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Esprit GT3 suspension options


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Can anyone give a quick summary of what the current options are regarding replacement springs and dampers for the 4 cylinder cars? I noticed one rear shock was a little damp the other day, probably not enough to worry immediately but with the Esprit its always best to plan the next nightmare job in advance!

I remember years back there being loads of discussion about the factory Bilstein replacements with matching red bushes, is that still available? SJ sportscars only list the rear bushes out of the whole lot.

I'd like original wherever possible, even if it isn't upgraded, but are those days gone now? A lot of Esprit stuff seems to have gone NLA in the last few years.

In the garage no-one can hear you scream 

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Thankyou. I'm not much of a modifier, so outside of mainstream names like Spax and Bilstein I'm not too clued up on the quality or desirability of some of the newer names - Gaz, ProTech etc all seem to be buzwwords these days.

In the garage no-one can hear you scream 

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I have Protech shocks currently fitted to mine, the springs SJ sells now are better than the earlier ones. they fit and work well but take a bit of time to set up so the car handles as they have a wide amount of adjustment in both height and damping and some settings make the car terrible to drive but once you find the correct damping and set the ride height to standard they offer a cost effective solution. 

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This is the thing I can't even set the TV remote, never mind suspension settings. I'd end up with a million versions that were "different" without being able to decide which was better. I'm leaning towards whatever factory kit is available, with advice from experienced owners how to get the ride height down to acceptable levels.

Anyhow another job has overtaken this one for now - 2 out of the rad fans have packed in so a more pressing job for the summer.......!

In the garage no-one can hear you scream 

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  • 9 months later...

I recently replaced my front shocks with a pair of the adjustable Protech's from SJ Sportscars.. (also replaced all the bushings with the OE rubber type)

Watched a video of how to set up the preload, a manufacture of some other brand explained that you lower the bottom collar to were the spring is basically loose and can be turned by hand.. Then tighten it so the collar raises the spring roughly the thickness of the spanner.. Just a smidgen of preload basically.. After doing this i have tried the dampner settings from the lowest setting all the way up to 9 or 10.. Car feels really rough and clanky on the streets around my house (which are shit by the way) car feels pretty amazing on the freeway.. but around town any pot hole makes the car feel like its gonna break apart! 

any advice on this would be helpful.. 

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For the front: it’s from the ground to the chassis rail. The chassis rail is what the anti roll bar is bolted to. I believe that most Esprits are 170mm.

If you are looking at the rear then it’s from the ground to the bottom of the U shaped chassis section. Again 170mm is standard.

if you are close to those measurements then it may be worthwhile posting a pic incase somethings not quite right.

I’m swapping out my front protechs this weekend so can take a few pics/measurements or check settings if it helps? 

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On ‎03‎-‎05‎-‎2017 at 17:32, Loose Cannon said:

This is the thing I can't even set the TV remote, never mind suspension settings. I'd end up with a million versions that were "different" without being able to decide which was better. I'm leaning towards whatever factory kit is available, with advice from experienced owners how to get the ride height down to acceptable levels.

Anyhow another job has overtaken this one for now - 2 out of the rad fans have packed in so a more pressing job for the summer.......!

Mark,

I you are going for the Lotac factory developed set, bringing Bilstein shocks and Eibach springs to your car, then it's are pretty tall, even if you ballast the car, loosen all relevant joints and tighten them from there.

There are a few things to do though.

1/ You can install standard wheels and tires.

2/ you can move the spring securing collar to it's lowest of two positions. That gives you 10mm.

3/ You could take a thorough look at the damper and maybe cut an extra recess to lower the collar an extra 10mm.

4/ the insulators on the spring tops, both front and rear are pretty high. They don't do anything for suspension, but are there to isolate the cabin from roadnoise and hinter vibration from roadsurface noise to the cabin. This can be all removed or better: install the Sport300 solution, which is a much flatter isolator. I have asked a dealer to fabricate a set for me in polyurethane and very flat, so I wil basically lower the car extra 10mm or so, as that is what lotus did to the Sport300 Esprit, while still retaining an isolation from road noise, and without altering the suspension setup, spring tension etc. as such.

All in all 20mm or 30mm lowering from standard if one so wishes.

Kind regards,

jacques

Nobody does it better - than Lotus ;)

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5 hours ago, Jacques said:

This can be all removed or better: install the Sport300 solution, which is a much flatter isolator.

