AGO

One more time reaching out to the vast experience of Rennlist community, this time as we were getting a bypass for the center muffler we realized that the side mufflers are cracked, both on the same place on the seam that faces to the back of the car right under the smaller of the two pipes that connect to the center muffler. It has been running like this for a while as you can tell there is some exhaust residues on the heat shield.

Is this something common? Anybody had a similar failure?

My goal was to keep volume checked and the center bypass was sufficient to satisfy my need for noise.

Options?
1- It seem that can be welded, but not sure about materials, integrity, etc.
2- Alternatively a new muffler is quite expensive, I wanted to keep volume checked but also want to have a cost effective solution...
3- Aftermarket, but as commented did not want to increase the DB ... any recommendations? I saw Tubi keeping side mufflers as an example, not sure how loud with a bypass will result...

Comments and inputs much appreciated!

Thanks!

JB911

I think Fabspeed and M&M might have the most options if you want a substitute for side mufflers-check out websites, and FVD seems to be the distributor in the US for M&M.
I ended up keeping my side mufflers with FVD center bypass for now but was considering side deletes with valves. That might be a good choice for you if you still have the OEM center.

AGO

Makes sense, clearly one of the options I was considering is the side delete with valves.

Thanks!

chasen1211

careful with side deletes with valves, the car gets a bit more drone.

AGO

What about without valves?

zumaron

More drone and ears bleed. Find a good shop and get them welded. Run center bypass. Otherwise, be prepared to spend $$$ in quest to find your preferred tone. Enjoy!

Spyerx

Drone is very individual dependent. I've had side delete no valvaes and oem center for 3 years and I feel the car while not super quiet is very tolerable and doesn't drone. Well at full tilt it's a bit loud. In a good way.

FLT6SPD

I have cargraphic headers catted and valved with side delete and stock center, no drone at all on .1, typical 4k howl but screams at 6k+.

I also have evoms catted headers on my .2 stock sides and sharkwerks bypass which sounds louder and angrier over entire rpm range, still no drone.

993GT

I did a BBi side delete on a 7,1GT3 recently and sound is nice to my ears....but my straight pipe GT2 may have broken them,,lol
If I had a GT3, side deletes would be the way I go...from a weight/simplicity perspective.

Tom@TPC Racing

AGO,

If you are already planning on installing an aftermarket center muffler then any aftermarket side muffler bypass pipes will increase sound level over the OEM side mufflers. The ones with valves will produce lower sound decible at lower rpm when the valves are closed. When the valves are open they sound the same as the non-valved side muffler bypass pipes.

I have two options I can offer to you:

1) A used pair of OEM side mufflers in good condition(no cracks, no dents) for 600.

2) Hand-crafted stainless side muffler bypass pipes with valves. Link- http://www.tpcracing.com/gt3-active-...er-bypass.html

PS- I have not seen any side mufflers crack so this occurrence is uncommon to me.

jaundice

So how loud would it be to add side bypass pipes if I already have the center bypass and catless headers?

JK. It would be straight pipes with no mufflers at all.

Protocav

Not to say that your side muffler delete plan is bad in any way, but mine also cracked and I welded the seams back up. Piece of cake. I pulled the mufflers, but this can easly be done in place with the rear bumper off.

Either way is good, one is more expensive.

AGO

Here are the cracks...

Left side


Right side




Tom, thanks for the info as it helps to figure out the direction to go. Do you know approx. miles or use on the OEM's you have?

Protocav, good to know that welding may be an option. How long since you've done it, is it holding ok?

Protocav

Been about two months, and 3 trackdays, holding fine.

Those are worse than mine, but definitely still correctable.

runet

I have the non-valved side delete pipes (Cargraphic) and OEM center muffler but I'm thinking about the valved version from TPC to bring sound levels down when needed. Do you have any measuements for the sound with valves both closed and open? On local trackdays noise limits are measured at 4500rpm at 45 degree angle, 0,5m from exhaust. I am now at appr. 102dB, would be nice to how many dB the valved version can lower the static noise at a given rpm.