e30 325i suspension upgrades?

[Apex Effects 3]

hey all ive just bought myself i 89 bmw 325i (facelift) 2 weeks ago and im wanting 2 upgrade my supsension in anyway possible as i think its a bit 2 soft and and doesnt handle aswell as i think it could b. so... i was also wondering on prices? and i was also wondering on prices and wat stuff 2 use to complete a hub conversion as i was wanting 2 b able to put sum e46 m3 19s on as i think it would look so much cooler than aftermarket 1s as its sticking with the euro bmw theme. so any 1 out there wana help me out in sourcing parts or if its possible? and how much dosh im looking at spending. thanks ive added sum pics of the wheels im after.

[Andrew 30]

Welcome to the site - please check you are posting in the correct section. I have moved your post from BMW Race Series Technical to Bimmersport Technical:

RE Suspension: Check other threads in this section - it has been done a million times before and you should be able to get an idea on what is good/bad & prices.

E.G http://www.bimmersport.co.nz/forums/index.php?showtopic=9653

RE E46 M3 wheels: The e46 has a 5 x 120 PCD hub and the E30 has 4 x 100 PCD. You could either convert your E30 to 5 x 120 (again use search) or try find a replica E46 M3 wheel.

[Apex Effects 3]

hey dude thanks and i was wanting 2 do the hub conversion so i could put genuine e46 m3 19's

thanks for corecting my posting error

[hybrid 1043]

its not so straight forward, there are a few ways to do it ... couple of us on here have done it different ways. Me using e30 m3 struts and m-coupe rear trailing arms etc etc

check glens conversion notes if your not looking at sticking silly amounts of power through your drive train.

http://www.ubersaloons.co.nz/uber3/5lug.htm

[Gus 5]

glens seemed to be cool up to 'only' 292 rwhp

[Andrew 30]

glens seemed to be cool up to 'only' 292 rwhp

with only like 500 Nm of torque also :-D

[Guest Denny Crane]

check glens conversion notes if your not looking at sticking silly amounts of power through your drive train.

http://www.ubersaloons.co.nz/uber3/5lug.htm

Pretty massive oxymoron there, Josh.

[martyyn 2]

3Pedals,

Check out the link I think Glenn had all that at the bottom.

[E30-323ti 66]

Out of interest what is the final suspension geometry for cars like Glens,

Caster 0 & 10 degreees, camber toe etc

As Martyyn said, have a look at the link.

That was when I first did the swap.

It now has just under -4d up front, and haven't got the backend together yet, but was around -3.5d which was a bit too much.

Now it's adjustable, back to 0d I'd say, for those drag events I'll attend, yeah right!!

Caster is around 9d

I run 1/8" total toe out on the front and in on the rear, very stable at speed and turn in is pretty crisp.

The 318ti (or E30) axles/CV's are the only issue with that setup.

Both darren and myself have put 300-350rwhp through them and not had any failures as such.

Sure there has been some pretty manky looking outer CV's, but if your not giving it a hard time (launching it on slicks etc...) then they are pretty tough.

The only reason I changed to the E28 backend was for future proofing, to run bigger brakes and better geometry, oh and coilovers.

Edited February 28, 2007 by E30-323ti

[Apex Effects 3]

sweet thanks for the methods 2 complete this conversion. just how much would i b looking at for ur stuff for the conversion or wats the difference between ur stuff and the e30 m3 stuff and cost?

[hybrid 1043]

You dont want to know how much the e30 m3 / m-coupe way costs .. its really only if you looking at sticking over 500whp on an e30. Ended up buying most of it brand new as there is next to 0 people wrecking either an e30 m3 or m-coupe in NZ.. its also not the only way to do this. The guys in sweden are using m5 bits.

Glens way is far more cost effective and probably more of what youre looking for and as glens proven its good for nice amounts of HP too.

[Apex Effects 3]

all gud dude. thanks again

[Apex Effects 3]

just a question 2 glen. y did u use 318 stuff thats all. would it b all gud 2 still use my 325 stuff?

[E30-323ti 66]

You dont want to know how much the e30 m3 / m-coupe way costs .. its really only if you looking at sticking over 500whp on an e30.

Especially when you think about the little benefit (eg. Bolt-in) you get from it.

At 500whp the M-Coupe backend will start feeling the pain, have a look at MrBlonde's M-Coupe!!

I've spoken to the guy's in OZ that built his car, All the axles, CV's, Stub axles are all custom built.

Realistically, if you have 500whp, you are going to be an animal to it, no question.

And the E30 M3 front doesn't leave much scope for wheel choice if you are wanting a BBK (with 4pots).

Ended up buying most of it brand new as there is next to 0 people wrecking either an e30 m3 or m-coupe in NZ.. its also not the only way to do this. The guys in sweden are using m5 bits.

It is the E28 M5 backend they use (same trailing arms and sized diff as the E34 M5), which is the same as mine, however they use the type 210 BMW diff where as I use a Supra Diff.

Glens way is far more cost effective and probably more of what youre looking for and as glens proven its good for nice amounts of HP too.

I gather this is in relation to the 318ti backend.

If you were looking for one, I think Darren may look at selling his soon (my old one) to go down a similar path to me.

All non-M E36 front knuckles and hubs are the same, so it doesn't matter what model you get them from unless you are keeping the stock E36 brakes, in which case don't use 318i or ti bits as they have solid discs.

