Stock Muffler & Hangers w/ R comps
 

I wanted to bring this up since it has happened on multiple occasions now. Once I switched to R-comps (NT01s), I have had the entire OEM muffler assembly fall off 3 times at 2 different tracks; it literally pops off the hangers and falls onto the ground during high G load cornering, dragging down the track.

So a few months ago I didn't have time to swap the muffler off for the muffler delete before a track event at Sebring, and first session out a few laps in the entire assembly falls onto the ground during cornering and trashed the midpipe. That was the first time I had the stock muffler on when running R-comps (215 NT01s). Luckily the safety crew helped me put it back up so I could drive back to the pits. So I put the muffler delete on at the track and ran fine the rest of the day.

Fast forward to this weekend, I just had a RevWorks UEL header installed, and am running a cat delete, so I ran the first day at Road Atlanta with the muffler delete, and it was just too loud. So I swapped back to the OEM muffler, made sure there was no lubricant on any surface, triple checked it was secure, wiggled back and forth really hard and couldnt get it to pop off at all. So the first session out, 3 laps in at Turn 6 I heard it fell off. Safety crew arrived, and the OEM hangers were still on the muffler, so I went to touch them and they were a lot softer than they were when I initially installed the muffler, and we were able to re-hang the muffler back on with ease, as the metal brackets slipped in with ease.

After we brought it back into the pits, we installed C clips ( like this: http://ecx.images-amazon.com/images/...vL._SX300_.jpg ) in front of every hanger to prevent it from poping off, and ran 2 more sessions with no more issues.

So the issue boils down to the combination of the super heavy OEM muffler, increased cornering load with the R-comps, as well as the OEM exhaust hangers stretching more than they should when hot, allowing the muffler to slip off. Next up are Polyurethane exhaust hangers, and we'll still install the C-clips behind them for good measure.

Just a heads up to anyone else who is going to be running a OEM muffler with R-comps.

Kartboy and Perrin both sell direct fit better hangers, probably a good upgrade for anyone tracking their car.

I'm running the Kartboy hangers with my Perrin exhaust, their exhaust also has clamp on keepers as well.

Perrin bushings on my hangers, I'm running R-Comps too. No issues.

Weird, I've been stickier r-comps (225 Hoosier R6's) with stock muffler for 5 events this year and haven't had any issues with my stock exhaust on stock hangers. They even survived hitting some roadkill that ripped my diffuser off on the way to the track.

Do you have any data to see what kind of G load you are seeing in the corners? Not saying this is you, but I know plenty of people that are running DOT slicks and R comps that are no where near the car's or tire's limits. We're at 1.2 G's according to the AIM Solo DL data on the corners that the muffler has fallen off.

interesting I have been using the same exact tires and even wider size (235/40/17) ever since I purchased this car and attended about 9-10 events so far with 3 different exhausts (stock, Tsudo and Invidia Q300 catback exhausts) and never had this issue.. and I am pretty sure my car sees a lot of lateral Gs ;) I think your issue is the softened hangers most likely due to extreme heat in Florida, I used to live in Tampa Bay so I know how hot it gets during the summer :)..

I've managed to hit 1.78g according to my Solo DL, but usually I'm more consistently in the 1.4-1.6g range.

Before with my S13, if I had issues with hangers popping off I just zip tie the crap out of them to prevent movement.

Probably better than clips and easier to replace, too.

-alex

Strange, we never had issues, but keep us posted!

I think you need to sanity check your data there....1.8 lateral g....yea no....just becuase your logger says it doesnt mean its real or sustained.

just curious, have you encountered any oil starvation issues with the R6s? Have you been using any sort of baffled plate and/or dry sump in your car?

It wasn't sustained, just peak, which is probably why I don't have any issues with oil starvation. I'm pretty sure its real though. Managed to crack my windshield that weekend. Went into turn 1 with no crack, came out with one.

@smbstyle this is John....I was the one with the black FR-S that was riding along....just thought I would say hi. Hopefully you resolve the issue, I can vouch that the g load plus hopping the curbing at turn 3 will definitely knock it off

Hey John! Glad you have you out there, it was a good weekend! Yes the turn 3 curbing with the passenger side going airborne may definitely help the muffler come loose lol

And if anyone is wondering what a straight pipe exhaust sounds like at full tilt on track....

@THEmailman is in the video too


[ame="https://www.youtube.com/watch?v=H9YF6BJ2fOM&list=UUI7_3qVwegS7kgSt8P_D3Yw"]https://www.youtube.com/watch?v=H9YF6BJ2fOM&list=UUI7_3qVwegS7kgSt8P_D3Yw[/ame]

I've hit 1.29G using the Solo DL on 245/40R17 A7s autoxing.

Haha. I am a former S13 owner and I find it funny how everything on those cars can be fixed with zip ties. Never thought of this though.

I switched to Perrin mounts when I installed the cat back. Running on 710's with no issues but I only pull a "measly" 1.2 G's as well :D

Still no issues? I just dropped my exhaust coming through the Watkins Glen Bus stop. Three aftermarket PU hangers of unknown provenance had gotten hot, stretched, cracked, then failed completely. Thereafter the two remaining (autozone) hangers failed. Trying to decide whether OEM hangers will be enough or if I should take this opportunity to reinforce.

I stick to OEM hangers; they're compliant and will flex quite a bit without failing, if/when needed.

As with all other rubber parts, they do *eventually* get dry and brittle....

I believe CSG has OEM hangers in stock!

Thanks, but so does my local Subaru dealer. Seems like another point to add to the inspection routine...