Hey guys whats up, I'm thinking about getting a GMMG to replace my Magnaflow, but I have a few questions.

1.) I was looking at pics of the system and the end of the I-pipe dosent look like it will hook up. I have 95 style headers so I'm using the S-pipe that came with the magnaflow, and I also have an s-pipe from thunder racing. It seems like the GMMG would slip over the s-pipe but the s-pipes I have are made for the exhaust to slip in. I definetly DON'T want to get it welded, so do they make it any other way? Or does somebody make an S-pipe that exhaust can slip over? Or are the pics I've looked different?

2.)How does it sound with headers and no cats? I don't mind drone to much, but I'm not crazy about rasp.


Thanks!

 

http://dodds.cc/chad/garage/z28/ls1_sounds/gmmg.htm (sound demos)

I wouldn't mind getting it myself. Can't answer your other questions though.

 

1.) Well, I don't know if this will help any, but I'll try...GMMG only produces the same cat-back system for any '93-'02 4th generation F-body (this includes a standard 3" I-pipe). I have it on both my '95 & '02 Z28's. On the single cat '95, the muffler shop that put it on my car did NOT need an "S" pipe or install kit to get it fitted (nor was it welded). All they did was cut a little bit of the end of the I-pipe to make it work. Basically, it fit like a glove and I've had NO issues with it whatsover. Any good exhaust shop can make it fit correctly.

2.) I first put it on my LT1 behind stock manifolds & cats (definitely a nice sound). I then added the single cat MAC headers without a cat (used a 12" Dynomax Bullet muffler right after the Y) and I honestly did not like how it sounded...It's not raspy like with a true offroad pipe, but it sounded tinny in the mid rpms and wasn't as deep...I then replaced the bullet muffler with a Random Tech highflow cat and it made the GMMG sound MUCH better IMO...It is really deep again and the tone is clean all the way through the rpms...Sounds very, very mean when you get on it! I've also heard another board members car on here with the MAC's, no cat, & GMMG and I didn't care for the rasp in the mid range. It is truly the best sounding exhaust (cat-back or true dual) at WOT I've ever heard (none deeper; Period.). There is a good reason why I run it on both my LT1 & LS1. But I personally would only use it with a good highflow cat (or cats)...

Mike

 

Hhmm, I was trying to get away not getting it welded, so basically it doesn't bolt right up? I was looking at slponline.com and there s-pipe looks like it would fit into the i pipe. I have a bullet muffler from my old texas speed cat-back i guess I could put that in there if it is to raspy.

 

It does bolt right up! BUT you have to cut your stock I-pipe right after it bends back to straight back (parallel to the driveshaft). You the use the clamp to bolt the GMMG I-pipe to the S-piece that is left of your stock I-pipe. This is what I did to make it fit on my car and it works great. If you don't want to cut your stock I-pipe, there's an adapter that SLP make to fit the Loudmouth (I think) to a single cat car that you can use. All it is, is the S-piece...

HTH

BTW, I am VERY pleased with my GMMG! It sounds very deep and does not have any drone or rasp anywhere in the rpm range. I wanted an exhaust that sounded good not loud and the GMMG is perfect in that way. It's only loud when you really put your foot down!

Sam