group n spring rates?

[p@blo]

Which numbers are you referring to mate? The motion ratio calcs or the spring poundage? I did my measuring ages ago and have it all written down somewhere so I'll have to try and find it, but for some reason the ratio of 1.7(ish):1 rings a bell. I eventually managed to work out what the rate of my rear springs were (kw v2's) taking known weights that were already there and adding a known weight and measuring deflection. Needed carol vorderman for the amount of maths involved though! Lol! When I eventually got the springs tested for their rates I was pretty much bang on too (allegedly a variable rate spring on kw's - er no they ain't! Well not until get them nearly fully compressed)

Both really

Just did a rough calc on s=rΘ and worked out the differential deflection for both positions versus the stub axle axis. From that got a value for the motion ratios and then wheel rates.

Sounds like you took your time with it and got accurate measurements - be interested to see how you arrived at the 1.7 value if you can find your workings mate.

 

[NorthloopCup]

Both really

Just did a rough calc on s=rΘ and worked out the differential deflection for both positions versus the stub axle axis. From that got a value for the motion ratios and then wheel rates.

Sounds like you took your time with it and got accurate measurements - be interested to see how you arrived at the 1.7 value if you can find your workings mate.

I'll have a look and see if I can find everything. I'm excellent at putting stuff in a safe place, then totally forgetting where that is when it's needed! Lol!

Do you run cup racer suspension up front then with the corrected roll centres? Correcting that was one of the biggest improvements I made to mine.

 

[NorthloopCup]

Front are 360ish or 60NM/mm - does feel harsh at all infact im thinking of going stiffer at the rear.

Interesting really if fancy damper allow you to run stiffer and get more compliance or run softer and more control???

Are the reigers that you have 3 way adjustable just out of interest? It's a shame they're not interested in doing stuff for track work as well. I'd have snapped a set up if they did!

 

[p@blo]

I'll have a look and see if I can find everything. I'm excellent at putting stuff in a safe place, then totally forgetting where that is when it's needed! Lol!

Do you run cup racer suspension up front then with the corrected roll centres? Correcting that was one of the biggest improvements I made to mine.

Good man, cheers. Not running the cup hubs & extender pins at the minute but have it all sat in a box to go on for next year. Just waiting on some strut casings to suit the lag hubs and get a n/s shaft knocked up and its good to go.

Without rc correction just bodged it with fairly stiff spring rate up front for now. It works ok for what it is so be interesting to compare with the corrected geo going forwards

 

[NorthloopCup]

Good man, cheers. Not running the cup hubs & extender pins at the minute but have it all sat in a box to go on for next year. Just waiting on some strut casings to suit the lag hubs and get a n/s shaft knocked up and its good to go.

Without rc correction just bodged it with fairly stiff spring rate up front for now. It works ok for what it is so be interesting to compare with the corrected geo going forwards

Mines just the original hubs but machined and custom billet uniball holders (I'm sure you'll have seen the group buy) as I wanted to be able to retain the flexibility you get from sticking with the original hubs. You'll find you can run less camber up front with the corrected roll centre as well. It will be very noticeable with that all corrected.

 

[p@blo]

Makes total sense with what you set out to achieve, seems a well thought out bit of kit.

Be interesting to see how the bump steer is on the lag hub as notice you'd included extender pins for the steering arms in your kit aswell.

Planning on measuring it all up while its apart to try and get a feel for how the two are different. Was this just an issue that was specific to the steering arms on the std hubs or just as problematic with the lag hubs?

 

[NorthloopCup]

Makes total sense with what you set out to achieve, seems a well thought out bit of kit.

Be interesting to see how the bump steer is on the lag hub as notice you'd included extender pins for the steering arms in your kit aswell.

Planning on measuring it all up while its apart to try and get a feel for how the two are different. Was this just an issue that was specific to the steering arms on the std hubs or just as problematic with the lag hubs?

Thanks. It's definitely had a lot of development time mate to get to where it's at now.

The steering arms have been dropped in accordance to the amount of correction used on the roll centre. I'll be using a different length extender pin and bump steer corrector on my set for next year. Mainly to push the development on a bit, but also for my own desire to run the car lower. If you come across any bump steer related issues on the lag hubs, let me know. The bump steer corrector is something that could be supplied you see.
In relation to how different the 2 setups of hubs are it's like night and day mate. 1*2 hubs look tiny in comparison. The lag hubs have the steering arms relocated from bottom to top (or vice versa - been a while since I looked! Lol) to try and combat the bump steer, whereas with the 1*2 you need to use extenders. Even the standard ride height car suffers from bump steer believe it or not.
Either way though, if the lag hubs need correcting it's not a problem. There is a solution.

 

[EVOgone]

Are the reigers that you have 3 way adjustable just out of interest? It's a shame they're not interested in doing stuff for track work as well. I'd have snapped a set up if they did!

