E36 compact ARB's on an E30

[charlE30]

I've been looking at stiffer ARB's and just wondered if the E36 compact bars could be made to work on the E30?? very similar suspension set up and 25/26mm fronts with 16mm rears.

Has this been tried?? if not do you see any problems.

Any input greatly appreciated

Charlie

[Bob_S]

I dunno mate.. could always grab a pair, are they standard fitment on any compact?

[nadz325i]

me thinks over sized?? overstiffned unless matched to shocks springs even.

i have hr bars and coilovers and the m3 cant corner well at all, understears then tends to overstear.. scary. with some research people reports the bars are over stiffening the body hence the effect.

not sure but im testing the theroy by reverting back to original.

i would say depends on spring rates but hey who know, might work out for you.

[Bob_S]

me thinks over sized?? overstiffned unless matched to shocks springs even.

i have hr bars and coilovers and the m3 cant corner well at all, understears then tends to overstear.. scary. with some research people reports the bars are over stiffening the body hence the effect.

not sure but im testing the theroy by reverting back to original.

i would say depends on spring rates but hey who know, might work out for you.

I'd be tempted to say your coil overs are too stiff for road use, more useful for track work.. your effectively floating above the road surface which is giving you this feeling.

[charlE30]

I dunno mate.. could always grab a pair, are they standard fitment on any compact?

From my ETK the compact is as follows:

316i 23.5mm front and no rear standard
316i 26mm front and 16mm rear Mtech
318ti 25mm front and 14 rear standard
318ti 26mm front and 16mm rear Mtech
323ti 25.5mm and 16mm standard

Doesn't list the 325 compact

I had just thought as some people use parts from the compact in 5 lug conversions it may be possible to have slightly beefier ARB's cheaper than £250

I have no idea on what the weight of a compact is but wouldn't have thought the ARB's would be overly stiff on an E30..

I'm currently running H&R springs with Koni adjustable shocks so it shouldn't end up to stiff like nadz coilovers

Charlie

[Bob_S]

shouldnt be too bad I found my koni adj rears to be bloody hard on the soft setting tho...
My B8/B4 combo seems pretty good though!

it's worth a go if not just ebay the buggers

[nadz325i]

I'd be tempted to say your coil overs are too stiff for road use, more useful for track work.. your effectively floating above the road surface which is giving you this feeling.

how can 1 determine from upgrading to softer springs or replacing ARB with smaller diameter roll bar (22/21mm front to 19mm and 18 to 14.5 rear)??

quick note, the ride quality round town and motorway is acceptable for me but can feel few bumps and crashs.

i did take this on track to silverstone with this setup but wider track and wheels, type 5's and et5. it was f'kin awesome. so much balance and grip. i miss it.

[Bob_S]

You've just stated exactly your problem.. tracks are uber smooth compared to roads, they dont have all the undulations and divets and holes in that roads do.. the coilovers are obviously so hard that they dont react to the variencies in the road quick enough to hold the wheels onto the tarmac and not skim over it. Try making the shock a bit softer if you can. You can always change the setting on the arb but I dont think this will benefit you in this case. Rock solid isnt great for the road why do you think we have shocks and springs and not a scaff pole welded in?

[jaistanley]

I don't think the fronts will fit at all.. I had a set of ZM arb's and compared them. You need an E36 subframe (which you cant I dont think) as they mount forward of the frame rather than to the rear like E30's.

The rears might. I don't remember checking.... Though they are a very different shape.

Remember kids, with arb's, diameter isn't everything. The rate is a fucntion of a couple of different matters. Basically the spring rate of the steel, the geometry of the component it's bolted to and the shape of the bar itself.

[Simon13]

the back end of a compact is an E30!

front won't fit Nadz your car is clearly set up badly and playing with the roll bars can make a big difference, remember you can dial understeer oversteer in an out to a large extent with them

coilovers on the road is a waste of time though

[jaistanley]

No the back end of a compact has similar suspension. The body is different and the ARB's bolt to the body.

They MIGHT still fit though.

Looking at the fronts again it might be possible to bodge the arb mounts to the E30 chassis rails. Little point IMO.

[Simon13]

how is an anti roll bar going to work bolts to the body and then back onto the body? it's attatched there and then onto the trailing arms. Compacts have the same drop links except they are much much shorter than E30 ones.

[jaistanley]

If the body shape is too different, then the geometry of the bars wont match/physically fit the E30. No-one's suggested the arb bolts to the body and back to the body

My main point was that the E36/Compact/Z3 front arb's mount forward of the subframe, onto the E36 chassis rails (actually in front of the subframe so ignore my suggestion you'd need an E36 subframe, I had a look at an E36 one today and it reminded me). It might be possible to make/weld new mounts to the E30 to support them but for the hassle you'll be better off going for a set of uprated arb's designed for the E30.

As I said, I had a set of ZM bars and had a quick look. As far as I can remember they looked a bit too different to be of use so I sold them. I didn't have a really good go at it so it might be possible, I was just raising my doubts.

And I have a pretty good understanding of how suspension systems work.