Uprated ARB possible ??

[tvr4ever]

My car has poly bushes, Koni race suspension (not the standard ones), Steve Heath droplinks and front and rear Anti Roll Bars. The bar at the rear was fitted when i bought the car, it didn't came standard. Whenever i do a trackday and people make actionshots of the car, it always amazes me how much bodyroll the car has. Despite the fact that i have done about everything to counter bodyroll, so i think. My question is, are there any thicker Anti Roll Bars that you can install ? Or maybe this bodyroll isn't that bad ?
Is this normal bodyroll http://us.a2.yahoofs.com/groups/g_2320617/51be/__s... ??

Fred

[Gerjo]

You just push it too hard, Fred !

Have you tried changing the damper rate?
I wouldn't know how mine looks in the corners, but yours doesn't look too bad in my opinion.

[Markh]

tvr4ever said:

My car has poly bushes, Koni race suspension (not the standard ones), Steve Heath droplinks and front and rear Anti Roll Bars. The bar at the rear was fitted when i bought the car, it didn't came standard. Whenever i do a trackday and people make actionshots of the car, it always amazes me how much bodyroll the car has. Despite the fact that i have done about everything to counter bodyroll, so i think. My question is, are there any thicker Anti Roll Bars that you can install ? Or maybe this bodyroll isn't that bad ?
Is this normal bodyroll http://us.a2.yahoofs.com/groups/g_2320617/51be/__s... ??

Fred

Steve Guglielmi does them I think

[steve-V8s]

Do you still have the original Anti Roll bar retaining bushes or are they solid as well. ? I found a fair reduction in roll by uping the spring rates. Not certain how the springs fit your dampers but on the Nitrons they are easy to change. As a starting point I put the front springs on the back and fitted 400lb ones on the front, this gave a 75lb rise all round. Just changing the damper rate probably won’t help, it will just delay the roll little longer, the actual amount will still be the same.

[350Matt]

Definitely go up on the front spring rate I replaced the std stuff ( about 270lbs/in I think) to 375 and its much better without being too harsh on the road

Matt

[tvr4ever]

steve-V8s said:

Do you still have the original Anti Roll bar retaining bushes or are they solid as well. ? I found a fair reduction in roll by uping the spring rates.

You mean the 2 bushes that are holding the bar to the chassis, the rubber ones right ? That's a good idea, the retaining bushes are still the original ones, maybe they are available in poly bush also. Another point to check out. About the springs, i must say i have no idea what rate they are, i will have a look and see if i can find any numbers on the springs. I know they are Eilbach springs, and that's about it.

[GreenV8S]

tvr4ever said:

steve-V8s said:

Do you still have the original Anti Roll bar retaining bushes or are they solid as well. ? I found a fair reduction in roll by uping the spring rates.

You mean the 2 bushes that are holding the bar to the chassis, the rubber ones right ? That's a good idea, the retaining bushes are still the original ones, maybe they are available in poly bush also. Another point to check out. About the springs, i must say i have no idea what rate they are, i will have a look and see if i can find any numbers on the springs. I know they are Eilbach springs, and that's about it.

I guess the Griffith ARB mounts are similar to the ones on the V8S, basically a steel / rubber sandwich. It looks squishy, but it's virtually rigid. I tried changing mine to a metal-on-metal fitting (absolutely solid) and it made no difference that I could tell. It's very definitely worth eliminating the rubber from the outer ends, but on mine at least not worth bothering with the inboard ones.

[tvr4ever]

[quote=GreenV8SIt's very definitely worth eliminating the rubber from the outer ends, but on mine at least not worth bothering with the inboard ones.
[/quote]
Peter, i have already installed Steve Heath his droplinks so the outer ends should be ok.

[red griff roger]

I am not an engineer, and happy to be shot down by all of you that are, but I can't visualise why poly (or solid) mounts would make much difference to the ARB? The force is down on one side and up on the other, to counter the roll. Don't the middle bits just hold it in place?

Bracing myself ...

[GreenV8S]

red griff roger said:

I am not an engineer, and happy to be shot down by all of you that are, but I can't visualise why poly (or solid) mounts would make much difference to the ARB? The force is down on one side and up on the other, to counter the roll. Don't the middle bits just hold it in place?

Bracing myself ...

The ARB has to be located in four places (two on the front suspension, two on the body) in order to resist roll. If any of those mounting points flex they will reduce the deflection on the ARB (for a given body roll angle) effectively softening it.

[spend]

I'm much in favour of stiffer spring rates, apart from roll you will also improve front/rear stability (particularly braking) remarkably. 450/375lb are still fine for road use (with Joos valved Nitrons anyway) and I would go up from that point not down if experimenting further.

