Lotus Elan

Optimum suspension setup for an S4 elan

PostPost by: holywood3645 » Sat Dec 21, 2013 10:40 pm

Ok, Car has been back on the road for a year. Very happy with the aesthetics (interior/exterior) Performance tuning engine and gearbox is also very nice. Still haven?t worked on the 2500rpm weber stumble, but not really a big issue at the moment.

My next round of work will be optimization and rework to improve handling and stance. I have not been happy with the handling since the car has gone back on the road. Also the S4/Sprints always seems to not just look as good as the S3 when it comes to stance. They usually seem to sit too high at the front. My car has a problem at the rear with the right side sitting ? inch higher than left. However, after a 5 plus year restoration, I got tried to trying to figure out where the issue was, and decided to just drive the car and enjoy it for a while. Most my lotus friends told me, the stance and difference it was normal or acceptable and/or it was only me that could see it.
During my restoration, I replace the front and rear suspension with SPAX adjustable. I used inserts on the rear with OEM spring setup. The fronts are new units (spring & shock) on the front. I ended up refitting the old OEM units on the front as the springs on the front adjustable Spax would not allow me to drop the car, and sat higher than with OEM. The front spring rating is ~95lb/in. and I figured the springs were too long.

I want to fix the stance, height and handling once and for all. I have a 3.5 diff I plan to replace while I?m at it.
My questions are:
Can you please provide advice on the best setup available for the S4 for fast road application? (I have about 150bhp available from my 420S QED spec? motor)

Is a rear antiroll bar a good upgrade? Can one be fitted with the ?Body on?

Are the TT mods and components the best way to fix these issues.

I don?t mind throwing the baby out with the bath water here, but that may be a little over reaction.

Please advise on optimal ride height for this car.

The body was off it only a year ago, all fitting nuts and bolts are fresh, is it advisable to remove the body to do these mods. It is very frustrating working on the rear with body on.
I have a ?new? set of OEM springs (never fitted).

Help and advice always appreciated.
James
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PostPost by: GrUmPyBoDgEr » Sat Dec 21, 2013 11:00 pm

If you fit dampers that have adjustable spring seats at the front & rear you will immediately have the opportunity to play different tunes on ride height provided that the springs are the right length.
One reads on here all too often about front springs being way too long. See the recent thread about how to compress the front springs in order to fit them on to the dampers.
I have been pleased with the "fast road" springs & dampers that TTR provides.

Cheers
John
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PostPost by: rgh0 » Sat Dec 21, 2013 11:15 pm

Hi James

For a "fast road" Elan and assuming you are using modern sticky tyres I would use the following set up. The Dave Bean Catalogue gives recommendations around suspension changes for fast road and track also which is similar to this.

22mm front roll bar - no rear roll bar. You really need to take the body off to fit a rear bar and it is not really needed especially in a road car and its usefulness in a track car is debatable with some people saying they are needed and others saying they are not.

About a 50% increase in spring rate front and rear. 50% spring rate changes is about the smallest an average driver will notice a handling difference with. The next step to 100% increase is to hard for the road IMHO

Ensure you have the original Aeon rear rubber springs or equivalent in place and space them down by about 20mm. This stops the outer rear sitting down to much in a hard corner and together with the stiffer front bar gets the Elan nicely neutral when pushed hard in most situations.

Get adjustable front and rear spring seats and small diameter rear springs and set the height to the way you like and ground clearance for your usage allows and the corner weights equal if you want to go that far!

Make sure the suspension geometry is right to specification, especially the rear toe in

I have used TTR for front spring / shocker supply with spring rates to my specification and been happy with his products

cheers
Rohan
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PostPost by: GrUmPyBoDgEr » Sat Dec 21, 2013 11:20 pm

Ah, yes, perhaps I missed a few of the finer points :)
Cheers
John
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PostPost by: jimj » Sat Dec 21, 2013 11:28 pm

Rohan, I`m intrigued, when you say "especially the rear toe in". How critical is it? what are the symptoms of it being incorrect? basically, is buying the Spyder adjustable rear wishbones to get it spot on worthwhile?
Thanks,
Jim
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PostPost by: AHM » Sat Dec 21, 2013 11:48 pm

Jim,

I like the rear as is, but the front I have found too high and too hard.

I have spax front dampers, and as with others the spring seat is raised to clear the adjuster. With the apparently standard S4 16 1/2" springs there is at least an inch too much spring, which I think is the cause.

So I've cut the springs down to 15 1/4" and I'll see how it goes from there.
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PostPost by: rgh0 » Sun Dec 22, 2013 5:46 am

jimj wrote:Rohan, I`m intrigued, when you say "especially the rear toe in". How critical is it? what are the symptoms of it being incorrect? basically, is buying the Spyder adjustable rear wishbones to get it spot on worthwhile?
Thanks,
Jim


I find both my Elan and Plus 2 very sensitive to toe in changes for both front and rear.
Not enough front toe in makes them unstable under heavy braking and not enough rear promotes to much oversteer.

Most people regularly check the front toe in when they buy new tyres but the rear is just as important and tends to be forgotten hence my emphasis. I prefer both to be middle to upper end of the quoted range. At the rear if your fixed A frames don't give you the right toe in then you need to get new ones that do or get adjustable ones.

