True Duals vs. Y

[spazzyfry123]

What advantages are there in having a true dual exhaust system in comparison to going with the Y-pipe design? Is the only "advantage" being able to say you have true duals while hardly anyone else does (in relation to how many have Y-pipes)? I was considering going with the true dual design, but if there are no real "pluses" in doing so, then...:dunno:
Thanks,
Tyler

[nhraformula]

youll make alittle better power under the curve.
peak h.p, both systems make about the same.

[~redlinels1~]

Slight better peak and curve power. Better sound IMO. And "can" be cheaper. Depends on the setups though.

[hammertime]

Slight better peak and curve power. Better sound IMO. And "can" be cheaper. Depends on the setups though.

Seems most of the cheaper setups dump the exhaust ahead of the axle. Driving a car like that on a daily basis is no picnic. Without full tail pipes, the sound reverberates under the car. Its especially loud off idle, like every time you leave a stop, etc.

When I was 20, I loved it - the sound set off car alarms, and got a lot of attention. Some of it good, some of it bad.

What other mods do you have. If you are stock or mostly stock, it woudn't be worth it in my opinion.

[~redlinels1~]

Seems most of the cheaper setups dump the exhaust ahead of the axle. Driving a car like that on a daily basis is no picnic. Without full tail pipes, the sound reverberates under the car. Its especially loud off idle, like every time you leave a stop, etc.
Yeah, I know. I can't stand the drone dumps make. Although Ive seen quite a few people go under the axle clear out the back without any problems or clearance issues. At that point its going to cost *roughly* the same as a y-pipe/cb.

The price sky rockets as soon as you mention over the axle.:hide:

[spazzyfry123]

Well my last car had the stock manifolds with an off-road H-pipe with Flowmaster 40 Series dumped right before the axle. I had spare change in my cup-holder getting airborne just from the drone. But that was coming from a 2002 4.6L Mustang. I can imagine the drone is even worse on a car with 1.1L more.:slap:

I don't even have the car in my possession yet. I am having a friend deliver the vehicle to me in a few weeks (it's about 900 miles away...haha). As far as I know, it is a completely stock '99 SS with a Hurst shifter. I plan on lowering the car a considerable amount, so I would guess that going with true-duals could affect ground clearence a good bit going under the axle if I did not dump?

[~redlinels1~]

Depends how good the shop is that does the work. Ive seen a few lowered 2'' with plenty of clearance with duals.

Also, I might as well throw this in but duals wll limit your options for a torque arm. Most trans mounted arms will work but many tunnel mounted arms wont. The only one I know of that doesnt seem to have problems with duals is the aslton TA...and that piece cost a pretty penny.

Unless of course you get the TA 1st and have them build around it.

[spazzyfry123]

So it would probably be best to go with a Y-pipe for compatability reasons with other aftermarket parts? I would assume that most companies are making their designs to go along with a Y-pipe seeing that that is what mostly everyone uses:drivin:

[~redlinels1~]

I think it would save you a headache going with a y-pipe but duals shouldnt be a limiting factor. It also depends how extreme you want your car to be. If you'll be happy with a typical aftermarket trans mount TA and standard SFCs duals wont be hard to work around. If you want a tunnel mount TA and diamond style SFCs it might become a problem.

Or...like I said before. Get the suspension upgrades first and start taking your car to shops to see if they can work around it...which probably wouldnt be a bad idea regardless what parts you go with.

[ss~zoso~ss]

if you want loudness get the SLP loudmouth and it'll sound deep but very loud when you get on it WOT (wide open throttle)

[spazzyfry123]

Alright. I suppose it would be better for me to get the car first before I start doing all of this though...:shots:
Thanks!

[spazzyfry123]

if you want loudness get the SLP loudmouth and it'll sound deep but very loud when you get on it WOT (wide open throttle)

I want to go with long tubes eventually and that will of course require a new mid pipe. Could I get the SLP Loudmouth kit for the time being and then as money allows, continue on with long tubes and still be able to keep the Loudmouth kit?

[~redlinels1~]

Yes you can. My advice? Stay away from the loudmouth if you get headers. It sounds awesome by itself...but its rasp city with headers.

[mrr23]

here's what happens when you go from a y-pipe single exhaust to tru-duals. this was on the wife's car. has bassani headers with the matching catted y-pipe to a borla exhaust. removed the y-pipe and added the bassani tru-duals which comes with a x-pipe. the bassani tru-duals goes all the way over the axle and out back.

http://www.stealthram.com/familypics/formula/dynos/borlavsbassani.jpg

[Snake Eater]

not meaning to jack this thread, but about how much clearance will a 1-2'' drop see w/ td's? I'm really considering switching my ory+cb to td's, but i'd also like to lower my car.

[spazzyfry123]

You're not jacking the thread. I am curious about the same:) I found this on LS1tech.com and he says that he has even more clearance going under the axle than he did with his standard over the axle Y-pipe:thinkin: Here, check it out: http://ls1tech.com/forums/showthread.php?t=442348

[spazzyfry123]

Yes you can. My advice? Stay away from the loudmouth if you get headers. It sounds awesome by itself...but its rasp city with headers.

