what spring rates are people running ?


It was one of the famous BM ones, think it was round Tskuba, crazy 26kg springs was hopping all over the play but damn fast..
 
8kg front, 6kg rear. Really nice ride quality (not too bumpy) but still does what I want it to in the corners.
 
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ah ok, so the spring rates really need to get harder the lower you want to go? what rates would you be looking at if dropping the car around 60mm?
is there also a reason why coilovers tend to run harder at the front than the back? is it to do with the standard supsension set up running both progressive and linear springs?
id ideally like to keep the cars neutral handling, and not start making it more understeery if possible.

Kozy said:
I had 6.3/5.5kg springs with Spoon dampers, it was
fine with R888s. The thing you have to make sure of is that with whatever ride height you choose, you do not bottom out the suspension in mid corner roll. The Spoon setup isn't that low so the low rates are absolutely fine for this, and the bonus is it's still great on the road, probably still a bit too stiff over really bumpy roads.
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natune said:
ah ok, so the spring rates really need to get harder the lower you want to go? what rates would you be looking at if dropping the car around 60mm?
is there also a reason why coilovers tend to run harder at the front than the back? is it to do with the standard supsension set up running both progressive and linear springs?
id ideally like to keep the cars neutral handling, and not start making it more understeery if possible.
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harder spring at the front mostly because of the weight of the engine Lloyd

suspension tuning on the type R is difficult as out the box its already very very good. I would polybush the whole car to start with and see how it feels then start worrying about camber and coilovers.

Your ITR btw is going through a bit of a transformation! ill hit you up with a PM soon

glad to see you saw sense and came back to Honda :drive:
 
ah cool, that makes sense!

yeh i know the standard suspension is good, but it just sits that bit too high for what im after, so im doing my homework before i buy all the bits.
the car will be getting hardrace bushes and arms all round, plus new oem rta bushes, ball joints and tie rod ends.
cool sounds good man! yeh id like to see how its doing, i miss how that car handled!
 
natune said:
ah cool, that makes sense!

yeh i know the standard suspension is good, but it just sits that bit too high for what im after, so im doing my homework before i buy all the bits.
the car will be getting hardrace bushes and arms all round, plus new oem rta bushes, ball joints and tie rod ends.
cool sounds good man! yeh id like to see how its doing, i miss how that car handled!
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ITR springs have almost the same rate and the car is quite low.

Good and cheap mod' :nice:
 
natune said:
ah ok, so the spring rates really need to get harder the lower you want to go? what rates would you be looking at if dropping the car around 60mm?
is there also a reason why coilovers tend to run harder at the front than the back? is it to do with the standard supsension set up running both progressive and linear springs?
id ideally like to keep the cars neutral handling, and not start making it more understeery if possible.
Click to expand...

The reason for harder rates up front is partly because of the weight of the engine, but the standard car starts with equal rates front and rear. What it really affects is the oversteer/understeer balance, a stiffer axle has less grip so stiffer front springs will tend towards understeer.

This is I believe largely a case of safety, a suspension manufacturer may face litigation if they sell an off the shelf setup with a heavy rear bias that causes inexperienced drivers to crash the first time they lift off mid corner. If you specify this yourself, then that's your issue, hence why a lot of manufacturers offer to let you pick your own spring rates. (You're kidding yourself if you think they actually change the valving to match though.)

There is also the 'JDM setup' which uses wide front tyres, skinny rears, stiff front springs, soft rears and a huge rear ARB, this is often what you'll see in the Best Motoring videos. This is a specific race setup though and bears no relation to street setups. A stiff front on a street car will increase understeer unless you take a number of steps to mitigate it.
 
ok ok, i think im starting to get it now.. its all starting to make sense :p
so you could run hard front and soft rear, with a big rear arb.. or..
you could run hard front and even harder rear, with a little or no rear arb and achieve similar effects in terms of balance?
would i be good to specify even spring rates front and rear, say 6/6 or 7/7 on coilovers, and not expect wild oversteer? i guess the camber and toe setup will have some say in this too! but lets get the coilovers sorted first :p
 
A rear arb also helps to stop the diagonal front to rear weight transfer which occurs when accelerating eg. out of corners. So it will help front traction by keeping the front inside wheel down aiding traction and corner exit speed. Don't go too stiff on front or rear as it can feel fast but can blind out any damping and use the chassis flex and the tyres instead.
 
