Headers & GMMG Exhaust
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From: UAE
Headers & GMMG Exhaust Hey guys, hope you’re all doing well.
I recently installed the GMMG exhaust & SLP lid on my 02 WS6 and I’ve been thinking about adding headers, let me just say that the GMMG exhaust sounds awesome and I don’t regret installing it, it has a distinctive sound to it that I’ve never heard on an exhaust before. I just hate the rusted looking OEM Headers and thought about upgrading them.
I’ve researched a bit and found that I’ll also need to get a catted Y pipe to avoid the raspy sound and overly loud noise, thinking of a TSP long tube headers with a catted y pipe, or ARH long tubes with their catted Y pipe, not sure about getting one from Kooks. But my main concern before buying is not just the sound but fitment as well, read some threads where the TSP headers got some fitment issues. just going for something with a quality build to help the exhaust flow better and get some refined note as well without having any problems while installing as I’m also getting lowering springs and panhard adjustable bar.
I appreciate your feedback on this. Thanks guys 👍
I recently installed the GMMG exhaust & SLP lid on my 02 WS6 and I’ve been thinking about adding headers, let me just say that the GMMG exhaust sounds awesome and I don’t regret installing it, it has a distinctive sound to it that I’ve never heard on an exhaust before. I just hate the rusted looking OEM Headers and thought about upgrading them.
I’ve researched a bit and found that I’ll also need to get a catted Y pipe to avoid the raspy sound and overly loud noise, thinking of a TSP long tube headers with a catted y pipe, or ARH long tubes with their catted Y pipe, not sure about getting one from Kooks. But my main concern before buying is not just the sound but fitment as well, read some threads where the TSP headers got some fitment issues. just going for something with a quality build to help the exhaust flow better and get some refined note as well without having any problems while installing as I’m also getting lowering springs and panhard adjustable bar.
I appreciate your feedback on this. Thanks guys 👍
I have TSP headers, the collectors are close to the floorboard. If you have poly engine mounts this should ok, but if you're running rubber you'll likely have issues with them tapping on the driver's side.
I didn't have any other issues, they cleared the k-member without any trimming.
I didn't have any other issues, they cleared the k-member without any trimming.
Thread Starter
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Joined: Jan 2015
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From: UAE
I have TSP headers, the collectors are close to the floorboard. If you have poly engine mounts this should ok, but if you're running rubber you'll likely have issues with them tapping on the driver's side.
I didn't have any other issues, they cleared the k-member without any trimming.
I didn't have any other issues, they cleared the k-member without any trimming.
I had severe fitment issues with TSP headers on my car. With old rubber, new rubber AND poly engine mounts. Collectors pointed up to the floor big time and nothing would slip together. 3 sets later I gave up! Went ARH and never looked back. Fit perfect the first time!
Catless GMMG=get ready for the rasp!! Thats why I ditched mine. My car was already low enough and the ARH have fantastic ground clearance with Strano coils. I didnt want to jeopardize that by adding crap to my I pipe or Y. I scrape on nothing as is. I have seen guys add a Magnaflow 14419 to the intermediate pipe to tame things down a bit.
Catless GMMG=get ready for the rasp!! Thats why I ditched mine. My car was already low enough and the ARH have fantastic ground clearance with Strano coils. I didnt want to jeopardize that by adding crap to my I pipe or Y. I scrape on nothing as is. I have seen guys add a Magnaflow 14419 to the intermediate pipe to tame things down a bit.
Thread Starter
TECH Apprentice
Joined: Jan 2015
Posts: 310
Likes: 55
From: UAE
I had severe fitment issues with TSP headers on my car. With old rubber, new rubber AND poly engine mounts. Collectors pointed up to the floor big time and nothing would slip together. 3 sets later I gave up! Went ARH and never looked back. Fit perfect the first time!
Catless GMMG=get ready for the rasp!! Thats why I ditched mine. My car was already low enough and the ARH have fantastic ground clearance with Strano coils. I didnt want to jeopardize that by adding crap to my I pipe or Y. I scrape on nothing as is. I have seen guys add a Magnaflow 14419 to the intermediate pipe to tame things down a bit.
Catless GMMG=get ready for the rasp!! Thats why I ditched mine. My car was already low enough and the ARH have fantastic ground clearance with Strano coils. I didnt want to jeopardize that by adding crap to my I pipe or Y. I scrape on nothing as is. I have seen guys add a Magnaflow 14419 to the intermediate pipe to tame things down a bit.
Last edited by d-mob; Aug 29, 2023 at 12:20 PM.
I had severe fitment issues with TSP headers on my car. With old rubber, new rubber AND poly engine mounts. Collectors pointed up to the floor big time and nothing would slip together. 3 sets later I gave up! Went ARH and never looked back. Fit perfect the first time!
Catless GMMG=get ready for the rasp!! Thats why I ditched mine. My car was already low enough and the ARH have fantastic ground clearance with Strano coils. I didnt want to jeopardize that by adding crap to my I pipe or Y. I scrape on nothing as is. I have seen guys add a Magnaflow 14419 to the intermediate pipe to tame things down a bit.