Well I'm wanting a pretty wicked sounding setup. So I have decided that I will go with true-duals after reading various things around the 'net regarding them. I want to go with a T-Rex cam, long-tubes, true duals (not sure if I will go with an X-pipe or no crossover at all just yet), and I am uncertain of which mufflers to go with (to my understanding, you cannot use a regular cat-back since this is a different animal, right?).

[~redlinels1~]

You want an x-pipe for the scavenging effect. The best sounding muffler would be sweet thunders but they dont flow as well as others so they become a restriction at higher power levels. A good sounding muffler that flows very well is the flo-pro twister. The best flowing would be a traditional bullet style muffler but it may not sound the best...but sound is subjective so you may like it.

As for me, Ill be getting flo-pro twisters when I get duals.

Like I said before...if the shop knows what theyre doing clearance wont be an issue.

[Snake Eater]

Dynomax bullets are the loudest/deepest and flow the best. Moroso is a bit quieter, and the sweet thunders just scream at WOT, although being a little more restrictive than the two. With either muffler choice, it's not going to be more than a 2-4 hp gain.

[spazzyfry123]

Well with such a small difference in power between mufflers, I would much rather go with the best sounding one. Sound by itself is a good enough reason to swap out exhaust systems:Popcorn:

[Snake Eater]

here.. this might help you..

http://ls1tech.com/forums/showthread.php?t=436376&highlight=true+duals

[spazzyfry123]

here.. this might help you..

http://ls1tech.com/forums/showthread.php?t=436376&highlight=true+duals

Ah, indeed it has:) After reading that and watching http://www.ls1sounds.com/true_duals/TDs-SweetThunder_PaceSetterLT_2.5inX_S2heads_TR224-114cam.wmv, I'm pretty sure I've decided on long-tubes with X-pipe for true duals and Sweet Thunder mufflers. I am unsure on what length mufflers to get though.:love:

[Snake Eater]

18''

[spazzyfry123]

Alrighty. This is the setup I have planned out:

Pacesetter Long Tube Headers (ceramic coated)
Texas-Speed Rumbler X True Duals w/18" Sweet Thunder Mufflers

Sound good enough?:burnout:

And if the sound is just too much, I will more than likely run under the axle since there doesn't seem to be any ground clearance issues and it appears to be a waste of money to go over the axle...

[spazzyfry123]

Now veering a little off topic, but still staying on...I plan to lower the car with Eibach Sportline Springs (according to their site, that's a 1.7"-2.3" drop). Do you think I'll be able to drive with the dumps or do you think they are just going to end up being torn off? I just really think that F-bodies look killer when they are slammed, so I am going to do this naturally. But I also want true duals to stand out from the crowd (and I also believe it was kind of an odd design to go with the Y-pipe...).
Another idea that has struck me is having the "turndowns" become "turnouts". Doing so, I could achieve another inch or so of ground clearance along with escaping a little bit of the drone associated with dumping an exhaust. Could this be done? Or would doing this intefere with other parts (fuel lines, suspension components, etc...)?

[Snake Eater]

Sounds like a good setup to me. It really depends on how good of work the shop does in order for you to drop it with good clearance. As far as turnouts, I'm sure they'll work just fine, but you'll still have drone..

[spazzyfry123]

Well yeah, I know I will still have drone. But I think that going with turn-outs might alleviate some of the drone.

Now all I have to do is get the car...haha. It's in Texas right now and I should be getting it towards the beginning of March (8th or 9th maybe?).

[Snake Eater]

Good luck with the car!:drivin:

[spazzyfry123]

Good luck with the car!:drivin:

Thanks! I cannot wait!:mail:

[Qwk94Z28]

what would you guys think of true duals x pipe and 2 loudmouth mufflers?

[SLOW346]

Now veering a little off topic, but still staying on...I plan to lower the car with Eibach Sportline Springs (according to their site, that's a 1.7"-2.3" drop). Do you think I'll be able to drive with the dumps or do you think they are just going to end up being torn off? I just really think that F-bodies look killer when they are slammed, so I am going to do this naturally. But I also want true duals to stand out from the crowd (and I also believe it was kind of an odd design to go with the Y-pipe...).
Another idea that has struck me is having the "turndowns" become "turnouts". Doing so, I could achieve another inch or so of ground clearance along with escaping a little bit of the drone associated with dumping an exhaust. Could this be done? Or would doing this intefere with other parts (fuel lines, suspension components, etc...)?


I have the Eibach Pro-kit and scrape on everything. I have to be real careful. I can't even imagine what a nightmare the sportlines would be, especially with TD's. With TD's and sportlines you'll have next to no clearance with a nice tuck job. Prepare to high center on a bottle cap lol.

[00SLPSS]

I switched from 2.5" TD's, with a H midpipe, and bullets-- to 3" TD's with an X and sweet thunders. Night and day sound difference in sound, I love it.

