place to buy parts from but I'd like to know where they're gathering their test data.
 
#12 ·
I often wonder if just keeping the mid muffler is the best setup without a tune. Right now I have superturbos and an intake tube. My cars performance has increased .2 seconds + in the quarter with those two mods. I am afraid doing an x pipe or h pipe will kill my performance without a tune.

The mid muffler is just an open chamber right? If that is true that it is acting as a cross over and I can't imagine it's overly restrictive but could be wrong Can anyone confirm this. If this is the case I am not sure how much more benefit an h or x would be other than the weight reduction (especially with the stock tune)
 
#16 ·
Got mine on the dyno today at Backstreet preformance in Medina, and got really good numbers. 223.13 H.P. 224.85 MAX tourq . Met some other G8 owners to, posted some pics on board on notrh east ohio g8s thread. planning to meet there in spring when they have a GTO meet. Hope you can attend .
 
#18 ·
thats pretty awesome. Its funny. I read thread the day you guys met and got the dyno. I wouldnt have been able to go but I am 15 minutes away. Oh well maybe next time. I would have loved to see what mine would dyno. Has anyone ever done a pure stock dyno on the V6. Just curious what a stock V6 would do. Keep me posted if you hear anything about the spring meet. Maybe I can make it.
 
#20 ·
Just for the sake of argument I replied back with with following and got the response that follows:

"Thanks. What do you think would happen for both performance and sound if I remove my mid muffler(which does act as a cross over) and just run strait pipes in its place (Running my system without a cross over)? Could there be any benefits in doing this or would I be better off sticking with my current setup?"

"It's hard to say for sure how the engine will react to this change. I personally believe the engine will perform best sticking with the current setup. Reason I say this is that making this change will likely result in more HP but it may also hurt low end torque production. So, doing this may improve the top speed but hurt off the line acceleration. "
 
#21 ·
I am about to have my setup installed. Mid muffler delete, keeping resonators in, x-pipe with thrush turbo mufflers, ill let you know how it sounds
 
#22 ·
Awesome! I am excited to hear your car and your performance impressions. Thanks for the update!
 
#24 ·
i think the h-pipe will be beter as long as you have the crossover right away. ill probably locate mine almost right off the headers. as for drone im hopeing long glasspacks will kill most of it and they will be located in place of the resonatores and may end up running shorter glasspacks in the axlebacks or a differnt type of muffler.
 
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