Catless GMMG=get ready for the rasp!! Thats why I ditched mine. My car was already low enough and the ARH have fantastic ground clearance with Strano coils. I didnt want to jeopardize that by adding crap to my I pipe or Y. I scrape on nothing as is. I have seen guys add a Magnaflow 14419 to the intermediate pipe to tame things down a bit.
Thread Starter
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Joined: Jan 2015
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From: UAE
Oof, three sets later. You have a lot of patience. @d-mob ARH is probably going to work out fine for you. I went with TSP because it was still stainless, it was half what ARH and Kooks were charging, and I figured I could fix any issues.
You’re right, the cost was what drew me to TSP in the first place as well as the material being stainless steel. But I don’t want to run into any issues or fitting problems so I better spend the money 💰 one time and get a decent set.
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Oof, three sets later. You have a lot of patience. @d-mob ARH is probably going to work out fine for you. I went with TSP because it was still stainless, it was half what ARH and Kooks were charging, and I figured I could fix any issues.
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I'm running TSP 1 7/8" long tubes and GMMG. I didn't have cats for the first 3000 miles after the LS3 swap and didn't like it. I have an electric cutout and it barely made a difference in sound because it was already so loud. The rasp is only bad between 2-2700 rpm but 2K is where I do my city driving so it was a big deal. Drone was also terrible on the highway. I installed 2 magnaflow cats and it really mellowed it out, rasp is gone. Still a tiny amount of drone around 2K but more than tolerable in my opinion.
As far as fitment, I literally just slid the headers straight up from below and they bolted in no problem.
As far as fitment, I literally just slid the headers straight up from below and they bolted in no problem.
Last edited by AdsoYo; Aug 30, 2023 at 07:12 PM.
Thread Starter
TECH Apprentice
Joined: Jan 2015
Posts: 310
Likes: 55
From: UAE
I'm running TSP 1 7/8" long tubes and GMMG. I didn't have cats for the first 3000 miles after the LS3 swap and didn't like it. I have an electric cutout and it barely made a difference in sound because it was already so loud. The rasp is only bad between 2-2700 rpm but 2K is where I do my city driving so it was a big deal. Drone was also terrible on the highway. I installed 2 magnaflow cats and it really mellowed it out, rasp is gone. Still a tiny amount of drone around 2K but more than tolerable in my opinion.
As far as fitment, I literally just slid the headers straight up from below and they bolted in no problem.
As far as fitment, I literally just slid the headers straight up from below and they bolted in no problem.
I'm running TSP 1 7/8" long tubes and GMMG. I didn't have cats for the first 3000 miles after the LS3 swap and didn't like it. I have an electric cutout and it barely made a difference in sound because it was already so loud. The rasp is only bad between 2-2700 rpm but 2K is where I do my city driving so it was a big deal. Drone was also terrible on the highway. I installed 2 magnaflow cats and it really mellowed it out, rasp is gone. Still a tiny amount of drone around 2K but more than tolerable in my opinion.
As far as fitment, I literally just slid the headers straight up from below and they bolted in no problem.
As far as fitment, I literally just slid the headers straight up from below and they bolted in no problem.
Joined: Nov 2003
Posts: 6,216
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From: Wichita KS / Rancho San Diego
Thats exactly how mine was! 2-2800 it would machine gun rasp so bad I did everything I could to avoid that RPM range. Leaving lights I would just blast through the gears so it never hung in that rpm. The rasp and drone got so freaking old. I bought a Magnaflow 14419 muffler to put on my I-pipe but never got around to it. I got a stupid good deal on the dual tip Magnaflow catback and tossed that on.
I ended up installing a Flowmaster merge, cats, a powerstick, and resonator tips on it and then it sounded good. But the system was ridiculously heavy.
I finally ditched the GMMG and all that extra stuff for a Hooker Maxflow. It gave equally good sound and i've been happy with it ever since.
Thread Starter
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From: UAE
I had the GMMG with stock manifolds and cats and loved it. But when I installed long tubes and ORY, it rasped like a jackhammer. It was intolerable.
I ended up installing a Flowmaster merge, cats, a powerstick, and resonator tips on it and then it sounded good. But the system was ridiculously heavy.
I finally ditched the GMMG and all that extra stuff for a Hooker Maxflow. It gave equally good sound and i've been happy with it ever since.
I ended up installing a Flowmaster merge, cats, a powerstick, and resonator tips on it and then it sounded good. But the system was ridiculously heavy.
I finally ditched the GMMG and all that extra stuff for a Hooker Maxflow. It gave equally good sound and i've been happy with it ever since.
Thread Starter
TECH Apprentice
Joined: Jan 2015
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From: UAE
Hey guys, just a quick question, when installing LTH and a catted Y pipe is there anything else you’d install while the car is up? And is there anything else required other than a tune at this point?
thanks
thanks
Poly engine mounts are so much easier with no headers in place!!!!
Thread Starter
TECH Apprentice
Joined: Jan 2015
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From: UAE