3" compared to the 2.5" makes no real noticeable difference on a regular bolt on car except for the sound.

Edit: I also noticed people talking about drone, 4.11's on the highway I still get no drone.

[spazzyfry123]

Well I have given it even more thought, and I think I will get some long-tubes and have an electronic cut-out immediately after the LT and then just keep the factory cat-back and get a new Y-pipe I guess. I will need a new Y-pipe with new headers, correct?

[Qwk94Z28]

yeah

[SLOW346]

Well I have given it even more thought, and I think I will get some long-tubes and have an electronic cut-out immediately after the LT and then just keep the factory cat-back and get a new Y-pipe I guess. I will need a new Y-pipe with new headers, correct?


You don't want the cutout right after the headers though. You need to put your cutout after the y-merge to allow the exhaust gasses to scavenge. Otherwise you might even lose hp.

[spazzyfry123]

You don't want the cutout right after the headers though. You need to put your cutout after the y-merge to allow the exhaust gasses to scavenge. Otherwise you might even lose hp.

Ah...I wanted to do this so I can pass the sniffer, but then bypass the cats when I wanted:dunno:

[SLOW346]

Ah...I wanted to do this so I can pass the sniffer, but then bypass the cats when I wanted:dunno:

You'd be better off getting offroad test pipes to swap in place of the cats, rather than bypassing the cats with cutouts. Your cutout's need to be after the merge, unless you don't care about losing performance and just want them for sound.

[spazzyfry123]

You'd be better off getting offroad test pipes to swap in place of the cats, rather than bypassing the cats with cutouts. Your cutout's need to be after the merge, unless you don't care about losing performance and just want them for sound.
Not trying to annoy you, but I like to learn. So...why? And how does it hurt performance?

[~redlinels1~]

In short, it is important because it acts to balance the two banks of the engine. The scavenging effect smooths out uneven exhaust pulses from the engine’s firing order thus increasing power and making the overall system quiter.

[rickssz]

Just keying on power and not sound did i get it right that true duals vs modded y catback picks up 15 rwhp so vs stock exhaust duals alone pick up min. 30 rwhp like on MRR23's car?

[mrr23]

Just keying on power and not sound did i get it right that true duals vs modded y catback picks up 15 rwhp so vs stock exhaust duals alone pick up min. 30 rwhp like on MRR23's car?


the graph is showed was on the wife's car. it has bassani headers, with catted y-pipe and borla 3" adjustable catback. i removed the borla and bassani y-pipe and added the bassani tru-duals. i had to make minor modfication to get it to fit the cats. so, extrapolating from an average gain of 10-15 rwhp when swapping from a stock catback to an aftermarket, you could see 25-30 rwhp from the bassani tru-duals. i'd say about 20 rwhp myself. you can't always compound gains.

[hammertime]

Well I have given it even more thought, and I think I will get some long-tubes and have an electronic cut-out immediately after the LT and then just keep the factory cat-back and get a new Y-pipe I guess. I will need a new Y-pipe with new headers, correct?

As already stated, you would probably be better off with some test pipes you could swap in place of the converter. Besides, putting just one cutout after the Y saves you from two expensive electronic cutouts.

Most racers who run open headers find they get the best times with 18"-24" extensions on the collector for scavenging purposes, I suppose that you'll get close to that putting the cutout after the Y. Too short of a pipe will cost you low end.

[spazzyfry123]

Gah...I'm so indecisive! I would really like to have true-duals because it appears that they sound better. I don't see that much of a difference in power made between true duals and a Y-pipe, so the choice is mainly for sound. I also enjoy making my car "unique" in a sense, and since the car comes with a Y-pipe design, true duals would go hand-in-hand with the "unique" aspect. This will more than likely be my first modification to the car (Long-tube headers, true-dual exhaust with Sweet Thunder mufflers). I just can't get over the idea that the Y-pipe design wasn't a good idea on GM's part. I have no doubts that it is sufficient and works great, I just believe it is odd that they did that instead of going ahead and going with true-duals.
So I guess I will save up for some coated Pacesetter long-tube headers and the TSP true dual system with Sweet Thunder mufflers dumped before the axle. (I am aware of the drone...my last car was dumped with an off-road H-pipe and the spare change in my cup-holder would get airborne at times just from the vibration of the sound)
On a side note, I have heard that LS1's need backpressure. Would running an off-road application such as this (no cat's) be okay? I may even opt for a couple electric cut-outs to put in right after the header for when I want to get loud. My friend has a 383 stroker LT1 in his '92 'Vette and has essentially done the same thing that I am considering doing...and man does that thing sound mean with the cut-outs open:love:

[Snake Eater]

i wouldn't run cutouts on a td system

[spazzyfry123]

i wouldn't run cutouts on a td system

Any reason why?:dunno:

[Snake Eater]

well considering you won't have that much power, the cutout will actually make you lose some power. if you want the sound, i guess go for it though.