Anti-Roll Control

[NickOrangeTVR]

Anyone got any experience of these guys http://en.intraxracing.nl/

They make shock absorbers - but importantly they claim to be able to control roll (see http://en.intraxracing.nl/techniek/arc%C2%AE-(anti...)

Now for anyone who does track days with a Chim will tell you even with hard springs roll is still a problem and given the old school suspension geometry any roll means less traction + stability, so having suspension to help solve this would be great, if it can be believed.

[ukdj]

I know the Ultima boys use their shocks, so maybe worth poking your nose over the fence and asking around

Regards

UKDJ

[900T-R]

I'll let you know how we get on

[Bluebottle]

they are fitted to a friends car, and I was very impressed with them, every bit as good as my NTR 3 way's.
But very expensive for mono 2 way adjustables.

[ChilliWhizz]

NickOrangeTVR said:

Now for anyone who does track days with a Chim will tell you even with hard springs roll is still a problem and given the old school suspension geometry any roll means less traction + stability,

Nick, have you guys looked at modifying the standard front and rear ARB set up? Think I read somewhere that Sportmotive's new evo chassis has addressed the ARB issue in some way...

Anyone out there put extended ARB's on??? I would of thought that if designed correctly ARB's that connect to the wishbones further outboard would be a big step forward in reducing roll....

I can see it now.... Transform your Chim's handling with the all new patented ChilliWhizz ARB kit, only ££££££££££ for a complete kit with full fitting instructions

And in other news, ChilliWhizz has retired from working offshore and has just purchased his third Sagaris, a blue one to sit next next to the red and white one's in his newly built centrally heated garage with wet room and bar......

[450Nick]

NickOrangeTVR said:

Anyone got any experience of these guys http://en.intraxracing.nl/

They make shock absorbers - but importantly they claim to be able to control roll (see http://en.intraxracing.nl/techniek/arc%C2%AE-(anti...)

Now for anyone who does track days with a Chim will tell you even with hard springs roll is still a problem and given the old school suspension geometry any roll means less traction + stability, so having suspension to help solve this would be great, if it can be believed.

Hey Nick,

I did a bit of research into this a few years ago after my car was rolling excessively at Snett on a set of new Nitrons with uprated springs, despite the dampers being wound right up to try and cure it. The first thing I found out was that this roll was nothing to do with the dampers; it was the ride height that was set too low. This has a profound effect on roll, as it alters the geometry of the ARB such that it takes far more roll of the vehicle before it actually starts to do anything. Sure enough, I had the car raised to normal ride height and the roll really backed off.

Pic for reference (not my car!)



So firstly the car needs to be at correct ride height for the ARB to work, unless you change the geometry of the ARB its self to sit lower to match the ride height you've set.

The next thing is the stiffness of the ARB its self; the standard one is pretty flimsey - I saw a few years ago that someone (Neil Garner maybe?) had a few thicker/stiffer than standard ones made up. These supposedly really helped with roll control. I would really like one, but have never got around to researching where to have one designed or made - perhaps your dad could help??

This will have a limit to how much it can help though as the next weak point is the chassis its self; specifically the square immediately behind the engine. This is the weakest point of the chassis due to its lack of torsional rigidity as the engine gets in the way of any brace points - this is the same on Tuscan race cars, and is very hard to cure. Ideally you want some triangulation such as this:



Though this is rather difficult to package. I've tried to do this on my Tuscan Challenge car and there simply isn't room with exhausts, engine, oil tank, windscreen etc.. So on a road car it would be even harder. You can look at things such as a roll cage, a stiffer body, a different engine used as a strength member, closing plates between the chassis tubes, but they start to get both expensive and complicated. The best/easiest solution would probably be to be to go to an upgraded chassis such as this one from Sportmotive:

http://www.sportmotive.com/evochassis.html

But even that doesn't have proper triangulation behind the engine - this is an inherent design flaw of using this kind of chassis.

So there are quite a few bigger contributors to body roll on a TVR which I doubt a clever set of dampers will cure as they are only a small part of the problem. Spring/damper wise, unless you have hours and hours of track time and a race engineer to very carefully tune the various settings on the damper, together with trial and error testing with spring rates, you won't really notice much difference against something like a single way Nitron or other good quality all in one damper. The better the damper the better the bump control (removing pogoing or crashing over bumps), but roll control is much more down to the ARB & chassis stiffness - I'd invest there to get more from the car..

Edited by 450Nick on Thursday 27th March 15:47

[900T-R]

450Nick said:

The next thing is the stiffness of the ARB its self; the standard one is pretty flimsey - I saw a few years ago that someone (Neil Garner maybe?) had a few thicker/stiffer than standard ones made up. These supposedly really helped with roll control. I would really like one, but have never got around to researching where to have one designed or made - perhaps your dad could help??

Thing is, in principle you really don't want an anti-roll bar at all as all it does is transfer load from the lightly loaded inner wheel to the other one that already is taking the brunt of the cornering load. In extremis, this leads to the inner wheel lifting in corners.