Note - a bit of data for the Wiki --In the Lotus manual the front toe-in is the total difference distance between the front of the wheels at the rim and the rear across the car , I set around 4 to 5 mm with the Lotus quoted range 1.6mm to 4.76mm . However it is not clear whether the rear number in the manual of zero to 4.76mm is quoted as the total toe in (the same as for the front) or just the toe in per side in the same way it is quoted for the Europa and Esprit. I queried the Lotus manual writer about this many years ago and he said the normal convention is to quote individual wheel toe in at the rear as the rear wheels are not connected for steering and this is what is explicitly stated in the Europa and Esprit manuals. However it is not stated in any Elan manual I have so far seen and he could not say whether they followed the same convention back then. My Elans individual rear wheel toe-in is 2mm each side or a total of 4mm for what its worth and I am happy with the handing.

cheers
Rohan
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PostPost by: [email protected] » Mon Dec 23, 2013 6:28 pm

Since you have the Spax adjustable dampers I would suggest changing the springs, as others have mentioned, and follow Rohans advice about toe in. I prefer a larger A/R bar of the .75" variety. The original springs are too long, too soft for contemporary tire grip. The front A/R bar change makes a more linear turn in. Adding a rear A/R bar is great for solo racing but makes a very nervous car on the road or track.
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PostPost by: collins_dan » Mon Dec 23, 2013 7:33 pm

I have the 7/8" sway bar in front and the TTR fast road setup all the way round, and like it. Have played with lowering front and steering got very heavy. Best to stick with the flat across lower wishbone rule. Agree with front toe-in comments. Car felt very unstable after replacing bushings and it turned out to be a toe out situation in front. Once corrected all was good. Ran an autocross later in the summer and tried different settings front and rear and basically came to the conclusion to tighten front and rear all the way. I do not correctly have adjustable rear wishbone, but suspect that I need it. Not as stable as I would like on high speed turns. My plan is to take the car to a local shop here in Maryland in the spring that has a track record of setting up elans. Good Luck, Dan
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PostPost by: rgh0 » Mon Dec 23, 2013 10:16 pm

Hi Dan
Stabilty on hi speed turns is the one area of Elan handling I have never got totally right either and it is where I am slow compared to other cars on the track. The combination of short wheel base, narrow track and relatively soft suspension means an Elan moves around a lot in this situation I believe. The only fix i believe is to go for a much harder suspension like the TTR full racing setup of around 300lb/in front and 200 lb/in rears. However that is unuseable on the road and not much fun in the wet or on the rough tracks we have here so I have resisted going that hard on my Elan.

If you learn anything about dialing it out from your Elan handling guru I would certainly like to know

cheers
Rohan
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PostPost by: Mazzini » Tue Dec 24, 2013 6:03 pm

Anybody know if the Tony Thompson anti roll bar 26R standard (TTRSS 001) is 7/8th (22mm)? If not I'll give them a call after Xmas.

Merry Christmas.
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PostPost by: alan » Tue Dec 31, 2013 1:53 pm

imho it's best to quote toe in as an angle (degrees)
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PostPost by: holywood3645 » Wed May 31, 2017 4:12 am

I cannot believe its 3 years since my first post on this topic. I have slowly collected the new parts to attack the rear of the car and they are now installed. I had an elan 40 years ago and remember the handling on that car being much better than my present elan. This was true however, now i can say my present car has improved vastly. I am trying to optimist the items i have recently added, which are the following;

3.5 diff
CV drive shaft
SPAX adjustable gas shocks.
TT rear adjustable coil-over kit
Rear adjustable wishbones.
Front TT adjustable coil-over shocks.
My front ride height may be a little low as sometimes it slightly scrapes the renders on tight turns (the front control arms are parallel to bottom of chassis cross member) But i think it droops slightly when i'm in car. This will be easily adjusted,
Rear height to rear 6.75
Ride height front 5.25
I have had crappy tires, but will fit better to complement the suspension (XAS or ?)

I have not changed the front anti-roll bar.

I want to set it up for fast road use. and would like a good baseline setup. Since setting the ride height the car feels so much better, and I am now trying to 'dial it in' and optimize these components

Is there a sequence I should follow. i.e. New tires, ride height (F R), front toe in, rear ride height, shock Stiffness front, Shock stiffness rear?
Ride height Front and Rear
What rear toe in would be recommended ?
Front toe would be recommended.?
Stiffness Shock setting for front and rear.?
Will a thicker front ARB help even more.

All input and advice is greatly appreciated.

Thanks

James
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PostPost by: holywood3645 » Wed May 31, 2017 9:21 pm

Raised the front to 5 3/8" front rubbing stopped.
Still interested in advice on previous post.
Thanks
James
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PostPost by: rgh0 » Thu Jun 01, 2017 10:03 am

[quote="holywood3645"

I want to set it up for fast road use. and would like a good baseline setup. Since setting the ride height the car feels so much better, and I am now trying to 'dial it in' and optimize these components

Is there a sequence I should follow. i.e. New tires, ride height (F R), front toe in, rear ride height, shock Stiffness front, Shock stiffness rear?
Ride height Front and Rear
What rear toe in would be recommended ?
Front toe would be recommended.?
Stiffness Shock setting for front and rear.?
Will a thicker front ARB help even more.

All input and advice is greatly appreciated.

Thanks

James[/quote]
The Dave Bean fast road set up in their manual is a good starting point.
What tires you want depends on usage but the stickier the better

Personally I would combine the Dave bean spring rates with a 22mm / 7/8 front roll bar and around 20mm spacers on the rear Aeon springs.
I would set front toe in near the maximum and try it with the standard rear toe in specification ( which is per wheel not total IMHO).

I dont think any specific sequence and I would try to do them all and play from there

cheers
Rohan
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