OMG (RPi GT's + GruppeM)

[r4gs]

this recording actually turned out a little less accurate a representation as compared with the iPhone 4 recording, but has video and is in full 720p HD. also, it showcases the differences between the tone and volume outside and in-cabin.

[crfine88]

Originally Posted by r4gs

^thanks for the response. really do need to know, did ur extensive sound deadening of ur entire trunk reduce highway drone to an acceptable level? by acceptable, i mean comfortable and relatively near quiet stock levels.

incidentally, when i spoke with eloy, he mentioned the rpi mufflers being extremely popular in the uk (rpi's number 1 market apparently) and canada, with ratios of rpi gt mufflers sold in those markets to those in the usa at 10:1 and 3:1 respectively. cited the reason tt certain classes of racing require mufflers and these being the closest to straight pipes (can most definitely see through them).

The sound deadening reduced the volume of the drone a great deal, but nowhere near stock levels. The drone volume is lower, but still there @ FWY speeds. The vibration and hum of the exhaust puts my wife right to sleep (this can be a good thing ). On long trips it does get annoying and it drowns out all the bass tone of the stereo system. If I did not love the way it sounds so much on the track and on canyon runs, I would have replaced it already

Like others have mentioned, the tone does "mature" after 1-2k miles. It is still incredibly loud, but not so ear piercing. It becomes more of an exotic wail.
Like Eloy said, this is the closest thing to straight pipes out there. To me it really makes the M sound like a GT class race car. I grew up going to the American Lemans in Monterey every year with family and friends. It’s a tradition we have kept up even though a lot of us have move to other places. Making my M sound like one of the cars out there on the track brings me right back to a lot of great memories.

The RPI’s will always be loud and I don’t think the insulation will be worth the $$$, time and effort if you are looking for near stock cabin volume. There are some other great options out there though.

Originally Posted by Z4-Villalona

....either way doing anything that CRFINE has done to his ride is just WIN, anyway you look at it. HIS RIDE IS THE GOLD EFFING STANDARD. hands down

Wow . Undeserved, but I thank you anyway. There are a lot of great M coupe builds out there. This is my interpretation and I have received a lot of positive and negative feedback. I tend to lean toward the motorsport side of things, so some of the mods I do are not for everyone. Thanks for the good feedback and I am glad you appreciate the build

[r4gs]

^thanks for ur feedback on sound deadening chris. i've actually gone ahead and added some dynamat extreme to the entire bare metal flooring directly above the muffler area as well as adjacent to the rear battery hump. only applied dynamat to completely flat and level surfaces, as i'm surmising that the vertical surfaces aren't the propagators of drone. my intention was to reduce the reverberations caused by vibrations, and so far it's worked pretty dramatically. overall volume (it has seemingly dampened the higher frequencies more than the low, bassy ones) has decreased and some quick highway testing yields a much more comfortable level of drone. it is omnipresent, as will always be, but more civilized. low frequency drone as u're accelerating through the low rev band is still very loud, but tt's precisely the effect i'm going for. dynamat is doubtless pricey stuff though. will be doing more long-distance testing this next weekend on my travels to austin and san antonio for the cupcake meet and chinese new year respectively.

overall, am feeling more confident tt i've achieved my objectives of adding more bass and rumble to the growl of the gruppem. in fact, after adding the dynamat, i've been better able to hear the gruppem over the exhaust and swear the drone also encompasses the deep and voluminous growl from the gruppem under throttle. the videos i uploaded already have the dynamat applied in the trunk area, which looks completely stock once the interior trunk bottom panel is put back.

maybe i'm psychologically unsound or something, but i find myself aching constantly to go out and drive just to hear those rpi's start up and roar!

[Eccentric]

last vids are sweet. Hey R4, can we get some drive-by clips with that camera? LA Zposters, youre thinking of a different kind of drive-by..

relax, jp- i think im just jealous of that left coast weather lol

[Z4-VILLA]

RPI's look unique and sound loud but mature.....
I love embarassing rx8's and such with the tone....ut thats just me

[r4gs]

Originally Posted by Eccentric

last vids are sweet. Hey R4, can we get some drive-by clips with that camera? LA Zposters, youre thinking of a different kind of drive-by..

relax, jp- i think im just jealous of that left coast weather lol

i'll get some in-car driving clips as well as 'drive-by' clips sometime during the week with the requested camera. still think it doesn't quite record sound particularly well but maybe i was partially obscuring the mic area. going to be making a fairly long trip out to austin and then san antonio after this weekend so i'll attempt to record the highway drone as well.

Originally Posted by Z4-Villalona

RPI's look unique and sound loud but mature.....
I love embarassing rx8's and such with the tone....ut thats just me

the rpi's do look unique and tt's what i'm fond of. just unlike the usual symmetrical set of four tailpipes. as for embarrassing other fellow drivers, can't say i subscribe to tt!

