2FNQUIK

iTrader: (17)

There is no dounbt in my mind that true duals flow better than any y-pipe setup on a basically stock bolt-on car but i was told that running true duals to the back will actually cost you power as opposed to dumping before the axle because you will lose some effects of scaveging...i imagine if your setup has a lot of bends(basanani td to gmmg type chambered into cme) but if you went with a setup like some of the guys in the sticky who run spiral flows or any type of muffler that you can fitclose to the gas tank with the only bend going over the axel it seems like a pretty free flowing exhaust to me...please chime in with any experience or proven results of dumped true duals versus out the back true duals....looking for a shop in georgia for the fab work too!!!

MeentSS02

iTrader: (11)

Although I don't have proof, a myth of this nature immediately gets thrown in the same pile as the myth that engines need and love exhaust backpressure, you were conceived by your mother who was and still is a virgin, and Bigfoot.

There might be some truth to this since you will be adding extra bends to your exhaust, but will it be enough to matter? Maybe in a *****-to-the-wall, full out race car, but otherwise, I wouldn't lose sleep over it.

The Alchemist

iTrader: (19)

For exhaust to be efficient, it needs to maintain velocity till it exits to the atmosphere. Although backpressure isn't good because it slows down exhaust flow, but the same can happen if the exhaust size is too large and too long before exiting to atmosphere.

teke184

iTrader: (5)

theoretically, more bends and extended tubing could cost some power. but in all honesty...you're talking a couple percent of the power gained in total.

so if you gain 15hp from dumped duals, you're looking at .25-.50hp lost with added bends....give or take.

are you worried about that last .5hp?

and i don't see how you get any more scavenging from dumped duals? doesn't that take place in the primaries/collector and in the Xpipe connection?

SladeX

I don't think you lose as much as you think... so I'll agree with myth on this one.

let's see.. QTP rates headers up to 40 hp gain... cats usually cost hp... add extra bends, 3 inch mufflers and over the axle out the back...

I still made a 43HP gain with a full true dual exhaust despite using off the shelf 3 inch magnaflow cats. Not rated hi-flow or anything. Just your run of the mill autozone replacement cats. Manufacturers always inflate their gains for the parts they sell so I doubt the headers gave me the 40HP and the true duals only netted 3HP.

2FNQUIK

iTrader: (17)

thanks guys for the responses i didn't think that i would lose that much power but i wanted to make sure to talk to someone else before i made my decision

ncnumber8

iTrader: (1)

I heard debate that a good y-pipe actually scavenges alittle better than an true dual, but I can't see it making more than 2-3 hp difference. And no, I don't think you will lose any power at all going over the axle because you have duals to begin with and thats more than enough flow for a bolt-on engine, the bends shouldn't make any difference.

NHRAMAN

iTrader: (1)

BIGFOOT IS REAL...

ChocoTaco369

The best Y-pipe in the world cannot outscavenge the best X-pipe. It's not possible. Y-pipes are more limited by design.

As for running TD's out the back costing you power, the added weight of the extra tubing is going to hurt you more than the power loss. It's nothing to worry about.

brad8266

iTrader: (23)

Y pipes suck ***** regardless of the power differences, real dual exhaust sounds 1000 times better. Id stick with duals just for the sound difference.

vetteboyc5

iTrader: (9)

agreed!

ncnumber8

iTrader: (1)

Refer to this thread:

https://ls1tech.com/forums/showthrea...&highlight=500

This is Patrick G making over 500 hp on a naturally aspirated hydraulic cammed, pump gas, 5.7L motor. And it was done with a y-pipe.

Its gets better:

Now I don't know about you but in my book 1 hp difference from open headers and even more torque between 2500-4000 is about as good as you can get. Find a true dual setup that makes more power than that from a 5.7L and I'll believe you. People go to the true duals for the sound period. But, you pay the price: ground clearance, period. And I doubt you would make that much more power if any than a well designed y-pipe as described in the thread above.

SladeX

I have to agree it's really down to a sound preference than anything. I just got tired of the whole y-pipe sound. I've seen y-pipes flow just as well as a true dual setup.

Some people get scared out of true duals due to cost, but in my experience they should cost about the same as long as the shop isn't charging an arm and leg for exhaust. I've seen some shops charge at least $1k for true duals while mine cost $400 and for stainless steel no less. I've also seen y-pipes alone go for $400 so it just depends on if you can find a good exhaust shop relatively close to your area.

