stiffer spring rates?


EKandrew

EKandrew

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Aug 11, 2012
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have bc racing coilovers in my track car at the moment, running 14kg springs at the front and 8kg at the rear.. where is the best place to buy stiffer springs ?
 
You valved the dampers to suit the 14k front springs?
Have a google about matching dampers to spring rates, I don't know a great deal about it but it's obviously quite important.

Meister r can make springs. Also use google. Any spring place will custom make you a set easy enough.
 
no i was down with a fella that runs in itcc for a long number of years and telling him about my set up, and he was saying that my springs were far to soft, was just wondering what evryone else was running.
 
How high did he suggest you go then to say far too soft? Highest I've heard on an ek9 was Steven ek9. Iirc something like 22k or something similar but you'll almost defo need a rework on the damper for that kind of jump.
 
For instance my meister r zeta r I can only jump up an extra 2k in the front and stay within the dampers capabilities. That came straight from jerrick of meister r.
 
Up to a point, I can accept 12kg/mm, possibly 14kg/mm at the very edge but I wouldn't like it.
We done a set of MeisterR Zeta-R SuperRace with a limited production run (I think I have a few set left), and that have reworked damper valving running 16kg/mm front and 12kg/mm rear.

Jerrick
 
well this fella is running meister r's in his new build.. he was saying anythin above maybe 22 would be the norm on itcc cars. thats on the rear!
 
22k on the rear....wow. You better not run over any kind of insect or any tiny object in the corner or you might lose the car :D Better make sure the tracks are very flat, 22k on the Nordschleife (which is kind of an extreme example, I know) would definitely kill you.
 
For touring car is a different kettle of fish as it is all different base on the chassis and the driver.
Mind you I still think 22kg/mm might be a little extreme based on the motion ratio the EK.
You have to calculate the motion ratio of the suspension, and for a race car / race driver running on stick, you normally end up around 3Hz of wheel frequency.

By translating the wheel frequency back through the motion ratio / ARB / corner weight, you can work out the springs rate you need to achieve what you need.
Just picking a number from the sky isn't really the mathematical way to work out what you need.

I have seen EP3 touring car using things up to 24kg/mm, but that is because the EP3 runs a pretty wild motion ratio.

Either way, it depends on what you need. But looking at race car springs rate and translating that to a road car is not a good way to specify a suspension.

Jerrick
 
EKandrew said:
what would you recomend?
Click to expand...

I can't do any mathematical recommendations, but I do wanna ask you the following: is the car really only run on track? Or also on road?
 
the car is only a track car. running a full custom cage and seam welded and strengthend shell, hardrace bushings and standerd ARB's
 
If the tracks are really perfectly flat then maybe it's the right rate. But as MeisterR said, this ain't guessing-work.
 
Another problem is the tyres and the dampers.
How much grip you can generate depends on the tyres.
And how much control you have over the suspension depends on the dampers.

On touring cars, you normally see a 3-way (BTCC NGTC Reg) or a 4-way dampers (BTCC S2000 Reg).
That is because you need to control that springs as much as possible which mean you normally run close to 100% critical rebound.
Then you can adjust the High and Low speed compression base on the track surfaces (bumpy or not) and condition (hot and dry, cold and wet).

This normally require a track side suspension engineer who will talk with the driver to understand what he wants, and adjust the suspension base on their feedback (you can be sure that every race team will have a vehicle dynamic engineer on board).

A good set of 3-ways will set you back about £3500 - £4000, a good set of 4-way will see you close to £10,000.
and you need to have an engineer on the team to make all the adjustments trackside unless you are very familiar with suspension tuning, and that isn't common from a race driver.

The new NGTC race specs for the BTCC cars are design to have limited part supplier in order to keep the cost down (We try to provide to a BTCC team but the current regulation force all team to use Penske, which every team are complaining about other than Honda).
But their "cheaper" race car is still £300,000 each to build... professional racing isn't a cheap sport.

