Supersprint powerloops vs Remus (with catless headers)

[filtercoffee]

Hi Folks, thought I'd share my muffler mod experience and get your opinions on the whole ordeal.

The first exhaust mod I did was Status gruppe catless headers. It makes the sound much more raw; when you blip the throttle you can distinctly hear the exhaust pulses, it kind of barks like a straight piped motorcycle. But I wanted more sound and I disliked how the stock mufflers appear from the back (hanging nuts, some say).

I originally wanted the RPI but was warned about drone and volume, so I opted to try Supersprint powerloops. ALL the posts I've read said they're not too loud, zero drone, etc. First impressions were, there was more bass and more volume than I was expecting. Also I thought it was a *little* too much volume when I was not really on it. But after a while the sound really grew on me and I was exhilarated to drive the car every single time. However once the mufflers warmed up, after a long drive, there was an unmistakable drone between 2k and 3k RPM. Also when driving with company on the highway, I was embarrassed at how loud the car was going at 80 mph (it doesn't help that I have a 3.91 diff and I have to go 3k+ RPM). The sound was addicting - I constantly wanted to push the accelerator to hear the sound.

The drone when driving around town eventually got to my nerves and I opted to try the Remus muffler. From outside, these sound great - nice and throaty. But when in the car, they sound mellow compared to the powerloops. I can hear nice treble noises but the bass (and NVH) was gone. However now I miss it!

I added an AFE intake at the same time as the remus, and it's amazing, but I still miss the excitement of the supersprint powerloop mufflers. I wonder if there's some way to just reduce the drone. I'm not too optimistic about dynamat. I've heard that adding small resonators or a J-pipe can help. Does anyone have any recommendations? Any experience corroborating this experience or is something wrong with my powerloops that's making them so loud once warmed up?

[XMetal]

I'm not sure what it is with our cars, but our exhaust seems to get louder after it's warmed up regardless what exhaust you run. I've had several exhausts and all of them do it. If you pay closer attention, your Remus should also get louder after a long drive. So, I don't think there's anything wrong with your powerloops' behavior.

[3002 tii]

J pipe would help but you really don't want to modify SS cans imo. That sounds like a potentially expensive experiment that could kill resale value.To me, the easiest and least costly options seem to be either add a cone insert in between x-pipe and cans (though that'll rob you few hp) and/or weld-in bottle "shorty" resonators/mufflers along your x-pipe. Sample links provided below but I have no idea if any of these will fit. You'll need to do your own due diligence on ID/OD measurements, and clearance (width & height):

Cone Inserts link
Shorty Resonator - link

[ZeD4Mr]

Originally Posted by filtercoffee

Hi Folks, thought I'd share my muffler mod experience and get your opinions on the whole ordeal.


I originally wanted the RPI but was warned about drone and volume, so I opted to try Supersprint powerloops. ALL the posts I've read said they're not too loud, zero drone, etc. First impressions were, there was more bass and more volume than I was expecting. Also I thought it was a *little* too much volume when I was not really on it.

Loudness and drone is all relative. Powerloop is one of the quietest exhaust. After I ran and got used to RPi, when I changed back to Powerloop, I thought there wasn't an aftermarket muffler there at all at any RPM.

Now with Bluewave built-in J-pipe. I'm happy as a clam. Still way louder than poweloop but minimum drone. You best bet is to try small resonator on the X-Pipe like above suggested. There's minimal room to weld in a J-Pipe long enough to be effective.

[3002 tii]

Originally Posted by ZeD4Mr

Loudness and drone is all relative. Powerloop is one of the quietest exhaust. After I ran and got used to RPi, when I changed back to Powerloop, I thought there wasn't an aftermarket muffler there at all at any RPM.

Now with Bluewave built-in J-pipe. I'm happy as a clam. Still way louder than poweloop but minimum drone. You best bet is to try small resonator on the X-Pipe like above suggested. There's minimal room to weld in a J-Pipe long enough to be effective.

Relative is a good point. After owning both a coupe and roadster, I realize the roadster has trick acoustics so you have to factor in chassis when reading reviews. With the canvas top up, it lets in a lot of outside noise compared to the coupe. But with the top folded down, it acts as a nice sound barrier from the trunk and then you get the best of both (hearing the exhaust w/o the drone).

