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Stiffening the ARB - Suspension/Brakes/Wheels/Hubs/Steering/Geo - The Lotus Forums #ForTheOwners Jump to content


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As some of you may know I find the front end roll on my 88 Stevens a little excessive. First my thanks to the kind gentleman at Lotus who noted my prior thread and made some recommendations to solve the issue.

(I think it's great when you own a 20 year old car and factory is still coming forward with help and advice)

The suggestion was to try the poly mounts from the sport 350, fitting might be "interesting" but once on should give an increase in roll resistance. I ordered these from SJ ( Steve wisely pointed out that these were incorrect for my car, a sort of be it on your own head warning)

They've been sitting in the garage for some time waiting for the all clear from the doc for me to fit them, so today was the day.

DSC_0008.jpg

Using my new (hand made) mobile work bench !

Fortuitously, these bushes are seemed so open up "C" section meaning I did not have to remove the bar.

DSC_0009.jpg

I have at the moment, as you can see, simply pushed the original rubber bushes to the centre, so that if I get horrendous under-steer, I can remove the new ones and simply slide the originals back into position.

But if they give me the desired effect ie, not pitching as much weight onto the front outside wheel on corner entry, I can then simply take a Stanley knife to the old ones.

Haven't driven it yet :smoke:

Life is like a sewer, what you get out of it, depends on what you put into it. (Tom Leahrer)

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17.25mm, those bushes are 16.something mm ID but as you can see it's do-able.

Incidentally that 17.25 bar don't arf hav some torsional stiffness, I was under it this morning reflecting that I'm complaining it's not stiff enough. :shock:

I'll report back after I road test it.

Life is like a sewer, what you get out of it, depends on what you put into it. (Tom Leahrer)

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Initial road test complete, not the full monty, but enough to give me a good indication.

First off, handling is a personal thing, some like understeer, some like oversteer, and others neutral. I like neutral with a tendency to oversteer, whilst not the quickest way to drive a modern Formula 1 car, it's nice to have something in common with the likes of Niki Lauder.

Exiting the driveway at an angle I could immediately feel an increase in stiffness, after that, in suburban conditions, absolutely no change. At higher speeds no increased tendency to understeer, so far so good.

High speed corners, markedly less roll, which makes me (personally) more comfortable. Now high speed entry, with trial braking, (braking as I turn in) wow, success, sits down with very little roll turns in with absolute precision, again no tendency to understeer (wouldn't want to if your on the brakes) but the best bit is the transition, to throttle, before the inside rear wheel could just start to brake traction, now that is gone the transition is much improved the car seems to be doing less work, moving less transferring it's weight front to rear in a more controlled manner.

I'm stocked that for under 20 quid I can get the result I was looking for, my thanks to Andy Graham, who spied my first post on this topic whilst on holiday and subsequently pointed me in this direction.

Finally I'll emphasise handling is a personal issue, this won't suite everybody, I do like exceptional roll resistance, but also be aware that the stiffer the front end roll the greater the risk of locking an inside front wheel.

None the less, I am really happy with this result. :thumbsup::animier::w00t::D:)

Life is like a sewer, what you get out of it, depends on what you put into it. (Tom Leahrer)

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Hi Roger.

Good job, you mentioned the bushes were from SJ's are they part number SJ082C0012 ? The ones he sent me were purple like yours just wondered if they were the same ones.

Too many Toys are never enough !

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These are a direct replacement (or so I'm told) for LOTAC05446, but manufactured in poly which was originally for the S350. As such the ID is smaller than the bar on our cars.

Steve was very reticent to supply them, but I had little trouble fitting them,

Update !

For reasons I have yet to analyse, on downhill corners, where the car used to have a tendency to understeer, that has now gone, so the car just seems flatter and more responsive to steering.

Life is like a sewer, what you get out of it, depends on what you put into it. (Tom Leahrer)

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The standard V8 front ARB is 16mm, the S350 is 17mm. I had the cambelts done at the factory a while back and asked them to also fit the S350 ARB at the same time. However, I didn't realise the S350 ARB-chassis bushes are PU. My bushes are black, PU is usually some bright colour (yellow, red, blue). I can't see how they could have reused the standard ARB rubber bushes due to the larger diameter.

