Longish post on best handling upgrades...

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jaistanley
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Thu Apr 21, 2005 2:48 pm

Hi.

I recently bought a 318is and i have noticed the suspension is becoming more and more wooley. This could be due to age but me getting my little mits on it and ragging the nuts out of it is probably more likely an explanation!

The little 4 pot doesn't have much go, I'd like to compensate in the handling department, especially since i plan to fit a more powerful engine of some sort when funds allow.

Since there is already a car in the range that has amazing handling, i'd like to emulate it. The E30 M3 was developed as a race car so the suspension geometry and rates are more likely to suit me. I dont mind a firm ride quality as long as it is right for the road and not just the 'track' (or asda carparks to use the chav term).

Can anyone give me the exact suspension specifications and measurements for the E30 M3 and the E30 318is? I have some understanding of suspensions and handling from Uni and am very interested.

Before I start buying parts I would like to know the differences between the M3 setup and the standard E30. Can anyone tell me the parts that are common to both, and which parts are unique to the M3?

From what I can gather:

The M3 is 5 stud. Front hubs from an E28 5 series will fit any strut for the M3 or 318is. They give the same geometry and brakes but have different ABS rings ( I dont have ABS anyway so that wouldn't be a problem).

The M3 has same diameter ARB's but pick up on struts.. Would I just need to fit the M3 droplinks or the whole ARB's.. Has anyone done this? How much/how easy to find are they?

The M3 Has wider track...This is due to the hubs front and rear right?

From what I can gather I can buy dampers and springs that are intended for M3's as they will fit straight onto my car, before or after I go to M3 hubs and rear wishbones..Is this correct?

I plan to fit poly bushes with offset controll arm bushes at the front. Apart from this, did the M3 have any other offset/different bushes? The topmounts for example.. Are they increase Camber/Castor on the M3? I did plan to fit E46 M3 cabrio rear topmounts and Z3 plates. Would it be a good idea to fit any adjustable bushes to the rear to adjust camber/toe on the rear for a drop of 25 - 30 mm max?

Is the rear subframe on the M3 the same as the normal E30? I understand the Gruppe A cars had the option of 2, one with 15 degrees of rear sweep (same as all other e30's) or one with 12 degrees (to give better dynamic camber and toe changes throughout the suspension travel). Is the M3 normally 15 or 12 degrees of semi trailing arm sweep?

Can I fit Z3 or E36 compact rear wishbones? IE are they the same dimensions as the M3 ones and are the brakes as big? They are easyer to get hold of after all.

Are there any nice 15" or 16" wheels from any model that will fit the 5 stud and are light and cheap? Are standard E36 etc wheels the correct offset for E30 M3's?

And finally, which dampers and springs to go for..

Eibach springs seem very good.. What about Apex? A friend has put them on his M3.

Which dampers? Was thinking Bilstien Sprint dampers as a friend can get them cheap and they seem very robust (the shaft for the damper is massive). Friends have Koni adjustable's and rave about them. Gaz shocks are new and seem to be good. I have no experience of them but they are adjustable, zinc coated and cheap.

Many thanks for reading this and for any help...

Jai Stanley :cool:
MONSPORT42
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Thu Apr 21, 2005 5:39 pm

Wow Jai, loads of questions there. Probably too many for any one person to answer. You'd probably be better off asking "What's the best suspension set-up for an E30"
I know you are aiming at M3 handling but without getting an M3 you ain't gone a get it and you'll probably spend more than the cost of one trying. But you can get close. Most people on here seem to rate the H&R Cup kit for springs and shocks. I have Bilstein Sports & Terra (Bilstein) springs lowered 40mm plus offset M3 offset control arm bushes and standard Sport ARB. People find this quite a hard ride but I find it a good compromise for road/track. There's a good thread posted by M5Pilot last week on "Hartge view on handling" with lots of good input from the zone. A lot of this centres on getting the right ARB it would seem. I would back track and have a read.
Sorry I can't answer all your questions on camber, etc. I leave all that up to someone who knows better than me!
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jaistanley
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Thu Apr 21, 2005 7:34 pm

I'm loathe to ask questions like 'whats the best suspension for an E30?' on a forum. Two things could happen, a massive row cos every chuck has different bolt on kits and think their car is the best in the world; or someone'll tell me to 'slam it an put 19's on bruv'. Either way, the guys with something interesting to say get drowned out or turn off in disgust!! It's the same in any car forum, world over!

I know it'll never be an M3.. But if everything is set up the same it'll be damn close! The difference would end up in the chassis, the M3 no doubt being a lot more torsionally rigid. Spose there's nothing to stop me seam welding and re-inforcing mine but I really cant see myself ever bothering. By the time I managed to muster the energy I'd have saved enough for a fleet of M3's!

Cheers though man.

Anyone else?
Demlotcrew
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Thu Apr 21, 2005 7:53 pm

Mate, if you were to ever get M3 parts and put in on your IS, it will still not handle the same. The M3 has near 50/50 weight distribution. You will get better results from using good dampers and springs for the IS, rather than the M3. The suspension geometries are the same for all the E30s inc the M3.

HTH

Andrew
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Thu Apr 21, 2005 8:21 pm

Can I fit Z3 or E36 compact rear wishbones? IE are they the same dimensions as the M3 ones and are the brakes as big? They are easyer to get hold of after all.
Referring to rear:

Compacts with rear discs and 4 pot Z3s, have 40mm wider track and smaller hub bearings/brakes than an E30 M3.

Z3M has the same track as an E30 M3, same bearing sizes and monster vents.
Last edited by M3Compact on Thu Apr 21, 2005 10:21 pm, edited 1 time in total.
Turbo-Brown
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Thu Apr 21, 2005 9:39 pm

Doesn't the M3 have a shit load more castor than the standard version to make for a better turn in?

Not sure how this was achieved, if it was just in the bushings or if the shock towers are further back though.
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astondg
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Fri Apr 22, 2005 8:55 am

Demlotcrew wrote:Mate, if you were to ever get M3 parts and put in on your IS, it will still not handle the same. The M3 has near 50/50 weight distribution. You will get better results from using good dampers and springs for the IS, rather than the M3. The suspension geometries are the same for all the E30s inc the M3.

HTH

Andrew
I read somewhere that the 6 cylinder E30's are 52/48 F/R so I thought the 4 cylinder versions would have to be close to 50/50. Maybe move the battery to the boot and a lightweight bonnet would do it if they aren't already.

Also you can get camber & castor adjuster plates that fit on top of the strut to help get better turn in.

BMW made the M3 from the basic E30 design so I don't see why someone else couldn't do the same, might cost a bit though.

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johnono
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Fri Apr 22, 2005 11:55 pm

bruvs, do the words "slam it" and "19Ԛ´s" mean anything to u

only muckin about :wink:
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