boostedt0y

I've had a GMG bypass on my .2 GT3 since I purchased my car a few years ago and have loved the sound of the bypass. To my ears, it's the most aggressive sounding of the center bypasses available and I have generally been happy with the setup.

However, as my car is being used more on the track nowadays rather than the street, I wanted to shed the weight of the side mufflers. I found a used set of BBI side muffler deletes as well as Fabspeed sport headers with 200 cell cats. To go along with the new exhaust setup, I contacted the boys at Sharkwerks for their exhaust tips for use with the OEM center muffler.

Also, from speaking to those more knowledgeable than myself, it seems like cracking the OEM center muffler is just a matter of time. So, I contacted Gavin at Autoquest for a set of steel muffler reinforcements to hopefully prevent the center muffler from cracking. Luke at blu808 did a great job tig welding the reinforcements to muffler.

I've only had the chance to drive the car for 20 min, but so far I'my happy with the setup. The car is a bit louder at the low rpm range compared to the OEM header/GMG bypass setup. At the higher rpm range the new setup is almost as loud as the OEM header/GMG bypass setup, if not a tad bit quieter. With the OEM header/GMG bypass setup I blew 104.1 db at Thunderhill for reference so my old setup was quite loud.

The tone of the exhaust is throatier compared to the GMG/OEM header setup and makes all sorts of burbles and pops now. The exhaust sounds amazing and I'm really happy with how the exhaust turned out. There is a little bit of drone between 2.5-3k, but doesn't bug me too much as I'm not super sensitive to drone. I'd say that's the only downside of the new setup.

From the butt dyno, the car also seems a bit more peppy now which is a nice plus.

Below are some pictures of the headers, center, muffler and some before and after videos. Enjoy.






Click on the photobucket videos which links to each video.
http://vidmg.photobucket.com/albums/...y/IMG_4110.mp4
BBI side delete w/ Fabspeed headers
http://vidmg.photobucket.com/albums/...y/IMG_4111.mp4

Spyerx

Interesting. I've had cup 100cell headers on mine and side deletes and many track days with no center issues. The ti ones are like paper mache. I know guys had cracking issues on the RS. Maybe the 3.8 is harder on muffler.
What does Gavin charge for those reinforcements.

boostedt0y

$98 for the reinforcements. I figured they were cheap enough for the extra piece of mind.

chillindrdude

Those with reduced cell cats, any issues with cel? Or are you guys running a spacer?

boostedt0y

Yes the Fabspeed headers use 200 cell HJC cats versus 400 cell cats in the OEM muffler. So far I haven't had any issues with a CEL with the O2 sensors contected directly to the headers. If a CEL is thrown I'll have to run a spacer.

garyever

Last winter I dropped the side mufflers, reattached to the center muffler with the BBI coupling pipes and for one tract season everything has held together without issue. My .1 GT3 went on a -100 lb weight reduction program last Winter and dumping those 45lb mufflers along with some other heavy stuff, has defiantly shown up in my lap times. That under 2500 drone is a little irritating, but once out of the pits, I rarely hit it again.

PS--Those banjo clamps loosen up for a while with the hot and cold expansion and contributes to the drone, so tighten them 2-3 times over a month or so and that will stop

John@Fabspeed

Excellent post and great feedback on the combination! My recommendation to most all my GT3 clients is our headers (sport/race depending on street/track use and sound level) with our valved side muffler bypass pipes and factory center muffler. Seems to be the golden ticket combination for the GT3 platform haha.

Let me know if there is anything else I can help you with, and enjoy!