Questions about Z3 2.8/3.0 Coupe vs. M Coupe

[e30polak]

Hey Guys,

So I've heard some conflicting information on the difference in the rear fenders, between the Z3 2.8/3.0 Coupe & the M Coupe. I know from experience that the rear subframe, trailing arms and axles are in fact different, but are the M Coupe fenders any different from the non-M?

Reason I ask is I already have an entire M Coupe rear suspension available and I'm really trying to justify if I really care to have the M. Granted aesthetically, I really do prefer the rear M bumper, quad exhaust, and the license plate being on the hatch. That being said, I will be swapping in an LS6, with T56 6 speed, doing all poly urethane bushings, bigger brakes, and coil-overs. Therefore the S52 and ZF (not trying to spend the money on an s54 model), along with the stock suspension and brakes aren't worth the extra money for me.

Basically I just want to know if I get a non-M z3 coupe, and install the complete M Coupe rear suspension, that I can still fit the same width wheels and tires (my whole reason for choosing the z3 M Coupe chassis).

I'm not a noob, and I'm not here to waste anyone's time. That being said I hate Bimmerforums search function, as it's terrible in comparison to other forums for actually providing the threads and posts I really want.

Thanks in advance!

[JoshS]

There should be no conflicting information. The chassis and exterior body panels are absolutely 100% identical. Only the suspension is different (and the rear wheel offset, to compensate).

So absolutely, you can get to exactly the same place by starting with a non-M.

[e30polak]

There should be no conflicting information. The chassis and exterior body panels are absolutely 100% identical. Only the suspension is different (and the rear wheel offset, to compensate).

So absolutely, you can get to exactly the same place by starting with a non-M.

Perfect! Thanks!

Now to find the right specimen to build my "Mini-Z06" project

[BMWBergy]

Basically I just want to know if I get a non-M z3 coupe, and install the complete M Coupe rear suspension, that I can still fit the same width wheels and tires (my whole reason for choosing the z3 M Coupe chassis).

When I saw the title of this thread, I was about to get peeved... ANOTHER Z3 Coupe vs. M Coupe thread? Geez. Thankfully, this is just a tad different.

Unless I'm mistaken, you can get the same width of wheels back there whether M or Zed - the difference will be the offset. Honestly, you might be better off with the standard Z rear configuration, because finding rear wheels with the very low offset required for the M fitment is a pain in the derriere unless you go with custom modular wheels, or are not averse to spacers.

Anyhow, this thread gives some good insight. Many of the cars in it are Ms, but there are some Zeds. I noted one Zed with 9.5" rears. I'm guessing that the lack of really wide rear wheels on non-Ms is due to the lower hp numbers, perhaps? However, there are a handful of folks with S/C-ed M52/54s... so maybe I'm wrong

[Sky1Z3]

Unless I'm mistaken, you can get the same width of wheels back there whether M or Zed - the difference will be the offset. Honestly, you might be better off with the standard Z rear configuration, because finding rear wheels with the very low offset required for the M fitment is a pain in the derriere unless you go with custom modular wheels.

Anyhow, this thread gives some good insight. Many of the cars in it are Ms, but there are some Zeds. I noted one Zed with 9.5" rears. I'm guessing that the lack of really wide rear wheels on non-Ms is due to the lower hp numbers, perhaps? However, there are a handful of folks with S/C-ed M52/54s... so maybe I'm wrong

indeed. Any Non M can fit big wheels and rubber, its the massive rear lips you miss out on. my car (3.0 m54 coupe)
is wearing 18x10 rears with 285/30/18s with tons of room to spare.

[BMWBergy]

indeed. Any Non M can fit big wheels and rubber, its the massive rear lips you miss out on. my car (3.0 m54 coupe)
is wearing 18x10 rears with 285/30/18s with tons of room to spare.

Got pics? I don't think I've seen your wheels!

[Sky1Z3]

Got pics? I don't think I've seen your wheels!

http://forums.bimmerforums.com/forum...0#post21797700

Old thread, but answers the questions about M vs non M wheel setups pretty well.

