Coilover spring rates

Post Mon Nov 07, 2011 9:55 pm

Hi All,

Having some issues with running a coilover setup on my e30.

Its waaaay too harsh for our under-maintained roads, with most of the blunt force trauma being taken by the wheels at the moment - they will be damaged if I don't do something about it soon.

Specs are:

Front coil 625lbs (coil over shock setup)
Tyres 215 35 17
S50B30

Im after something a bit more forgiving - advice and experiences would be most appreciated.

Thanks all,

adil

Post Mon Nov 07, 2011 10:15 pm

I'm not sure the weight of the engine etc... But in race car I would only suggest 450/500 up front with 550/275 (inbound/coil)

What dampers do you have? I may have some springs of those kind of rates you can have for not a lot.

On a related note, don't underestimate bush and thee compliance, if you have removed that it has a big impact as well.

Post Tue Nov 08, 2011 9:55 pm

Hi there,

Thank you for your reply. The dampers are bilstein with AC Schnitzer stamped on them, so am assuming they were from the ACS range to begin with.

I am interested in the springs you have, could you PM with a price? Would like to see how much of a difference they make.

Also, you mentioned "bush and thee compliance" - could you elaborate on this?

Thanks again,

adil

Post Tue Nov 08, 2011 11:43 pm

I'll have a butcher in the garage tomorrow and let you know what I have, however if your setup isnt coilover they wont fit.

Excuse my inablity to type. "Bush and their" compliance. i.e. its not just the main springs that effect ride quality but multiple things. Tyre, Bush, Spring, Damper, ARB etc.. overall these added together are the overall spring rate if you like.

So if you have low profile tyres, Poly Bushes etc they could be killing the ride quality as much as the main springs.

Post Thu Nov 10, 2011 12:31 pm

215/40 tyre would help!!

I was running a 510lb front spring ok previously..

Post Thu Nov 10, 2011 9:19 pm

Thanks Jhonno, Black_Potato,

I will be getting a higher profile tyre soon - just experimenting with sizes - 35 profile is out...

They are coilovers, but home made. They were advertised on sale on the forum not so long ago.

At the moment I cant drive the car due to their stiffness - its really taking its toll on the wheels.

Black_potato - if you could let me know if you have a set, I will buy them!

All the Best,

adil

Post Fri Nov 11, 2011 10:40 am

Sorry I have been a bit shit and havent been to the garage yet, I considerd it last night but decided to play poker on my laptop, drink beer and watch Family guy instead.

I'm pretty sure the fronts will be 2.5" in 450/475/500/550/600 (there maybe one or 2 of those missing)
Rears will be 2.25" in 275/300/350 (and some variable rate springs) I expect. I may also have flat wound tender and joners for the rear as well.

Anyway, I will post back shortly when I know for sure.

Post Fri Nov 11, 2011 11:04 am

adil325i wrote:Thanks Jhonno, Black_Potato,

I will be getting a higher profile tyre soon - just experimenting with sizes - 35 profile is out...

They are coilovers, but home made. They were advertised on sale on the forum not so long ago.

At the moment I cant drive the car due to their stiffness - its really taking its toll on the wheels.

Black_potato - if you could let me know if you have a set, I will buy them!

All the Best,

adil

what top mounts are you using?
How low are you running?

I just ask because one can run out of suspension travel with coil over converted struts quite quickly. Happened to me on my first attempt.
Harshness also heaily depends on you shocks. You can run a stiff spring on the road with a soft'ish shock but that's not recommended. You need to spec the stuff in relation to each other.
From my trial and errors I wouldn't go much stiffer than 400lbs at the front for a mostly road going car. (BTW that's what roughly is what KW runs in their V2 Street kits)

Post Sun Nov 13, 2011 6:32 pm

I finally got around to sorting out the springs and I;ve put them on Ebay..

Search on this item number 140640857225
and look at sellers others to see them all.

The lightest set I have is 7x2.5x500lbFront /10x2.25x275 Rear

Happy to do a bit of a deal for folks on here.

Post Mon Nov 14, 2011 8:47 pm

Hi Black_Potato, Uwe,

500lbs is a bit too much - would like to stay below 400 if possible.

Uwe - the car does sit low, however are on the same setting the previous owner had - and his was mostly for the track, so would explain their harshness.

Im going to contact someone at Gaz to see if they can supply a pair.

All the Best,

adil

Post Tue Nov 15, 2011 7:01 pm

No worries & no doubt GAZ have some for you.

Post Tue Nov 15, 2011 8:53 pm

Black_Potato ive sent you a PM

Post Wed Nov 16, 2011 10:40 am

adil325i wrote:
Im going to contact someone at Gaz to see if they can supply a pair.

adil

springs or shocks?

If your shocks are harsh, a softer spring isn't going to improve the ride.

Post Wed Nov 16, 2011 11:12 am

UweM3 wrote:
adil325i wrote:
Im going to contact someone at Gaz to see if they can supply a pair.

adil
springs or shocks?

If your shocks are harsh, a softer spring isn't going to improve the ride.

This.

I was running just over 500lbs with a decent shock and it was not harsh.

