Chassis Differences between E30 M3 and non-M3?

[Motorhole]

The E30 M3 is widely regarded as one of the best handling saloons of all time...I have heard Impreza drivers claim their cars are getting lairy before an E30 M3 when following.

But how was this improvement made on the basic E30? What are the main suspension and chassis differences? Is it possible to upgrade a base E30 with E30 M3 suspension parts, or similar from the BMW parts bin?

[Dan318-is]

To start with the m3 had different suspension and struts; it had revavled shocks and it had 5 lugs instead of four to enable larger wheel bearings (off teh e28)

it had a thicker rear anti roll bar, both roll bars were bolted directly to the struts

The car also had a wider track. and the springs were stiffer and shorter

[M5pilot]

I think the shell is alot stiffer aswell as suspension upgrades + weight distribution is different.

[Dan318-is]

weight distribution is 52/48, although apparently the s14 lump is quite far forward and on a slight slant!

[orangecurry]

the whole steering geometry/parts are different - that's why they were LHD only

I would imagine as they were track cars they would have been seam welded as well - lets ask google shall we children?

[orangecurry]

can't find anything definitive on welding, but here's an interesting site; american, but still informative

http://mph-online.com/mag/rearviewmirror/008

[bigun]

does the 320is have the M3 set or the 2.5 sport

[Dan318-is]

325i sport mate, 99% sure it does

[bigun]

i couldnt remember where the anti roll bar was on my mates 230is i know its got a r/d anti roll bar but couldnt re-call if it was fixed to the strut

[Simon13]

320is had 325i sport running gear but still a smashing car by all accounts

Good question

fit M3 front struts and rear trailing arms and u will gain most of the benefits the M3 had over a stock E30. This will give u bigger brakes, 5 stud, M3 track and offset. U won't have the aerodynamic aids from the body, but it was the suspension tweeks thats done alot of it

Thing is a well setup E30 is a fine handling car, but the M3 had the majic those extra things that makes it still now a fine handling car

S14 is not far off the weight of an M20 either 20kgs in or so

i'm not sure on the anti roll bar thing Dan, all E30 roll bars mount in the same places. regardless of engine size or shape

only the factory made bmw works racers where seem welded, along with the cars they made for non factory backed teams and privateers with loads of money! Ԛ£71,000 they cost roughly! Road cars weren't seem welded

hth

[Widge]

can't find anything definitive on welding, but here's an interesting site; american, but still informative

http://mph-online.com/mag/rearviewmirror/008

From that site

Second, the S14 essentially borrowed the block from BMW's venerable sixcylinder "M10" Formula 1 racing engine. BMW Motorsports engine guru Paul Rosche took the M10 and lopped off two cylinders. In addition, he used the DOHC cylinder head from the BMW M1 engine, again minus two cylinders.

I don't remember the M10 having 6 cylinders!

[Dan318-is]

i'm not sure on the anti roll bar thing Dan, all E30 roll bars mount in the same places. regardless of engine size or shape

Thats just what i remembered from M registry which i thought was a good source of Info??

[mysteron35]

One thing I can add is in the past I've jacked up a 325 sport on one side and the doors are hard to open , but when I do the same with my M3 you can still open all the doors so it must be a lot stiffer .
Just something I noticed .
Steve .

[Simon13]

no it's the fact sports rust like gooduns and the shell becomes alot more flexible!

[Demlotcrew]

I also think the m3 shell is stiffer, it had bonded windows and other reinforcements that the E30 doenst have.

Andrew

[Widge]

The rear window was at a different angle too wasn't it?

[kam-325i]

I also think the m3 shell is stiffer, it had bonded windows and other reinforcements that the E30 doenst have.

Andrew

A bonbed windscreen/Rearscreen add's about 30-40% more stiffness to the chassis.

[Simon]

i'm not sure on the anti roll bar thing Dan, all E30 roll bars mount in the same places. regardless of engine size or shape

Thats just what i remembered from M registry which i thought was a good source of Info??

Dan is right, the front anti roll bar links mount to the leg instead of the control arm on the M3.

[Simon13]

so how come all E30 roll bars are the same?!

[Simon]

so how come all E30 roll bars are the same?!

It's the links that are different, not the bar, they're the same links as fitted to E24, E28, E31, E32.

[Demlotcrew]

I also think the m3 shell is stiffer, it had bonded windows and other reinforcements that the E30 doenst have.

Andrew

A bonbed windscreen/Rearscreen add's about 30-40% more stiffness to the chassis.

I would not expect as much as 30% but ive not looked into the percentages, im about to get a front M3 screen fitted to a Stock E30 shell so will get back with what i notice.

Andrew

[kam-325i]

I also think the m3 shell is stiffer, it had bonded windows and other reinforcements that the E30 doenst have.

Andrew

A bonbed windscreen/Rearscreen add's about 30-40% more stiffness to the chassis.

I would not expect as much as 30% but ive not looked into the percentages, im about to get a front M3 screen fitted to a Stock E30 shell so will get back with what i notice.

Andrew

That is just across all cars for both screens, not just the M3. I can find out from my dad what the exact figure is for the M3.

[Andy335Touring]

im about to get a front M3 screen fitted to a Stock E30 shell so will get back with what i notice.

Andrew

I'd be interested to know how you get on with that mate, i guess you will need some M3 window trim bits to finish it off ?

[M5pilot]

What ever the differences are they make a very very big difference on a track or twisty roads.

Ive seen 325i's roll caged with Ledas on slicks get obliterated by M3's with only light suspension upgrades. There is no comparison. The E30 M3 is not a handling legend for no reason.

The anti roll bars on an E30 M3 are mounted in a different place - they create alot more force because of this. The thickness of an Anti roll bar isnt the only factor.

[l88eef]

the frt and rear anti roll bars are thicker and the frt mounts onto the strut via drop links which makes the car respond quicker to steering changes and turn in quicker, the struts have differant geometry with twin tube gas dampers,the rear trailing arms have 15-degree rake on them, wheel bearings and brakes came from the 5 series and a 19.6:1 quick ratio rack was fitted. the frt+rear screens were bonded for ridgity as someones said and the big arches were to allow 10" wide race wheels, the 320is never recived any of suspenshion improvements only a sleeved down vershion of the m3 engine.