[z3papa]

Having an Z3M rear suspension means nothing to me. The stock units for M or non M Z3's weren't that different except maybe a little ride height and certain nothing to crow about. All the aftermarket units for M vs. non-M are the same. You may be able to fit a little more tire in an M with the shorter half shafts but that's probably not worth the trade off of having use funky offsets. If you are swapping in a LS6 and that trans, the suspension will be an afterthought. Should be a beast.

[Zman57]

http://forums.bimmerforums.com/forum...0#post21797700

Old thread, but answers the questions about M vs non M wheel setups pretty well.

Great looking set up for the nonM's , missed the original post.

[e30polak]

Thanks for the clarification guys. The final offsets for the rear are of great concern to me, as I already have quite the low offset wheel collection from my E30 M3 and E34 touring, which I would attempt to utilize for this project.

Swapping over the Z3 M rear suspension, trailing arms and axles to be able to suit my wheel and tire goals if crucial for my decision. I need to be able to fit 305s out back, and plan to widen a couple pairs of rears from my wheels sets to accomplish my goals.

I have no high offset wheels, nor do I care to acquire any. I would simply sell the Z3 rear 5 lug to an E30 guy and call it a day.

[BMWBergy]

Thanks for the clarification guys. The final offsets for the rear are of great concern to me, as I already have quite the low offset wheel colleciton from my E30 M3 and E34 touring, which I would attempt to utilize for this project.

Swapping over the Z3 M rear suspension, trailing arms and axles to be able to suit my wheel and tire goals if crucial for my decision. I need to be able to fit 305s out back, and plan to widen a couple pairs of rears from my wheels sets to accomplish my goals.

I have no high offset wheels, nor do I care to acquire any. I would simply sell the Z3 rear 5 lug to an E30 guy and call it a day.

Sounds like your answer is definitely the M rear end, then. My setup is 285s on 18x10 ET18 with about 1/2" to spare on the outboard side... Don't have a firm figure for inboard clearance yet, but there's plenty.

[e30polak]

Sounds like your answer is definitely the M rear end, then. My setup is 285s on 18x10 ET18 with about 1/2" to spare on the outboard side... Don't have a firm figure for inboard clearance yet, but there's plenty.

Ya, I know Ghery and MSilvia personally, and their set-ups along with jonesmechanical's are what make the Z3 M Coupe so attractive to me.

Love the way your coupe looks with the FM5s!

[BMWBergy]

Ya, I know Ghery and MSilvia personally, and their set-ups along with jonesmechanical's are what make the Z3 M Coupe so attractive to me.

Love the way your coupe looks with the FM5s!

Hey, this isn't about me! But thank you, I do love the FM-5s. Can't wait to be in a place where I can drop it another .25-.5" - just not doable here in Carmel.

[e30polak]

Hey, this isn't about me! But thank you, I do love the FM-5s. Can't wait to be in a place where I can drop it another .25-.5" - just not doable here in Carmel.

Your car is perfect height! I like to be low, but not at the expense of performance or driveability (to my standards at least). I refuse to stretch tire as well, I'm all about meaty stance!

This pictured changed my life years ago:

[BMWBergy]

Your car is perfect height! I like to be low, but not at the expense of performance or driveability (to my standards at least). I refuse to stretch tire as well, I'm all about meaty stance!

Thanks, but my sig doesn't match current reality. Since that pic, I installed 600# rear springs and the static height is actually a bit taller than the 400#ers they replaced, so I'm about 1/4" up from the ideal. I'll eventually get short springs to install with ride-height adjusters (which I have in a box), but for now I deal with it.

I'm all about the squared (vice stretched) shoulder. It's the look I prefer on myself, and my car.

- - - Updated - - -

This pictured changed my life years ago:

That's a spicy meatball!!!

[z3papa]

I am assuming you are not going to putting flares on the front. If you go all the way to 305's with maybe 255's out front, your car is going to understeer like a total pig. If you can't get traction with 285's which is what Sky1Z3 is running, with 255's out front, then you have some real issues. Specifically, do you want a cool looking straight line M coupe or do you want to be able to also corner competently. Personally, I'd buy the stickiest tires possible (I notice you live in LA, CA so NT01's is an option) and go 255 using 9" wheels/285 using 10" wheels.

