Moton clubsport suspension

[DeaconRoc]

Originally Posted by wparsons

Any reason you've gone so much softer rear compared to front? Stock yours are 2.3k F and 3.3k R, I'd imagine with 5k F and 3k R it's very pushy?

It was the rates Moton wanted to try to get a good bumpy road ride. The dampers themselves are so firm that actually there is very little difference between the 5/3 set up as there was with the 8/6 set up. The 5/3 just takes the edge off a little.

I'm back at Moton on the 7th and the plan is to revalve the rears to soften them off and go back up the spring rates - it may end up at a 5/5 or maybe 5/6 or 7 even.

The front seems to be pretty well dialed in but the rear is skipping which is the reason to soften up the spring rates initially and then soften the rear damping as the next step.

The beauty of the Motons is that they can handle a huge range of springs. Even on the 5/3 set up a little playing with the bump and rebound gives what looks like a pretty decent circuit set up. I'm on track on Thursday so will see if that shows anything up.

[DeaconRoc]

Spent some of today at Moton to try some different springs.

Going really soft didn't really work - in fact the more I drove it the more I realised it made the car quite harsh and disconnected. It was however still good enough to put me third in my sprint class and that was me only managing 3 laps due to being ill and being on my road wheels and tyres rather than my track set up which were pretty hopeless!

Anyway back to today - we tried the opposite and went pretty stiff on the spring rates - 9 front and 14 rear.

Common sense would suggest this should be horrific but it's actually much, much better. 14 is a little stiff for the rear however for road use so Moton are getting a selection of 10, 11, 12 and 13's in for us to try next time with the thoughts being it's probably going to end up as 9/11 or 10/12.

I'm honestly staggered by how good the ride is on those springs but then it's the sort of springs the Motons are made for. In fact while we were looking through the springs they have in stock they had some 26kg springs which they use with these dampers on some porsches!

[DeaconRoc]

Another update. I was back at Moton yesterday. We softened the valving and dropped the rear spring to an 11kg to give 9f/11r. Seems pretty decent for a liveable street spec and good for bumpy track use. We've got a few clunks to try and eliminate and may try a freer flowing piston in the dampers too to soften them just a little more.

[xwd]

Originally Posted by MaximeT

Great to see someone using proper suspensions. They are supposed to be very close to the JRZ RS Pro. As they were made by the "J" guy in JRZ.

Jerome left Moton when AST bought them several years ago and started MCS (Motion Control Suspension) with the rest of the folks who made up Moton USA. Now I'm sure the Moton design is similar to the old one, but afaik AST does the development on them now.

[DeaconRoc]

For a street and sprint use are there any suggestions for other spring rates that would be good to try?

[xwd]

For US autocross a lot of people are using even spring rates or slightly stiffer in the rear. 7k/7k or 7k/8k, depends on sway bars or just personal feel. I think your rates for track use at 9k/11k are good.

[DeaconRoc]

I spent the day at Moton today to try a different spring rate combo (7kg front, 8kg rear). We also dyno'd the dampers which I thought may be of interest. Dyno plots show fully open and closed for the front and rear.

[DeaconRoc]

To give them a bit of a try me and my girlfriend took a spontaneous journey into Wales and put a couple of hundred miles on them today. We drove there with them set soft and back with a stiffer set up I thought would work well on track and wanted to try on the road (c6 r8 front and C4 r5 rear).

The journey there was good. There is a little bit of low speed bobbling that still needs to be resolved but otherwise it was quite impressive - comfortable but firm I'd say - very well controlled.

The journey back was much stiffer and bumpier. Not a set up I'd want to use for normal road use but liveable if you had to for some reason (can't have been that bad my girlfriend l slept for most of the return journey!) I think it'll work fairly well on track though.

One of the effects of going down on the spring rate a little is that the cup 2's definitely seem to be working better - there is a noticeable improvement in grip. I think the previous set up was a little too stiff for the cup 2's and would work better with a stickier tyre and possibly aero. The other finding is fairly obvious - the car is definitely tracking the road better (it was good before but is better now). The bumpy road performance has definitely improved and I'm fairly sure the track times (at least on the cup 2's and in my cars current configuration) will also have been improved too.

It's taken a while but I think we are quite close now to a good fast road and very capable track set up.

[solidONE]

Can you describe the low speed oscillation you are experiencing? Is it coming from the rear or front end or both? Did you try reducing the damping pressures to try to alleviate some of the oscillations at low speeds? Tire pressures?

[Tor]

Did Monton calculate wheel frequencies for the front and rear?