Did the factory say the the standard S350 ARB bushes are PU, or is it just SJ's aftermarket ones?

May: DON'T hit it with a hammer!

Clarkson: Why?

May: Cause it's the tool of a pikey.

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"my understanding" part number LOTAC05446, is the standard rubber mounting bush for the 350s ARB. Lotus did later produce a poly version but these were never fitted as standard equipment.

Life is like a sewer, what you get out of it, depends on what you put into it. (Tom Leahrer)

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  • 3 weeks later...

Thank you for posting this great idea.

Urhetane comes in two flavours:

a) graphite impregnated (black in colour) and

b) blue, red which does not contain graphite

The latter will eventually wear down unless fitted with a Zerk fitting

I'll try to fit one of the kits from http://www.suspensio....b.bushings.htm

Roger,

How wide and deep is the mounting bracket?

ALSO: Did anyone attempt to fit 19mm bar? It must be x-reffed to some pre-existing part.

Honda Civic has 19mm adjustable rear sway bar or may be some van part can be adapted(because Lotus width)?

http://www.hellwigproducts.com/products/street-performance/solid-sway-bars/

Edited by MrDangerUS
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Different materials will produce different distortion rates, so it was easy to go with what the factory had experience of, eliminating guess work. It's all too easy to end up chasing your tail with handling, so go with with known entities where possible.

With the diameter of the bar the problem becomes the mount into the wishbone. For me to change the bar would mean removing it and having measured for torsional deflection and then guessing how much to increase it by (best guess would be 12-12%) have a new one made, about $400,-$800 if I guess wrong, so $40 for bushes the factory had already tried with success was a no brainer.

For my driving style I felt the Esprit proportioned too much weight onto the outside front wheel on corner entry, which I didn't like, it also gave a less comfortable transition to power on. It is surprising how a such a small and inexpensive part can make, the car has markedly less body roll and puts it's power down better, as well as making it's driver feel much more comfortable.

Again my thanks to the factory.

Life is like a sewer, what you get out of it, depends on what you put into it. (Tom Leahrer)

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How old were the original bushes?

I'm only asking because if they were old then I'd be interested to discover how much of the improvement is due to the difference in design, and how much to the fact that they are new as compared to the originals, if you see what I mean?

Regards

Mat

post-1-0302470001278592957.jpg

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2 years, or 6000 miles. I replaced them when I changed all the original bushes to poly, but was not aware the ARB ones were available in poly. Also the ARB to wishbone ones are about 12 months old.

Life is like a sewer, what you get out of it, depends on what you put into it. (Tom Leahrer)

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  • 1 month later...

Well I'm almost embarrassed to admit that today was the first real opportunity to do some spirited riving, since the upgrade.

I had to go to a meeting south of Coffs Harbour, all free-way now. But on my return I elected to use the old road. Not really on the limit stuff (I'll get there) but certainly high speed, fast sweeping curves with good vision. I was moving but had the air con on and Cecilia on the stereo, the car was fabulous, no role, no understeer, no oversteer, no sudden weight transfer, just doing what a Lotus should. Just come to a corner, maybe just a light brush of the brakes with the left foot to settle it and turn, it just goes round, almost boring really.

I'm really pleased, I seem to have fine tuned into a really responsive car doing just want I want it to. The gear change is a vast improvement, the steering is direct without oversteer, the brakes are a little spongy but I have a kit on it's way.

What's next :devil: I'm bored now.

Life is like a sewer, what you get out of it, depends on what you put into it. (Tom Leahrer)

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Maybe you can change that cambelt next, then a new clutch later in the year. Also try out that water injection you were talking about and then maybe a brake upgrade ? After that have a glass of wine and wait for something to break. :wine: ( just an excuse to use the smiley )

How about building a kit car ?

Too many Toys are never enough !

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Maybe you should put the wing back on and do a comparative analysis.... :hrhr:

Funny you should mention that, I was reflecting on that very thing.

