Tuscan 2 Suspension
Discussion
Hi,
I've strayed over from the S forum with a quick Tuscan question for the wise and knowledgable amongst you.
General perceived wisdom seems to be that the Tuscan 2 got significantly revised suspension/steering from the Tuscan 1 setup. My question is, does anyone know the details of what the changes actually were, and how much difference they made to the handling, stability, steering etc?
Secondly, how easy might it be to modify a Tuscan 1 to Tuscan 2 suspension specs? (You may be able to guess where I'm coming from now...)
Thanks!
I've strayed over from the S forum with a quick Tuscan question for the wise and knowledgable amongst you.
General perceived wisdom seems to be that the Tuscan 2 got significantly revised suspension/steering from the Tuscan 1 setup. My question is, does anyone know the details of what the changes actually were, and how much difference they made to the handling, stability, steering etc?
Secondly, how easy might it be to modify a Tuscan 1 to Tuscan 2 suspension specs? (You may be able to guess where I'm coming from now...)
Thanks!
Not 100% sure but they got revised spring/damper rates (although Nitrons are still better), and slightly modified front uprights and upper wishbones. Exactly what those changes altered in terms of overall suspension geometry I'm not sure. The Mk2 also has a slower steering rack which possibly also has a different mounting height.
In theory it's possible to fit the later suspension components as they're all pretty much interchangable. Whether it will make a noticable difference I don't know? Give it a try and let us know!
In theory it's possible to fit the later suspension components as they're all pretty much interchangable. Whether it will make a noticable difference I don't know? Give it a try and let us know!
Thanks for the replies. Looking at the links to other posts it sounds like:
Std car has very low scrub radius (steer axis intersects the ground at the centre of the tyre) - this is a problem because variations in road camber cause the centre of pressure of the tyre to move laterally across the tread and gives torque reversals - difficult to control.
Low castor - this gives less self centring torque and less damping of any steer oscillation. Increasing castor will also increase toe-out compliance under cornering forces (an understeer characteristic, reduces steering sensitivity)
Raising the steering rack appears to be common - suggests that the std car may have had bump toe-in, or at least very little toe-out. Raising the rack would reduce any toe-in and/or increase toe-out. This again reduces steering sensitivity and improves stability.
Basically I wanted to know if there were any changes to the suspension mounting points to the chassis, whether the rack gear ratio was changed (can Tuscan II racks be bought?), and what if any suspension components were changed (wishbones, uprights?) - One of the threads suggested that the castor was adjustable via shims, if so, what is the maximum castor angle that can be acheived?
Sorry about all the questions, I'm wondering whether to buy a Tuscan I and improve the handling, or to buy a newer Tamora.
Std car has very low scrub radius (steer axis intersects the ground at the centre of the tyre) - this is a problem because variations in road camber cause the centre of pressure of the tyre to move laterally across the tread and gives torque reversals - difficult to control.
Low castor - this gives less self centring torque and less damping of any steer oscillation. Increasing castor will also increase toe-out compliance under cornering forces (an understeer characteristic, reduces steering sensitivity)
Raising the steering rack appears to be common - suggests that the std car may have had bump toe-in, or at least very little toe-out. Raising the rack would reduce any toe-in and/or increase toe-out. This again reduces steering sensitivity and improves stability.
Basically I wanted to know if there were any changes to the suspension mounting points to the chassis, whether the rack gear ratio was changed (can Tuscan II racks be bought?), and what if any suspension components were changed (wishbones, uprights?) - One of the threads suggested that the castor was adjustable via shims, if so, what is the maximum castor angle that can be acheived?
Sorry about all the questions, I'm wondering whether to buy a Tuscan I and improve the handling, or to buy a newer Tamora.
The T2s power steering is still hydraulic, just the pump is powered by an electric motor rather than straight off the crank. A half-way house between the full engine powered hydraulics and the latest fully electric systems, where the steering column is powered rather than the rack.
Don't know how its controlled in TVRs but in some (probably more sophisticated setups) the speed of the motor can be varied to alter the amount of assistance, or even turned off completely at high speed.
I'll check tonight, but I believe the inboard suspension and damper pickups are different at the rear between the Mk1 and Mk2.
Don't know how its controlled in TVRs but in some (probably more sophisticated setups) the speed of the motor can be varied to alter the amount of assistance, or even turned off completely at high speed.
I'll check tonight, but I believe the inboard suspension and damper pickups are different at the rear between the Mk1 and Mk2.
pete said:
I believe the T2 has electric power steering along with a slower rack, so it wouldn't be trivial to change from the mk1's conventional hydraulic setup. *In theory*, if you can live with the hyper quick ratio on the mk1, the hydraulic system should provide more feedback.