The 9/14 setup sounded interesting since there are not really any setups with the higher wheel frequency in the rear, which allegedly should be better for comfort. Were there any considerations of doing a similar split but with lower rates that might be better suited for extreme performance road tires? Like 6/9 or 6/10 or even just 6/8?

Are you on stock anti-swaybars?

[DeaconRoc]

Originally Posted by solidONE

Can you describe the low speed oscillation you are experiencing? Is it coming from the rear or front end or both? Did you try reducing the damping pressures to try to alleviate some of the oscillations at low speeds? Tire pressures?

The oscillation is basically a small amount of bouncing on 'normal' road surfaces. It effectively feels like the suspension is not reacting to the small road imperfections - like the suspension is following them rather than absorbing them.

Tyre pressures are currently the standard 35psi all round and haven't been altered to try to alleviate the problem.

Moton are currently designing a freer flowing pistons which should hopefully help the dampers respond better to these small imperfections and so remove the bounce.

[DeaconRoc]

Originally Posted by Tor

Did Monton calculate wheel frequencies for the front and rear?

The 9/14 setup sounded interesting since there are not really any setups with the higher wheel frequency in the rear, which allegedly should be better for comfort. Were there any considerations of doing a similar split but with lower rates that might be better suited for extreme performance road tires? Like 6/9 or 6/10 or even just 6/8?

Are you on stock anti-swaybars?

Wheel frequency would obviously depend on the springs used - the club sports have enough 'range' to accommodate most springs.

The 9/14 was in all honesty a happy accident. We had tried going quite low on the springs but with a heavier front spring and it wasn't working so tried going much stiffer and with a far heavier rear spring to see the effects. It was a definite improvement but made the car a little too tail happy and the rate was too high for normal tyres - slicks and aero for track only use and it'd definitely be a good route to take.

The splits we tried were 8/6, 5/3, 9/14, 9/11 and now 7/8. We haven't tried as extreme a split as the 9/14 again though yet.

I am on Whiteline adjustable front and rear arb's.

[Tor]

Originally Posted by DeaconRoc

The splits we tried were 8/6, 5/3, 9/14, 9/11 and now 7/8. We haven't tried as extreme a split as the 9/14 again though yet.

I am on Whiteline adjustable front and rear arb's.

Something like 6/8 would give the higher wheel frequency in the back given my crude calculations (including motion ratio and corner weights):
2.27 front and 2.44 rear approximately if my calculations are right.

7/8 might be close to harmonic with 2.45 front and 2.44 in the rear, which is to be avoided. I don't know if that could explain your bounciness.

Someone should definitely check my calculations.

My used values are:

Front (per side):
Sprung weight: 660 lbs
Unsprung weight: 80 lbs (not certain this is accurate)
Motion ratio: 0.95 (1.05 in the calculator)

Rear (per side):
Sprung weight: 495 lbs
Unsprung weight: 80 lbs (not certain this is accurate)
Motion ratio: 0.75 (1.33)

Using: http://www.racingaspirations.com/app...ncy-calculator


If I had the opportunity like you do I would try the 6/8 combo out. 5/7 might be interesting too with 2.07/2.28.

Having the rear frequency higher in the rear is referred to as "flat ride". There is an explanation about why that is beneficial for comfort (and ultimately grip) in this document:

http://www.optimumg.com/docs/Springs...Tech_Tip_1.pdf

I guess you could fine tune the handling with the Whiteline anti-swaybars, or even revert to the stock rear bar if it's too tail happy.

For reference, a stock FR-S is 1.40/1.57 given the above parameters. For flat ride you should have a 10-20 % split with a rear bias.

[cjd]

Really awesome that you're sharing your experiences - it's helped me a lot in corroborating some things I think I've observed without the confidence to believe myself.

We'll see how things go next week at nationals, but I know that 9k square is also out there for AutoX with a fast driver...

I'm on 10/12 and as far as I can tell it is simply too high a rate for the available grip I get out of the RE71's while autocrossing - unless everything is just perfect, perhaps. Certainly, as grip falls the car simply starts skating once the smallest thing unsettles it (like, say, a puddle...) I often find it challenging to get heat into the tires. Strano FSB, stock rear. Different coilovers entirely, of course. When the traction is there, it's pretty crazy - but I don't experience that enough I trust it yet.

10/12 is pretty even F/R frequencies and does indeed present some uncomfortable ride in a few places - probably similar to what 7/8 does. Changing vehicle speed helps some, but it also feels like the suspension is not following the surface and the vehicle is being pitched front/back - it's a certain stretch of road that is concrete, laid in short stretches that are all slightly higher in the middle, slightly lower each time the machine stopped. I'll not mention how the ride is on Chicago's lovely streets beyond saying that it's horrible.