Lotus Elan

Reduce the roll

PostPost by: Bienfu » Tue Nov 17, 2020 6:44 pm

Hi,

I have a question about shock absorbers.
My Elan was fitted in 2009 with Koni sport special for fast road at the rear. And at the front there are TTR + fast road springs shocks fitted in 2009.
I find the ones fitted a bit soft, even with the maximum stiffness settings, maybe due to age, so, in fast corner, my Elan roll too much for me. :?
I contacted TTR and the rear Koni sports specials for fast road are the same as back in 2009, and the front fast road springs have become slightly stiffer, the shock absorbers have been upgraded with upgraded oils etc.
I planned to change all my shock absorber and springs, and for the rear, there is two choice in Koni : fast road and for Race/Rally/Hillclimb/track days.
Anyone tried the Race/Rally/Hillclimb/track days ? Does it increase the stiffness too much for a road car ?

https://www.tonythompsonracing.co.uk/parts/models/elan-s1/rear-ttr-koni-sport-for-race-rally-hiilclimb-track-days-pair/

Thanks
Last edited by Bienfu on Wed Nov 18, 2020 7:05 pm, edited 1 time in total.
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PostPost by: 1owner69Elan » Tue Nov 17, 2020 9:42 pm

Are you running a stock anti-roll bar (ARB)?

If so, you might consider a stiffer one to reduce roll.

My Elan with a 1” tubular ARB has much reduced roll. Also, with neutral handling and excellent control. I do have TTR fast road shocks and springs as well and wide sticky tires (185/60)

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PostPost by: rgh0 » Tue Nov 17, 2020 11:48 pm

I agree the first thing to try if not already done is a stiffer than standard from roll bar , I would try a 7/8 inch solid bar or 1 inch tubular bar which depending on the tube used will be about the same stiffness. I would also try reducing the gap between the shocks and Aeon rubber springs at the rear with spacers.

After that I would work on the spring rate from and rear depending on your intended use and finally think about shock changes if needed.

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PostPost by: Bienfu » Wed Nov 18, 2020 12:04 pm

I don't know for my anti roll bar, I will check this.
Also, I think that my elan does not have Aeon rubber springs, but others bump stop because my springs are in 2.25", and there is no spacers.
I planned to change shock and springs in any case, due to age and oil leak problem at the rear. But maybe the road rear Koni from TTR will be enough for me, if my Elan has stock anti roll bar.
I only use my elan on the road, and a lot in mountain roads, with 165/70/13 tyres fitted on original wheels. But tyres are not the problem at the moment, only the roll.
Many thanks for your advices. ;)
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PostPost by: Craven » Wed Nov 18, 2020 1:38 pm

Would new shocks with adjustable Bound AND Rebound adjustment be beneficial?
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PostPost by: nmauduit » Wed Nov 18, 2020 2:17 pm

Bienfu wrote:I don't know for my anti roll bar, I will check this.
Also, I think that my elan does not have Aeon rubber springs, but others bump stop because my springs are in 2.25", and there is no spacers.
I planned to change shock and springs in any case, due to age and oil leak problem at the rear. But maybe the road rear Koni from TTR will be enough for me, if my Elan has stock anti roll bar.
I only use my elan on the road, and a lot in mountain roads, with 165/70/13 tyres fitted on original wheels. But tyres are not the problem at the moment, only the roll.
Many thanks for your advices. ;)


if the roll is the problem , anti roll bar should be the first point to check (easiest, too...)

I had the hollow 1" ARB and it worked very well for me on track days (165 lb/ft front 120 lb/ft rear standard red Konis 1 click above the minimum) on Yokohama A048 - since that anti roll bar broke I have tne next size under as a replacement (1" was out of stock then), supposedly for the wet, but it's still quite good on the dry (only tried it an hour or so).

For road use (or even track days, up to moderately competitive participation) I would not see the need to have 2 way adjustable race shocks. But knowing the spring rates front and rear (and beig able to perform a corner weight adjustment) would help figuring out where you stand and where to go to tune the chassis.

PS: the Aeon (or beige VW replacement cut off at the proper length) are important and should not be missing (or replaced with something of either null or enormous spring rate).
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PostPost by: Bienfu » Wed Nov 18, 2020 7:28 pm

I checked my anti-roll bar, and it seems to be a standard. 17.8mm (0.7")
A front 1" tubular anti-roll bar like this can be a good idea? No problem with a spyder chassis?
https://kelvedonlotus.co.uk/product/front-tubular-anti-roll-bar-1-inch/

Here is an old picture of my rear suspension. Bump stop does not seems to be Aeon standard, but more short, right?
DSC04163.JPG and


Not sure Aeon will fit in 2.25" springs. Do I need to put some thing like this ?:
https://kelvedonlotus.co.uk/product/progressive-bump-stop/

And to reduce the gap, any idea where and what I can buy something?

ps: I just renamed the topic. Now it's definitely not only a question about shock absorber :D
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PostPost by: nmauduit » Wed Nov 18, 2020 8:04 pm

The 1" hollow arb was what I had and was very pleased with it (I now have 22mm instead of 25mm, as Kelvedon did not have the 25mm in stock this summer)

The yellowish Aeon replacement would fit and do just fine, I have cut off the 3 smaller sections on my car (leaving only 4 larger ones)

as you already have the adjustable plateforms, I would recommend spending time adjusting that well, and the geometry (toe in) also, then with good tires the car should be exhilarating (make sure there is no play in the suspension rubber bushings steering etc). Last step before late braking in a crowd would be to minimize bump steer, but you should be able to try out and enjoy the car first.

keep it on the road !
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PostPost by: 1owner69Elan » Wed Nov 18, 2020 11:19 pm

You can adjust the distance of when the bump stop (really a secondary spring) engages by using "strut packers". Discussed in an earlier thread.