Really I don't know where the guy who told you that read that but, in the parts manual it's the same part for the Sport 300 and S4 and S4s (at least at the front)

 

On 23/04/2017 at 19:07, Loose Cannon said:

I'd like original wherever possible, even if it isn't upgraded, but are those days gone now?

The LOTAC set (bilstein shocks and eibach spings) is available, and the bushes set seem available as well (from tls/shop for instance)

I can't comment on the ride height yet but should be able soon.

 

5 hours ago, Jacques said:

the insulators on the spring tops, both front and rear are pretty high. They don't do anything for suspension

I wouldn't be so sure about that. I don't know about the Esprit, but for today cars, the rubber cups are definitely taken into account when designing the spring. You should trust me on that one.

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10 hours ago, Herbert Harvey said:

I recently replaced my front shocks with a pair of the adjustable Protech's from SJ Sportscars.. (also replaced all the bushings with the OE rubber type)

Watched a video of how to set up the preload, a manufacture of some other brand explained that you lower the bottom collar to were the spring is basically loose and can be turned by hand.. Then tighten it so the collar raises the spring roughly the thickness of the spanner.. Just a smidgen of preload basically.. After doing this i have tried the dampner settings from the lowest setting all the way up to 9 or 10.. Car feels really rough and clanky on the streets around my house (which are shit by the way) car feels pretty amazing on the freeway.. but around town any pot hole makes the car feel like its gonna break apart! 

any advice on this would be helpful.. 

Since you replaced only the front, you now have a different spring rate between front and rear.  You also have a different wheel rate than you used to in the front.

Any difference in the balance front to rear can cause hopping, bouncing, porpoising, and make the ride uncomfortable.

You really should only replace all 4 at a time for that reason.

Lotus actually uses a LOT of pre-load on their springs. They take a very long progressive rate spring and smash it into a very small space.  After market coil overs usually have very short springs with very little pre-load (just enough to take up slack for when the suspension droops after bumps).

Alos, VERY Important!  You must not tighten any of the rubber suspension bushing bolts until the car is on the ground (or at ride height anyways).  The bolt pinches the bushing and then essentially locks it in that spot, so that any suspension movement also add torsion through the bushings. This can make the car feel as though it has asymmetry in the handling and ride height will be too high.

Travis

Vulcan Grey 89SE

 

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Reference checking the correct ride height, I found it very useful to machine up two round sections of bar of the correct lengths to use as gauges placed under the chassis. I used poly-acetyl, but any suitable material will do.

On the subject of insulators, I’m sure I saw somewhere that there are some for one of the Esprit’s made from aluminium. Not sure what use they’d be as insulators, but there you go.

Margate Exotics.

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And exactly that would have another influence on noise etc.

I had the Sport300 info from a Sport300 owner. As we know Lotus did cahnge many parts over production, for example the first Sport300 had old door handles and so on. So maybe it turns out that many variations came upon the isolators as well.

I am having a flat set in polyurethane made for my car. Lowers, isolates and lightens.

Kind regards,

jacques

Nobody does it better - than Lotus ;)

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The aluminium pieces referred to for use at the rear of Esprit may likely be spacers, in fact. From the earliest cars I believe Lotus used a spacer on one side rear for the sake of balancing ride height, particularly with LHD cars where the engine leans over onto the side where driver's weight is biased. Can't see any value in isolation by use of a metallic spacer, in any case.

Observations offered by Travis and Jacques are top-notch and I would advise anyone venturing into suspension tinkering for the first time to read and understand the points made. On damper settings, FWIW, the OEM Armstrongs removed from my S2 exhibit a great bias toward rebound restraint, the jounce rate being remarkably soft by comparison. Koni, always known for fine dampers, published a white paper in which they addressed the basic approach to setting dampers. As I recall the jounce damping is calibrated in terms of adequate restraint of the unsprung mass over uneven road surfaces, so damping the wheel/tyre motion when driven upwards by a sharp-ish impact. The rebound damping was to be set as best compromise between restraint of movement of sprung mass ( i.e. the rest of the car and contents ) versus rate of return motion of the wheel/tyre ( unsprung ) to pavement after the sharper, higher frequency impacts.

