RPI GTC Exhaust Review

[OerdingE93]

i am running the same rpi mid pipe paired w/ ae performance mufflers....if i had rpi mufflers would i get more power? currently @ 362 whp w/ ms pully - evolve tune.

[rjd598]

Originally Posted by OerdingE93

i am running the same rpi mid pipe paired w/ ae performance mufflers....if i had rpi mufflers would i get more power? currently @ 362 whp w/ ms pully - evolve tune.

doubt it. the mufflers can't do much you've botled on wisely

[OerdingE93]

Originally Posted by rjd598

doubt it. the mufflers can't do much you've botled on wisely

Buddy of mine just dynoed 391whp w/ full rpi exhaust , stg2 ms intake w/ OUT a tune... I'm kinda jealous... Haha

Would the convertible dyno differently for any reason?

[Vybz]

Originally Posted by rjd598

doubt it. the mufflers can't do much you've botled on wisely

You're asking if the e93 would dyno differently? No.

I still have not gone to the other shop to get a confirmation dyno. I hate jumping from one shop to another, cause then I feel like my baseline was invalid, but if I get the same numbers at Carb Conn. then something is obviously up.

I have 3 more videos that require minor editing and then I'll post them rjd. A small burnout, revs, and almost 2-3 mins of highway pulls including tunnel scenes which don't even come close to doing the exhaust any justice... tunnels are ADDICTING

It's been what? 4 months of ownership now? So the sound has settled in. Let me clarify on the drone/resonance. Drone is not completely nullified on this exhaust system. However, to bring it about you have to be crusing at ludicrious slow speed in high gears to bring it about. If I ever find myself driving through a neighborhood at 35-40 in 6th gear, drone will be there. Easily resolved by just downshifting, it's really not a BIG deal, but I know that there are some out there who will probably care.

Now for resonance. If I'm going EVEN slower then before, lets say 25-30 in 5th or 6th gear, resonance will occur. At the point where you're about to induce resonance you might as well be on the verge of stalling. DCT owners wont have an issue as the ecu will probably never let you cruise that slow in such a high gear. But yes resonance can be observed in this car, and it can and will vibrate the cabin making you discover all the loose articles you never realized you had in your M. You literally have to try to make it happen though.

Sound from inside the cabin. Docile, quiet, conservative. Cold starts aren't THAT bad at all, and furthermore it only last for 20-30 secs. This is all with the windows up.
Windows down, you start to realize that your M is no longer the same, and it's a lot more apparent that your M's balls have been re-attached, but you're still probably only hearing about 50% of what others around you are ... I think? lol
Outside or behind the car, is where the system shines. Keep the rpms down, casual cruising. Bring the car into it's powerband, and she starts making noise, WOT she screams.

I already described the sound, but you really have to hear it in person. I'll get my sound clips up ASAP, I just want to merge the videos together, and take out useless chatter.

[rjd598]

I already described the sound, but you really have to hear it in person. I'll get my sound clips up ASAP, I just want to merge the videos together, and take out useless chatter.

Thanks man look forward to the vids

[rjd598]

Videos ready?

[Vybz]

Originally Posted by rjd598

Videos ready?

Wow... thanks for reminding me man, I've been so caught up with work that it completely slipped my mind. Here's the 1 that I recorded locally. I still have to grab the tunnel/highway one from my friend.



Hope it gives you some insight to help you make your choice.

[rjd598]

Originally Posted by Vybz

Wow... thanks for reminding me man, I've been so caught up with work that it completely slipped my mind. Here's the 1 that I recorded locally. I still have to grab the tunnel/highway one from my friend
Hope it gives you some insight to help you make your choice.

Thanks man really appreciate it! I'm pretty set on this set up but I'm just worried it will be TOO loud in person that's why I'm trying to get a sense of it in the videos. I have heard the full gtm in person and as amazing as that was that was just too much

[geneatals]

I think a video from inside the cabin is always appreciated, even tho videos rarely ever capture exhaust tones well...

[BLACK OPS]

Originally Posted by Vybz

Wow... thanks for reminding me man, I've been so caught up with work that it completely slipped my mind. Here's the 1 that I recorded locally. I still have to grab the tunnel/highway one from my friend.



Hope it gives you some insight to help you make your choice.

Nice video!

[rjd598]

Originally Posted by geneatals

I think a video from inside the cabin is always appreciated, even tho videos rarely ever capture exhaust tones well...

There actually is a very long one of the gtc exhaust on YouTube hahah just search rpi gtc m3 and it'll be one of the first ones

[Vybz]

Originally Posted by geneatals

I think a video from inside the cabin is always appreciated, even tho videos rarely ever capture exhaust tones well...

I give my absolute word that the only way you'll even notice that there's an after market exhaust on my car, is with the windows down OR... as I said before if you're cruising in 6th gear at 30 mph, cause if the sound doesn't clue you in then, the resonance as everything inside vibrates will lol

It's entirely calm and collect inside the cabin, I wish you guys were closer I'd have no issues letting you hear it in person

Outside of the car is different. It's loud, not GTM loud, but loud enough for people to notice & at WOT it's screaming. Nothing but compliments and smiles since I got the exhaust. I've heard, "That's the most aggressive sounding Beemer I've ever heard into my life!" to random people giving me a thumbs up and telling me to rev her up. WA state cops suck, and I've NEVER been bothered by them even once. Drive casually, it'll sound a lil more aggressive then stock, drive balls to the wall, you'll attract attention.