Btw one last option is to keep the Remus but run a straight pipe section 1 which will definitely increase sound but you then have to worry about emissions if you don’t have software already.

[filtercoffee]

Thanks for the suggestions!
I emailed supersprint and they mentioned adding in some small resonators might help. Those shorty ones look great and are cheap. The issue is I don't yet have an exhaust shop that I can trust.

Had more roadtime with the Remus, I'm getting used to it. My rational mind is saying this is the perfect exhaust if you have headers. The tone is great, the volume is very proportional to throttle position - quiet when coasting, a nice throaty growl when you're on it. But the powerloops were exciting on an emotional level.

I think there must be some kind of internal chambering in the Remus that cancels out all the bass at the drone frequency. No matter how much I floor it, the bass layer of the sound of the SS powerloops is just not there. I don't think straight pipe section 1 would change that.

For now I'm living quite happily with the Remus. I would love to try those shorty resonators but I don't know of a good exhaust shop. Looking for recommendations not too far from NYC. I have accepted I might have to travel. I once tried a shop in Queens with plenty of good reviews, I get there and they send me away saying my car is too low for the lifts. I tried another small repair shop near my apartment and the mechanic is a pain to work with. He gets irritated if I try to get involved, and then when I give him freedom, he does a mediocre job (installing mufflers. I don't have a garage where I could do this myself). Struggles.

[3002 tii]

Originally Posted by filtercoffee

Thanks for the suggestions!
I emailed supersprint and they mentioned adding in some small resonators might help. Those shorty ones look great and are cheap. The issue is I don't yet have an exhaust shop that I can trust.

Had more roadtime with the Remus, I'm getting used to it. My rational mind is saying this is the perfect exhaust if you have headers. The tone is great, the volume is very proportional to throttle position - quiet when coasting, a nice throaty growl when you're on it. But the powerloops were exciting on an emotional level.

I think there must be some kind of internal chambering in the Remus that cancels out all the bass at the drone frequency. No matter how much I floor it, the bass layer of the sound of the SS powerloops is just not there. I don't think straight pipe section 1 would change that.

For now I'm living quite happily with the Remus. I would love to try those shorty resonators but I don't know of a good exhaust shop. Looking for recommendations not too far from NYC. I have accepted I might have to travel. I once tried a shop in Queens with plenty of good reviews, I get there and they send me away saying my car is too low for the lifts. I tried another small repair shop near my apartment and the mechanic is a pain to work with. He gets irritated if I try to get involved, and then when I give him freedom, he does a mediocre job (installing mufflers. I don't have a garage where I could do this myself). Struggles.

Been years since I’ve been there so not sure if things have changed but Leo at Motorcepts in Richmond Hill was great.

[filtercoffee]

Oh nice, I got my headers done from there. Thanks.

[filtercoffee]

Regarding roadster acoustics, I suspect the drone / bass volume is reduced with the top down because the low frequencies are allowed to escape rather than bounce around and resonate. A similar bass-boost phenomenon happens with subwoofers in small rooms vs outdoor fields.

[3002 tii]

Bump for update, always love a good exhaust thread

[filtercoffee]

No update regarding tweaking the powerloops, but I am loving the remus + headers + afe combo now. It's liveable enough to daily, yet sounds so good when you press the throttle. I definitely notice the tone change once the exhaust system is warmed up - that's when the sound wakes up a bit. I also put an epic motorsports 93 octane tune on it, which changed the tone of the engine under load. Sounds like it has a slightly higher pitched tone to it. I think the sound is where I want it now and I'll probably let go of the powerloops.

The epic tune really completed the car in the powertrain front. I also have a lightweight flywheel, and rogue short-shift kit, and the resulting throttle blips are HEAVENLY in terms of both sound and feel.

Got a bit off-topic there. Tl;dr happy with the remus, will be selling the powerloops. Next up, sorting out the suspension. Got set of fortune auto MSC-1's from a forum member: linear spring rates, valved for comfort, going to give it a shot and see how it is.

[3002 tii]

Nice! Maybe we can get a tri-state GTG to compare notes (exhaust, suspension, etc) before winter arrives...

[MBan]

Originally Posted by filtercoffee

The epic tune really completed the car in the powertrain front. I also have a lightweight flywheel, and rogue short-shift kit, and the resulting throttle blips are HEAVENLY in terms of both sound and feel.

