peteggl

I have a '99 trans am cammed with longtubes, a gmmg catback, a ptc 4000 stall, 3.73 gears and a few other things. Frankly the car is getting unbearably loud at interstate speeds (which is mostly where I'm driving) I'd like to know how much power if any I would lose swapping out the gmmg exhaust with a stock exhaust and no cats and adding an electric cut out around where the cats would be (or wherever you guys think is the best place to put one) what do you think?

LuxuryVetteCO

I have tested the hp difference with e-cutouts on a 6.1 hemi open and closed. The gains were within 2-3 whp. That is just one case but i highly doubt you gain or loss will be noticeable. Pre-cat will be louder obviously so it is all personal preference/ how strict your emissions testing is, if you have any. hope this helps

peteggl

no emissions in south carolina, so I can do pretty much whatever I just want the car to not be as loud and lose as little et as possible

ULTIMATEORANGESS

iTrader: (4)

id say a few HP. not a lot.

sokr915

iTrader: (3)

Add a resonator

HCI2000SS

iTrader: (2)

So you want to switch out the entire exhaust back to stock?

reinesos

I just want the car to not be as loud and lose as little et as possible

peteggl

I'd keep the headers but everything else back stock except no cats and a cut out

jig

iTrader: (6)

i would just buy a different muffler instead of putting the stock exhaust back on

MyFirstLS1

iTrader: (8)

why not just go an actual muffled exhaust ?

I recently had to change my exhaust set up because i moved into a townhouse and eneded up going with a borla adjustable and put the cutout where the plates would go. Muffled is damn quiet compared to the GMMGs that I had or with the cutout open.

literally one extreme to the other though what you were thinking

MikeWS6

Stock catback with a cut out is the way to go. My next car will have that setup. I doubt he will lose anything. The GMMG is a full 3" vs the stock 2.75 but the cut out will be less restrictive than the gmmg "muffler".

Blownbayou

iTrader: (7)

slp dual/dual and you will be happy

RevGTO

iTrader: (12)

Get a f-body Magnaflow muffler and build your own catback with Walker-Dynomax I and OTL pipes. That way you avoid the cannon tips of the MF catback. You will actually gain few hp.

I got rid of my GMMG years ago and did that with a Hooker Maxflow single 3" out. But you need dual tailpipes on a T/A.

peteggl

I only say stock because I'm trying to do this as cheap as possible and there is a stock exhaust on craigslist for $50 lol

ULTIMATEORANGESS

iTrader: (4)

i agree. i like mine a lot.


they might be hard to find though.