The other video has a small scene of driving w/ windows down, but I'll ask to borrow my friends gopro and make a dedicated cabin vid, with windows up and down.

[FROZN]

ya currently putting down 391wph with ms pulleys, intake and no tune! With just the full gtm exhaust sytem and scoops i was putting out 368whp... the sound is amazing but could be loud for a lot of people... video does not do justice for how loud it is.

[nerwyll@trinityautosport]

Originally Posted by FROZN

ya currently putting down 391wph with ms pulleys, intake and no tune! With just the full gtm exhaust sytem and scoops i was putting out 368whp... the sound is amazing but could be loud for a lot of people... video does not do justice for how loud it is.

nice numbers =)

[rjd598]

Originally Posted by FROZN

ya currently putting down 391wph with ms pulleys, intake and no tune! With just the full gtm exhaust sytem and scoops i was putting out 368whp... the sound is amazing but could be loud for a lot of people... video does not do justice for how loud it is.

I'm curious if you knew what your baseline dyno was. Asking because I'm wondering how much power the gtm put out specifically

[Vybz]

Originally Posted by rjd598

I'm curious if you knew what your baseline dyno was. Asking because I'm wondering how much power the gtm put out specifically

DYNO UPDATE! It was kind of random and wasn't really planned out, but we did go to Carb. Connection in Kirkland to get my friends Cobalt dyno'ed. Little more professional and advanced then my usual shop, but for those that remember my 1st dyno experience with new exhaust, I was going to cross comparison anyways.

Carb Conn, still uses a dynojet, but Intec Racing has the 248c and carb conn uses a 424x which is Dynojet's most recent dynamometer. Not to mention Carb Conn uses much better fans to simulate air flow, anyways on to the main point.

Million dollar question: Did I see any gains?

From my stock baseline, the RPI GTC Exhaust by itself, netted me 24 rwhp 17 tq. So that is a definite YES!. The hp gain was right around what I was expecting. The torque gain was short of what I expected, but not significant enough for me to be disappointed. 17tq is still substantial, no matter how you look at it.

The shop did as many runs as it took to get consistent numbers and I got a majority of it on film so I'll post the vid up soon with the dyno sheet.

The car now sits at 374 rwhp and 267 ft/lbs tq. No regrets with the GTC & I'm significantly closer to hitting my goal of a 400 rwhp all motor track car

[rjd598]

Originally Posted by Vybz

DYNO UPDATE! It was kind of random and wasn't really planned out, but we did go to Carb. Connection in Kirkland to get my friends Cobalt dyno'ed. Little more professional and advanced then my usual shop, but for those that remember my 1st dyno experience with new exhaust, I was going to cross comparison anyways.

Carb Conn, still uses a dynojet, but Intec Racing has the 248c and carb conn uses a 424x which is Dynojet's most recent dynamometer. Not to mention Carb Conn uses much better fans to simulate air flow, anyways on to the main point.

Million dollar question: Did I see any gains?

From my stock baseline, the RPI GTC Exhaust by itself, netted me 24 rwhp 17 tq. So that is a definite YES!. The hp gain was right around what I was expecting. The torque gain was short of what I expected, but not significant enough for me to be disappointed. 17tq is still substantial, no matter how you look at it.

The shop did as many runs as it took to get consistent numbers and I got a majority of it on film so I'll post the vid up soon with the dyno sheet.

The car now sits at 374 rwhp and 267 ft/lbs tq. No regrets with the GTC & I'm significantly closer to hitting my goal of a 400 rwhp all motor track car

very nice power gains! i wonder if the conditions had to do with the low tq numbers. rpi claims how much for hp/tq?

[S65NAPWR]

kind of sounds raspy...

[Vybz]

Originally Posted by S65NAPWR

kind of sounds raspy...

There is a little rasp in the low end, but it's non existent from when you hit powerband up. When I get the highway video from my friend you'll be able to see what I'm talking about. It's nothing but highway pulls and tunnel scenes and there isn't the slightest bit of rasp. It's almost 4 mins of footage too.

RPIs numbers are 28/35 rjd, so from that session I'm only seeing 50% of the claimed torque gain.

[mikeokimster]

[Vybz]

Originally Posted by mikeokimster

Haha and there is the tunnel videos courtesy of Mike Gotta love unexpected surprises

I was going to edit out some of the filler in the video, since there are scenes that are pretty much exactly the same, but regardless it's a solid 3 mins of what the exhaust sounds like on the open road.

As I said earlier no rasp whatsoever at power band and higher, and the tunnel clips don't even do the sound justice.

Enjoy I'll get dyno results up asap.

[Marcovan]

thanks for your extended review about this system! It sounds good and the hp gains look good