Off topic, I know, but what brand of lightweight flywheel do you have and how do you find it from a noise perspective? I have really enjoyed lightweight flywheels in previous cars but have heard mostly negative things about using them in this platform.

[filtercoffee]

JB Racing, 10lbs paired to a south bend M3 stage 1 clutch IIRC.

Pros: throttle blips are fun. pulls hard at lower gears especially. more direct drivetrain feel. it's a very fun mod.

Cons: the biggest annoyance is that in 3rd gear at 1800rpm or so, there's rattle if you press on the throttle more than 20% or so. I suspect the torque pulses and the clutch springs resonate at this RPM and the springs bottom out. secondary annoyance is the chatter at idle. but you get used to it.

I would do this mod if your clutch or flywheel needs servicing, but I wouldn't go out of my way. My use is not racing though. Just a fun street car.

[MBan]

Thanks for the feedback.

Given how hard it is to squeeze much more power out of the S54, mechanical mods like lightweight flywheels and shorter final drive ratios are interesting.

[filtercoffee]

Update: I put the powerloops back on. This time I installed it myself instead of letting a shop do it. Zpost user Jumbosock mentioned that sometimes tightening the exhaust hanger to the car too tightly causes drone. So I made sure not to overtighten it beyond what was necessary. I also suspect the previous mechanic installed the muffler hanger incorrectly or in the wrong orientation because I remember there was a bit too much tension when he was trying to align the tips.

Anyways the outcome is that the powerloops are on and sound amazing, I missed the sound so much. As for the drone, it's not as terrible as I remember. I took my dad for a ride, he said it's not that loud. I took my friend for a ride, we were able to comfortably have a conversation on the highway.

Where it's still a little too loud is around 2k rpm when you press the throttle. The bass from the muffler is a bit boomy. however, I don't mind it all that much. The car is overall more fun to drive now. I think I'm comfortable putting the remuses up for sale. If the loudness bother me I'll ask a shop to modify the xpipe or section 1 or something. Or maybe try dynamat.

Mban, I was just reflecting the other day that I might actually want to go back to stock flywheel and clutch if the chance presents itself. It would make daily drivability a lot better (for that 3rd gear 1800rpm rattle).

[3002 tii]

Happy it worked out! Dynamat... been there, it helps but barely. Problem is you sit right in front of an open trunk. I even bought a second trunk trim piece (double stacked with original). The one thing I didn’t do

I talked to a retired sound engineer and he said the best chance is applying sound deadening in between the chassis and exhaust heat shielding but not worth the effort. Just embrace the cans, it’s probably not that bad when you drive solo anyway

[MBan]

Originally Posted by filtercoffee

Mban, I was just reflecting the other day that I might actually want to go back to stock flywheel and clutch if the chance presents itself. It would make daily drivability a lot better (for that 3rd gear 1800rpm rattle).

Thanks - good advice 👍

Given minor noises from a short shift kit are bothering me at the moment, I think a lightweight flywheel is well beyond my tolerances!

[filtercoffee]

Update: The bass boom is starting to annoy me again. I measured it - it happens around 85-90hz. I had my trunk loaded up with a couple of suitcases and I noticed the drone was almost gone. Then when the exhaust got hot it came back again. Based on the temperature dependence and the trunk-loading making a difference, I'm fairly sure the exhaust + cabin is resonating at 85-90hz. My current theory is that when the exhaust gets hot, its length changes and it makes the muffler put tension on the exhaust hangers. To cancel this frequency out with a j-pipe, it would have to be a meter long. A helmholtz resonator tuned to 87hz is doable but it would be complicated to fabricate and might require iteration to get it tuned right. But I'm optimistic the issue can be mitigated by using mass-loaded vinyl on the trunk, or clamping a weight to the exhaust, or by replacing my exhaust hangers.

In the mean time my remus mufflers are for sale.

[3002 tii]

Are you running stock gearing? I wonder if you’re spending more of your cruising speeds at a different rev range

[filtercoffee]

3.91 final drive. the drone is not when cruising on a highway where I'm at 3k rpm, it's more when Im driving around town, 2nd to 3rd gear, throttle blips in between are annoyingly bassy at times because of the resonance around 87hz / 1600pm

[maupineda]

I feel you, this was my case with the stromungs, i put the OE mufflers on and issue solved, I miss the noise at times but I rather miss some exhaust sound that get annoyed as f... by the droning.