Optimum spring rates

[Caveman]

Long post - apologies! :)

After fitting some lowering springs to the Leggie a few weeks ago and being very impressed with them, I've decided that I want to go the extra mile and fit some proper coilovers.

Now, as most people, I've been doing my research and looking into the various kits available for our cars; Tein, D2, G4, K-Sport etc. From what I understand, as we have double wishbones on the front this necessitates a much harder front spring compared to normal macpherson strut setup cars.

Most of the Jap/Taiwan derived kits seems to recommend about 16k/7.2k front/rear which seems incredibly hard. I want to get the best setup possible for my car, but with the UK roads as they are, I don't want the car skipping all over the place.

I used to have a Scoob P1 which was famed for it's excellent on-road ability and ride on UK roads. From what I remember the guys at Prodrive set it up with soft springs, but hard dampers. This seems to be the optimum set up for a road car which was confirmed with a phone call to Powerstation who set up the Litchfield Type 25 AST suspension.

So my big question is, without buying every spring combination available and trying them out, how can I ascertain the best spring rate for our cars?

I don't want the suspension soft, wallowy or bouncy - I want it to handle like an angel, but at the same time be able to soak up the lumps and bumps and keep a line on bumpy corners.

Any thoughts? What spring rates do you guys with coilovers have on your Legnums and does your car skip or hop on bumps and bottom out?

Answers on a postcard please... ;)

Any help would be appreciated!

Cheers,

Mart.

[EdmundVR4]

Subscribed !
I wonder what the stock spring rates are ? Anyone know ?
I am thinking of using KYB AGX adjustable dampers with the stock springs.
I use the AGX's on my 7G with Ground Control Coilovers, Eibach springs, 400lb/" front & 275lb/", rear.and they are quite stiff.

[bradc]

Just for the record, that is 7.158kg/mm and 4.921kg/mm

[EdmundVR4]

Yes Brad, good conversion there !
But what about the stock spring rates ?
I would have thought that you would know ???
Thanks.

[White Lightning]

For Legnum VR-4 the standard spring rates (thanks Kieran) are:

3.6kg/mm (F)
2.5kg/mm (R)

I am not sure what they are for the Galant VR-4 but I expect only the rear is different.

I have just ordered a set of Tein Super-Wagon coilovers for mine and one of my biggest concerns was retaining the ride comfort whilst improving the handling. I did plenty of research and I think this particular kit from Tein will do the job ... :scholar:

Got this information about the Tein kits (also from Kieran):

Super-Wagon kit

5.0kg/mm (F)
5.0kg/mm (R)

GT-Wagon kit (more performance focused)

8.0kg/mm (F)
5.0kg/mm (R)

[Caveman]

Hi guys,

Thanks for the replies so far!

Has anyone actually got coilovers on their Legnum at the moment? Can people share their experiences? WHat spring rates have other people opted for and how hard are they?

I just can't see how the Jap manufacturers can recommend 16k front and 7.2 rear - it just sounds balmy!

Cheers,

Mart.

[Nick Mann]

I think that somewhere around the 5-6 kg front and 3-4 kg rear would be the best compromise. But that is based on being in cars with hard suspension and soft suspension, rather than being in a car with that setup. I personally think the stock setup is nearly firm enough, so don't want to tweek it up too much more!

[Caveman]

Hi Nick,

Thanks for the reply.

Is it right to compare the spring rates to the stock setup as the stock shocks are obviously going to have a much longer rate of travel? I'm just curious as coilovers are likely to have much shorter travel, so shouldn't springs be harder to compensate for the shorter travel? Obviously with a lowered car won't you need narder springs to stop it bottoming out or will harder damper settings compensate?

I'm considering the following at present, but unsure which is best:

10k front / 8k rear

8k front / 6 k rear

6k front / 4 k rear

On another note, what says that the rear should be softer - wouldn't equal rates all round be best?

Aaaaarghhhh!!! Tearing my hair out here, somebody must have a definitive answer!?? :D

Any input appreciated,

Mart.

[Nutter_John]

the front of the car is a lot heavier than the back , therefore you want a higher rate spring to balance out the dynamics of the car .

I'm running 14kg front 10kg rear coilovers , these are not progressive but fixed and the back feels a lot firmer than the front when going over bumps

[Wodjno]

I'm running Tanabe Sustec Pro Height Adjustable Coilovers.
They are actually off a 1.8 gdi Legnum. (Mrs Wodjies Car)

they were far to hard for the GDi(Bouncy, Bouncy, Bouncy) So i thought that the extra weight of the VR4 would be about right for them :thinking:
And for me they are /yes

They are great for track and road use, although at the height i have them adjusted down to.. There are quite a few B Roads i can't drive hard on.. /pan

I'll see if i can find out the spring rates !

And if i had my choice again ! I'd sitick Lowering spings on the OE spec VR4 shocks /yes

Cos i think there the Mutz :scholar:

[Caveman]

Hi John,

Thx for the reply. I actually hoped you'd comment as you have the coilovers I'm considering.

How does the car cope with such hard springs then? That's obviously a lot harder than the stock setup.

Is the car a mess on bumpy B roads and bends, does it skip or hop on bumps?

I don't care about ride quality, I just want to get the best handling possible for UK roads. I'm just worried that if you go hard with the springs then you have to compensate by softening the dampers which in-turn will make the car bouncy?

