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oh2ryan

5 Lug Suspension Quandary: E30 M3 Vs. Z3 M

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Hey guys,

 

I need some help in figuring out which of the following suspension options is more ideal for the 2002 project I am just about to begin. I am very new to 2002s, but have plenty of e30 experience.

 

I am positively going to 5- lug swap my 2002. I enjoy not only the wheel choices and brake upgrades, but also I enjoy putting in the time and thought on the more unusual and challenging projects. I want this 2002 to stand out, and for all the modifications to flow well together.

 

Background information:

The chassis is a 1974 2002, no sunroof. The car will be getting an m20b25 temporarily until my s14 can be reworked and built up to one day be swapped in. I’ll be running a Getrag 265/5 dogleg close ratio gearbox behind the m20/s14 (I have both bell housings to make this work). Also being used are both e30 front and rear sub frames modified to bolt onto the 2002 chassis. The sub frame swaps allow for a Z3 steering rack to be installed, engines mounted simply, and of course allows for the 5 lug trailing arms to be bolted up in the back of the car.

 

First swap option: full e30 M3 suspension components. This set up offers 280mm/ 282mm rotor sizes front/ rear. Large wheel bearings are an advantage, and this set up changes track width exactly the same as the standard e30 4x100 trailing arm (this measurement I cannot accurately find, to those who have done it please chime in). 15” wheels are the minimum size using e30 m3 parts

 

Second swap option: full Z3 M suspension components. This set up offers 315mm/ 312mm rotor sizes front/ rear. Also, the wheel bearing is even larger than the e30 m3 equivalent and this trailing arms is braced and reinforced. This set up does change track width even more drastically, increasing the width ~20mm more over the e30 M3 (which is already wider than that of the factory 2002). Another notable item is the weight change; the MZ3 components weight another 12 lbs more per corner than the e30 m3 parts, due mainly to the much larger rotors and calipers. 17” wheels are held as the minimum size to clear the Z3 M brakes, although a handful of 16 inch wheels are reported to fit.

 

So to the enthusiasts and racers out there, which set up sounds more appealing? I’d like to keep this thread on topic with just discussing which 5x120 swap is more “ideal”. Either way, this 2002 will require some fender flares; I am aware of this and have been searching for weeks as to which flares I like best. I enjoy the turbo flares look most of all, but these cannot be utilized if the MZ3 parts are used. I would probably go with the Schnitzer flares, if they could be sourced, if the MZ3 parts are installed. Are the bigger MZ3 brakes a better way to go despite the weight and track width increases? Are Z3M brakes  on a 2002 with ultimate power goals of ~200whp from the 4 cylinder s14 overkill? Or are bigger brakes at the end of the day always more ideal on a car that will see much spirited driving. Keep in mind wheel sizes, 17s on a 2002 are large, but they do offer better tire sizes. However, should the 2002’s suspension be as light as possible and thus use the e30 M3 parts to keep the feedback from the car optimized, matching the lightness of the overall chassis?

 

I have the full e30 m3 suspension set up, and the rear Z3 M parts on stand-by in the barn sitting next to the 2002. I just cannot decide if I should run the e30 M3 bits or scoop up the front Z3M/ e36 M3 suspension and go the full blown crazy route with the Z3 M parts.

 

Any insight, comments, concerns or questions appreciated!

 

 

-Ryan

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Ryan, as I'm sure you're aware a lot of what you're asking is subjective to personal opinion rather than anything more substantial.  For that reason I'm a strong believer in following what you want to do.  Forums are like peanut galleries for things like this, it seems there are an influx of heavy stylized 2002 "builds" recently, are you building something for 15 minutes of attention or building something you will enjoy for years no matter current "trends"?   

 

From a "racers" perspective neither option sounds appealing as you'd be limiting the car to track-day only status or put in a class where you likely wouldn't be competitive.

 

I'll comment on the technical side of things....

If a true rear coilover is being used, especially with E30 or Z3 subframe then you will be putting in a cage (or at least half a cage) to support the rear tires).  Depending on how you drive the brakes are certainly overkill.  You may find it would be much easier in the front to run tii struts with e12 hubs to achieve the 5x120 pattern you want.  This also means you wouldn't need to recalculate all your steering/suspension geometry in the front.

 

I sincerely wish you the best of luck with your project though, hope you have fun.

 

 

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Thanks for the response. I do see how this topic is very subjective, I guess I was hoping there would be a few out there who have done something similar or aspired to; and that input would be very helpful. My goal was to determine if the e30 M3 components offered more than enough for this build with this power range and being predominately a daily driver or if the MZ3 parts are worth installing since I have sourced them and they offer a few perks.

 

Regarding input from those who race their cars on the track, I was wondering if the brakes offered mainly in the Z3 M were just overkill for a car that would only see the occasional auto cross event or open track day. This cars main purpose is to be a fun and more unique project car than it is to be a race car.

