E92 M3 ZCP in SCCA Solo F Street

[sgreer78]

Originally Posted by mobilenemo

I recently bought a new dinan bar off another member. Would cutting off 1.5" allow the entire soft to stiff range to be used or would more be needed?

For drilling, powerdrill with the endlink in a vice should work? Thanks

I can use the full range now.

That should work. I used a drill press, but the material seemed to drill pretty easy do you should be fine.

[PedalFaster]

Long shot, but any of you know of anyone who's dynoed the OEM exhaust mod? I'd like to actually be able to hear the car on course, but I'm a cheapskate, so there's no way in hell I'm spending four figures on an aftermarket exhaust for a car I just plan to campaign locally.

All the threads I've seen have been from people who either don't care about any impact on power, or who are relying on subjective feel.

[Richbot]

The bottleneck is the 400cell OEM primary cats, you're not making any negative impact on HP without changing those, and you're not making any meaningful positive impact on horsepower without at least fiddling with the section behind the primaries that has the secondaries in it...take it from somebody who was in this cesspool back when people were figuring it out there were wild claims and all were debunked the back box makes statistically no impact on power even if you remove it entirely though if you do that you'll eventually die and/or your axle boots will melt and catch fire

Depending on which one you do, OEM exhaust mod essentially changes the stock internal piping the muffler to a slightly longer version of the flow path on the M Performance Exhaust (straight through, but with side paths)

[PedalFaster]

Ok, thanks. My past experience with two previous cars was that changing mufflers absolutely did result in a power loss, so now I'm generally kind of hesitant to flail around with a hacksaw and a welder back there. I randomly ended up with not one but two OEM exhausts, though, so it would be relatively cheap and easy for me to do so now.

[Richbot]

I think the difference is no close-coupled cats on these in an era when almost everything else had a cat within 10" of the exhaust ports and/or turbo. They really had to choke it in the midpipe (and make it rattle your windows on cold start) to get it to pass regs

Also, the MPE is seriously just two perforated straight pipes with a couple side paths to cancel out drone at lower flows or whatever...I don't *think* bmw screwed that up too bad. You can see straight through the MPE muffler to the tips

[CSBM5]

I went with the Dinan exhaust which was designed to not drone and to actually achieve a slight hp gain. I bought it used for $1400 (as opposed to $2600), and I can probably resell it in the future if/when I'm done with it. It's a heck of a lot lighter than the stock monster. Back in 2007 I bought a Dinan exhaust for my E39 M5 when it was on sale (net of 30% off through my local dealer) at the time for ~$1250, and 10 years later I sold it for $900. I'd probably stick to either Dinan or BMW MPE (V2) as they might hold resale value better than others.

[Tommysalami]

I wasn't going to drop that kind of money either but found a Stromung exhaust used on here for only $650. Saves 13 lbs over stock after weighing them, and no noticeable change in power as we'd expect. Sounds great as well and is only like $1200 new, it's kind of a wonder why there's not more info available on it or other people who have it. I guess people prefer the more baller brands.

[CSBM5]

I recall looking at Stromung years ago, but as I recall they didn't have an E90 version, so the tips would stick way out on the sedan. I see you have an E92 though. How has it worked out drone-wise? I was always curious.

[Tommysalami]

Originally Posted by CSBM5

I recall looking at Stromung years ago, but as I recall they didn't have an E90 version, so the tips would stick way out on the sedan. I see you have an E92 though. How has it worked out drone-wise? I was always curious.

I came from an STR class S2000 and then an STR NC Miata, both with single pipe exhausts, which droned a lot. So, I'm not very sensitive to drone. I hear what might be described as drone from idle to maybe 1750 rpm when I'm getting the car moving from a stop, and then nothing but exhaust noise after that. It's more of a boomy sound than the exhaust note I hear at higher RPMs but it's not bad at all and I think it sounds great. I've got nothing else to compare it to so it's hard to say but I love the exhaust.

[Richbot]

Billy Boat had a fantastic-sounding exhaust for these cars too that never took off and was just a little more than the Stromung

And bimmerworld's 2-resonators-on-two-sticks setup is around that much too

but we must have FOUR tips and they must be VERY titanium or VERY carbon from VERY foreign-sounding names

[CSBM5]

Originally Posted by Richbot

Billy Boat had a fantastic-sounding exhaust for these cars too that never took off and was just a little more than the Stromung

And bimmerworld's 2-resonators-on-two-sticks setup is around that much too

but we must have FOUR tips and they must be VERY titanium or VERY carbon from VERY foreign-sounding names

LOL, reminds me of later model's BMW MPE (i.e. F80, F87, F10, etc) where you have to buy the "exhaust" and then you have to spend another $1000 or more for the four tips. The crazy part? The pricing strategy apparently works well and people flock to spend many thousands of dollars for an "exhaust."

[Tommysalami]

I appreciate the weight savings from titanium and Iconel, but damn, I can't imagine spending $4k on a new muffler

[Richbot]

The pain fades eventually...I think I got mine for anniversary/christmas/bday combined gift in like 2012? Still sorta stings

Retail is in the low $3k range in real life, which is SO REASONABLE opposite...

[z3papa]

I went the Megan Racing (Agency Power knock off) unit. Saves weight, sounds alright but clearly doesn't do much for power. I can hear my car when it's WOT if my stereo is not cranked up and don't need much more than that.

[z3papa]

There is a request to move the M3 ZCP to BS which is out for comment. If you want the ZCP to remain in FS where it ought to be, write your letters to the SEB.

[Richbot]

Grab your torches and pitchforks everybody. This is duuuuuuumb

[thasuperdude]

They just can't stop dicking with the classing these days. It's hard to keep up. There's always going to be one platform that preforms better in each class. The poor BRZ can't find a class to stay in.

[Richbot]

It's not even performing better, it's on par, but people like the car (M3's are good cars to live with every day, and now that they're old they're holding their value well so it's no longer ruinously expensive to buy one and sell on in a couple years), some very fast people drove one and won nats twice, but plenty of defeats for te M3 at high level events as well, new Mustangs and Camaro trims and options come along every year, we haven't seven seen the potential of the latest Performance Pack S550 or Gen 6 camaros yet, a new "base" pony comes out and goes faster almost every year, it's duuuuuuumb

[thasuperdude]

Right? It's called progress. Your case in point, is the 1LE Camaro getting bumped to AS. Albeit, the magna-ride suspension is a pretty big upgrade for a 3600lb + car.

[kyoo]

submitted my letter

[Tommysalami]

Right in time for me to join the class! I'll be writing my letter

For everyone to write, here's the site for submitting the letter:
https://www.crbscca.com/

And here's some background:
https://www.scca.com/articles/199713...-rules-process

You can include that this is in relation to:
Change Proposals
Street Category
#25430 Move BMWs out of the stock pony car class to BS
The SAC would like member feedback on the following move:
Move from FS to BS
BMW
M3 (Competition Package)(E9x chassis)

Everyone keep in mind that the two people that have won FS with the E9x have been Jeff, who is a 12 time national champion, and Bryan Heitkotter who is a professional race car driver.

[z3papa]

Originally Posted by thasuperdude

Right? It's called progress. Your case in point, is the 1LE Camaro getting bumped to AS. Albeit, the magna-ride suspension is a pretty big upgrade for a 3600lb + car.

I wrote two letters for the 1LE Camaro to be placed in BS. It's a whole lot of car, wheel, tire, and suspension. If it came to FS, I'd jump all over it and sell my car.