I actually would show you a video, but it's in hungarian, so you wouldn't understand a word. The guy talking in it is the engineer of Norbert Michelisz. He says that fwd cars in wtcc runs stiffer on the rear, and softer on front, so in cornering the driven wheels can transfer force, so won't skid that soon. Rwd cars should run softer on the rear.
Anyway I got 8f 6r setup, just about the limit, since we have terrible roads.
 
Yes, if you know accurate measurements of all the suspension points then you can balance the car using different combinations of bars and springs. I did this with my EK4, aiming for the balance of a stock EK9 but slightly stiffer, with an adjustable rear ARB to loosen the car up for auto-testing and sprinting. Have a read of these if you haven't already, should answer a few of your questions. :nice:

http://www.ek9.org/forum/suspension/29404-suspension-101-part-1-tyres-load-transfer.html

http://www.ek9.org/forum/suspension/29405-suspension-101-part-2-springs-dampers.html
 
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14kg front and 8.5kg rear race setup

I still have your shell and rear bar in my workshop Kozy!
 
I miss that car, still gutted it got broken up. :(

You guys must have made a few quid on those parts? Really should have done it myself!
 
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No I bought it complete from the bloke you sold it to but he put a b18c4 in it. I have gearbox shell etc and joe Thompson has the wheels and suspension we just wanted parts from it. The shell is in good condition and will ride again if I bend my track car!
 
Ah fair enough, I thought they broke it for parts.

Maybe I'll buy it back at some point! :p
 
cheers guys.. just read the 101 posts, well atleast tried to.. i havnt read that much maths in a long while :p
my situtation at the minute is, standardish ek9 n1, nothing on the supsension changed at all and is running uniroyal rainsports, these seem to have the softest sidewalls ever and give the car more roll than i think it should have!
i have just bought new oem rta bushes, front ball joints and track rod ends as they have never been changed. i also have all adjustable arms on order from hardrace with the hard rubber bushes, this was easier for me than getting the car completely rebushed.
i did not want to go poly bush and effect the supsensions natural characterstics too much. arbs are standard, but will have new hardrace droplinks.
i will be getting r888's to replace the rainsports, and then i am left with the coilover choice. i want to acheive similar handling characteristics as standard, but have it sitting that bit lower than standard.
the car is a non power steering version, and weighs around 1000kg if my maths are correct.
would running coilovers with say 6/6, or 7/7 spring rates achieve similar results to standard, and then dial it in with adjustments to camber and toe front and back?
any suggestions would be much appreciated :)

lloyd
 
Equal rates would be good, however if you really want the balance to remain the same as stock, you actually need to increase the rear spring stiffness more than the front. This is due to the additional effects of the roll bars.

Given that the roll bars on the car generate a roll stiffness of around 2000lbs.in/degree at the front, and 4000lbs.in/degree in the rear, and the stock springs generate around 2500/2500 respectively, then we can see that the total roll stiffness is 4500/6500 or a 40.9% front roll stiffness distribution. If we double the spring rates to 5000/5000, sure we end up with an equal RSD contribution from the springs, but when considered in conjunction with the roll bars we end up with a total RSD of 7000/9000 with a 43.75% front RSD. So for the same increase in spring rate front and rear, we have actually increased the front RSD by 2.85%. In order to keep the RSD the same as stock, the rear springs would need to be increased by a greater proportion, in this case by an extra 22.3% to 6115.

Setting up for a specific RSD is of course only one way of setting up the car, but probably the way I would go if I was looking to build another EK for competition. It allows you to balance the car properly and run closer to optimal camber angles on all four corners, instead of effectively 'throwing away' grip at the rear by running near 0 camber to get the front to grip.
 
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