Yes and they will do track ones as its only the valving and springs that are different? does easy. Even mine have enough adjustment to accomodate double the spring rates

 

[p@blo]

Thanks. It's definitely had a lot of development time mate to get to where it's at now.

The steering arms have been dropped in accordance to the amount of correction used on the roll centre. I'll be using a different length extender pin and bump steer corrector on my set for next year. Mainly to push the development on a bit, but also for my own desire to run the car lower. If you come across any bump steer related issues on the lag hubs, let me know. The bump steer corrector is something that could be supplied you see.
In relation to how different the 2 setups of hubs are it's like night and day mate. 1*2 hubs look tiny in comparison. The lag hubs have the steering arms relocated from bottom to top (or vice versa - been a while since I looked! Lol) to try and combat the bump steer, whereas with the 1*2 you need to use extenders. Even the standard ride height car suffers from bump steer believe it or not.
Either way though, if the lag hubs need correcting it's not a problem. There is a solution.

This was exactly my thinking when I saw your kit.

Will try and figure out how much of an issue it is once I've had chance to measure it all up. Be keen to see how you develop it on, i'll be sure to keep an eye on your progress thread.

 

[NorthloopCup]

Yes and they will do track ones as its only the valving and springs that are different? does easy. Even mine have enough adjustment to accomodate double the spring rates

That's interesting then as I'm sure they declined when it was mentioned about the use of the car as they said they prefer to stick with rally stuff. What did your set cost out of interest? If you don't mind me asking of course.

 

[EVOgone]

That's interesting then as I'm sure they declined when it was mentioned about the use of the car as they said they prefer to stick with rally stuff. What did your set cost out of interest? If you don't mind me asking of course.

Ask away, a lot is my answer.....

 

[NorthloopCup]

This was exactly my thinking when I saw your kit.

Will try and figure out how much of an issue it is once I've had chance to measure it all up. Be keen to see how you develop it on, i'll be sure to keep an eye on your progress thread.

You need to set your car to the ride height you want and take a quick visual check at the angle of the steering arms. That'll give you a good idea of if they need much correction. The aim of development is to break the 8min 15 btg time at the 'ring. When that happens I'll probably pack it all in, but I don't have a progress thread mate I'm afraid.

 

[NorthloopCup]

Ask away, a lot is my answer.....

Lol! Yes I seem to remember them being pricey. Quality costs though at the end of the day.

 

[p@blo]

Lol! Yes I seem to remember them being pricey. Quality costs though at the end of the day.

Is yours full grp N, you running the bilsteins or ohlins with the external cans?

 

[NorthloopCup]

Is yours full grp N, you running the bilsteins or ohlins with the external cans?

No mate the only Grp n bits on my car is the ecu and cam timing! The suspension is kw v2 but that's going to be upgraded to sportline 2's in the near future hopefully. I can only dream of running an ohlins setup!

 

[sam JFM]

Maybe ohlins would solve my problem lol!

I did consider upping the front and rear by 150lb so that is what I will do to start - with the roll center kit aswell it should make a nice difference

 

[p@blo]

No mate the only Grp n bits on my car is the ecu and cam timing! The suspension is kw v2 but that's going to be upgraded to sportline 2's in the near future hopefully. I can only dream of running an ohlins setup!

Ah right, wasn't sure if you'd taken the same route as Andrewclio.

The AST are a good shout for the money. Always got the option to retrofit for compression adjustment at a later date if you're keeping them longer term.

Maybe ohlins would solve my problem lol!

I did consider upping the front and rear by 150lb so that is what I will do to start - with the roll center kit aswell it should make a nice difference

What internal dia front springs are yours Sam?

 

[NorthloopCup]

Ah right, wasn't sure if you'd taken the same route as Andrewclio.

The AST are a good shout for the money. Always got the option to retrofit for compression adjustment at a later date if you're keeping them longer term

That is very very very good to know!! Nice one mate!

 

[sam JFM]

Ah right, wasn't sure if you'd taken the same route as Andrewclio.

The AST are a good shout for the money. Always got the option to retrofit for compression adjustment at a later date if you're keeping them longer term.



What internal dia front springs are yours Sam?

2.5's

 

[sam JFM]

Is it the VLN springs you're running sam - they're around the 450lb mark aren't they?

View attachment 105942

What springs are they?

 

[p@blo]

What springs are they?

Don't know any more than what's on them Sam. Presumably a unified spec that the Clio 2 use to run in the VLN events.

Assuming I've read it right that they're in kiloponds rate is 80kp/cm = 78.45N/mm = 448ib/in

 

[sam JFM]

And what were the vln events?

 

[NorthloopCup]

And what were the vln events?

German endurance races Sam. I've watched it at the nurburgring!

 

[sam JFM]

ahhh i see - that makes the rear of those cars quite soft then? or maybe im looking at over springing with 550lb/in? rear

 

[NorthloopCup]

ahhh i see - that makes the rear of those cars quite soft then? or maybe im looking at over springing with 550lb/in? rear

They're set soft as the ring is quite a bumpy circuit to race on. Anywhere between 450-550 should work well for you, but it all comes down to the damping rates. You'd need good rebound settings.