 

I did consider doing the e12/ tii front 5 lug swap (hence only having the rear Z3 M parts as of now), but since I have all the e30 m3 bits, and the e36 m3 components offer more in terms of braking, I was leaning that direction over the e12 parts.

 

This 2002 will be with me for years to come, its not something I plan on getting rid of.

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I would prefer the lighter M3 setup. That's because all that Z3M offers is just overkill. Of course if you're just building a fun car, not a racecar, overkill isn't that bad. With M3 setup it would be possible to keep the classic look of -02 which is pretty much gone with 17" wheels - if it matters to you.

 

I have 17" M5 wheels under my racer. Realized using E12 struts and E28 rear arms with plenty of home made parts and mods.

 

  Tommy

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(edited)

Here's a couple to help inspire you (you may have already come across).  Regardless of what you decide to do I hope you'll take plenty of pics.

 

Kevin's

http://www.bmw2002faq.com/topic/110268-the-heist/

Jonathan's

http://www.bmw2002faq.com/topic/103970-75-2002-sleeper-m20b32-itb-lsd/

Oscar's

http://rejsa.nu/forum/viewtopic.php?t=31676&view=previous&sid=d71e218fc409fb905e5b8d06cf99b92a

Frank's

http://www.bmw2002faq.com/topic/123639-please-no-hate-f20c-content/

Edited by AceAndrew

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On the topic of brakes (which seems to be the whole dilemma with the Z3M setup), you have to remember that you can only do as much braking as your tires will allow you to, after that you're just adding extra weight. So unless you're going to be running something super sticky and quite wide, I'd say the E30 M3 setup would serve you just as well.

 

Also remember that space is at a premium when talking about wheels and tires with the 02', even with flares. If you're extending track by 20mm with the Z3M setup, you're starting to get close to your outer fender even with Schintzer or Turbo Flares if you're running a wider wheel. That would limit you to a high offset wheel selection and even then you may run into brake clearance issues because of this. Granted, this is all assuming you're not trying to stretch tires or anything and you're looking for more of a performance oriented build.

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How do you plan to use the car?

 

I think a lot of what you are doing may be overkill, but do what you like!

 

And, you can get more than 200rwhp from an S14 :)

 

Cheers,

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I would prefer the lighter M3 setup. That's because all that Z3M offers is just overkill. Of course if you're just building a fun car, not a racecar, overkill isn't that bad. With M3 setup it would be possible to keep the classic look of -02 which is pretty much gone with 17" wheels - if it matters to you.

 

I have 17" M5 wheels under my racer. Realized using E12 struts and E28 rear arms with plenty of home made parts and mods.

 

  Tommy

 

Tommy I am building this mainly to be a fun car to zip around town in. Thats a great point about the classic look being unattainable if larger wheels needed to be used. Ive been sifting through images of 2002s on 17s to see if its something Im willing to do, and if they can still allow the car to be lowered a little bit and not rub with the changes  I am making to the car.

 

Here's a couple to help inspire you (you may have already come across).  Regardless of what you decide to do I hope you'll take plenty of pics.

 

Kevin's

http://www.bmw2002faq.com/topic/110268-the-heist/

Jonathan's

http://www.bmw2002faq.com/topic/103970-75-2002-sleeper-m20b32-itb-lsd/

Oscar's

http://rejsa.nu/forum/viewtopic.php?t=31676&view=previous&sid=d71e218fc409fb905e5b8d06cf99b92a

Frank's

http://www.bmw2002faq.com/topic/123639-please-no-hate-f20c-content/

 

These links are great! I follow the 75 sleeper build on the e30 forum I am a member of, hes given me some valuable info regarding this swap. The first link Im very glad you posted also, I have seen pictures of the car, but have never stumbled upon the build.

 

On the topic of brakes (which seems to be the whole dilemma with the Z3M setup), you have to remember that you can only do as much braking as your tires will allow you to, after that you're just adding extra weight. So unless you're going to be running something super sticky and quite wide, I'd say the E30 M3 setup would serve you just as well.

 

Also remember that space is at a premium when talking about wheels and tires with the 02', even with flares. If you're extending track by 20mm with the Z3M setup, you're starting to get close to your outer fender even with Schintzer or Turbo Flares if you're running a wider wheel. That would limit you to a high offset wheel selection and even then you may run into brake clearance issues because of this. Granted, this is all assuming you're not trying to stretch tires or anything and you're looking for more of a performance oriented build.

 

Great points... for tires I think Id be running a high performance street tire most always. I used the e30 M3 suspension on my 1988 325iS M Technic II before it was totaled a few months back. The braking with the 25mm master cylinder and good pads was awesome, I just always wanted a little more stopping power/ brake feel on those days I took her out. I guess the 2002 is much lighter, and the tire selection would warrant huge brakes (225 45 15 or 225 35 17 would be what Id choose depending on which set up I used). 