Personally I would spend money on camber adjustable wishbones rather than ARB stuff, after stiffening up the springs.

Dave

[tvr4ever]

spend said:

I'm much in favour of stiffer spring rates, apart from roll you will also improve front/rear stability (particularly braking) remarkably. 450/375lb are still fine for road use (with Joos valved Nitrons anyway) and I would go up from that point not down if experimenting further.

Personally I would spend money on camber adjustable wishbones rather than ARB stuff, after stiffening up the springs.

Dave

Eeehhh, isn't the suspension on the Griffith camber adjustable ? I had my camber set to 1.5 deg negative last time i was at my alligment place.

[GreenV8S]

spend said:

450/375lb are still fine for road use

I'm on 600/400 (V8S suspension, so the effective leverage may not be identical especially at the rear!) and with some rather nice Nitron dampers that's tolerable for road use on smooth roads but borderline tbh - and I think it's too much for optimum grip on anything but the smoothest surfaces. To be fair the metal seat is bolted to the chassis and the dampers have rod end bearings so basically the only thing between me and the road is the tyre. In my mind this is as far as it is practical to go on the road springs. It handles like a go-kart compared to most road going TVRs but it still rolls far too much. New ARBs are on the shopping list, but nowhere near the top of the list at the moment.

[spend]

Right Fred said:

Eeehhh, isn't the suspension on the Griffith camber adjustable ? I had my camber set to 1.5 deg negative last time i was at my alligment place.

A good set of tubular wishbones (as well as being less flexible!) come with 'vernier' adjustment - the ability to dial in/out camber to suit is high on my list of upgrades Its far easier to experiment yourself to find what you like than rely on what someone else advises. From the rust/maintenance point of view all wishbones should be tubular in an ideal world IMHO

Dave
ETA damned quoting

Edited by spend on Thursday 15th November 17:49

[red griff roger]

GreenV8S said:

The ARB has to be located in four places (two on the front suspension, two on the body) in order to resist roll. If any of those mounting points flex they will reduce the deflection on the ARB (for a given body roll angle) effectively softening it.

Knew it. Should have held counsel till after the experts

[Ab Shocks]

Springs would be my favorite starting point, establishing what rates of Eibach you have on the car is not difficult because they are all stenciled onto the springs and then a shock revalve to suit what springs you decide on.

I'm very wary of Spend's suggestion on tubular wishbones for road cars because the existing design is made to crumple if you have an accident thus protecting the chassis and many of the expert TVR indies agree with me that more chassis damage would result from fitting stiffer wishbones if you whacked the car.

[spend]

Ab Shocks said:

I'm very wary of Spend's suggestion on tubular wishbones for road cars because the existing design is made to crumple if you have an accident thus protecting the chassis and many of the expert TVR indies agree with me that more chassis damage would result from fitting stiffer wishbones if you whacked the car.

Lower rears are tubular as standard? - it is the lower ones which would be under compression in most impacts I would have thought

Dave

[trackcar]

Your pic doesn't work for me so i can't see how far your car is rolling, but if you have sufficient camber compensation in roll I can't see that stiffenin it up would result in anything significant .. are you wanting something other than reduced roll? .. extra grip? more precision to steering inputs? or are you just worried that it's rolling "too much" ? ..

[tvr4ever]

trackcar said:

Your pic doesn't work for me so i can't see how far your car is rolling, but if you have sufficient camber compensation in roll I can't see that stiffenin it up would result in anything significant .. are you wanting something other than reduced roll? .. extra grip? more precision to steering inputs? or are you just worried that it's rolling "too much" ? ..

I'm certainly no Schumacher, so who am i to say this, but. When i look at the photo it seems like a fair ammount of bodyroll to me. You have loads more knowledge of these things than me, so i may be completely wrong and my car is doing just fine, i just wanna know for sure.
When you visit my own website http://home.planet.nl/~stege542/ and choose "Driften RDW 2007" on the left you should see the same photo, it's the third from the left. From my last trackday at Zolder i know i have a bit to much toe in on the fron, but that's going to be taken care off before the next one. So yes i would love more grip and an even more precise steering input, so any advice is welcome. Maybe next time i can not only keep up but overtake that Porsche GT3 on Zolder. (photos via the left menu option "VAB autohappening 2007", only some scenic shots no action shots of the TVR, Porsche battle)

[GreenV8S]

tvr4ever said:

i would love more grip and an even more precise steering input

If that's you trying to find grip you don't need less roll, you need less slip angle! That body roll doesn't look excessive to me tbh.