 

[sam JFM]

They're set soft as the ring is quite a bumpy circuit to race on. Anywhere between 450-550 should work well for you, but it all comes down to the damping rates. You'd need good rebound settings.

I think im going to have to ring leda, my shocks are compression and rebound combined!

 

[NorthloopCup]

I think im going to have to ring leda, my shocks are compression and rebound combined!

They should be able to revalve them to suit no problem.

 

[sam JFM]

Just had a thought - if I want to.increase the rear spring rate by 150lb/in I'm going to need a 300lb stiffer spring?

 

[NorthloopCup]

Just had a thought - if I want to.increase the rear spring rate by 150lb/in I'm going to need a 300lb stiffer spring?

What spring rate are you wanting to run Sam?

 

[sam JFM]

Well currently is 300F 200R (400Rear spring) so as you suggested 450F and 350R but to achive that i will need a 700 rear spring?

All in LB/IN

 

[EVOgone]

Whats it like with those rates?

Well currently is 300F 200R (400Rear spring) so as you suggested 450F and 350R but to achive that i will need a 700 rear spring?

All in LB/IN

 

[sam JFM]

Its ok but i have used 100% adjustment on the rear and 75% on the front to stiffen it up

 

[p@blo]

Sam, If the 350-400lb/in wheel rates as suggested are suited to a clean/consistent surface would it be worth factoring in a little more compliance for surface imperfections/grip levels that you'd presumably be encountering on tarmac stages?

Steve/evogone would presumably be best placed to advise on just how much softer you'd want it to be for your particular application?

 

[sam JFM]

Sam, If the 350-400lb/in wheel rates as suggested are suited to a clean/consistent surface would it be worth factoring in a little more compliance for surface imperfections/grip levels that you'd presumably be encountering on tarmac stages?

Steve/evogone would presumably be best placed to advise on just how much softer you'd want it to be for your particular application?

Yes this is what makes it such a head scratcher - im not sure what to do for the best, maybe just get the shocks serviced and run with what i have?

 

[mark123]

I have 450F 400R (ASTs with rear coilover) on my car and I would say it is too stiff to risk even on a tarmac rally unless you knew the surface was smooth.

I am planning to do some stage rallies and I think I'd probably look at reducing the spring rates by about a third for that. And I'd like to go a bit stiffer for circuits lol.

 

[sam JFM]

Maybe the answer then is to leave the spring rates as they are and look at the possibility of increasing the damping settings to give me more stiffness that way?

 

[p@blo]

Maybe the answer then is to leave the spring rates as they are and look at the possibility of increasing the damping settings to give me more stiffness that way?

Stiffness is a spring rate issue though surely? Shim stack adjustment would only alter rate of transfer wouldn't it? You experimented much with the rear platform height/rake on yours Sam or you had it corner weighted and just left it as is?

 

[NorthloopCup]

Well currently is 300F 200R (400Rear spring) so as you suggested 450F and 350R but to achive that i will need a 700 rear spring?

All in LB/IN

My kw's have 330lb front springs as standard and they're a bit too soft for track work as it allows the front end to roll over itself a bit, but on the back road lanes near me it's very composed. I'd be very tempted to up the fronts to only 350lb.

So am I correct in understanding that you have a 400lb rear spring in the original position now? Or is it a 200lb spring. Forget about the motion ratio stuff for now as it's just causing a bit of confusion. IF your running a 200lb rear spring bang a 350lb in the back a give it a go. Don't worry about revalving anything until you've tried it, but I think you'll be pleasantly surprised by it. I've ran 350lb springs in the original rear position and it was really good on the road and reasonable on track too.

 

[sam JFM]

Stiffness is a spring rate issue though surely? Shim stack adjustment would only alter rate of transfer wouldn't it? You experimented much with the rear platform height/rake on yours Sam or you had it corner weighted and just left it as is?

It's not corner weighted and I have some rake back to front. Yes it is a spring issue but you get the same effect as a feel?

 

[sam JFM]

My kw's have 330lb front springs as standard and they're a bit too soft for track work as it allows the front end to roll over itself a bit, but on the back road lanes near me it's very composed. I'd be very tempted to up the fronts to only 350lb.

So am I correct in understanding that you have a 400lb rear spring in the original position now? Or is it a 200lb spring. Forget about the motion ratio stuff for now as it's just causing a bit of confusion. IF your running a 200lb rear spring bang a 350lb in the back a give it a go. Don't worry about revalving anything until you've tried it, but I think you'll be pleasantly surprised by it. I've ran 350lb springs in the original rear position and it was really good on the road and reasonable on track too.

Sorry - yes it is slightly confusing I am running 300lb/in front springs and 400lb/in*rear springs they are they actual spring rates