01_ram-air

iTrader: (3)

Why is it that more people don't run true duals? Is it a money thing or are there advantages to running the Y-pipe to a single muffler gimmick? I wouldn't think that there is a back-pressure issue with the LS1s, but I don't know that much about them, so there could be. Is there a true performance difference running true duals? I know, a lot of questions, but I'm getting ready to do my exhaust and want to know what the Best way for me to go is. What I'm looking at doing is getting everything set up where I can just throw on a set of headers and not have to change anything else with the exhaust. What's the difference between running an X pipe vs a H pipe? Any suggestions on what you guys think I should go with would be welcomed as well. I'm a racer, not a waxah, so performance comes before sound in my book.

orangeapeel

iTrader: (18)

Cause they are pricey for starters. And most people don't know what they are missing out on having a y-pipe! j/k

I would have to say ultimately because of price/fittament. Back pressure will not matter. What you are lookng for is more velocity.

H-pipe: You will have more down low, and it will have a deeper tone.
X-pipe: You are gonna be a top-end performer for the most part, and it will sound a tad different from an H.
Honestly I can't tell just by listening on identical setups minus the H or X choice, but that might be due to the fact that I have been around to many loud instances my entire life and have terrible hearing.
hope this helps ya out some.

I went with the 2.5 true duals through twister mufflers. I have quite a bit of pull in the 3800+ range too. Are you A4 or M6?

orangeapeel

iTrader: (18)

BTW: Your are F'in quick for being damn near stock! nice times.
Unless by juice you mean a 75 dry shot.

01_ram-air

iTrader: (3)

Thanks, I'm an A4, big Stall (ST Yank 4000) and spraying a wet 100 shot. Thanks for your input too

dschmittie1

iTrader: (64)

a lot of people probably don't have true dual's like me for state inspection reason and needing the exhaust to exit from under the body of the car

JBIRD02

iTrader: (4)

Thats true. Also, because alot of exhaust shops will tell you it cant be done, or that it can but it will cost alot of $$$. Some people are just a little apprehensive ordering the parts and having it custom fit, they'd rather just buy something made for the car.

SouthFL.02.SS

Over the axle and out the back true duals are expensive.
Dumped at the axle TD's are lots of fun at first, but grow tiresome for some people (like me).

I went from Y to X to Y again, only to see the greatest dyno numbers being put out by my final Y-pipe setup (QTP HVMC LT's -> QTP ORY -> SLP 2OTL catback).

Duals dumped are awesome. You also smell like fuell when you arrive at work in the morning (take that as a good thing or a bad, hehe).

tillery

iTrader: (4)

me slp headers, ory into a flo y (flo-y300400) 4" I pipe back into a same flo y to split at rear into sweetthunders. Also to pass visual insp. I have my mufflers installed in oversized tips that resemble stock WS-6 tips for a "stock" apearance.

300bhp/ton

As for duals vs Y, it appears to be a never ending debate.

In essence, a GOOD Y setup will match a GOOD dual setup. A Y pipe scavenges just like an X pipe does, so you still have the benefit.

The only problems arise with Y setups when the amount of gas flowing down the tubing becomes too great and the tubing itsefl becomes the limitation.

A 3" Y setup is more than good enough for a bolt on LS1, even a mild cam setup will not be a problem.

But another problem is the muffler, as the gases from all 8 cylinders go through a single muffler. Many after market mufflers do not flow well enough. Flowmaster being most notible. The Hooker Aerochamber is good for upto 375bhp before the flow rate exceeds the muffler.

Borla are generally very good, as are Stainless Works and GMMG. and I'm pretty sure the SLP LM flows pretty good.

Remember many race and rally cars use a Y setup over duals, because they are generally easier to route, lighter and cuase less restrictions with the rear suspension setup.

Duals, are best if you custom fab them, so do not get them until you replace the headers. Normal Y Catbacks are bolt ons so you can get one know and dot the headers and mid pipe later without needing to fabricate anything.

My recommendations for good setups would be:

Headers:
-Cheap and cheerful, Pacesetters coated. Good quality and fit for the money.
-Edlebrock headers, coated. More money than the Pacesetters but look nice.
-Stainless Works, very high quality in stainless steel.
-QTP or Kooks, these seem to be the favoured as the premium setup. I doubt they are really any better though, they just happen to be very good and in stainless steel.

Mid pipes:
-If you are going for a Y and Pacesetters then TSP (Texas Speed & Performance) offer their own Y pipe, and a catted variant. Great value for money.
-All of the other header makers offer Y pipes (not always availble with CATS though). 3" would be my choice, although a 2.5" Y would lend better for a low down torquey engine, but at the sacrifice of top end power.
-Magnaflow make a nice X pipe if you plan on duals.

Catbacks:
-Stainless Works Chambered
-GMMG
-SLP LM
-Borla

CATS:
If you plan on high power and wants CATS (either Y or dual) then Random Technology 7000 Series Metal Matrix CATS are what you want, they out flow many mufflers and will be fine on motors of 550bhp.

Mufflers:
To be used in a dual setup or an addition to a Y setup.
-Classic Chambered Exhaust Powersticks
-Stainless Works chambered mufflers
-Borla XR1 series
-Sprialflow

Complete systems

Budget Y:
Pacesetter long tube headers
TSP Catted Y
SLP Loud Mouth

This should sound good, and flow well enough for a solid bolt on car

Premium Y:
Stainless Works Long tube headers
Stainless Works 3" Y and Random Technology 7000 Series CATS
Stainless Works chambered exhaust

This will be fine on a h/c engine or even FI and sound and look great.

