M3 Suspension

[lilme 0]

Hey all

Ive been looking around and it seems the only difference between a run of the mill e36 and and an e36 m3 is the shocks, struts and sway bars

Apparently the m3 swaybar mounts straight on the strut and Ive even read that m3 swaybars are thinner than standard e36 ones as they are in a more efficient spot

Can anyone clear this up for me

If its this easy to get m3 handling im going to ditch buying an m3 and just buy a 328 and maybe a big turbo to go with it

[conrod 1]

If its this easy to get m3 handling im going to ditch buying an m3 and just buy a 328 and maybe a big turbo to go with it

An M3 will be cheaper and worth more when you go to sell.......

I have E36 M3 front and rear "swaybars" and springs if you want to go the 328 route.

[BobSagat 1]

You also need the different, upper mounts.

[lilme 0]

Thanks for the help

Just after I posted I found a page with the conversion info

and saw everything you mentioned

Whats wrong with the 328 chassis surely strut braces and cross braces could tighten it up

Conrod you gotta tell me where your getting your M3's from :drugs:

Every 328 Ive seen has been around half the price

of the usual $30,000 M3

If I can pick one up at that price Ill buy two

[conrod 1]

The M3 "chassis" or bodyshell is identical to the lesser models- it is the same part! It is just everything that is hung off it, that has been uprated. And it is just about everything too on the M3, diff, diff cradle, "Z" arms, halfshafts, bearings, brakes, struts, top shoock mounts, ARB's, etc. are all different on the M3. The bodyshell is the same part though, so whatever fits an M3 can be transferred on to your 3 series whatever. Mind you, the M3 3.25 diff in your 320i auto probably won't be a good idea!

[E30-323ti 66]

The M3 "chassis" or bodyshell is identical to the lesser models- it is the same part! It is just everything that is hung off it, that has been uprated. And it is just about everything too on the M3, diff, diff cradle, "Z" arms, halfshafts, bearings, brakes, struts, top shoock mounts, ARB's, etc. are all different on the M3. The bodyshell is the same part though, so whatever fits an M3 can be transferred on to your 3 series whatever. Mind you, the M3 3.25 diff in your 320i auto probably won't be a good idea!

forgot:

the rear subframe on the 3.2l is different to take the bigger 210 diff.

rear subframe & diff (188) is the same as other 6cyl E36's on the 3.0l but output flanges are different (to go with the bigger CV's).

[conrod 1]

forgot:

the rear subframe on the 3.2l is different to take the bigger 210 diff.

rear subframe & diff (188) is the same as other 6cyl E36's on the 3.0l but output flanges are different (to go with the bigger CV's).

No I didn't forget Glenn, you didn't read my post properly! "diff, diff cradle....."

[kerrynzl 3]

I agree with Lilme, It's easy to get good handling out of a 328 [when you get closer to the limit the weakest link lets you down, Hence the M3 solution] Start with the widest, best tyres you can fit to the car. The next trick is to keep the footprint perpendicular to the road under extreme cornering, soft springs need stiff bars,and/more static negative [neg camber causes camber thrust,& tyre wear] Hard springs need less negative and softer bars [hard springs flex the chassis] High speed handling needs hard springs[higher spring frequency] and harder shocks[the shocks are bed partners with the springs] never use soft springs with hard shocks[the tyres skip bumps] never use a bar too stiff for the springs under compression.eg.cornering [the outside spring tries too compress the inside thru the bar] with handling everything is a compromise,even lowering a car has its downside, BE HONEST TO YOURSELF WITH WHAT YOU WANT, the M3 is a very good compromise. But you can dial in some of the M3 characteristics, relatively cheaply as long as you have a gameplan and good access to the right knowledge[not from some salesman selling you parts]

[lilme 0]

Heres a link to the page I found

http://forums.bimmerforums.com/forum/showthread.php?t=3476

After reading this it looks like it might be a cheaper option to modify rather than buy an M3. Even if you triple the amount he spent to cover the things he had missed out it would still be a cheap M3.

How can you measure how well brakes work with kw? Whether the car is modified or not, shouldn't the standard brakes work the same slowing from the same speed, unless the cars were different weights of course.

[petone 0]

How can you measure how well brakes work with kw? Whether the car is modified or not, shouldn't the standard brakes work the same slowing from the same speed, unless the cars were different weights of course.

yes, but will you be going the same speed with a modified engine?

[lilme 0]

True but 3pedals was only talking about a small increase in power therefore you wouldnt be able to reach dramatically faster speeds. If we were talking about 300kw atw that would be a different story.

[kerrynzl 3]

You need some serious maths to do brake calculations.To do a simplified version you need to ; Corner weigh your car & get your 'Center of gravity Height'

You need the rolling radius of the wheels[at the contact patch], the rolling radius of the discs [fr & rr] the Co-efficient of friction of the pads [this combined with disc radius gets brake torque] you also need the swept piston area of the front & rear calipers[in pairs] this gets line pressure, then you need the piston area of the master cylinder(s) and the brake pedal leverage ratio and pedal pressure(foot)

Brakes can safely be over engineered, the limiting factor then is weight vs traction .The more G's of decceleration you get, the more front bias you need [on a race car (in wet conditions)we dial in more rear bias to prevent front lock-up caused by slower decceleration at the limit of traction]

My advice is to buy the M3 brake set-up that Conrad has for sale, they are cheaper than some Racing Pads.

Standard M3 Brakes [with the right pads]would be sufficient enough in a club type race-car [maybe not 24hours of Le Mans]

[BobSagat 1]

Hi, I heard that the shells were different, the M3 is lighter and a bit stiffer, how true this is i dont know. It put me off getting a crashed LHD and doing a roller tho.