Now if you could control roll, pitch and dive through the dampers - either by interconnecting dampers on one axle (Tenneco/McLaren) or discriminating between high-speed movements (wheel control) and low-speed events (pitch, roll, squat and dive) you can soften spring and ARB rates, and possibly do away with the latter entirely... Think of ARC as a 'high end' version of Koni's FSD system and you'll probably not be far off - and there's no reason why it should work less good than electronic 'semi active' options (Henk Thuis of Intrax reckons ECU-controlled stiffening or softening of the damping rate always comes just after the event...).

[Bluebottle]

450Nick said:

The next thing is the stiffness of the ARB its self; the standard one is pretty flimsey - I saw a few years ago that someone (Neil Garner maybe?) had a few thicker/stiffer than standard ones made up. These supposedly really helped with roll control. I would really like one, but have never got around to researching where to have one designed or made - perhaps your dad could help??

Hi ya Nick :wavy: TVR used to sell an upgrade option which was 25mm diameter ARB's iirc. Andy Race had them on his old Griff.
Willow Sportcars are using me as a guinea pig to develop uprated arb and drop links for St8's race car so may be worth while giving them a call if you are still looking to upgrade yours.

[spitfire4v8]

I don't understand how a damper can control roll, it can only control the rate in time at which that roll angle is reached. Have they actually built something that the likes of ohlins and penske can't or is it purely marketing ?

[NickOrangeTVR]

Already have upgraded ARB and we run at original recommended ride height as we are very aware of the Chim only handles when it rides at that height.

Putting in a bigger ARB would require modifications I don't want to do (as a note we ARE doing that in the Cerbera rebuild) - so I was interested in these shocks as a easy 'fix' - but nobody has explained how they understand the difference between bumps + roll.

[450Nick]

NickOrangeTVR said:

Already have upgraded ARB and we run at original recommended ride height as we are very aware of the Chim only handles when it rides at that height.

Putting in a bigger ARB would require modifications I don't want to do (as a note we ARE doing that in the Cerbera rebuild) - so I was interested in these shocks as a easy 'fix' - but nobody has explained how they understand the difference between bumps + roll.

Its just clever valving I think, some of the race Tuscans used to run special Nitron 4 way dampers which did a similar thing only the other way around; they let the damper release in the event of sudden movement (kerbs), so you could hit a kerb at full pelt without breaking the suspension/chassis. I guess this is just the other way round so it stiffens under slow speed travel. The thing is though, my car even with the dampers turned up to full stiffness will still roll, the damper is only a small percent of the roll movement on TVRs. These are for cars where the roll movement comes from soft springs/dampers, while the rest of the car is stiff I think..

Even a Tuscan with 1000+lbs springs will lift a wheel clean in the air through chassis twist, and they have stronger chassis to start with!

[450Nick]

Bluebottle said:

Hi ya Nick :wavy: TVR used to sell an upgrade option which was 25mm diameter ARB's iirc. Andy Race had them on his old Griff.
Willow Sportcars are using me as a guinea pig to develop uprated arb and drop links for St8's race car so may be worth while giving them a call if you are still looking to upgrade yours.

Ooh that sounds great! I may well give them a call, thanks Hamish! Might actually drive my car this too!

[SILICONEKID346HP]

What did TVR do to get the Tamora to handle so well ? could it be replicated for the Chimaera ,watch the video ,I don`1 think you could drive the Chimaera that way .

http://www.youtube.com/watch?v=sJrP8Pg2xTQ

Edited by SILICONEKID346HP on Thursday 27th March 20:32

[Bluebottle]

SILICONEKID346HP said:

What did TVR do to get the Tamora to handle so well ? could it be replicated for the Chimaera ,watch the video ,I don`1 think you could drive the Chimaera that way .

http://www.youtube.com/watch?v=sJrP8Pg2xTQ

just disconnect the rear ARB...power drift all day long ...mind you I trashed a brand new rear set of trip 8's when I broke an arb mount half way thru a trackday but was pretty cool power drifting tho

[spitfire4v8]

450Nick said:

Its just clever valving I think, some of the race Tuscans used to run special Nitron 4 way dampers which did a similar thing only the other way around; they let the damper release in the event of sudden movement (kerbs), so you could hit a kerb at full pelt without breaking the suspension/chassis. I guess this is just the other way round so it stiffens under slow speed travel. The thing is though, my car even with the dampers turned up to full stiffness will still roll, the damper is only a small percent of the roll movement on TVRs. These are for cars where the roll movement comes from soft springs/dampers, while the rest of the car is stiff I think..

Even a Tuscan with 1000+lbs springs will lift a wheel clean in the air through chassis twist, and they have stronger chassis to start with!

I've seen this written so many times it's going to become gospel.
It's not chassis twist that causes the wheel to lift, if the chassis was floppy then all four wheels would stay on the ground. think about it, and think about the old analogy of the box with no lid - then put a lid on it to make it stiff. the floppy box will deform so that all four wheels remain on the ground during cornering forces, it's the stiff box that will cause a wheel to lift if one end is stiff in roll and the other soft in roll.
it's because the chassis is stiff, the front end is stiffly sprung/high roll stiffness, and the rear is softly sprung / low roll stiffness that they wag a wheel in the air.
If the chassis was flexible enough to allow for several inches of movement you'd be welding fractures in the tubing every time the car went out or it would simply fold up at the first glimpse of a race circuit kerbing ...

Edited by spitfire4v8 on Friday 28th March 06:29