In summary, enough jounce damping to keep the upward wheel/tyre movement within reasonable limits of response to sharp bumps, and enough rebound damping to keep the overall vehicle from wallowing through the larger, lower frequency motions while maintaining roadholding over rough surfaces by not overly restraining the downward motion of wheel/tyre after a sharp bump. I await the inevitable onslaught of remedial technical instruction from our properly trained fellows, in serenity. 

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55 minutes ago, drdoom said:

Can't see any value in isolation by use of a metallic spacer, in any case.

Neither do I, it's just that, I believe, they started with a rubber isolator, and on the latest cars (V8 and possibly GT3 but I haven't checked!) they replaced it with an aluminium variant.

Do you happen to have an URL for that Koni white paper? That looks interesting :)

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Agree with @drdoom

Most single adjustable aftermarket shocks tend to adjust the rebound damping more so than the compression damping. That really isn't a good way to improve handling.  Too much rebound damping will lead to what's called "jacking down", where the suspension is compressed by a bump, and then the high amount of rebound damping prevents the wheel from returning back down to maintain tire contact with the ground. Not good for grip. It also then makes the compression damping totally incapable of absorbing the next bump. This results in a large weight shift, also not good.  it is best to use as little rebound damping as feasible, and work on compression damping (start from softest/least and work up). Then adjust rebound damping up (if a 2+ way adjustable damper).

The SE isolators were pretty thick rubber

front

MOdlSv-PFkM1WxAudCc1WYcN5ev_XH_dr3uilS_X

rear

RlIQ5PE6SVKJa-ofgAJoR3TESEDEdb1gz2FRPFAW

CUcHzmcWTyJBgxFL6c5S4UTfQNEluC2vDtHNDNdp

For my rear JRZ double adjustables I made some aluminum adapters to fit the 2.5" springs in the rear, and added some thin isolators from Energy Suspension

http://www.energysuspension.com/universal-products/coil-spring-isolators.html

9kM-cdQRcacCDL4jb6nusamaTrc7hkc9kppqs4PR

LX6J9KlEK-g5nmOw8sbJ5761Zv_oot64cnbPLiVQ

ElFbwEavThkmSJTXiEdqw_py6QnlNEuEoqQiRcTI

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Travis

Vulcan Grey 89SE

 

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17 hours ago, chris said:

For the front: it’s from the ground to the chassis rail. The chassis rail is what the anti roll bar is bolted to. I believe that most Esprits are 170mm.

If you are looking at the rear then it’s from the ground to the bottom of the U shaped chassis section. Again 170mm is standard.

if you are close to those measurements then it may be worthwhile posting a pic incase somethings not quite right.

I’m swapping out my front protechs this weekend so can take a few pics/measurements or check settings if it helps? 

It appears that 170mm in inches comes out to 6.69 inches.. took these pictures this morning, looks like my front end might be about a 1/2 inch too low.  Will most likely raise it this evening when its not so hot outside! you might notice I don't have my anti roll bar in at the moment.. Didn't want to install it until I am sure i am not taking the front shocks off again.

untitled-0593.jpg

untitled-0594.jpg

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Sort of a side question too this topic, I noticed the Spax coil overs i took off the front of my car have a bushing on the very bottom that attaches to the lower control arm, The Protech's I picked up from SJ Sportscars is simply metal, Yes there are the 2 brass spacers that go on each side to center the damper.. But is this not good? seems to me that little bushing has a purpose, why eliminate this?

IMG_0595.JPG

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Giniw, I looked through my folders and found nothing of the sort so no URL at this time. There is a printed excerpt from the Koni Racing manual on pages 205 - 206 of race engineer, Carroll Smith's fine book, "Engineer To Win" which covers the topic very well. Lotus was a race car company first and it seems that the superb street cars we play around with reflect the pertinent influences prominently. In plain language Lotus build a car with fine chassis characteristics typical of a better race car - sensitive and communicative steering, quick yet stable chassis behavior born of optimal distribution of masses coupled with deep understanding of suspension articulation effects.

Travis, you are correct in saying the single adjustable Konis largely afford adjustment in rebound, not much in bump ( jounce ). I've fitted them to quite a few cars over the years, including Elan and Esprit, and they have been lovely. Lotus turned out a fine handling car with the early Esprits, with dampers decidedly biased to rebound control. No doubt the ride benefitted substantially from the soft bump values, as well. It would seem that Koni Racing advise from a differing point of view, "Bump damping controls the unsprung weight of the vehicle. It controls the upward movement of the suspension as when hitting a bump on track. It should not be used to control the downward movement of the vehicle when it encounters dips. Also it should not be used to control either roll or bottoming.  ..."