[Z4-VILLA]

i know Im jerk to ricers especially unless they got something really rare.....

[Z4-VILLA]

but yeah....I heard RPI's in Person and I was sold.....

[Jbs]

I have to chime in and say that the RPi completely transforms this car. While in stock form it is very comfortable, refined and filled with creature comforts, it is not supposed to be a luxury car, or even a commuter for that matter. This car is purpose built, and RPi follows that mentality IMHO.

Who says you can't have a little fun along the way either? the sound is amazing!

Drone is awful (crack your windows if it really bothers you ), and I find myself putting the clutch in whenever I come across a police officer, but I don't usually get unwanted attention. Like someone else said, there is a big difference in sound when driving a loud car like a sane person and driving like an ass

I am hesitant to buy and intake though, I am worried I will not be able to hear it!

EDIT: blipping the throttle on downshifts makes every other car that isnt a scuderia jealous

[crfine88]

Originally Posted by Jbs

I
...EDIT: blipping the throttle on downshifts makes every other car that isnt a scuderia jealous

^This x 1,000,000,000

Could not have said it any better

[Beedub]

the drone is painful....... i have actually felt my eyelashes vibrating while at motorway speeds!! lol i did a 2 hr journey last summer and my god, i can honestly say, i was completely glad to get out of the thing, but........ the bonus with the roadster is you can take the roof down, with the roof down you dont get half of the drone, and its about 70% more pleasurable, but with the roof uo i feel the true pain of drone!!

i can promise you, you guys have it lucky.... as cfrine88 no's, the supercharger system makes it louder again........ its 100% adds volumn and deepens the note further.

[r4gs]

Originally Posted by Jbs

I have to chime in and say that the RPi completely transforms this car. While in stock form it is very comfortable, refined and filled with creature comforts, it is not supposed to be a luxury car, or even a commuter for that matter. This car is purpose built, and RPi follows that mentality IMHO.

Who says you can't have a little fun along the way either? the sound is amazing!

Drone is awful (crack your windows if it really bothers you ), and I find myself putting the clutch in whenever I come across a police officer, but I don't usually get unwanted attention. Like someone else said, there is a big difference in sound when driving a loud car like a sane person and driving like an ass

I am hesitant to buy and intake though, I am worried I will not be able to hear it!

EDIT: blipping the throttle on downshifts makes every other car that isnt a scuderia jealous

honestly, the intake growl is somewhat drowned out by the exhaust at anything below 4500rpm. the classic s54 song only takes over under hard acceleration and if u're on the autobahn going about 150mph take this opinion for what it's worth to u, but i don't think an intake is worth the outlay for whatever little, almost negligible, power gains and a drowned-out-by-rpi increase in depth and volume of engine growl.

granted, i will take some videos both in-cabin and from outside to showcase the gruppem a bit more and capture exactly what it's offering soundwise.

on a side note, i've ordered some ensolite closed cell foam to reduce the volume of in-cabin drone (dynamat does little for volume but absorbs some of the higher frequency drone) and will report on the comfort level on my trip to austin. it's embarrassing to admit, but no way the rpi's are livable on a daily basis unless u do mostly city commuting (where u won't stay at a constant engine throttle amount and rpms) or have relatively short commutes to/from work. fortunately in my case, i really only drive my m coupe on the weekends and have some lovely hill country roads to explore, so the rpi's will pass. long distance with the rpi's will literally drive one nuts though.

[ga41]

Originally Posted by r4gs

...no way the rpi's are livable on a daily basis unless u do mostly city commuting (where u won't stay at a constant engine throttle amount and rpms) or have relatively short commutes to/from work.

My commute is less than 15 minutes long and it's city driving with lots of stops and starts...


Anyway i agree with Jbs and crfine88, a well performed rev-match or heel-toe downshift will turn many heads.

[r4gs]

alright, excited to be reporting this, but i just couldn't resist and went out to take a nice 70 mile roundtrip blast to one of my favorite scenic passes. it has the entire gamut of driving - slow stop-start traffic lights, intermediary service roads, highway and hill passes. title sums it up - WOW. this past weekend was almost 90% highway and 10% stop-start traffic, so i never really got to open her up. once i got north of del rio towards lake amistad, started testing highway (roads here are rough and noisy) drone from 60mph up to 100mph all in 6th gear. i have the bottom two panels of the flooring in the trunk lined with a single layer of dynamat extreme.

