Lotus Elan

How hard should Sprint standard suspension be?

PostPost by: TroonSprint » Sat Jan 02, 2016 5:53 pm

Now that I have covered several hundred miles in my Sprint FHC, I am disappointed in the very hard ride. I have no experience of other Elans so don't know if my car is extra hard, or if they are all like that. Road test reports from the sixties all mention how good the ride is - well, I am used to MGBs and Midgets, and the Elan feels at least as hard riding as any Midget I have owned. It doesn't seem to absorb road bumps, but leaps upwards each time it encounters one, giving a jarring ride on all but the smoothest roads. It is terrific on smooth roads with amazing cornering ability, but round here we have a lot of poor road surfaces.

The car has been built up using mostly new components and has a complete Spyder suspension set. The front springs are 1.9" ID rated at 70 lb.in. The dampers are Spyder adjustables. If you look at my photo taken with the car on the ground, the spring looks almost coil bound to me. Is that normal?

The rear springs are 2.25" ID again at standard rating. These don't look so near coil bound, but I can't bounce the car by pressing down on the top of the rear wheel arch. The rear dampers are Spax set at the minimum setting. Springs, dampers and wishbones are all new from Spyder. Rear bushes are original style Metalastic, with poly bushes on the front.

I know there is a wealth of knowledge to be found among the contributors here, and I have been trying to find an answer in the archive, but without much success. I would value some opinions please.

Mike
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PostPost by: 512BB » Sat Jan 02, 2016 6:14 pm

You are correct Mike, in your assertion that the front spring is totally wrong, and as you say, the slightest upward movement of the suspension will result in a springbound coil, and lead to the jarring that you are experiencing.

I would send that picture to Spyder and ask them to comment / supply the correct damper and spring if they supplied.

The spring rating sounds about right from what you quote, even a little on the soft side, but I suspect that the length is wrong.

Leslie
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PostPost by: RichardS » Sat Jan 02, 2016 6:21 pm

Hi Mike
Others more expert than I will advise on what is wrong - something obviously is!
The ride on my Sorint is superb - I have the Spyder RSC and TTR at them front. I have the shocks on the softest settings and the ride is very compliant and comfortable but equally good round the bends.
Richard
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PostPost by: elanfan1 » Sat Jan 02, 2016 7:37 pm

I'm not exactly known for mechanical knowledge but that spring looks very wrong even to me, there seems to be very little space for much dampening effect. Could it be you have Plus 2 springs - are they a bit longer? I suspect you've done very well getting them on!
Steve

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PostPost by: Craven » Sat Jan 02, 2016 8:26 pm

Hi,
The track rod ends are in the way in your pic, but the spring platform look as if they are adjusted high up, is your front ride height correct.
Ron
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PostPost by: elansprint » Sat Jan 02, 2016 8:42 pm

Hi Mike the overwhelming memory of a drive in any Elan is the compliance of the ride and the handling. Does the spring/shock unit have an adjustable spring seat are the shocks Avo ? Is the shock fully extended with the weight of the car on it ?
Ian
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PostPost by: TroonSprint » Sat Jan 02, 2016 9:39 pm

The track rod ends are in the way in your pic, but the spring platform look as if they are adjusted high up, is your front ride height correct.
Thanks for the replies so far. To answer the above comment, the ride height is perfect and the lower arms and the track rods are close to parallel to the ground, but in any case winding up the spring does not compress it further. It simply pushes the car up in the air. The spring will be the same length at the lowest setting as at the highest setting. The amount the spring is compressed is a function of the spring rate and the weight applied to it.

Could it be you have Plus 2 springs - are they a bit longer? I suspect you've done very well getting them on!
Are they Plus 2 springs? There's a thought I hadn't considered. As for putting them on, Spyder did it for me as part of the package deal.

Is the shock fully extended with the weight of the car on it ?
I honestly don't know, but I can check tomorrow when (or if) I get out to the garage.

I'll see if I can get a photo of the rear spring too. There's no camera access with the wheel on, so I would have to jack the car up, remove the wheel and then lower the car onto a block so the weight is on the suspension.

Watch this space.
Mike
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PostPost by: Grizzly » Sat Jan 02, 2016 10:18 pm

That looks like a stock spring on a Uprated Strut, if you look at the stock strut the spring platform is allot further down. I'd guess some one has fitted the stock length one by mistake.

Not the best picture but do you see what i mean (the spring sits almost on the lower bushing (the platform looks a good 2" lower)

p1030617.jpg and
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PostPost by: rgh0 » Sat Jan 02, 2016 10:42 pm

Can you take a picture of both the front and rear springs with the normal weight on the suspensions. At then with maximum load and minimum or no load. This will show what actual travel you are achieving on the suspension and you can compare that with the travel showing in the manual drawing.

It is easy to do this by supporting the suspension under the outer pivots with a jack and remove the tire then adjust to jack up and down from the normal ride height position.

The front suspension photo looks like the spring has collapsed to be almost coil bound at normal load and the adjuster wound up to maintain ride height. This can be caused by the use of the incorrect spring length and / or rating or by the spring collapsing due to incorrect hardening. The front springs on Elans and especially Plus 2's are very highly stressed and cheap springs rapidly collapse.