I feel fairly confident to say that tinkering with suspension settings on a Lotus will be well informed by sound practices applicable to non-aero effect racecars. Carroll Smith's fine books, "Prepare to Win", "Tune To Win" and "Engineer To Win" are to be recommended.

Cheers

Chris, be mindful of hard pivots in place of rubber where complex suspension arcs may be anticipated. Race shocks would have spherical bearings to accommodate angular change while seeking to eliminate bushing deflection, so unless your dampers have some measure of angular compliance in those bushes I'd give the matter some further thought.

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25 minutes ago, drdoom said:

There is a printed excerpt from the Koni Racing manual on pages 205 - 206 of race engineer, Carroll Smith's fine book, "Engineer To Win" which covers the topic very well.

From the photo it looks like you are measuring the height from the ground to the wishbone, but I think it should be measured from the ground to the chassis rail (at least it's what you are quoting from @chris ^^)

 

25 minutes ago, drdoom said:

There is a printed excerpt from the Koni Racing manual on pages 205 - 206 of race engineer, Carroll Smith's fine book, "Engineer To Win" which covers the topic very well.

I had heard about "Tune to win" and it looks like a very good read indeed. Thanks for that second reference! (edit: and third one too)

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agreed drdoom.

To widen this very interesting subject a Little bit, to incorporate all the bushings under the car, they were originally made from a certain hardness of rubber, which can be all fine when new. Time, uv, heat, Cold, movement (squishing the rubber over and over), will change their charateristics to be different, and even to other dimensions, and unreliable, to a certain value decided in this case by Lotus. Therefore I really like their Lotac bushings, which are made for street driving, quick back road driving and the occasional track day, not being super hard (Black index) track formulation, while keeping their charateristics for much longer, being predictable. In my humble view, it's done to control movement (of the whole car) in a more predictable stable way make the movement of suspension and chassis under varying load do it's job without other factors counteracting it. This way the dampers and springs can do their job better, and have less walloping around of the Whole car. Regarding ball joints in arms from hub to chassis, I was told that this would be too tough on a streetcar, possibly leading to cracks in chassis, or at least stress. One end being bushed is okay'ish if one does not drive many road miles, but not both ends (upper rear arm) having ball joits. I therefore decided that for now, I'd stick with changing the upper rear arms to adjustable to keep the best angle on tire and Wheel using wider Wheels from the v8/Sport300, while combining that with Lotac poly bushes, in total offering more control. The spring isolators as I mentioned will be poly ones too. All in all I want suspension that talks to me about what's going on all the time and being predictable and repeatable (and on the very sporty side). Therefore I also got the Sport300 engine craddle brace and bridge plus the gear master cut out strenghening kit from a  Sport300. Loosing weight both in suspended parts and unsuspended parts is also part of what I do to the Esprit, amongst others to lessen the weightshift, but also lessen the heat buildup in suspension a bit. Btw. that would change the preload of weight in the car one have to do, before tightening everything up.

I did something similar to my golf earlier on, and I went much faster around corners on time trials on beginners autocross (hill climb - with very Little hills). The control of the car got better and more precise, less understeer, more controllable and communicates better. Therefore I did the same to my Corrado.

My next suspension in the Esprit should therefore also have at least variable dampening and rebound control. If I can stretch it, both slow and fast ditto, plus of course adjustable spring tension, height and maybe preload springs. I like the idea of lowering a car with flat isolators, rather than altering springs.

So far I have tried to control the rolling a bit by experimenting with 3 diferent front arb bushing hardnesses. I now prefer the hardest of the three.

I think Öhlins have managed to control ride well with a compliant ride and having very good Wheel control. When I installed these instead of marzocchis (and even Konis), I felt more secure in corners and especially in fast sweepers. They valve and polish the internals very well amongst other to minimize stiction and lessen the heat arising inside the damper. They can then lessen springs and rebound damping a bit. That can be felt.

Btw. thanks for the link Travis.

Kind regards,

jacques

Nobody does it better - than Lotus ;)

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