Wakefield Times!

[tinkerbell]

i would love for you to explain how 12k fr and 8k rr springs might be affecting my (and anyone else on the traditional japanese coilover route) lap times negatively...

i was running 400lb (7.1k) fr and 300lbs (5.3k) rr springs on koni yellows in my old LS Integra and found these too soft on most circuits (particularly EC)

that was with a custom 23mm Whiteline rear bar.

by 'too soft' i mean that i thought body roll was excessive...

(thanks for your comments Jim, i know lots of other guys will be reading them with interest, that is the good thing about such a specific Honda forum, comments in relation to one persons car will generally be translatable to many others.
it is wonderfull to have such an experienced suspension expert join Ozhonda.com)

[ekslut]

i would love for you to explain how 12k fr and 8k rr springs might be affecting my (and anyone else on the traditional japanese coilover route) lap times negatively...

I would also really like to hear about this too, as I am currently searching for a good set of coilovers for my track only ED civic, and I was looking at getting some spring rates similar to what tinkerbell has 12/8.

I always thought that without going too extreme, stiffer is better on track. I would of defiently thought that 7.5/5.5 would be too soft. As on track it is usually much smoother than street, so you dont need to take as many bumps.

[Whiteline]

G'day everyone,

Thanks for the kind words.

I'll take some time to answer this properly so we can use it on the suspension tech forum, give me a few days. It's a very popular question and points to one of the most popular retail misconceptions in suspension tuning. We have a lot of material used in training to explain why but need to format into one of our tech discussion papers.

In the meantime, please consider following;

- HRT's V8 Supercars use front rates of around 12 kg on a car that weighs considerably more, runs on slicks and would lap Wakefield in under a minute.

- Our P-Rex XRD (97 Sti) used 8.5 kg to do the 1:05's.

- The fastest road based car we run at the moment is Project EVO VIII which is primarily setup for tarmac rally but was configured for slicks for an endurane race at Wakefield last December. It qualified 2nd on the grid at 1:04's and used 9 kg.

- There is a direct relationship between tyre grip potential and spring rate. The more grip you can generate the more spring rate you need. Conversely, the lower the grip potential the less spring rate you CAN USE.

- There is a direct relationship between road surface and optimum spring rate. The better the road surface the less suspension travel you can get away with and consequently the higher the spring rate you can GET AWAY with (though not neccessarily need).

Be back soon

Cheers

Jim
Whiteline

[wynode]

Sounds very interesting there Jim.....welcome to Ozhonda and we look forward to your reply.

[ekslut]

Excellent information you are sharing with us. Thank you.

Are these spring rates that you are mentioning just in relation to Wakefield. I think I saw somewhere that you said that its surface was not too smooth. What about on a smoother surface? Would it be wise to increase the sping rate a bit? Have you had any experience with Phillip Island?

[_CiVIC_]

Hi Jim, names Alfy.. Are you an actual representative for Whiteline?? If so, I am really interested in getting a front Strut Brace for my EK civic.. How much would I roughly be looking at spending??

[tinkerbell]

Alfy:

http://www.whiteline.com.au/

part number KSB570 = $239

[CoZZm0]

[QUOTE=_CiVIC_]Hi Jim, names Alfy.. Are you an actual representative for Whiteline??QUOTE]

Signing his posts as "Jim" might indicate that he is Jim Gurieff.

[tinkerbell]

- HRT's V8 Supercars use front rates of around 12 kg on a car that weighs considerably more, runs on slicks and would lap Wakefield in under a minute.

- Our P-Rex XRD (97 Sti) used 8.5 kg to do the 1:05's.

- The fastest road based car we run at the moment is Project EVO VIII which is primarily setup for tarmac rally but was configured for slicks for an endurane race at Wakefield last December. It qualified 2nd on the grid at 1:04's and used 9 kg.

btw - i always throught comparing spring rates between different cars was pointless due to different motion ratios as defined by the type of suspension system?