On my car, I used the cutdown Kelvedon bump stops. I think these are actually much stiffer than the Aeon springs and have reserved for a later project to replace these with something with a spring constant closer to the Aeon's to provide a less abrupt transition when the bump stop is engaged.

I further decreased the bump travel before engagement by using spacers ("strut packers") that I can insert and fine tune without having to remove the rear unit and spring. They can be readily slipped on the Koni shaft, in situ, just above the white plastic spacer at the bottom. They clip on the shaft and no further fixing is needed. Much more convenient and allows for easy modification by stacking them to any desired dimension.
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PostPost by: Bienfu » Thu Nov 19, 2020 9:55 am

Many thanks for all your advices.
1owner69Elan wrote:On my car, I used the cutdown Kelvedon bump stops. I think these are actually much stiffer than the Aeon springs and have reserved for a later project to replace these with something with a spring constant closer to the Aeon's to provide a less abrupt transition when the bump stop is engaged.

Do you have any idea for the replacement of the Kelvedon bump stop?
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PostPost by: nmauduit » Thu Nov 19, 2020 10:59 am

Bienfu wrote:Do you have any idea for the replacement of the Kelvedon bump stop?


I think that a "fast road" car does actually need stiffer Aeon than the original ones to keep the whole setup homogeneous (as well as stiffer shocks, which is why I've clicked up my red Konis 1 notch, so that the damping frequency increases and tends to match the stiffer springs otherwise you tend to get into the oscillation regime).

In that situation (stiffer springs and shocks) the travel would typically be less than with a stock setup, which would call for less use of the "travel limiter"/secondary springs that are Aeon/yellow foam replacement, so rather than increasing their length I would rather decrease it and stay within the linear range more (i.e. without using the secondary spring), them becoming more of a bump stop in effect. These yellow foam limiters are easy to cut and shape to your need, you may use the thin section if you deem it more appropriate for your use (say moderately stiffer springs/shocks) or liking (only trouble is to have to take out and apart the combos).
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PostPost by: ecamiel » Thu Nov 19, 2020 7:27 pm

Rear bump stops, which are actually auxillary springs, cause a rising spring rate when they engage resulting in higher rate spring in the rear, This increases overstear which can be sudden in a bumpy corner leading to real problems and is also very slow. They have no place on a track if proper springs are an option.
Dave Bean full comp springs (220 - 160 ???) keep the shocks from bottoming out and 1/2 inch bump stops prevent damage over big bumps. Try it and you will never go back.
PS I find those springs surprisingly work fine on the street if you eliminate "sticktion" in the suspension..
On the street the Aeon rubber springs help to allow the long travel, soft suspension that the Elan is famous for.
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PostPost by: rgh0 » Thu Nov 19, 2020 7:52 pm

ecamiel wrote:Rear bump stops, which are actually auxillary springs, cause a rising spring rate when they engage resulting in higher rate spring in the rear, This increases overstear which can be sudden in a bumpy corner leading to real problems and is also very slow. They have no place on a track if proper springs are an option.
Dave Bean full comp springs (220 - 160 ???) keep the shocks from bottoming out and 1/2 inch bump stops prevent damage over big bumps. Try it and you will never go back.
PS I find those springs surprisingly work fine on the street if you eliminate "sticktion" in the suspension..
On the street the Aeon rubber springs help to allow the long travel, soft suspension that the Elan is famous for.
Eric
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While the statement above are directionally correct the effects I personally believe are more subtle and there is a place for the use of rising rate springs using the Aeons at the rear on the track with the right combinations of other springs and roll bars. If your building a roller skate with TTR recommended levels of suspension stiffness then at that point maybe the aeons or other rubber rear springs can be dispensed with but at that point you may want a rear roll bar also and it will all be a handful in the wet. On the road you certainly need them if youre other springs are anywhere near standard rates

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PostPost by: Evante » Fri Nov 20, 2020 10:15 pm

Eric,

Sorry for my naivete but could you please define "sticktion?"

Thanks,

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PostPost by: el-saturn » Sat Nov 21, 2020 9:56 am

i also have the ttr complete fast road/race set (all black konis) A N D a 1inch tubular rollbar - much more BITE at the front - a great improvement. tyres: yoko a539 175 60 13: these are sticky enough to do about 3000miles; so they´re pretty close to the semi slicks and no comparison to the common and useless 145, 155, 165 mm of rubber (if you could find 100mm cross-section, some´d probably use em!!) sandy
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