Getting Mac LT's and O/R H

98GreenStallion · **Getting Mac LT's and O/R H**

I am about to purchase whats in the title, and right now I have a custom setup with spintechs and no crossover (cut off right behind y-pipe). It was done by a local exhaust shop. Now Im about to free up some horsepower by getting rid of my stupid cats that are clogged and getting some Lts while Im at it. Ohh and, im doing this installation (as I have an arc welder, not the best... but will do) So how would I connect my new h-pipe to the spintech mufflers? I know the H-pipe has the bolt connection which normally bolts to the MAC cat-backs, but anyays, Im sure you get the idea... any suggestions?

RGR · 03-04-2005, 08:25 PM

Post pics, I've done exhaust work (it's pretty easy)
but the Muffs should bolt up once the H is on there.

You still have the stock "Y" in there now?
It could be part of the problem, any system
that keeps the stock "Y" is not really duals,
cuz everything has to flow thru the small 2"
single opening at the "Y". You ARE well
past the point that it becomes restricitve.

Jose was at ~190 RWHP and picked up 2 with
true duals. Fact.

You should be past 200 RWHP with everything working right.

98GreenStallion · 03-04-2005, 08:38 PM


Quote: Originally Posted by RGR Post pics, I've done exhaust work (it's pretty easy) but the Muffs should bolt up once the H is on there. You still have the stock "Y" in there now? It could be part of the problem, any system that keeps the stock "Y" is not really duals, cuz everything has to flow thru the small 2" single opening at the "Y". You ARE well past the point that it becomes restricitve. Jose was at ~190 RWHP and picked up 2 with true duals. Fact. You should be past 200 RWHP with everything working right.

I no, I dont still have the Y crossover, as I have no crossover at all... sorry for the confusion

I will take some pis but I dont have the exaust yet... but I know from looking at pics and looking under my car that its going to be an enteresting installation. The only way I know how to put it is my current setup is welded and has no bolt on connections, and the h-pipe Im getting does. So I wanna know how I would go about that, also, my muffler have the 2.25 inlet/outlets and the h-pipe is 2.5. So I guess I would just ignore the bolt on connection on the H-pipe, cut the current pipe off where previously welded and try to weld the h-pipe on like that?

97Stallion · 03-04-2005, 08:54 PM

Well what I did was buy some GT-take offs and then I bolted up my O/R h-pipe my self and then I bolted on the GT take offs and suspended the rear side and had a shop weld the tail pipes on. that way I have a "bolt on" exhaust.

97Stallion · 03-04-2005, 08:56 PM

How much did you or are you paying for you exhaust parts. I have them at my site for $438 shipped

coolstang · 03-04-2005, 11:01 PM

Here's my problem my grandpa doesnt want me to have the cats taken off my car so what should i do? Go with chrome short tube header or stay with the stock headers. Just wondering

**Brent** · 03-04-2005, 11:05 PM

Stay with stock headers unless you plan on going inside the engine and doing a head/cam/intake swap or adding a power adder

97Stallion · 03-05-2005, 12:30 AM


Quote: Originally Posted by coolstang Here's my problem my grandpa doesnt want me to have the cats taken off my car so what should i do? Go with chrome short tube header or stay with the stock headers. Just wondering

Or you could go with some hi-flo cats. You won't be taking them off, just replacing them with something more efficient hp wise.

RGR · 03-05-2005, 08:09 AM


Quote: Originally Posted by 98GreenStallion I no, I dont still have the Y crossover, as I have no crossover at all... sorry for the confusion I implied the wrong thing, my bad! I will take some pis but I dont have the exaust yet... but I know from looking at pics and looking under my car that its going to be an enteresting installation. The only way I know how to put it is my current setup is welded and has no bolt on connections, and the h-pipe Im getting does. So I wanna know how I would go about that, also, my muffler have the 2.25 inlet/outlets and the h-pipe is 2.5. So I guess I would just ignore the bolt on connection on the H-pipe, cut the current pipe off where previously welded and try to weld the h-pipe on like that?

You really need a 2.25" H-Pipe or even better, 2.5" mufflers.
Bad situation going with a bigger mid pipe then smaller again.

RGR · 03-05-2005, 08:10 AM


Quote: Originally Posted by Brent Stay with stock headers unless you plan on going inside the engine and doing a head/cam/intake swap or adding a power adder

What he said, unless it is a 99^ then use 94-98 shorties.

98GreenStallion · 03-05-2005, 09:33 AM


Quote: Originally Posted by RGR You really need a 2.25" H-Pipe or even better, 2.5" mufflers. Bad situation going with a bigger mid pipe then smaller again.

Danget! So it would be better if I went with a whole new cat-back system? I never can get outta anything for realitively cheap!

So if I went with another cat-back, what would you fellows recommend? I would guess MAC sice that would just bolt right up with the H-pipe.

Ohh and, if I do get a WHOLE new exhaust, them my current setup will be put up for sale. So if any one wants some stock headers down to cats, then custom mid pipes (2.25) that are welded so some awesome spintech prostreets (about, 14,000 miles) and come out with 3 inch slanted chrome tips, let me know... Ill let it go for a reasonable price.

RGR · 03-05-2005, 09:48 AM

You could temporarily get reducers, but that is not ideal.

Do you have the "H" yet?
Does it come in 2.25"???

98GreenStallion · 03-05-2005, 09:52 AM


Quote: Originally Posted by RGR You could temporarily get reducers, but that is not ideal. Do you have the "H" yet? Does it come in 2.25"???

no I dont have the H yet, but I believe it only comes in 2.5 (which is kinda what I want anyways)

Take a look at these diffrerent MAC cat-back systems and let me know which would be best for my setup, I dont think I need to get the one for 3.8 as it appears to come with some sorta y-pipe adapter.

http://motors.search.ebay.com/MAC-ex...Z6000QQsaspiZ2

RGR · 10:21 AM

You could the SpinTech flanges cut off and made larger...

Knowing how they are made, it is possible.
You could also leave the tailpipes as-is but add dumps
out the back of the Spins

removable ones beside
the tailpipes. Open them at the strip!

98GreenStallion · 03-05-2005, 10:22 AM


Quote: Originally Posted by RGR You could the SpinTech flanges cut off and made larger... Knowing how they are made, it is possible. You could also leave the tailpipes as-is but add dumps out the back of the Spins

Why would it be so bad to go from 2.5 to 2.25 at the mufflers? Its not even that much of a difference. Surely it woulnt hinder me all that much...

RGR · 03-05-2005, 10:29 AM

It won't kill you but the bigger pipes reduce velocity, then it has to
speed back up at the mufflers. Best to be small to large or same
all the way thru. It is never advisable to taper down in exhaust sizing.

RGR · 03-05-2005, 10:31 AM

If yo u keep the 2.5 H and 2.25 muffs, use good reducers, that will minimize turbulance.

98GreenStallion · 03-05-2005, 02:14 PM

Arg, well I might just go ahead and get the MAC cat-back so I dont have to do much (if any) welding at all, mainly just because I dont wanna do alot of welding with my arc welder, definately not the best welder for the application.
So what I might do is get the MAC cat-back, but what I wanna know is... which should I look in to the one fore 94-98 3.8 or the one for 96-98 4.6 or what?
Also, what all will I need as far as O2 extentions and MIL elminatiors go? Although I dont think my CEL works anyways so it doesnt really make any difference unless the MIL will add horsepower. Besides I think Mik said he could turn off the CEL when I get the re-burn which hopefully will be some time in april-may. Will I need the O2 extentions with the long tubes though?