big exhaust systen on higher hp car???

Posted By: John Burdine

big exhaust systen on higher hp car??? - 01/20/14 05:04 AM

I'm going to build a 4" exhaust system for the Demon with a straight threw style race muffler and it will have tail pipes to the bumper. I'm going to use turbo clamps so I can remove it and slam bullet mufflers on the collectors for at the track. I would still like the exhaust system to flow as good as possible.
my question is, is an x-pipe worth all the bends it takes to install one. I thought the school of thought was exhaust likes as few bends as possible.
so, I'm need to decide to either run an x-pipe, or run the pipe straight to the muffler (maybe a balance tube) the out the tails.

Posted By: 383man

Re: big exhaust systen on higher hp car??? - 01/20/14 05:07 AM

Do you plan to run tailpipes out to the rear bumper ?

Never mind as I see where I missed that. Dont know how much room you have but are you planning to downsize the tailpipes to maybe 3" ? Ron

Posted By: MR_P_BODY

Re: big exhaust systen on higher hp car??? - 01/20/14 05:13 AM

John... if you can get the muffs at the bumper it
helps due to the exhaust being cooler back there...
if you run a X pipe they do work BUT its suppose to
be 1/2 way from the end of the primaries to the muffs
or the expansion point(if no muffs are used)... A
H-pipe you put at the end of the collectors(or close
to the primaries)

Posted By: John Burdine

Re: big exhaust systen on higher hp car??? - 01/20/14 05:19 AM

is the x-pipe worth the extra bends?

Posted By: MR_P_BODY

Re: big exhaust systen on higher hp car??? - 01/20/14 05:27 AM

Quote:

is the x-pipe worth the extra bends?

Yes.. it does add HP to a system with muffs... if it
has back pressure... so if you run a straight thru
muff MAYBE you dont want the X.... its your choice
based on back pressure... all it does is kick pulses
back and forth

Posted By: Al_Alguire

Re: big exhaust systen on higher hp car??? - 01/20/14 05:28 AM

IMO yes an X pipe is worth it. Will even quiet the car down a good deal. IF you have the room.

Posted By: bdaz smblk

Re: big exhaust systen on higher hp car??? - 01/20/14 05:32 AM

A friend of mine that runs a 7 sec true ten five n/a combo has a shop with a chassis dyno.He has tried everything and said on a car like yours a h pipe makes more power.Now on like a mustang or a car that runs 11 or 12's he said a x pipe has made more power.hope this helps.

Posted By: MR_P_BODY

Re: big exhaust systen on higher hp car??? - 01/20/14 05:38 AM

Quote:

A friend of mine that runs a 7 sec true ten five n/a combo has a shop with a chassis dyno.He has tried everything and said on a car like yours a h pipe makes more power.Now on like a mustang or a car that runs 11 or 12's he said a x pipe has made more power.hope this helps.

I would say that his data was with some type of muffs
(with the 11-12s car) which again is a back pressure
thing... I like the H-pipe myself but it has to be
up close to the engine(primaries) to be efficient

Posted By: 451Mopar

Re: big exhaust systen on higher hp car??? - 01/20/14 07:23 AM

I think the X is a bit quieter than an H pipe system. Not sure how it is for power, but 4" is going to take a lot of room under the car. I had 3-1/2" on my car with straight through mufflers and it was way too loud for the street, but sounded good at the track.

Posted By: John Burdine

Re: big exhaust systen on higher hp car??? - 01/20/14 10:54 AM

I don't care if its quieter, just want what whichever will cost the least hp.

Posted By: 72Swinger

Re: big exhaust systen on higher hp car??? - 01/20/14 01:49 PM

You have to pay close attention to how the x merge is made. If the two pipes are merged to close together it will defeat to purpose and cause a lot of restriction.

Posted By: Streetwize

Re: big exhaust systen on higher hp car??? - 01/20/14 05:17 PM

Vizard did a recent article for Pop hot rodding where he said anything over 2.2cfm per horsepower doesn't gain you anything (but extra weight).

Mainatining Velocity away from the exhaust valve and minimal downstram restrictions are at least AS important as OD. FAST guys are going high 9's with full dual 2 1/2" exhausts and Factory casting exhaust manifolds (obviously ported but still not as good as a race header)....that's pretty telling to me.

Posted By: bdaz smblk

Re: big exhaust systen on higher hp car??? - 01/21/14 12:29 AM

Quote:

Quote:

A friend of mine that runs a 7 sec true ten five n/a combo has a shop with a chassis dyno.He has tried everything and said on a car like yours a h pipe makes more power.Now on like a mustang or a car that runs 11 or 12's he said a x pipe has made more power.hope this helps.

I would say that his data was with some type of muffs
(with the 11-12s car) which again is a back pressure
thing... I like the H-pipe myself but it has to be
up close to the engine(primaries) to be efficient

Both his test were with muffs.He has to run them in the class he runs.

Posted By: 572charger

Re: big exhaust systen on higher hp car??? - 01/21/14 12:50 PM

ive got 4 1/2 inch threw a set of top ten flowmasters and back to the bumper tail pipes no crossover or x pipe car runs the same with the 80 +lb exhaust on or off 9.60s at 140+

its not quiet but then again its hard to make 600cubes quiet !!!

Posted By: ProSport

Re: big exhaust systen on higher hp car??? - 01/21/14 01:56 PM

When I was running 9.80's with a 3.5" exhaust I added an x-pipe and it made the car sound really nice, and didn't slow it down one bit, system weighed about 75 pounds and the car ran a couple hundredths quicker and a tiny bit more mph than open headers.

Posted By: gsmopar

Re: big exhaust systen on higher hp car??? - 01/22/14 05:52 AM

I have the Pypes 3.5 X-pipe kit.

Posted By: quickd100

Re: big exhaust systen on higher hp car??? - 01/22/14 01:06 PM

I run a 3-1/2" system, X-pipe, 3-1/2" ultra-flows. I set it up like that when I built my 528 Hemi and it made more hp without the pipes on. By the time I built my 605 I had a dyno and tested the motor with and without the exhaust system in place. The 3-1//2" system cost 117hp and 97ftlbs on my 605. I can live with that though as hooking that much power on the street isn't going to happen anyway.Dave

Posted By: kielbasa

Re: big exhaust systen on higher hp car??? - 01/22/14 01:54 PM

WOW, that seems like a HUGE loss!!!!!!!!!

Posted By: ProSport

Re: big exhaust systen on higher hp car??? - 01/22/14 05:30 PM

Big Hemi's are a different ball game, they sometimes don't like an exhaust system.
Some guys make them work though, such as 572Charger.

Posted By: an8sec70cuda

Re: big exhaust systen on higher hp car??? - 01/22/14 05:46 PM

Quote:

Big Hemi's are a different ball game, they sometimes don't like an exhaust system.
Some guys make them work though, such as 572Charger.

Mine doesn't like mufflers. I still use my 4" H pipe system on the street, but at the track I put my short 4" bullets right on the collectors.

Posted By: quickd100

Re: big exhaust systen on higher hp car??? - 01/22/14 07:30 PM

To be fair my headers are 2 sizes to small for the motor as pipemax says I should be using 2-3/8" primaries and a 4 to 4-1/2 collector. I've got 2-1/8x3-1/2 on it now. Once I can get the chassis to plant the power I've got to the ground, I'll think about building a correct size system.Dave