Currently I am running Mac mid-length headers, Mac 2-1/2" oryp w/ magnaflow metallic spun-cats, SLP loudmouth cat-back with a Dynomax superturbo muffler added to it.
My dilema is this: The exhaust is quiet and I like quiet but when I put on the superturbo I could tell the breathing was choked. I know quiet and well flowing usually don't go together but I am trying to find a happy medium. I have done research on the superturbo's cfm but found different numbers and just tests where they said that they flowed pretty well compared to others.
Everyone says a cutout before the hooker won't gain more than 5-10 rwhp but I'm sure as you increase your rwhp numbers that difference will also go up.
My final plans include either a H/C car making around 420rwhp with a 100 shot or 402LS2 setup at around 490rwhp with a 100 shot.

Here are my exhaust options I have given myself based on my needs and preferences and I am trying to get an idea of what the maximum rwhp that each setup would be good for.

Option 1.) Just adding an eletric cut-out in the I-pipe right before the rear axle.

Option 2.) Just adding a hooker cat-back to replace the SLP/superturbo setup.

Option 3.) Replacing everything with Pacesetter LT's, TSP catted y-pipe, Hooker cat-back exhaust.

I am trying to get opinions as to when you think the mac headers and 2-1/2" catted y-pipe are going to cause real restriction compared to LT's and 3" catted y-pipe and also at what point a cut-out in the I-pipe would give real gains over the hooker muffler.
My experience is this: Mac's, 2-1/2" oryp, flowmaster mufller and dual cutouts for the y-pipe on my 2000 TA.
I gained 15rwhp and 20rwtq when I opened the cutouts compared to going through the flowmaster.

Thanks for any opinions, advice, or experience you might have, James.

 

3 hands down. Those Macs are screwing you out of some power.

 

Yup, Id deffinently start with some long tubes

 

Redo the whole setup, a bunch of power is just waiting, still sound tame but awesome.

 

3rd for 3

 

I would go with some longtubes as well

 

option 3, cant beat that setup imho.

 

See my mods in sig. I'm losing close to 20 hp with my dynatech supermaxx 2.5" y pipe. I have learned its impossible to reach the potential of a good head/cam set up with anything less than 3" all the way.

 

LT's or go home IMO

 

Option 3 is what I really want to do. Just needed some extra reinforcement to justify the $1100 in exhaust components.
Do you think that I would need a cutout in the I-pipe or is the hooker muffler capable of 550-600rwhp?
Thanks, James.

 

#3 ...Cutout is also good for extra breathing.

 

 

buy stuff on here and you wont have 1100 in it ....

 

Lt's... 3inch tru duals either other the axle or under. Cats if u need to and bullets.

 

How on Earth could you tell that??? Did you do a dyno comparison?

Regardless,

The exhaust you have now may not be ideal. But it isn't that bad.

Downers:
-Mids only scavenge at stupidly high rpms, so only work on certain setups.
-Mac mids only have 2.5" collector, a V8 or this level of performance requires 3" as a minimum.
-2.5" Y is restrictive on a stock LS1
-catback muffler is unknown to me so may be fine but then again may not.

A regular LT setup with 3" Y pipe and ORY or metal matrix cats into a good catback will work very well. Many people have been able to produce over 600rwhp on boosted setups no problem.

However the tubing itself is a restriction at this level of HP. Duals will offer more potential once you reach ~500rwhp. If you plan on boost and 600rwhp then 3" duals would be the best option in regards to HP.

Read the stick induction/exhaust (link in SIG!!!!!!) posts 6 and 13 onwards, it will explain it.

BUT

As you have already got a better than stock exhaust setup I would sort out the rest of your mods first. Get the motor sorted THEN go back and look at the exhuast if you are not happy with the HP.

 

Are you talking about buying used? Because brand new Pacesetter LT's and catted y are $700 from TSP and Hooker cat-back is $350 from jegs.
If you know something I don't, please let me know.

[QUOTE=300bhp/ton]How on Earth could you tell that??? Did you do a dyno comparison?{/QUOTE]
It was very easy. As soon as I turned the key and the car started you could tell the idle was more labored than prior to the muffler, that and the car doesn't pull near as hard in the upper rpm's. The super turbo is not a direct through design and probably flows about the same as a stock muffler.

I really wanted to see how much rwhp people with the same or similar exhaust setups to my option 3 were making and basically if that setup could handle 420-440rwhp which is what I am estimating from my planned H/C setup. I know true duals would be the best hp option but like I stated before, I am looking for a medium between loud (i know it is relative) and good flow. The reason why I chose option 3 as my main choice is because I believe that setup meets my loudness requirement and hopefully can handle 440rwhp NA and 540rwhp with a 100 shot. And I was just wondering how much extra hp a cutout would get me compared to running through the muffler, again trying to find someone with concrete comparison data.


Again, Thanks to everyone for the nudge I needed to make the decision on the exhaust, James.

 

Be careful comparing dyno numbers, different dyno types, graph smoothing and SAE/STD correction can yeild as much as 20-40rwhp variance in figures from the same car.

In short dyno numbers mean bugger all 99% of the time.

ANY exhaust including stock will handle any HP. It's not going to stall the engine or explode, but it may limit potential.

A 420rwhp setup is pretty poor for a h/c unless you are talking SAE corrected Mustang Dyno numbers. But a good 3" catback, 3" Y pipe and LT's will work fine on such a setup. 2.5" duals have the ability to see slightly better PEAK numbers, but it probably wouldn't be by much at this level of performance. But the setup needs to be well thought out in either case.

Duals can be near silent if you want them to be. A Y pipes flow fine, the biggest limitation is tubing diameter.


There is no simple answer.

A good muffler (Borla XR-1, SLP resonator, Powerstick 3" core) will actually out flow the 3" tubing of the catback. So using a cut-out to by-pass the muffler will see ZERO gain in flow. It may affect turbulance, but that far downstream its really not an issue. The biggest affect a cut-out may have is on the exhaust pressure wave. But this may be a postive or negative affect.

So a cutout may yield some power but then again it may not or it may evenn hinder performance.

On a lot of the good exhuast people generally only see 2-5rwhp gain with a cutout open, even in decently cammed motors. So it really won't be a lot either way.

 

FWIW I always read your posts with an English accent.

 

........ I thought everyone did, mate. ......

 

LTHs FTW.