70 lb/in front springs are a little soft if that is their actual rating and that could cause part of the problem. The fronts should be 75 lb/in with a fitted length at normal ride height of around 9.5 inches. From your photo the length at normal ride height would be around 6 inches.

The rear on an Elan feels signficantly softer than the front with its standard spring rate of 67 lb/in and you should be able to easily depress the rear with your weight when you sit on a back corner a couple of inches.

cheers
Rohan
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PostPost by: elansprint71 » Sat Jan 02, 2016 11:04 pm

Here's a load of shots, you can see that yours are almost coil-bound.

https://www.google.co.uk/search?q=lotus+elan+front+suspension&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiFpubHnYzKAhWBOxoKHdSSBkIQ_AUICCgC&biw=1920&bih=1036

I too have TT Front and rear with Spyder RSC, the suspension is, for a roads sports car very compliant ("soft") but damping is firmer.

Of course with all adjustable it is very easy to get things out of kilter. I would run the spring perches down to near the bottom end of the thread and see what the spring looks like. If you have access to a set of racing scales, check the corner weights.

EDIT: Actually, looking at your shot I can't actually see if the spring compression is adjustable- is it?
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PostPost by: Craven » Sun Jan 03, 2016 1:28 am

Hi,
Set of Spyder shocks with springs fitted by Spyder for an Elan S3 with RSC. May give an indication to a loaded setup.
Ron.
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PostPost by: TroonSprint » Sun Jan 03, 2016 10:05 am

Great comments fellas. Thanks. Some replies for you.
Here's a load of shots, you can see that yours are almost coil-bound.
Yes, I looked at the Google images too, but they are all with the suspension in full droop and I couldn't find one with the weight of the car on the spring.
The front suspension photo looks like the spring has collapsed to be almost coil bound at normal load and the adjuster wound up to maintain ride height. This can be caused by the use of the incorrect spring length and / or rating or by the spring collapsing due to incorrect hardening. The front springs on Elans and especially Plus 2's are very highly stressed and cheap springs rapidly collapse.

70 lb/in front springs are a little soft if that is their actual rating and that could cause part of the problem. The fronts should be 75 lb/in with a fitted length at normal ride height of around 9.5 inches. From your photo the length at normal ride height would be around 6 inches.
I agree Rohan that the spring looks collapsed and I have wound up the platform to get the right height. As for the springs themselves, I asked Spyder for springs to be equivalent to the standard set up as I prefer comfort at my age! :) On the delivery note the springs are described as 1.9" x FL 14" x 70LB, Closed length 6". I will definitely try what you suggest on both front and rear and report back. Spyder didn't give any spec for the rear springs.
Set of Spyder shocks with springs fitted by Spyder for an Elan S3 with RSC. May give an indication to a loaded setup.
If I'm honest, the front springs in your photo, Ron, look pretty close to spring bound also.
Of course with all adjustable it is very easy to get things out of kilter. I would run the spring perches down to near the bottom end of the thread and see what the spring looks like. If you have access to a set of racing scales, check the corner weights.

EDIT: Actually, looking at your shot I can't actually see if the spring compression is adjustable- is it?
Pete, if I run the perches down to the bottom the ride height will be too low. Yes, the perches are adjustable.

I'm looking for ammunition to go back to Sean at Spyder and try to get this resolved. I have spent a lot of time and money building this car and am gradually overcoming the problems, but it's a frustrating process and I often wish I had never taken it on! If I could only run the car into Spyder I'm sure it would get sorted, but they are 400 miles from here.

Mike
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PostPost by: elanfan1 » Sun Jan 03, 2016 10:43 am

I find Sean pretty straightforward, just send him a photo and your thoughts and give home a ring. I don't think you need ammunition as such he'll be keen to sort it out I'd have thought.
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PostPost by: rgh0 » Sun Jan 03, 2016 11:13 am

"On the delivery note the springs are described as 1.9" x FL 14" x 70 lb, Closed length 6"."

A little soft at 70 versus 75 lb/in and a little short 14 inch versus 14.5 inch free length versus standard which will result in a shorter than 9.5 inch length at normal load. Combine that with the spring loosing length due to it not being hardened properly and you will end up where you are I believe. Cheap springs are "cold wound" and will not withstand the stresses on the elan or Plus 2 front suspension. You really need "hot wound" springs.

A six inch closed length is about standard but your front springs are very near this length at normal ride height judging from the photo when the should be about 9.5 inches at normal ride height and around 7 inches at full bump.

cheers
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PostPost by: Grizzly » Sun Jan 03, 2016 3:29 pm

I've never seen platform adjustable coil overs like that? I have Nitron Coil overs on my Race car and they have quite a long stroke to the strut with a much shorter springs with helper springs so when you move the platform up and the main spring don't compress (the helper spring are just there so the springs don't dislocate when you jack the car up), yours look almost like there fixed height springs with the platforms there for easy assembly?

I know not quite the same but here is an example of what i mean, i just don't get how you can adjust the spring platform with out loading or unloading the spring? so by doing your corner weight you could be messing up the spring pre load at the same time?
ntrr3.jpg and
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