[Sky1Z3]

I am assuming you are not going to putting flares on the front. If you go all the way to 305's with maybe 255's out front, your car is going to understeer like a total pig. If you can't get traction with 285's which is what Sky1Z3 is running, with 255's out front, then you have some real issues. Specifically, do you want a cool looking straight line M coupe or do you want to be able to also corner competently. Personally, I'd buy the stickiest tires possible (I notice you live in LA, CA so NT01's is an option) and go 255 using 9" wheels/285 using 10" wheels.

I have to agree here. I am running 245 F 285 R and while I don't experience much understeer, if you added another 20mm of contact patch then added sticky tires (im on sumitomo cheap street tires) you would have a problem. Im all for big wheel packages, but if you are gonna go as big as 305 rears, you really need to fit a 265 front like Jones did on his coupe.

[e30polak]

I have to agree here. I am running 245 F 285 R and while I don't experience much understeer, if you added another 20mm of contact patch then added sticky tires (im on sumitomo cheap street tires) you would have a problem. Im all for big wheel packages, but if you are gonna go as big as 305 rears, you really need to fit a 265 front like Jones did on his coupe.

I don't plan on running flares up front, as I don't believe any are offered. The 285 with a 10" may work, but it will be a handful with 400+whp/400+wtq. The under-steer could be aided by spring rates, sway bar size and bushing compound. I could always run stiffer springs out back with a bigger bar, race vs. street compound poly bushings and if that's not enough, then control with throttle modulation.

I've had multiple swapped e30s, which have similar wheel bases and suspension and I know how to set-up the suspensions for different applications. I had 17x8.5 front, with 235/40/17 front and 17x9.5 rear with 255/40/17s and it felt perfect with a soft bar, with 550# front/600# rear and poly street compound rear bushings, with a 16mm 3 way adjustable bar. If I ran a 305, with a 255 up front, I would probably run 500 or 550 front, and a 700-800 rear with a 18 or 19mm rear bar and race compound poly bushings. I know it would take a while to dial in the spring rates, but I'm up for that. I also plan to run long gears, so either the stock 3.23 gears from an M-Coupe or a 2.93 if need be with the Camaro T56 (Camaro comes with 3.42 final drive stock). Long term goal would be to fabricate the Corvette 4-link rear suspension to work.

[BenFenner]

Funny, I asked the same question(s) and more similar in this thread: (Newbie Z3-coupé thread) Differences between M models and non-M?

(Coincidentally, it is linked in The Manifesto.)


Edit: JoshS seems to love these threads. =D

[f50nut]

Sounds like your answer is definitely the M rear end, then. My setup is 285s on 18x10 ET18 with about 1/2" to spare on the outboard side... Don't have a firm figure for inboard clearance yet, but there's plenty.

Rough guess, you should have about .8" of clearance to the trailing arm assuming your tires are not bulging past the barrel. Max backspacing on the M Coupe is about 7". It's a little more if you move up to 19" wheels in the rear as the trailing arm angles inward.

[JoshS]

Edit: JoshS seems to love these threads. =D

When I know the answer, I answer :-) And, the non-Ms need a little love now and then.

[e30polak]

Funny, I asked the same question(s) and more similar in this thread: (Newbie Z3-coupé thread) Differences between M models and non-M?

(Coincidentally, it is linked in The Manifesto.)


Edit: JoshS seems to love these threads. =D

LOL. Well it got answered either way.

[BMWBergy]

Rough guess, you should have about .8" of clearance to the trailing arm assuming your tires are not bulging past the barrel. Max backspacing on the M Coupe is about 7". It's a little more if you move up to 19" wheels in the rear as the trailing arm angles inward.

You would know, Larry!!! I'll crawl under the loaded car this weekend to verify.

[robrez]

Hey Polak, run, don't walk. 8.5K M coupe in your area

http://losangeles.craigslist.org/sfv...274475571.html

[z3papa]

Sounds like what you need up front is similar to what is done in this wide body Z3 thread. http://forums.bimmerforums.com/forum...ight=wide+body