MSM Axleback Power Limits
 

First of all, sorry for the noobish post, but I haven't been able to find anything relevant online.

Any idea what kind of power limits you'd expect from a MSM muffler? I know there are a ton of low 200whp MSM's running around but it seems like they've all changed out the exhaust. I've got a catless 3" downpipe that I was planning to run through the MSM muffler that I had on the car when n/a.

Are there any serious drawbacks (other than the obvious diminishing power) to seeing how far it'll go? Potential damage to the turbo or drivetrain? I'd love to see 300whp out of a super stealthy stock exhaust, I just don't want to damage anything trying to get there.

No damage to turbo or drivetrain from what I know. MSM exhaust will never see 300whp :dunno:

You're better off with 3" all the way back for allofit spool and using that elite magnaflow straight through muffler. It sounds fairly quiet from what I can tell. @EO2K I believe has one as well as a few others here.

Tried this on my Ti MSM. after a little while it started rattling like crazy, which is why I switched it out. I also think it will choke you up like crazy at 300whp, but try it and see what happens.

It pretty much chokes at 220ish from what I've seen. You don't want your backpressure skyrocketing on a turbo car, your engine won't appreciate it

Have you pushed one enough to know where it becomes a major restriction? I don't have any idea what to expect out of it.

*Edit - posted before I saw 18psi said ~220hp. I think that's worth playing with. It might be nice to have a super quiet muffler to swap on for long trips.

I've got a NA 3" Enthuza I was planning to have the hangers moved to fit my NB. I just figured I'd research the MSM muffler a little more since it's already mounted and would be easy to just cut the midpipe and add a flange vs hacking up a nice Enthuza.

The NA enthuza will not move to the NB. It is way to different in the mid pipe section to work.

I only ever went to 230 something on the msm, so no.
but on my '00 I did have stock exhaust for a while (same as msm, just ever so slightly more restrictive) and even with a 3076R at 7-8psi it didn't go past low 200's. I think 207 or something was what it did.

Then I installed full exhaust and result was DRASTIC. Went from traction in all gears to no traction in 1st and 2nd. big change

I have a customer running a BEGi turbo kit (log manifold), GT2560, BEGi's midpipe with high flow cat and a stock MSM muffler. A couple weeks ago I tuned the ECU and made 265hp at 16psi at the wheels on a Dynojet (torque was around the same value, but I do not recall exactly). We asked ourselves the same question so, we removed the muffler and made another run. No change, the power and torque were virtually identical to the previous run. Boost level did not change nor did AFR. The stock MSM muffler is not holding the car to 265hp. On a previous iteration of this car, when it had a GT2860, it made 277hp through the MSM muffler.

Wow, that sounds a lot more hopeful. Thanks for the feedback.

That's odd, I had way different results.

Welp, one thing to do: test this out and post back to back results OP. Should be simple enough to be enjoyable, for science :party:

I got my 3" catless downpipe necked down into the rear section of my MSM exhaust. My wastegate is dumped, so that exhaust is bypassing the muffler. The stock MSM exhaust starts about 2 feet before the axles. I just got the exhaust installed so I haven't really seen what it will do yet, but so far it seems to be holding up really well.

Made a couple back to back pulls at 10psi on Virtual Dyno that look promising. This was on E85.

Attachment 182926

I got my EBC working, still needs tuning and the car is rich in the 200kpa row (my wideband reads 0.5 lean), but I think I'm finding the limits of the MSM exhaust.

160kpa logged 260whp
200kpa logged 283whp

Weather is a good bit warmer now, but almost 6psi bump for just 23whp seems like I'm heading for a losing battle and I'm clearly losing some significant spool time too.

Attachment 182919