Picked up a L98 GTA a few weeks ago and was looking into bolt-ons and decided that headers are not in the cards, but want to change out the y-pipe and get a Mufflex 3.5" cat back (like on my Camaro).

Previously I had used Gale Banks Y-Pipes on my 2 LG4 cars, worked great - but they don't make them anymore. It was an easy fix to mate LG4 manifolds to a 3" cat without headers...

So the question is, how is the fit of the Magnaflow 16450 and the Mac 48692 y-pipes on a single 3" cat L98 motored car? Also are they true 2.5" pipes into the 3" merge before the cat? Are the Magnaflows actually made out of SS and the Mac out of aluminized steel? Wondering about the gains anyone has gotten too.

 

http://www.hawksthirdgenparts.com/pr...ifolds%29.html

Mac Performance has, (had), a regular steel one but their site is fubar'ed at the moment.

 

Did see that, but want to keep the cat (which is a brand new Magnaflow high flow)...

 

Picked up the Magnaflow last week - can't wait to get it and the 3.5" Mufflex exhaust installed...

 

I used the Magnaflow 16450, and it's a great piece. Fits nice, sounds great, and I'm sure it flows better than the stock "Y"... I mean "T" pipe.

 

Where did you find a Magnaflow y-pipe for factory manifolds? Never have seen one of those.

 

http://www.magnaflow.com/02product/d...rtnumber=16450

 

What a waste of $400.............

 

$190 at Summit...

http://www.summitracing.com/parts/MPE-16450/

 

How much performance/hp did it actually give you for the $190 spent?

 

They say 5 to 10hp, not all that much. But keep in mind the amount of labor involved in putting in headers for a 10 to 15hp gain - it's not a 2 hour project by any means. All that has to be done with the y-pipe is cut a few manifold to y-pipe bolts and replace them and the y-pipe.

 

Without getting into the pros and cons of headers, if you want to keep the exhaust manifolds this pipe is a good move. If you ever see a stock pipe laying right next to the Magnaflow 16450, you'll know what I mean.

 

And we all know just how honest & accurate the manufacturers hp gain claims are.

Lemme know if you compare dyno/track results back to back or find someone who has tested that way. I suppose even SOP results will be a good thing to hear.

 

Exactly...

Although I did post an old article on the thirdgenfbody blog that shows a good aftermarket y-pipe is worth 5hp on a stock TPI L98 motor. I'm not wasting time on a dyno, since I don't have one in the shop and would hate to pay for just that... Turbo City y-pipe in the article.

http://thirdgenfbody.wordpress.com/2...ft-april-1989/