In saying that, if anyone wants a cheap, or Lightly damaged M3 itll prolly be LHD for under 10k let me know.

[kerrynzl 3]

Hey Bob do you have one coming in to NZ I could be interested for a race car, are you talking US or Euro spec? give me an email

Kerry

[lilme 0]

Man this post has gone well off topic.

In keeping with an off topic theme, I found out today that a family member is selling a 325 for cheap.

Considering the price I can go all out on it, so expect a very long topic in the not too distant future

[conrod 1]

yep around tuesday, give me a call to arrange a time.

[lilme 0]

WTF

Stop loitering in my topic you hoons

[kerrynzl 3]

With camber [E36's I will soon find out for myself] you want 1/2degree negative for maxamum adhesion]. So if your car bobyrolls 2 degress, you need 2-1/2 degrees static negative. Most suspension systems are designed to have dynamic [induced] negative so that less static negative is needed [for straight line driving] the best way to view this is with a camber guage and a trolley jack and the spring removed. If geometry can't be altered, The best thing to do is: Drive the car Hard [on the track]around a few corners. Then measure across the tyre with a Pyrometer [if it's too hot on the outside, use more negative. If its hotter on the shoulders of the tyre and not the center, it's under inflated etc etc] the trick with suspension ,is to set it up to how it's going to be used.[and to use information correctly] You don't need fancy shiny parts [just a good match of the right components]

[kerrynzl 3]

The normal compromise way to increase 'induced negative' is to 'raise the roll center' by lowering the outer ball joint [ this way, the Macpherson 'kicks out' at the bottom when it goes thru its range of movement] But Raising the roll center higher than the height of the outer ball-joint height causes problems,because the loads induced thru lateral acceleration can be greater than the weight of the vehicle,causing a jacking effect [a la triumph herald & dubby rear suspension]

Generally on macpherson suspension this isn't needed, it will naturally induce more negative as it is compressed because of it's triangle[3 pivot point] design [have a look at cars that are lowered]

[kerrynzl 3]

I forgot to mention, The only thing that is fixed on a macpherson strut suspension is the Scrub Radius "the angle of the strut to the stub axle[vertical plane]" all other mediums change angle thru movement, including caster [if needed to].

From a side view .If the lower 'A' arm is horizontal, and the strut has caster in it. The Caster will increase under compression [when the front dives]. The Brake Caliper attached to the strut tries to decrease caster thru torque [which counteracts against the caster induced thru dive] which is how anti-dive is engineered into geometry.[Doing the opposite in the rear is called anti-squat]

[lilme 0]

This may be a dumb question as I have never even seen these before but, would pillow ball top hats help with "induced negative" on the front?

"Ball" and "top hat" would suggest to me that they would have more movement at the top of the shock helping with camber under compression but im no mechanic.

[kerrynzl 3]

Not a dumb question at all. A macpherson system is a triangle from the upper [Tower] to the inner pivot to the outer ball joint. one side of the triangle shortens [the strut] changing the angle of the lower leg. Most manufacturers have a bearing mounted in rubber at the top of the strut. If you want to remove the compliance caused by rubber, you have to use a spherical bearing in the top hat.

So if anyone uses a strut brace with standard 'Hats',the strut brace only supports the owners ego.

[Silver Fox 43]

Pardon my ignorance too Kerry, but does that mean that there's no point in shelling out the bucks for a front tower strut in the E30 series cars, as spherical bearings are not allowed in the front, only the rear? And if that's the case, how much will a rear tower strut help the back of the car? Thanks for your help.

[kerrynzl 3]

Generally there is more flex in the 'hats' and the inner bushes, than you can ever possibly get in the inner guard & chassis rails. In my first posting on this thread I stated something 'about chasing the weakest point'. On a racecar most of the compliance is removed from the suspension,Combine this with stiff springs and race tyres and the chassis will flex. I personally think strut braces on street cars are just 'bling bling' BUT. . . . . . I've also seen road cars go faster on the track with them. so who really knows?

I've seen in some production classes, where they dial-in extra camber to allow for chassis flex [with this E30 class there is a 2-1/2 negative rule so everything helps]

I don't know if this would be a too thin an interpretation of the rules. Put a Rose joint on the ends of the strut brace and somehow bolt them directly to the shock [shaft]

It is technically not a mount

[Gus 5]

Generally there is more flex in the 'hats' and the inner bushes, than you can ever possibly get in the inner guard & chassis rails. In my first posting on this thread I stated something 'about chasing the weakest point'. On a racecar most of the compliance is removed from the suspension,Combine this with stiff springs and race tyres and the chassis will flex. I personally think strut braces on street cars are just 'bling bling' BUT. . . . . . I've also seen road cars go faster on the track with them. so who really knows?

I've seen in some production classes, where they dial-in extra camber to allow for chassis flex [with this E30 class there is a 2-1/2 negative rule so everything helps]

I don't know if this would be a too thin an interpretation of the rules. Put a Rose joint on the ends of the strut brace and somehow bolt them directly to the shock [shaft]

It is technically not a mount

bling on the street? i can hardly say if it makes it faster (not that it matters on the street) but an e30 with a strut bar, driving back to back with it on and off and on again, is noticably different. more stable on bumpy corners and under braking. as for bling who looks under bonnets anyway? i noticed 3 bonnets max being popped at our recent saturday meet, one for 5seconds, one for the 2.8 compact and the other for andys race car.

as for rose jointing the end on the strut brace/shock for the race series is kind of defeating the purpose in having standardized rules for everyone to have cheap, even racing. plus the rules main proviso is if its not expressly mentioned or allowed for, its not allowed.

Edited June 28, 2006 by Gus