When I first had the car the PO had had the wing put on the car, He claimed it improved high speed stability, whilst I have my doubts, it certainly needed some high speed stability, in fact I would categorise it as bloody scary ! My first high speed run revealed a nasty tendency for it snap to over steer the moment you came off the throttle on corner entry. The was no transition it was just BANG did not give me any confidence at all, partially this was due to very little remaining in the way of bushes, some well past it shocks, etc. if the wing was aiding high speed stability it was keeping secret from me. Simply there was no control over weight transfer, I would describe it's handling as ugly. I did the front bushes first, no actually I think the wing came off first, the front gave me more confidence, but I did not change the ARB bushes (make a note) I then re-bushed the rear with new link pins, again an improvement. Then bit the bullet and replaced the shocks, I wanted adjustable ones as I feel capable of adjusting these and getting the right result, and so it proved, despite some adverse remarks I have found the Protech shock well up to the task, as certainly good value for money. MY thanks to Steve at SJ who urged me to change the ARB bushes in the lower wishbones in the first place I should have listened to him then because this also yielded an improvement.

This had all been over the course of a year to 18 months, and I was quite happy until another high speed run late last year, when some DH in a Porsche thought he could outrun me, he didn't, but it revealed too much body roll on corner entry, not sever but something I though I could improve on. In step Brian Angus who saw my original thread about stiffening the front, I was able to learn that there were some ploy bushed for the ARB mounts to the chassis, a bit of a tight fit but worth a go. Eventually I got these in the car, and they gave me just the edge I was looking for.

All on all there are no great variations on my car from original, but here's the thing, if you regard the tyre as a part of the suspension dynamic, and I very much do, and you accept that tyre technology has moved on in 20 years, then by virtue of running modern rubber the dynamic changes.

I really think most of what I have done is to match the suspension to the modern tyre. OK, I don't like under-steer, so I've balanced that out which as a trail braker is not hard.

The difference between the first run (with wing) and no bears no comparison, come to bend, turn wheel, go round. :thumbsup:

Stone motherless neutral, with a slight tendency to over-steer, just the way I like it.

So will the wing go back on, since even the factory admits it's cosmetic only, and I don't like the look of it, guess.

Life is like a sewer, what you get out of it, depends on what you put into it. (Tom Leahrer)

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  • 1 month later...

A little bit of an update for this thread; The Lotus polyurethane anti-roll bar to chassis mount bushes are orange in colour. Lotus have confirmed that the same bush is used for both the 16mm and 17mm bars. The part number is LOTAC05456 for a kit of two bushes (Polybush part no. 29D).

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  • 3 months later...

A real road test.

Well it's only been 6 months, but today I had a chance to really test it out, 3 Esprits, out on a run (I got there first) I can now run at the corner if I get there a bit too quick I can brake it down right into the apex, immediate transition to throttle, watch the bumps for braking traction, on the way out. I can "pop" the clutch on a down turn, to step the tail out just a smidge to help turn in, it's fabulous, in fact very similar characteristics to my old Elan. An absolute joy to drive, I can get to do exactly what I want, the comparison now is it just sits flat into the corner, even when loading up the brakes

The run was up the mountain range, coming back down I may have got the brakes a little hot, but that's another story.

Life is like a sewer, what you get out of it, depends on what you put into it. (Tom Leahrer)

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  • 6 months later...

A little bit of an update for this thread; The Lotus polyurethane anti-roll bar to chassis mount bushes are orange in colour. Lotus have confirmed that the same bush is used for both the 16mm and 17mm bars. The part number is LOTAC05456 for a kit of two bushes (Polybush part no. 29D).

So far as I've been able to find out, there are actually two sets for the ARB poly bushes:

(29D) LOTAC 05456 - (I believe this set is for post MY98 V8 and GT3)

(29E) LOTAC 05455 - (I believe this set is for pre MY97 all cars)

I'm not exactly certain if that distinction is correct, and am trying to find out for sure what the difference is.

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Don't supose you have an ilustration ? I susspect this is for the later model whishbone.

I'd love to think there was a poly alternative for my 88 Stevens, but there again I saw 8 tons on the press before the rubber one popped, so poly would be sacary to fit. :shock:

Life is like a sewer, what you get out of it, depends on what you put into it. (Tom Leahrer)

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  • 1 month later...

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