Budget dual:
Pacesetter long tubes
Hi-flow cats
Magnaflow X pipe (2.5")
Powerstick mufflers x 2
2.5 tubing and some tips

Will sound nice, and flow well. Run over the axle and out the back.

Premium duals:
Stainless Works long tube headers
Random Technology 7000 Series CATS
Magnaflow X pipe (2.5")
Stainless Works Chambered mufflers and tips.

Manic Mechanic

iTrader: (3)

Excellent post from the Brit.

Vernon

you2slo

I went with a Y setup because a true dual dump is not practical for my car. I travel to clients' homes and can not have a race car show up at their door. I have to appear somewhat refined. I really wanted a dual set up, though.

MeentSS02

iTrader: (11)

I see a lot of conjecture floating around in here with little proof to back it up. Seriously. Until someone does back to back to back (and possibly even more) dynos with each of the setups mentioned above, all tuned to their max potential, everyone is just taking a shot in the dark. Stop quoting theory. Please.

300bhp/ton

It's not just theory, it's physics.

Check the sticky out about exhaust, it has some good info in there, also use Google and search for David Vizard (he has several books in publication).

And yes there is always conjecture, but that's because too many people beleive what one person says instead of actually researching it.

01_ram-air

iTrader: (3)

Very good post, thanks for the info. Now, you just made the decision harder.

MeentSS02

iTrader: (11)

Even in your own post where you say the Hooker Aero Chamber is limited to 375 bhp...where did that number come from? There are a good number of people I know back in my old home state of Indiana running the Aero Chambers on some pretty stout setups (heads/cam), and only losing ~5 RWHP on a dyno to a cutout.

You made a good post, but there is still a good deal of generalization where plain physics isn't filling the gap (see above paragraph).

Another big one I see on here is that 2.5" true duals is only good to about 450 HP (not sure if that is bhp or RWHP).

There is some good info on this site, but there is also a lot of rubbish. I'm just trying to keep everything factual.

300bhp/ton

No notlimited, will be fine upto that bhp lvel, beyond that it will become a restriction.

Sadly that doesn't prove a great deal, as cut outs can cause a loss or limited gains. There are two sides to exhaust performance:

1. Flow rate
2. Exhaust pressure wave

The cut outs would certainly affect the exhaust pressure wave.

No, I'm sure physics can explain it all. However it gets far too complex to explain in just a few posts. Plus I'm not a Physicist just an enthusiast.

Not sure where you read this, the closest I said was if you are planning on 550-600+bhp then 3" duals would be more beneficial. And it would always be engine flywheel BHP, as measuring BHP at the rear wheels makes it inaaurate at the as flow rate would be much higher.

There, is. But physics is physics regardless. And much of the info where I have said look is well respected.

Look at this thread: https://ls1tech.com/forums/showthread.php?t=139142

Check out posts 6 & 7, and posts 13 onwards.

David Vizard is very well respected in the industry, has published many books, writes for one of the hot rod magazines, has race proven history, and has helped design mufflers (Spiral flow if memory serves).



If you can determin the flow rate of a muffler, then you can caculate whether it will be a flowrestriction.

According to David Vizard, use 2.2cfm per 1HP

So the Borla flowed 1100cfm.

If the engin is producing 500bhp.

500 x 2.2 = 1100cfm, so you could put this in a Y setup and it would not restrict flow (provided the tubing of the Y flowed at least 1100cfm).

On a dual setup, each bank and muffler only has to handle the gas flow for 4 cylinders instead of 8. So on our 500bhp engine, the muffler only has to handle 250bhp, or 250 x 2.2 = 550cfm. This is where dual setups re beneficial, as you can use lower spec parts and achieve the same results. With a Y setup you needto make sure it can handle the gas flow without restriction.

If the Aerochamber muffler from Hooker is good for 375, then 375 x 2.2 = 825cfm, not bad but limiting with a LS1, as 400bhp is pretty easy from them.

SouthFL.02.SS

Not all Mufflers have diffusers, baffles and chambers however.
Look through a Magnaflow 4x9 oval or an SLP 2OTL muffler and all you see is whatever is on the other side of the perf. pipe (i.e. asphalt, hand, feet, etc., hehe).
Mufflers should not be out of the question for a high flow design.

TJ

iTrader: (10)

y pipe and catback..... good and quiet.
noise attracts other people.
unless its a track car, then duals dumped gets it done.

TheBlurLS1

iTrader: (8)

I have duals, I love the sound better than any system I've ever heard on a street car (especially with the cam).

I have duals, I hate the interior noise when I'm trying to listen to music or talk to my girl.



You will think the duals are the best thing in the world for a few weeks, and everytime someone compliments you. But they dont realize that you have to drive it every day and can't hear yourself think. Duals with an x-pipe are going to flow and make more power than any other, and most likley sound better, but you are going to have to give up comfort, which will start to **** you off I promise. I would stick with a catback, and put bigger jets in the nozzles if you want more power

Ride in someones car who has them before you make a decision. I'm currently trying to change my setup, check my thread in this section I started yesterday. Its got a pretty crazy idea for the best of both worlds.

Full-Force

iTrader: (11)

i lost 2moh in the 1/8 going from, 3" duals to ory and hooker catback

i knew as soon as i drove down the road for the first time i had made a mistake getting rid of teh duals

my car used to just keep pulling up top but with the y pipe and catback it just gave out early compared to the duals