I just ordered mac midlength headers sterling silver coated. I know this isnt the right order to do things in, but I have an exhaust leak somewhere in the area of the stock exhaust manifolds and y-pipe, so i figured i might as well do this first. Will the stock exhaust cancel out the gains or will I still notice a gain?

 

the exhaust will bottleneck after the y-pipe, but i would think you will still see some gains...it will just be that much better when you get your catback

 

You will see the biggest gains by eliminating the factory manifolds and Y pipe. So I'd say you're doing fine, by doing those first.

 

Well, speaking of doing things backwards, I am looking at getting the same exhaust modifications as you but I am doing it in the opposite order, my GMMG will be coming tomorrow and then sometime soon I will get some Macs and SLP CAI. Good Luck with your car and happy modding. I think we will be the first that I have seen with the GMMG/Macs combo, unless I somehow toss up the extra $400 for Lt's.

Oh and to answer the post, yes you'll get gains but the headers will be at full potential with a nice cat-back.

BTW "Brandon 95 Z28" on this board has Macs with the stock cat-back maybe ask him for input?

Bersaglieri

 

alright thanks for the responses

expensive **** eh Bersaglieri? how soon do you think you will be doing the rest of your setup?

 

Yes, its always expensive but these days what isnt? I was lucky enough to find a used GMMG from Jeff Woods in Texas but even then it cost $500 + 75 for shipping but I got those famous SS oval tips. Anyways, my g/f is planning on getting me the SLP CAI for Christmas (what a great girl huh?) and hopefully after that during break I can afford to get some Macs used or new. The only reason LT's are looking like a second option is b/c of the time comsuming install (I'd have a anger issue and would end up destroying the headers in the heat of the moment) and the overall cost factor. I am however debating coating the Macs, but we shall see. As far as GMMG goes it is the best catback in my opinion and is the next best sounding exhaust option without running duals and even then its a close call depending on the dual's quality. We'll have to keep in touch and compare times/dynos with the set up, maybe even meet up in Indiana somewhere. But good luck and enjoy your car. I let you know how the GMMG sounds when I put it on. Later.

Edit: I talked with a GMMG rep/techie and he said the gains on GMMG are exceptional and they flow so well that open cut-outs give you no gain over the standard cat-back, just some extra info for you. Did I mention it sounds heavenly? Maybe Ill meet you half way just to exchange the Mac/GMMG info on our cars. See ya on the Road.

Bersaglieri

 

NO GAINS? I havent even talked to a GMMG rep yet but thats amazing i was considering cutouts as well, good thing I hadnt bought them.

and congrats to finding it used, thats rare for these. nobody seems to get rid of them. Yeah we should exchange info on our setups once we get them running. Will the GMMG be your first mod?

 

Yeah I have Mc's with the stock catback, but i run a open cutout 24/7, so its basically like haveing a catback because i dont have the restriction of the stock muffler. I never wanted to throw a couple hundred into a catback, and I wanted good performance so I had a cutout welded on for 20 bucks and I love it. But yeah when I cap it (for long trips) I do lose a decent amount of power.
Brandon

 

Well if you are looking to buy a used GMMG search in Ls1.com b/c I saw one for $475 a few days ago you might be able to get still. They are for sale there alot more than here. Yes the rep/tech Matt, was who I spoke with. I had to speak with him b/c I bought a GMMG for a 98-99 Ls1 and I needed him to put together a conversion package to fit the 94-95 Lt1. Of course he said it could be done and just to send him digital pics of the exhaust when it got to me and he would put a kit together. If nothing was altered the kit would be only $15. Pretty good deal I think, but If you call GMMG you'll get Angel and just have her transfer you to someone, just decribe what you are looking for. They have great people down in Georgia, nice southern folk. Yes Matt said there was no gain with cut-outs, even when they tested a Z with a big block. So I think it flows just fine. Great product, and you couldnt convince me otherwise. Yes the GMMG will be my first mod, and no one gets rid of them b/c they are so damn good. Unless they run duals like the guy I bought mine off of did.

Dustin

 

why not just get an electric cutout? cheaper than a catback and you get the biggest performance gain.... cruise around almost stock sounding for just daily driving, flip the cutout open for when its time to get it on.