RPI v's Supersprint for MCoupe

N

NMC100

Member
 Cotswolds / London
I've been researching replacing the OE exhaust system on the M Coupe. Initially I'm replacing the rear section and x pipe. I thought I was sold on the Supersprint Race route but then started looking at RPI.

Has anyone experience of a comparison of these two systems? I've read Beedub and ga41's posts about the RPI and have had the Supersprints recommended by two very experienced BMW guys.

Loudness that detracts from the engine is a concern but character is more important. On two previous Lotus' (Sport 135 and Exige ) I have had full Larini systems which were sumptuously crackly, with bangs and pops. Also v. LOUD but drowning out a VHPD K series engine wasn't necessarily a bad thing.

Ideally I just want to enhance the sound from the exhaust, with a bit more character. Any bhp gains are a bonus but not the primary reason for changing and also avoid the drone.

Any input appreciated :thumbsup:

Nick
 
Rather less hi tec solution but after researching this topic myself I've opted for the back box bypass route. Everything I read and heard described the effect of this was exactly as you've described wanting i.e. enhancing the already characterful noise. Ordered the pipes from Warren Engineering which were £38 delivered and arrived in 2 days. Now booked in with a friendly local mechanic to do the welding tomorrow. All in will cost less then £150. I'll let you know how it sounds but many have done it before and commented very positively. There is a before and after video on here somewhere and it sounded great!
 
Thanks T66RGA. I have seen those mods in pictures but would interested to hear your feedback. I guess the benefit of buying replacement boxes is that you can always put the OE ones back on. With the bypass mod you're stuck unless you get donor boxes.

Look forward to hearing about your experience though.
 
NMC100 said:
Thanks T66RGA. I have seen those mods in pictures but would interested to hear your feedback. I guess the benefit of buying replacement boxes is that you can always put the OE ones back on. With the bypass mod you're stuck unless you get donor boxes.

Look forward to hearing about your experience though.
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It would be easy to reverse the bypass mod.
 
I'm guessing you mean Supersprint Race? Both those and the RPI's offer lots of pops and crackles! I believe the Supersprints do not come with OEM style flanges to connect them to the X-pipe but the RPI's do. I love my RPI's and have gotten used to the volume but i'm thinking of getting something tamer by the end of the year.
 
ga41 said:
I'm guessing you mean Supersprint Race? Both those and the RPI's offer lots of pops and crackles! I believe the Supersprints do not come with OEM style flanges to connect them to the X-pipe but the RPI's do. I love my RPI's and have gotten used to the volume but i'm thinking of getting something tamer by the end of the year.
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Notice how we keep saying this but never actually do it ??? I don't think our rpi is going anywhere and they've become a much wanted part now rpi have stopped production!


Sent from my iPhone using Tapatalk
 
Ha! I'm just biding my time. Waiting for the right opportunity (and price!) :D

Truly though, i know they're not for everyone but the RPI's at full chat through a long tunnel is something to behold.
 
ga41 said:
I'm guessing you mean Supersprint Race? Both those and the RPI's offer lots of pops and crackles! I believe the Supersprints do not come with OEM style flanges to connect them to the X-pipe but the RPI's do. I love my RPI's and have gotten used to the volume but i'm thinking of getting something tamer by the end of the year.
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This is correct, the Supersprint Race have sleeve fittings between back box and X-pipe.

I have no experience of RPI, but the Supersprint Race are absurdly, ridiculously loud and will ensure you never get on any track day in the UK. Except possibly an unsilenced day at Donington.
 
Hi ga41. Enjoyed reading your RPI write up. I think I'd be tempted by the RPI system if it wasn't for the droning you've experienced. I'm leaving towards the SS race system - hoping it doesn't suffer in the same way.
 
Droning is a major issue with them between 2.8 and 3.2 thousand RPM. As said i'm used to it by now and so are my usual passengers but if it bothers them too much i just slow down, speed up a bit or downshift a gear to get off that small drone range.
 
ga41, is your ///M back on the road now? Hope it's been sorted without too much expense...

Back on topic, I have Remus back boxes. They sound fantastic and they're quiet enough to meet track day noise restrictions.
 
The engine should be back in the car by tomorrow, maybe today. The cost might be a bit less than expected but roughly around 3000 euro. Also found out that i needed a clutch disc, it was "burned" as per the local expression, saw it myself and it was indeed very worn. Got a Sachs equivalent for that. Also got ARP head bolts and ARP connecting rod bolts for S54 which by the way don't fit on mine! Some years the S54s came with M11 con-rod bolts and some years with M10. The ARP items are M11 and my bolts are M10 so we found a set of stock con-rod bolts for those. ARP confirmed to me that the correct kit for my case is 201-6102 which is their kit for S50 engines and also much cheaper.... So now i have an extra kit of these if anyone wants: http://www.turnermotorsport.com/p-2211-arp-connecting-rod-bolt-kit-for-e46-m3-mz3-m11-size.aspx

Back to exhausts though, THANKFULLY there's no such thing as noise restrictions on our 1 track in Cyprus. It's in a farming area so no houses around to make complaints.
 
BMWZ4MC said:
ga41, is your ///M back on the road now? Hope it's been sorted without too much expense...

Back on topic, I have Remus back boxes. They sound fantastic and they're quiet enough to meet track day noise restrictions.
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+1 for the Remus back boxes. They do sound fantastic especially when really hot! As BMWZ4MC states they are fine on track days in the uk. Only problem I had was at Bedford but their noise limit is so low if you farted in the pit lane you would break it.
 
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