[Whiteline]

G'day everyone.

I started putting together an elaborate answer over the weekend and realised that it all sounded rather familiar. A quick check of the www.suspensionparts.info forum showed that I'd already covered around 90% of the issues in one of our Tech Talk series. Here's a link to the specific thread;

http://www.suspensionparts.info/show...=&threadid=272

Would be happy to continue with further questions or discussion after that.

Alfy, we try not to talk about sales or pricing on forums etc, would rather keep it technical. Would you mind contact one of our distributors or our sales area on sales@whiteline.com.au.

tinkerbell, you raised a very good point re comparisons of spring rates, I guess I took this issue for granted and as a given when commenting before as it works toward our argument in a way.

All common suspension systems have a motion ratio, by this we mean that the wheel and spring do not move at the same rate for a given amount of travel. Its a standard part of our design process and we measured, the EJ-EK to have a spring to wheel motion ratio of 0.67:1 at the front and 0.81:1 at rear.

That means that for every millimetre of wheel travel at the front there will only be 0.67 mm at the spring. The rear is a little closer at 0.81 mm at the spring for every 1 mm at the wheel. To put into context, most conventional strut based cars like Commodore and WRX will have a ratio of around 0.95:1. Needless to say this will have a bearing on the actual spring rate at the wheel which is significantly more important than the rate at the spring and what we actually calculate when we design our suspension products.

As for the affect this has on the numbers specific to the Civic, I'll let the above settle a little bit before we go further.

Cheers
Jim

Whiteline

[tinkerbell]

thanks for the link Jim, nice forum there

Heave and Pitch modes need sufficient rate to stop the car bottoming out over uniform bumps or the front or rear axles running out of travel as this would have the same effects as excessive resistance on a loaded wheel as detailed above. Specifically, we run the risk of a tyre(s) momentarily losing contact with the road leading to loss of grip. In simple terms, this loss of grip is part of what you feel when the car understeers or oversteers. Understeer being a relative loss of grip on the front while oversteer is the relative loss of grip in the rear.

Whiteline believes in using as little spring rate as absolutely possible for these reasons. We start from a small amount and increase, as we need it, not the other way round. As a full range suspension manufacturer, we believe in using the right component designed for each job to deal with its chief responsibility. That’s why we use swaybars and not springs to control body roll. We would no more design a swaybar to hold a car up in pitch or heave than we would try to get the spring to hold the body up in roll.

but, i see no 'reasons' there Jim, could you eludicate?

i understand that stiffer springs may bounce & lose contact with the road - but this is dependent on the quality of the damper is it not?

if springs push tyres onto the road, would not stiffer springs help this?

what is the disadvantage of using stiffer springs on the track? and on the road?

[DOHCVTEC]

from my thoughts and things ive learnt

harder spring rates actually push the car further from the wheels...
harder spring rates = less weight (when moving and tranfering of weights through cornering, braking and forward acceleration) on the wheels
IN TERMS OF PITCHING
so a harder FRONT spring/damping rate would mean MORE WEIGHT pushed towards the rear (or less weight pushing to the front) wheels leading to more UNDERSTEER
and a harder REAR spring and damping rate would mean MORE WEIGHT PUSHED TO THE FRONT meaning less weight on the rear and more OVERSTEER... so a front 8kgf rear:12kgf MIGHT actually make the car OVERSTEER HEAPS MORE IMO

but i do believe there is more to that

IMO i think that spring rates have to be relative to the suspension's CAMBER CHANGE during the travel?
i think thats why they have relatively HARDER spring rates (and less travel) on race cars
cos if the travel movements move too much, the CAMBER will be changed too much, which makes setting an OPTIMUM CAMBER (keeping a good tyre contact) very hard
thats why the DOUBLE WISH-BONE suspension system is preffered??
cos the camber does not CHANGE as much during the TRAVEL since it has 2 pivot points or something...?? making it possible to have better handle even on softer spring and damping rates?