Pete
The T2 just has an electric pump for the hydraulic PAS, rather than the earlier engine driven one. The pump can be retro fitted to the earlier rack, with a few people using Citroen Saxo pumps as an alternative.Pete
There was a change to the chassis around 2001/2 with updated suspension mountings, but no idea if the same one carried through to MK2s.
Damn, too slow!
Edited by Basil Brush on Tuesday 17th August 18:05
Basil Brush said:
There was a change to the chassis around 2001/2 with updated suspension mountings, but no idea if the same one carried through to MK2s.
I think this was probably done from the Mk1 S onwards as it was billed as having revised suspension designed around the 18" spider wheels.Edited by Basil Brush on Tuesday 17th August 18:05
Without getting a few up on lifts and comparing like for like it'sd quite hard to determine exactly what? I think I might stick mine up on a lift with the wheels off and take some pictures to get the ball rolling.
dvs_dave said:
Basil Brush said:
There was a change to the chassis around 2001/2 with updated suspension mountings, but no idea if the same one carried through to MK2s.
I think this was probably done from the Mk1 S onwards as it was billed as having revised suspension designed around the 18" spider wheels.Edited by Basil Brush on Tuesday 17th August 18:05
Without getting a few up on lifts and comparing like for like it'sd quite hard to determine exactly what? I think I might stick mine up on a lift with the wheels off and take some pictures to get the ball rolling.
I checked with Graham Varley’s excellent Sagaris Manual.
As I understand it the Sagaris and the T2 share the same chassis.
The rear suspension definitely has alternative inboard pickups. This may be to make the chassis compatible with both Sagaris and T2 bodies, but most importantly the inboard damper pickup is such that it makes the damper considerably more vertical than on the T1 (i.e. not over at 45deg).
This will have a large effect on the way the car feels as the suspension rate (lb/in) will get stiffer as compressed rather than softer and the damper will have greater control.
As I understand it the Sagaris and the T2 share the same chassis.
The rear suspension definitely has alternative inboard pickups. This may be to make the chassis compatible with both Sagaris and T2 bodies, but most importantly the inboard damper pickup is such that it makes the damper considerably more vertical than on the T1 (i.e. not over at 45deg).
This will have a large effect on the way the car feels as the suspension rate (lb/in) will get stiffer as compressed rather than softer and the damper will have greater control.
Edited by Hot Tuscan on Wednesday 18th August 10:41
Edited by Hot Tuscan on Wednesday 18th August 14:07
Hot Tuscan said:
I checked with Graham Varley’s excellent Sagaris Manual.
As I understand it the Sagaris and the T2 share the same chassis.
The rear suspension definitely has alternative inboard pickups. This may be to make the chassis compatible with both Sagaris and T2 bodies, but most importantly the inboard damper pickup is such that it makes the damper considerably more vertical than on the T1 (i.e. not over at 45deg).
This will have a large effect on the way the car feels as the suspension rate (lb/in) will get stiffer as compressed rather than softer and the damper will have greater control.
Sagaris has greater supsension travel than Tuscan - part of the difference.As I understand it the Sagaris and the T2 share the same chassis.
The rear suspension definitely has alternative inboard pickups. This may be to make the chassis compatible with both Sagaris and T2 bodies, but most importantly the inboard damper pickup is such that it makes the damper considerably more vertical than on the T1 (i.e. not over at 45deg).
This will have a large effect on the way the car feels as the suspension rate (lb/in) will get stiffer as compressed rather than softer and the damper will have greater control.
