Suspension mods for nightrally

[jkarran]

My suspension has taken a bit of a pounding of late so it needs some work

It's a (very low) budget build. Front is OEM 45mm struts, platforms moved up 35mm. E34 520 springs. Rear is stock + 17mm spring spacer platforms. When it works the handling is ok if a little vague but the ride height is well worth it for the rough tracks. I'm just after some ideas really.

There's loads of vibration under acceleration from the rear, it's also quite disconcertingly 'loose' and 'skitish' at the rear on rippled tarmac/smooth gravel. My top mounts are clearly fooked with over an inch of play. How much are E46 M3, EuroCarParts don't list them so I guess its OEM BM stuff Or... I have a lathe so can convert the old mounts to spherical joints. Worth the work?

Front suspension and steering is getting wayward after the last rough event. I'm thinking it's time for new ball joints and rod ends all round. Are the ECP arm assemblies up to spec or should I just press in new joints (they list them so I assume you can). The arms take a real beating (I occasionally bend wheels) so I don't want to fit just-good-enough-for-the-road bits.

Is it worth uprating the rear rubber bush? What too? I don't want poly bushes, the rubber probably saves the arms in big impacts. I'm thinking of filling the air spaces with windscreen adhesive to stiffen them up a bit

Anyways, all ideas and tips appreciated.
jk

[alan1272]

i'm going for poly bushes on my roadrally car as the axle tramp i get when pulling out of controls and junctions with a bit of aggression can be horrific
if you don't want poly bushes i'm sure new rubber ones will make a big improvement over the 15+ year old ones that are on.
or there's always those rear bush void fillers.

i can't really help you on the quality of the ECP stuff though i'm afraid.

you could always lower it, double skin the turrets and fit bigger gaurds

[jkarran]

you could always lower it, double skin the turrets and fit bigger gaurds

I like your thinking but with the tracks we use I've been wondering about trading the old dog in for a Cherokee Ltd 4L. You can never have enough ground clearance and guards don't come much bigger than the one already on it

Good tip, I'll look into the void filler option at the rear, there's no way in hell I'm dropping the rear subframe to do it all properly.

I've decided I'm going to spherical joint the rear dampers, I've a big bar of 6061 lying around doing nothing, the joints are cheap and it looks like an easy job so why not. Can't go wrong for £6 a side

jk

[handpaper]

If you can press new ball joints into the arms it'll save you about £18 a side; the steel control arms are designed to have this done.

The rear rubber void bush can be replaced with a solid rubber M3 one, dealers have them fairly cheap.

Your vague handling could probably be improved with some more negative camber on the front - 35mm of jack will have all but eliminated it. The PBMW topmount mod will bring some back.

[jkarran]

If you can press new ball joints into the arms it'll save you about £18 a side; the steel control arms are designed to have this done.

Cool, I can but I'd have to drive to a friend's garage to use the press. Whole arms (no messing about) are tempting if the quality is ok.

The rear rubber void bush can be replaced with a solid rubber M3 one, dealers have them fairly cheap.

Top mounts or subframe? I don't fancy tackling the subframe unless it becomes essential.

Your vague handling could probably be improved with some more negative camber on the front - 35mm of jack will have all but eliminated it. The PBMW topmount mod will bring some back.

More like 3" lift with preload and big springs! Oddly it looks (by eye, I've yet to measure) to still have some negative camber though I know it shouldn't. Bent struts I guess

Vague handling is as you say almost certainly messed up geometry + worn joints + 4 1/2" mud and snow tyres. It drives much better on 6" gravel tyres but I don't have a matching pair currently

Any idea where I can view the PBMW top mount mod article, I presume it's a backissue? Cheers for the good advice.
jk

[handpaper]

It is possible to replace ball joints with a vice and a lump hammer, but it's not much fun
The void bush I'm on about is the one at the rear of the control arm, not the rear of the car It's pressed into a steel 'lollipop' just behind the front wheel.
The top mount mod is one done by (I think) JimmyC on here for the PBMW Championship; it's not in PBMW magazine. A search should unearth it.

[jkarran]

Ah... right <brain clicks into gear>

I was thinking of filling the rubber bush on the front wishbone.

I'll search for the PBMW mod.