Look at the cheap coilover kits, they are soft and harsh at the same time. All in the damper.

Post Sun Nov 27, 2011 12:37 pm

I found 600lb fronts & 295lb rears to be pretty much spot on with a 40 profile tyre and Gaz dampers. There was still enough compliance to cope with the crap roads around here. 16's ride much nicer than 17's imo.

Post Sun Apr 22, 2012 12:38 am

Thanks for the input gents.

6 months on, and ive still not found a solution.

A real toss up at the moment between buying the coilover setup from RPM, and just sorting out the springs. The rears are way too soft, and the front too stiff.

Don't really have the money to throw at the car either.

How can I tell if the stiffness is due to the shock or the spring?

All the Best,

adil

Post Mon Apr 23, 2012 1:27 pm

adil325i wrote:Thanks for the input gents.

6 months on, and ive still not found a solution.

A real toss up at the moment between buying the coilover setup from RPM, and just sorting out the springs. The rears are way too soft, and the front too stiff.

Don't really have the money to throw at the car either.

How can I tell if the stiffness is due to the shock or the spring?

All the Best,

adil

I am curious, can you post a picture of your front strut?

Post Mon Apr 23, 2012 3:37 pm

adil325i wrote:Thanks for the input gents.

6 months on, and ive still not found a solution.

A real toss up at the moment between buying the coilover setup from RPM, and just sorting out the springs. The rears are way too soft, and the front too stiff.

Don't really have the money to throw at the car either.

How can I tell if the stiffness is due to the shock or the spring?

All the Best,

adil

Sort the springs out then..

I don't think Gaz coilovers will do what you are after.

Have you gone to a 215/40 tyre yet?

You are running stiff springs no doubt, I'd try a 500 front and leave the rear and see how that balances out. What makes you say the rears are too soft? Inboard coil or coilover setup?

Post Mon Apr 23, 2012 3:45 pm

Uwe - Will get some pics up ASAP - car isn't accessible at the moment.

Sorting springs means finding the right coilover for the front, and getting a pair of balloon springs for the rear.

Trying to evaluate costs here...

RPM kit - £700 plus £200 fitting (est) £900
Less sale of old kit (£250) if lucky
£650 total and straightforward, no messing.

Springs - £60 for front but need to be taken off to check - need to find someone willing to do this.
Rear springs - £60, still need to confirm whats required again.
£120 parts plus fitting (say the same again at £250)
£370 and a lot of headache.......

Jhonno - can you elaborate on your views on the Gaz coilovers? I have a similar setup to yours with the s50 - what worked for you?

Thanks All,

adil

Post Mon Apr 23, 2012 3:52 pm

Why are you going coilover at all?

Post Mon Apr 23, 2012 4:05 pm

Hi Andrew,

I ended up with them after committing to buy a set off a fellow zoner - was actually after his brakes, and ended up with them.

I would take the set off and just go with a decent shock spring combo, but am unsure of the results.

In reality I just love the look of a low e30, and coilovers give you that option, whereas a shock/spring combo won't. Quite easy to change the height in a private area with some basic tools and a jack...

Plus would like to keep it until I'm too old or poor to drive it, so can justify the outlay.

Post Mon Apr 23, 2012 4:06 pm

adil325i wrote:Springs - £60 for front but need to be taken off to check - need to find someone willing to do this.
Rear springs - £60, still need to confirm whats required again.
£120 parts plus fitting (say the same again at £250)
£370 and a lot of headache.......

Jhonno - can you elaborate on your views on the Gaz coilovers? I have a similar setup to yours with the s50 - what worked for you?

Thanks All,

adil

Tyres? Serious point.. The extra sidewall WILL help.

As said, why are the rears too soft? Handling balance out?

It's no ballache..

Check front spring length, order 500lb's in same length.

Rears, don't touch for now.

Changing springs is simple with coilovers! Deffo not £250 fitting! That's 5hrs @£50/hr.

Gaz are ok. The best coilover on a budget, however, the damper isn't as good as an Intrax/AST etc, which means they end up being harsher on the road and don't deal with bumps as well. (My point being about a quality damper).

I ran 215/40/17's all round. With Intrax coilovers ~500lb fronts can't recall rears atm. It was daily'd. It was firm, but comfy, didn't crash/bang etc.

Ran my e36 on Intrax coilovers also, similar spring rates iirc, and that again, was firm, but not harsh. Rode quite well tbh, esp considering the small tyre walls and 18's.

Post Mon Apr 23, 2012 4:13 pm

Hi Jhonno,

Thank you for that feedback - to be honest, thats precisely what im after - a firm ride with your Intrax coilover described.

Tyres are 215/35/17s on the front at the moment, which I know is a contributing factor, but not a cause.

Reference the rear being too soft - the springs are cheap old lowering springs bought from ECP around 10 years ago - never were good enough.

The springs that came with the coilover kit had been cut, which resulted in the rear being so low it was resting on the wheel.

Would love to drive the thing daily - ended up driving it for a month and watching the tax expire instead, plus a bend in the NSF alloy.

I will give it some time and effort and move forward from there. Final exam is May 1st, so your sound advice will be my starting point.

Thanks again,

adil