Edited by Hot Tuscan on Wednesday 18th August 10:41
Edited by Hot Tuscan on Wednesday 18th August 14:07
Mk3 has different colm.. And as mk2 different rack to the "tuscan",hence inner track rod joints in better position for bump steer (which is horendous on the "Tuscan" (or mk1 as some call it ))
top arms definatley modified,again for better aligment, (i have a patern to make them but think they are available from stock again now )
hub uprights have different part mumbers (but i havn`t had em side by side so cant say for deffinate)..(I THINK top balljoint may be repositioned on em but DONT quote me on it,}
I have a mk3 rack and chassis sat doing nothing if you need the length, number of teeth (rack and pinion). Suspention mountig point details etc to compare.(P.M.me)
But never had mk3 chassis and a "Tuscan" chassis in the same place at the same time so dont know about mouting points
racks look same hights,but Never measured (i have height shims) All racks are hydrolic (later driven by electric pump) and APEAR to use common outer casing and input housing. the stearing arm to track rod end could do with some better alignment (i think someone modded an arm or rose joited one for beter alighnment,(try a search here or sagaris forum)
Ajustable Bilstein shocks with Ebach blue/green springs were fitted to the later cars, `S` spec being different to the lesser standard ones (got the specs some where)
,The Russian cars have a lot of the British cars hidious problems sorted out ,(although mk2 electroics a bit dodgey hence the more reliable mk 3 was born same electrics as covertable) even the engines were sorted the verry last cars
The above is what I HAVE PERSONALY EXPERIANCED.... NOT HEARSAY
top arms definatley modified,again for better aligment, (i have a patern to make them but think they are available from stock again now )
hub uprights have different part mumbers (but i havn`t had em side by side so cant say for deffinate)..(I THINK top balljoint may be repositioned on em but DONT quote me on it,}
I have a mk3 rack and chassis sat doing nothing if you need the length, number of teeth (rack and pinion). Suspention mountig point details etc to compare.(P.M.me)
But never had mk3 chassis and a "Tuscan" chassis in the same place at the same time so dont know about mouting points
racks look same hights,but Never measured (i have height shims) All racks are hydrolic (later driven by electric pump) and APEAR to use common outer casing and input housing. the stearing arm to track rod end could do with some better alignment (i think someone modded an arm or rose joited one for beter alighnment,(try a search here or sagaris forum)
Ajustable Bilstein shocks with Ebach blue/green springs were fitted to the later cars, `S` spec being different to the lesser standard ones (got the specs some where)
,The Russian cars have a lot of the British cars hidious problems sorted out ,(although mk2 electroics a bit dodgey hence the more reliable mk 3 was born same electrics as covertable) even the engines were sorted the verry last cars
The above is what I HAVE PERSONALY EXPERIANCED.... NOT HEARSAY
Thanks for all the excellent feedback!
I will have my new (to me) Tuscan mk1 hopefully on Tuesday, so then the investigations will begin in earnest!
Test drive on Friday confirmed my suspicions; too little understeer (kinematic and compliant) resulting in excessive steering sensitivity and poor on centre connection (try cycling the steering gently on a straight road and see how easy it is to get a noticable delay between steer angle and vehicle response).
My first try will be to look at bumpsteer (raising the rack) and more castor (a previous thread poster seem to suggest this might be possible with standard wishbones?).
To be honest, I don't necessarily want to exactly copy a mk2 or mk3 (didn't know there was a mk3!), I just want to improve the handling to a level I'm happy with.
Will post pics (in another thread) when I have the car, in case anyones interested.
I will have my new (to me) Tuscan mk1 hopefully on Tuesday, so then the investigations will begin in earnest!
Test drive on Friday confirmed my suspicions; too little understeer (kinematic and compliant) resulting in excessive steering sensitivity and poor on centre connection (try cycling the steering gently on a straight road and see how easy it is to get a noticable delay between steer angle and vehicle response).
My first try will be to look at bumpsteer (raising the rack) and more castor (a previous thread poster seem to suggest this might be possible with standard wishbones?).
To be honest, I don't necessarily want to exactly copy a mk2 or mk3 (didn't know there was a mk3!), I just want to improve the handling to a level I'm happy with.
Will post pics (in another thread) when I have the car, in case anyones interested.
Interesting.....can you post up some pics of the Mk3 chassis you have with close ups of the the front and rear steering and suspension parts? Easy to compare with other models then.
As an aside, how and why have you got a Mk3 Tuscan chassis lying around and where did it come from? Any plans to do anything with it?
As an aside, how and why have you got a Mk3 Tuscan chassis lying around and where did it come from? Any plans to do anything with it?
NorfolkSteve said:
My first try will be to look at bumpsteer (raising the rack) and more castor (a previous thread poster seem to suggest this might be possible with standard wishbones?)
Congratulations on the car. What year is it?Based the bits I've done on mine, it's not possible to raise the rack enough to sort out the bump steer without other changes. The oil cooler stops it being lifted more than around 10mm.
Edited as I've just seen your ins thread so realise it's a 2001.
When you say there's a lack of response in the steering, could it be down to play? I've just swapped the rack and put a new column in mine to get rid of this. I just need to replace the lower sliding column section as it's got a bit of slop (is a well known weak point in Vectras) and then it will be sorted.
Too much toe out can give a similar feeling as well.
Edited by Basil Brush on Monday 23 August 21:16
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