60mph = low volume, low frequency hum that is acceptable. 70mph = medium volume, low frequency drone that will get on one's nerves. 80mph = low volume, medium frequency hum that is acceptable (this speed is the sweet spot imo). 90mph = medium volume, high frequency drone that is marginally acceptable. 100mph = low volume, high frequency hum that is acceptable. conclusion = dynamat extreme worked as advertised and significantly dampened the medium to higher frequency range where most of the annoying droning occured on the highway. previously, anything above 60mph only got louder and more droning. overall volume is mildly decreased, but the low, bassy drone is still omnipresent and u WILL cross this range with anything more than light throttle.

now on to the fun stuff - spirited driving! have an off-highway scenic, twisty, hilly route tt drives into the sunset facing the lake. almost always devoid of any traffic and makes for plenty of downshifting and accelerating out of corners. i have to concur with someone who mentioned how exotic the rpi's sound. it's much more succinct now after adding the dynamat cos previously the voluminous and incessant droning under heavier throttle would drown out the absolutely exotic, high-pitched tone. i swear it is almost flat-plane-crank-esque ala ferrari or carrera gt (of course not on par, but between the magic 3500 to 4500rpms, sounds mighty similar). accelerating from a standstill right through to redline is just out-of-this-world. i mean, it's a completely visceral, no-holds-barred experience! i know i know, no video, but i WILL have to get out and film this. windows down is a life-altering, spine-wringing experiencing (raw motoring sound). windows up is a girly-giggling, grin-multiplying experience (refined, pure ferrari-esque sound). this is exactly what i was after and i'm officially addicted to the rpi's. granted i've not had the pleasure of listening to any other aftermarket exhausts for the z4m's, but these are mighty fine indeed.

videos are on the way, promise!

[Kream]

Originally Posted by r4gs

honestly, the intake growl is somewhat drowned out by the exhaust at anything below 4500rpm. the classic s54 song only takes over under hard acceleration and if u're on the autobahn going about 150mph take this opinion for what it's worth to u, but i don't think an intake is worth the outlay for whatever little, almost negligible, power gains and a drowned-out-by-rpi increase in depth and volume of engine growl.

That was my biggest concern with the RPI exhaust. I love hearing the GruppeM intake on our cars. Not to mention my other car has a ridiculous droning exhaust even after I dynomat the trunk. The noise makes my little yorkie puke. We can't take her in the sedan now. I do love the tips and the high rpm sound of the RPI though. Makes me want to run electronic bypass valves.

PS. I might run into you at the CC Meet. I will be there with the CentexVQ (Nissan/Infiniti) group.

[esqu1re]

How many pounds did the dynamat add back to the car?

[Kream]

Originally Posted by esqu1re

How many pounds did the dynamat add back to the car?

The C's trunk is bigger than ours. I was a noob and I used the dynomat brand. I used 1 1/2 trunk kit and it was around 22lbs.

For the M Coupe I went to an audiophile store bought another brand (I'll edit the post when I remember) and it was much lighter. The kit worked out great and only weight 6lbs.

[Pheonix]

Originally Posted by Kream

The C's trunk is bigger than ours. I was a noob and I used the dynomat brand. I used 1 1/2 trunk kit and it was around 22lbs.

For the M Coupe I went to an audiophile store bought another brand (I'll edit the post when I remember) and it was much lighter. The kit worked out great and only weight 6lbs.

I also lined my trunk with Dynomat but not sure how much used! I am not too worry about the weight gained since a gallon of gas weight about 6lbs. There for i could just filled the tank slightly less and offset it. I definitely noticed the reduction in sound (more so with the elimination of rattles and vibration)

[r4gs]

dynamat is expensive and the version i bought wasn't so much for noise reduction as it was for absorbing higher frequency vibrations. this dramatically reduced highway drone between 3000rpm and 4500rpm, so much so that at any speed above 60mph, the drone becomes progressively quieter and higher-pitched. ultimately, this has been far less fatiguing and much more enjoyable now, also considering that i can hear my gruppem pretty distinctly again. i only added 4 sq ft of dynamat extreme, so tt weighed in about 3lbs or so. super easy to cut (with a simple pair of household scissors) and apply (peel and stick), adheres great, and lays completely flush with the bare metal bottom of the trunk. everything still looks 100% stock and tidy.

i believe eloy can incorporate some kind of bypass valve thing ala kks/kreissieg for about $100 or so extra, but the installation would be a lot more complicated with having to wire something into the cabin itself.

[Beedub]

heres my ess blown z4m with rpi rippin ass at the local sprint course...

[r4gs]

as promised, here's a drive-by video accelerating through 2nd and 3rd gears and downshifting back into 2nd at the end of the recording. tried to minimize wind noise as much as possible. tried getting a couple of in-car video recordings accelerating from a standstill, but the extremely bass-heavy tone of the rpi's caused excessive distortion.

as u guys can tell, absolutely gorgeous weather in west texas

[ga41]

That sounds awesome. (From the outside anyway )