As you can see, we are moving quite a bit further from a simple 1-way adjustable dampers.
A 1-way damper is simple to adjust, but it is limited in characteristic if you are really thinking about comparing it to full on race car.

If you ask me if a 1-way adjustable will be able to provide the characteristic needed for a professional race car, even if you have a suspension engineer that can "valve" the damper for each race? My answer would be "No", as there are too many variable and unless you have a way to adjust the High / Low speed bump independently, there are too many compromise to be made.

You can get away with a very good 1-way system on the track-day / club class racing... but if the grid is full of 3-way suspension... your simple 1-way isn't going to cut it if racing competitively.
Only exception to that is if it is a one make race such as the Porsche Carrera Cup, where every car have to use a standardised non adjustable suspensions... then everyone end up on the same boat on the track.

Jerrick
 
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Reactions: _JT
_JT said:
22k on the rear....wow. You better not run over any kind of insect or any tiny object in the corner or you might lose the car :D Better make sure the tracks are very flat, 22k on the Nordschleife (which is kind of an extreme example, I know) would definitely kill you.
Click to expand...

MeisterR said:
For touring car is a different kettle of fish as it is all different base on the chassis and the driver.
Mind you I still think 22kg/mm might be a little extreme based on the motion ratio the EK.
You have to calculate the motion ratio of the suspension, and for a race car / race driver running on stick, you normally end up around 3Hz of wheel frequency.

By translating the wheel frequency back through the motion ratio / ARB / corner weight, you can work out the springs rate you need to achieve what you need.
Just picking a number from the sky isn't really the mathematical way to work out what you need.

I have seen EP3 touring car using things up to 24kg/mm, but that is because the EP3 runs a pretty wild motion ratio.

Either way, it depends on what you need. But looking at race car springs rate and translating that to a road car is not a good way to specify a suspension.

Jerrick
Click to expand...

_JT said:
I can't do any mathematical recommendations, but I do wanna ask you the following: is the car really only run on track? Or also on road?
Click to expand...

Spring rates? Vehicle dynamics? Maths? Sounds like my kinda thang... :D

Here's exactly what you are looking for chaps: Honda Suspension Dynamics Calculator

Default setup is DC2. Change the spring rates and aim for a rear wheel frequency around 2.5-3hz. Adjust the front to give a 'Front Diagonal' of between 40-45%. That'll keep the understeer/oversteer balance sweet. Mess around with ARBs too if you want.

Sorry, but spring rate input is only available as lbs/in at the moment. For conversion, 1kg/mm is around 56lbs/in.

Increasing the lateral acceleration to account for increased grip from track tyres will be worth a look, but be aware of inside rear wheel lift, past this point, IRWL renders the rear axle redundant as a tuning parameter.

Bear in mind that the EK9 has a fantastic chassis, a little roll is not a bad thing. A completely flat cornering attitude is not desirable if it compromises grip.
 
Last edited:
Kozy said:
Spring rates? Vehicle dynamics? Maths? Sounds like my kinda thang... :D
Click to expand...

When it is topics like this, got your name written all over it huh?

Personally, for a road car I aim to go under 2hz.
As you are limited by the road tyres compound and road surfaces quality...
Going over 2hz can be dangerous on bumpy wet road surfaces and road tyres.

For a race car, around 2.5hz - 3hz...
We have gone close to 4hz on some race car but these are really high level pro drivers car. :)

Also, for all you mathematic nerd (myself included).
To convert lb/in to kg/mm and back, it is factor of 0.0179

10.0 kg/mm / 0.0179 = 558 lb/in
450 lb/in * 0.0179 = 8.0 kg/mm

Think that might be useful for some of you... ;)

Anyways, kind of gone off topic.
So here is a conclusion: Can you throw a heavier springs on a coilovers and hope it just work? No.
There are a lot of factors to consider... and if you are not sure then it is best to leave it alone or get someone else to work out the numbers for you. :)

Jerrick
 
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