The 318ti backend is fine as stated above, and you can use your 325 axles as the CV's are thicker.

[Apex Effects 3]

ok im a little lost on ur explanation dude sorry not up with the lingo. i was just wondering wat prices its going 2 cost me and this darren guy what has he got of ur old set up? and wat 318 parts did u use?

[hybrid 1043]

Especially when you think about the little benefit (eg. Bolt-in) you get from it.

At 500whp the M-Coupe backend will start feeling the pain, have a look at MrBlonde's M-Coupe!!

I've spoken to the guy's in OZ that built his car, All the axles, CV's, Stub axles are all custom built.

Realistically, if you have 500whp, you are going to be an animal to it, no question.

Yeah, but remember hes running it on the drag circuit constantly launching it hard on drag radials a lot ... they have only just gone to this setup .. he was stock before this. If this car ends up down that road competitively .. ill do the same no doubt.

And the E30 M3 front doesn't leave much scope for wheel choice if you are wanting a BBK (with 4pots).

Getting custom wheels made so no worries ... and we are running 6 pot up the front on 332x35mm rotors. Will post the pics soon after welds are done ..

[Apex Effects 3]

Yeah, but remember hes running it on the drag circuit constantly launching it hard on drag radials a lot ... they have only just gone to this setup .. he was stock before this. If this car ends up down that road competitively .. ill do the same no doubt.

Getting custom wheels made so no worries ... and we are running 6 pot up the front on 332x35mm rotors. Will post the pics soon after welds are done ..

just a final question the wheels im looking at are m3 replica wheels which are 19x8 and 19x8.5 would these fit under my guards? im doing the five lug conversion like glens i just wana know if they will fit so i dont waste my money buying them and they dont fit so any ideas would b awsome asap as im planing 2 start this with in the next month.

cheers for all your guys advice

Shaun

[Guest Denny Crane]

And the E30 M3 front doesn't leave much scope for wheel choice if you are wanting a BBK (with 4pots).

A rotor spacer means an E36 M3 caliper will bolt to the hub, and you can get a conversion kit from mov'it to run porsche brembo GT 6pot calipers.

With the rotor spacer, you change to a much higher offset, so e36 m3 wheels are the way to go, which mean you can stuff a massive BBK in there.

[E30-323ti 66]

A rotor spacer means an E36 M3 caliper will bolt to the hub, and you can get a conversion kit from mov'it to run porsche brembo GT 6pot calipers.

With the rotor spacer, you change to a much higher offset, so e36 m3 wheels are the way to go, which mean you can stuff a massive BBK in there.

Bolting it all together is the easy part...

And still only with selected wheels!!

No deep dish style wheels will work without even more spacers, hello huge scrub radius (this is where the E36 frontend is superior to the E30 M3, and giving giving a better roll centre). making it "work" is the hard part.

Plus when it's on a E30, the guards aren't nearly as generous as a E36 to accomodate big spacers for BBK's, so wheel selecton is important with BBK's.

[Guest Denny Crane]

Can you further explain scrub radius and why its important Glenn?

[E30-323ti 66]

Can you further explain scrub radius and why its important Glenn?

The scrub radius (very crudely) is the distance from the CL of the wheel to the steering axis intersection with the ground.

Adding spacers increases this (if the wheel is a similar offset to stock). In the E30 M3 case, you need ~12mm to get the E36 discs on (which is offset by the change in wheel offset), plus another 15-20mm is req'd to fit a BBK under M3 wheels.

So by the end you have ~40mm of spacing from the hub, long bolts or studs, plus big loads on the wheel bearings.

If these are close (ie small dist.) the the wheel will pivot within the tread, if they are further apart the wheel will "scrub" forward and back as it turns.

This creates heavy steering, tramlining, excessive steering pull under hard braking (as the wheel moves or is pushed fore & aft), excessive wear on wheel bearings, and changes (softens) the wheel rate of the suspension.

Add to this the tonnes of castor that E30's have, the wheel can go forward/back, up/down, whilst sitting on the spot.

Have a search on the net, it should be described pretty accurately some where.

[hybrid 1043]

you really should be running about 16mm offset for BBK and wide wheels to counter it ... in other words custom ..

[martyyn 2]

I was thinking he really should get out more

[Apex Effects 3]

I was thinking he really should get out more

guys!!! could some one answer MY question please!

just a final question the wheels im looking at are m3 replica wheels which are 19x8 and 19x8.5 would these fit under my guards? im doing the five lug conversion like glens i just wana know if they will fit so i dont waste my money buying them if they dont fit. so any ideas would b awsome asap as im planing 2 start this with in the next month.

cheers for all your guys advice

Shaun

[E30-323ti 66]

guys!!! could some one answer MY question please!

just a final question the wheels im looking at are m3 replica wheels which are 19x8 and 19x8.5 would these fit under my guards? im doing the five lug conversion like glens i just wana know if they will fit so i dont waste my money buying them if they dont fit. so any ideas would b awsome asap as im planing 2 start this with in the next month.

cheers for all your guys advice

Shaun

oops, got a bit off topic didn't it.

So to clarify, you will have E36 front & E36 ti rear!?!?!

If so, get all 19x8's the 8.5's won't let you run any more tyre and will be a pain when rotating them to optimise wear etc...

What tyres are you going to run?? 225/35's, even that may be too tall for the E30??

What offset are the wheels??