As far as I understand, soft springs but hard dampers seems to be the optimum for UK roads.

Jon - how are you coping with your setup day-to-day?

WODJNO - thx for your input too - be cool to get those spring rates!

Cheers,

Mart.




the front of the car is a lot heavier than the back , therefore you want a higher rate spring to balance out the dynamics of the car .

I'm running 14kg front 10kg rear coilovers , these are not progressive but fixed and the back feels a lot firmer than the front when going over bumps

[Nick Mann]

John, are the numbers you have quoted kgs or pounds? I'm not sure of the measurements, but 5 kgs are 11 lbs. So your numbers would be slightly higher than mine if lbs, but more than double if kgs.

[Nutter_John]

They are in KG's / mm

Had them on my car for about 3 1/2 months now done around 9000 miles and not much problems with them , B roads can be a little skitish at times but throw it round a nice corner and it sticks to it like glue ( I don't have this fancy namby pamby AYC electricery to hinder me :p )

After a couple of days of drive with em on you don't notice the firmness as much and at JapShow I took K , Anthony and White Lighting out in the car for a spin and it did not bottom out or ride that harsh for them ( please correct me guys if you were being kind )

[Kieran]

After a couple of days of drive with em on you don't notice the firmness as much and at JapShow I took K , Anthony and White Lighting out in the car for a spin and it did not bottom out or ride that harsh for them ( please correct me guys if you were being kind )

Hmmm.... I'm gonna be (slightly) nasty here... :embarasse

My comparrison of John's setup is obviously against my own Legnum, which was previously standard but now wears this setup:

http://www.clubvr4.com/forum/showpost.php?p=187940

Bear in mind also that my evaluation of my own kit is from a driver's seat perspective, whereas my thoughts on John's kit are from a rear-seat passenger perspective.

Anyway, regarding John's kit... I would describe it as very focused towards a track. On smooth, unbroken tarmac it worked very well indeed with absolutely zero body roll and it felt like it had far more to give, despite being thrown about quite a bit.

My biggest issue was that of ride quality and the overall 'feel'. The ride quality to me was far too harsh - particularly over the rear axle and I felt this spoiled the 'fluidity' of the car. It thumped and jolted (though it did not crash) along less than perfect tarmac and I wonder how well the suspension would cope in a sweeping bend with rutted/broken tarmac... It made the car feel a little 'skittish' in my book.

Having said all that - If you want to take corners above all else, then my setup would not suit either. There's plenty of compliance and whilst feeling firm, my car sponges away the worst of the bumps nicely. The downside is that the compliance imparts a little of the 'float' that bugs the standard setup, albeit much less... It still has a 'Big Car' feel about it when entering a corner - A hot hatch would still change direction quicker, even though once 'dug in' the VR-4 would have a much higher cornering speed.

It really depends on what you want. I would say that the 'Sweet Spot' of Spring Rates is somewhere around the Tein Super Wagon rates if you want the ultimate compromise of comfort and performance. If you want the ultimate edge on track and on good fast roads, a setup like John's is for you, but the trade off is a hard ride. On the flip side, if you want a driving experience that's an improvement on standard, but is geared more towards comfort than grip, check out my setup.:happy:

I would say 'hope this helps', but I fear I've just thrown more mud in the water?!:inquisiti /pan

[Kenneth]

I find 12Kg front and 8Kg rear comfortable enough to drive every day, but solid enough to corner fast as well.

It makes a big difference to be able to change your damper rates as well, I run the 12Kg/8Kg combo at 4/8 clicks (out of 32) respectively and find this gives good daily driving in the Legnum.

btw, Joanne finds this configuration comfortable also... :)

[White Lightning]

It really depends on what you want. I would say that the 'Sweet Spot' of Spring Rates is somewhere around the Tein Super Wagon rates if you want the ultimate compromise of comfort and performance.

:D

And that's the kit I have on it's way from Japan ... :pimp2:

Yes, John very kindly took us out in his car at Japshow. My initial thoughts were that the suspension was not too hard for day to day use. I could live with it. However, when I jumped in my (standard suspension at the moment) car afterwards it did feel more comfortable. As you would expect really.

Without a doubt I would feel a lot happier throwing John's setup into a fast (flat) corner at speed as there is little to no body roll but I am not 100% convinced about the performance of the suspension on bumpier roads. Certainly the ride is a little harsher. But I suspect this was more noticeable for Kieran in the back. One good thing ... it certainly never bottomed out with 4 people on board.

Caveman - have you checked out the Tein suspension on RHDJapan at the moment? The prices are very good with the current currency conversion rates.

I think the Diayama kit is a good piece of kit for the money. But in my honest opinion it may be worth the extra small amount of cash to go for the Teins. There are a number of people on here using that kit and no bad things have been mentioned. :happy:

[phosty]

I have ordered the same Daiyama's as Nutter_John but with F:10kg/mm & R:6kg/mm.

I didn't want to have too firm a ride and after speaking with John that's what I settled on.

They should be arriving anyday soon (Gary at MY Garage has them in Glasgow) so I hope to fit them soon as. Will let you know how they feel on bumpy Aberdonian roads!

It would also depend on the adjustable damper setting too though surely - you have the DPX modules fitted don't you John? What were the dampers set on when you took people for a spin at JapShow?