 

I think on the Z3 M track is increased much more than 20mm also, its 20mm over whatever the track increase measurement of an e30 trailing arm is installed on the 2002... But yes, no stretched tires here. I can respect that look, but its not for me on this build at all. I was hoping to use a 7.5-8.5 inch wheel width. 

 

I guess I need to research how much space is actually under the arch/ flare lip and between the spring so I can do some calculations. Ive seen Ireland Engineering's website page where they talk about tire sizes under flares on the 2002, but I have seen members builds exceed those specs listed. 

 

How do you plan to use the car?

 

I think a lot of what you are doing may be overkill, but do what you like!

 

And, you can get more than 200rwhp from an S14 :)

 

Cheers,

 

The plan is just a super fun daily driver mainly. I LOVED my e30, every time I got in it it was like re discovering what happiness it. I know the 2002 has even more to offer than the e30 also, so I just want to use it as a canvas and build something that will do that same very thing when I fire her up everyday. 

 

The 200rwhp is a good starting place in my mind, not sure how wild I am going to go on that thing due to the extreme costs. A 2.5 s14 may be where I cap things off for the engine.

 

Thanks for the comments guys, I have more research to do yet it seems.

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(edited)

Sounds like E30 M3 setup is the way to go. You can reduce weight more if you want to spend $$ on aftermarket calipers. On my track car I run Wilwood calipers with 300mm rotors front/rear and 15" rims (4 lug setup). It turned out the larger rotors and aluminum calipers weighed within a few pounds of my earlier "big brake" kit of 528i calipers, 323i front rotors (tii spindle) and 320i rear drums. Of course the large steel rotors have more rotating mass, which is a downside. Is it overkill?...I don't know, but I like it and never cook the brakes :). I also installed Tilton overhung pedals with a balance bar--I like the feel of running direct with no booster, plus it frees up room in the engine compartment. When my new engine is done it will have over 200 RWHP -- the car weighs 2000 lb with full 12 pt cage.

 

BTW, interesting info on the E30 front subframe and Z3 steering rack. I might look into this sometime.If you can, please post a link on the mods required. I've always wanted to reduce weight by fabricating front and rear aluminum subframes, but I don't have the skills or facilities at this point.

 

--Fred

Edited by FB73tii

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K.I.S.S.

 

Its a 2002, after all. 

 

I bought this car with the intentions of turning it into something fun, a long term project. I guess I accepted long ago that some things might not be simple in terms of this build. 

 

Sounds like E30 M3 setup is the way to go. You can reduce weight more if you want to spend $$ on aftermarket calipers. On my track car I run Wilwood calipers with 300mm rotors front/rear and 15" rims (4 lug setup). It turned out the larger rotors and aluminum calipers weighed within a few pounds of my earlier "big brake" kit of 528i calipers, 323i front rotors (tii spindle) and 320i rear drums. Of course the large steel rotors have more rotating mass, which is a downside. Is it overkill?...I don't know, but I like it and never cook the brakes :). I also installed Tilton overhung pedals with a balance bar--I like the feel of running direct with no booster, plus it frees up room in the engine compartment. When my new engine is done it will have over 200 RWHP -- the car weighs 2000 lb with full 12 pt cage.

 

BTW, interesting info on the E30 front subframe and Z3 steering rack. I might look into this sometime.If you can, please post a link on the mods required. I've always wanted to reduce weight by fabricating front and rear aluminum subframes, but I don't have the skills or facilities at this point.

 

--Fred

 

Glad to hear some more first hand experience with the larger brakes Fred. E30 M3 seems more ideal, especially with additional weight savings in 15 inch wheels and tires, and a more aesthetically pleasing final product with period correct wheels.

 

The sub frame swap up front is hard to find info on. Ive seen a few incomplete project threads and a few who mention seeing this swap done but no published builds and pictures. Ill be posting things as I go on further with this project.

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The reason you haven't seen much on front subframe swaps is that it's going to be bloody hard.  The E30/E36Z setup is located 

by the arm and a rear point off the body.  The 2002 is located by the arm and a FRONT point off the subframe.

 

So when you create that rear point to mount the eyeball, you're going to have to make a structure to support it-

the 2002 rails are softer than the E30/E36  (they may be one of the few points that are!!!)

 

That said, there's no reason you  can't do it, it'll just be a lot of work.

 

As to wheels, the largest tire that really fits under a 2002 has a circumference of maybe 22 inches and a width of about 7.

Anything much bigger than that starts to foul the front valence and the rear inner fender well at full lock.  You CAN go bigger

(I ran 22x9" for a while) but you'll start having to limit lock and do sheet metal work.  Which it sounds like you're not afraid of!

 

Honestly, if you're going this far (I know, I know, I've gone beyond your defined scope) why not put E36 rear suspension in?

It's SO much better than anything that came before it...  and yes, it's a shitton of work, but so's all the rest of it...

 

that's me.

t

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