LivingCanvas

iTrader: (4)

There's holes in your theory here.

--He never tried it with a well designed x pipe dual system, so there's nothing to compare to, per the topic.
--Its pretty common knowledge that open headers suck for power, so comparing numbers to open headers is dumb
--As for ground clearance, I seriously doubt that a 4" system has that much better ground clearnce than my TSP system. My system tucks close to the floor and follows where the Y pipe used to go. its not like stock, but it aint bad
--I gained 15 ft-lbs in the low end with my duals, versus a LM setup.

But you go ahead and keep trying to convince yourself that the Y pipe system is better, its ok

ncnumber8

iTrader: (1)

And there is a reason why he didn't try it because there was no need to.

Wow! Are you calling Patrick dumb?? Those were his words not mine. I was just qouting him. I would take those back since he is a moderator and you might hurt his feelings!

Also, open headers suck for low and midrange torque, not peak power. This is pretty common knowledge. So you are saying that all the 8,9, and 10 second bracket/index/heads up racers out that run open headers should put on a dual exhaust so they can run faster? I can tell you are from CA. LOL.

You lose exactly 1" ground clearance with a 4" y-pipe. And truth be known, most people will not need that much y-pipe. Patricks setup is much more radical than a typical bolt-on setup as this thread is about. 3" is plenty for a bolt-on setup. Or even a 3.5" would do. I considered true-duals at one time and called around several muffler shops and they all said the same thing: terrible ground clearance, don't do it. And this is coming from people that would have made money from me!

Do you think that 15 ft-lbs in the low end is going to help you win many races? If you do, then you are living in a dream world.


Ha ha, I think you should do just the same. Keep coming up with reasons why you spent all that money on your duals. LOL.

ChocoTaco369

Uh huh, and he'd be making EVEN MORE if he switched that to an equally well-made true dual setup, so what's your point?

You can make 500 horsepower with a Procharger and a stock cam. Guess what happens if you upgrade the camshaft? You make more power. Amazing.

It doesn't matter how much power you're making with a Y-pipe setup. I don't care if you're making 2,000 horsepower on a Y-pipe setup. The fact is, you'll make even more with an equally well-made TD setup.

orangeapeel

iTrader: (18)

This thread was truly an asswhipping to read. It is clearly gonna always be 50/50 in these types of arguments. X setup out the back is what I run. I like it, that is why. Bottom line for ALL OUT performance is usually gonna be all top end anyway. Only thing I would prefer to run over the setup I have now is a single sided boom tube.

LS1>Imports

iTrader: (2)

true duals will always out flow a y-pipe
lets say u make 400hp with a y-pipe throw some true duals on and you'll make more. As for price, cat-backs and y pipes are expensive, $450 dollars for tsp true duals or almost $400 slp dual/dual(which is one of the cheapest and best flowing cat-backs) and thats not including the y-pipe.
and look at corsa,borla, and other cat-back brands almost $700+ for those
ill pay the extra $50 for better sound and flow
as for custom true duals, you could get them dumped or ran out back
for real cheap, all depends on where you go.

SladeX

I don't think the question ever came up that true duals is better than a y.

I believe the question was, do true duals cost power?

I run true duals, but in all honesty, a y pipe can flow as well if DESIGNED correctly. Flowing 500HP or even 600HP out a y-pipe has been done before.

You thread hijackers! Please don't make this into a war between which setup is better. It's really down to a sound preference I think especially since in the range most of us bring our cars up to, both setups can be fabbed to handle the power.

ncnumber8

iTrader: (1)

My point is that until you PROVE to me that a dual setup makes more power than a well designed y-pipe, than I'll consider this an opinion only. And I never stated that y-pipe is superior to true duals. Here is exactly what I said:

I simply said that I've heard debate that a y-pipe actually scavenges alittle better than a true dual. For me, it comes down to a preference. I like true dual sound also, but not willing to sacrifice ground clearance for it.

I'm not sure what your point is. We are talking about true duals vs y-pipe on a naturally aspirated motor. What do prochargers have to do with this discussion? Of course you can make 500 hp on a stock cam with a procharger. You can probably make even more if the boost is there and your bottom end can handle it.

Show proof and I will believe you.