Discussion
Evening all,
After enjoying my first weekend with the Tuscan in absolutely ages, it's so much fun and still enjoy it, but aside from needing a few minor jobs doing it keeps reminding me how incredibly unstable it is at anything over 60~. It gets worse with speed, I had the chance to give it a right good blast up a straight (but slightly bumpy) road and I had to back off as I couldn't keep it in a straight line, twitchy doesn't start to describe it!
It's a 2000 non S, I don't think the lack of a splitter will be the cause of this problem, as it's not a particularly high speed problem, and it doesn't feel like lift, more like completely garbage geometry!!
I know I need to start by checking geo, but could the steering rack height be why it is so nervous (bump steer)? It would be nicer if the rack was slightly less sensitive, but I know I can't change that.
Any thoughts welcome!
After enjoying my first weekend with the Tuscan in absolutely ages, it's so much fun and still enjoy it, but aside from needing a few minor jobs doing it keeps reminding me how incredibly unstable it is at anything over 60~. It gets worse with speed, I had the chance to give it a right good blast up a straight (but slightly bumpy) road and I had to back off as I couldn't keep it in a straight line, twitchy doesn't start to describe it!
It's a 2000 non S, I don't think the lack of a splitter will be the cause of this problem, as it's not a particularly high speed problem, and it doesn't feel like lift, more like completely garbage geometry!!
I know I need to start by checking geo, but could the steering rack height be why it is so nervous (bump steer)? It would be nicer if the rack was slightly less sensitive, but I know I can't change that.
Any thoughts welcome!
I am beginning to think that the MK1 is just like that, you can improve it but the rack rate, geo angles and ofset of wheels is more difficult to alter.
Things I have learnt from my Mk1
Very selective on tyres, especially the front.
Spacers
Rack height
Geo setup (not all setups are the same)
Suspension
Tyre pressure
Wheel size (16's are better than 18's)
rack height (not changed on mine)
ride height
wishbone bushes
Any I have missed? The strange thing is that the MK2 vert has a completely different feel to it, much more relaxed and confident.
Things I have learnt from my Mk1
Very selective on tyres, especially the front.
Spacers
Rack height
Geo setup (not all setups are the same)
Suspension
Tyre pressure
Wheel size (16's are better than 18's)
rack height (not changed on mine)
ride height
wishbone bushes
Any I have missed? The strange thing is that the MK2 vert has a completely different feel to it, much more relaxed and confident.
Posted similar before but my MK1 is a good as my Sag in my opinion. I have 19" wheels on Michelins with Gaz pros and poly bush black throughout. I run quite a lot of camber on the rear with neutral/zero toe on the front and a touch more camber than standard with caster at 5deg, I want to put more caster on so will make half spacers soon and try. The rack is spaced 3mm. It is very low. The front offset is a long way out, simply because the bling wheels that were on it didn't clear the calipers so it had spacers, it drove quite well so they stayed on... despite new bells and bespoke capliper brackets to move the calipers back.
Yep unbelievable but it drives well.
Tyre pressures make a big difference. Remember these cars are light so take some air out and try, as long as you don't flex the sidewall too much you will be OK. 19s Vs 16s can be softer as you have more on the road.
Keep us posted.
J
Yep unbelievable but it drives well.
Tyre pressures make a big difference. Remember these cars are light so take some air out and try, as long as you don't flex the sidewall too much you will be OK. 19s Vs 16s can be softer as you have more on the road.
Keep us posted.
J
Sounds a lot like mine! Very scary on occasion, & oddly is worse since fitting shocks from an S - lots of bump steer which I never had before. Went out with my local club on Thursday night last week & had shoulder ache all the next day from clinging on down the B roads!
I've not had a geo setup done but tried different tyres & pressures with little difference. Also have the spacers fitted. If anyone has a genuinely really good geo set up, knows the figures & doesn't mind sharing then please do so!
I've not had a geo setup done but tried different tyres & pressures with little difference. Also have the spacers fitted. If anyone has a genuinely really good geo set up, knows the figures & doesn't mind sharing then please do so!
I don't think the rack actually changed. The top wishbone shape was changed to allow the wheel to turn further, giving more lock. This meant more turns lock to lock but I think this gets confused with rack ratio being slowed.
Sag and later Tuscan wishbones are the same. The mounting points are higher and further out on the Sag chassis giving the added track.
Sag and later Tuscan wishbones are the same. The mounting points are higher and further out on the Sag chassis giving the added track.
Does anyone have any issues when braking hard from speed ? have had a couple of major brown trouser moments doing this, car feels really unsettled and weaves from side to side. Big fight to keep it pointing
forward, feels like its about to swap ends at any second,
Not investigated yet but car has been well maintained (I have receipts for 20k + spent over last 5 years by previous owner on routine maintenance and servicing at a TVR specialist garage)
they seem to have picked up on even the most mundane stuff so would be surprised if they have missed worn bushes etc, pads and discs including rear calipers are all fairly new
In for MOT this week, so will check brake balance, am wondering if one of the new rear calipers is not bled up properly
Also suffers from bump steer and is hard to drive briskly on bumpy B roads.
Still loving it, just need to be very careful.....am planning a good fettle over winter including some handling mods.
forward, feels like its about to swap ends at any second,
Not investigated yet but car has been well maintained (I have receipts for 20k + spent over last 5 years by previous owner on routine maintenance and servicing at a TVR specialist garage)
they seem to have picked up on even the most mundane stuff so would be surprised if they have missed worn bushes etc, pads and discs including rear calipers are all fairly new
In for MOT this week, so will check brake balance, am wondering if one of the new rear calipers is not bled up properly
Also suffers from bump steer and is hard to drive briskly on bumpy B roads.
Still loving it, just need to be very careful.....am planning a good fettle over winter including some handling mods.
Edited by alspeed on Monday 20th July 21:35
I used to have the same braking reaction on mine. The biggest benefit came from setting the rack height properly to get rid of the bump toe in my early Mk1 had with the standard set up. I also swapped wishbones and uprights to the later Tuscan spec which improved things again.
The brake balance was also too rear biased as standard but upping the front discs to 322 and leaving original size rears has helped.
The brake balance was also too rear biased as standard but upping the front discs to 322 and leaving original size rears has helped.
Basil Brush said:
I used to have the same braking reaction on mine. The biggest benefit came from setting the rack height properly to get rid of the bump toe in my early Mk1 had with the standard set up. I also swapped wishbones and uprights to the later Tuscan spec which improved things again.
The brake balance was also too rear biased as standard but upping the front discs to 322 and leaving original size rears has helped.
When you refer to "later Tuscan spec" is that MK2 ? my car is a 2003 Mk1 I understand the last Tuscans shared wishbones (so i guess uprights too) with the SagarisThe brake balance was also too rear biased as standard but upping the front discs to 322 and leaving original size rears has helped.
alspeed said:
When you refer to "later Tuscan spec" is that MK2 ? my car is a 2003 Mk1 I understand the last Tuscans shared wishbones (so i guess uprights too) with the Sagaris
Late Mk1 and 2 are the same in terms of top wishbone length and uprights. That's what I have on the front of my early Mk1, along with electric PAS pump. Your problems sound awful, should have bought a chim 
Seriously, my handling was that poor when I swapped to a new set of dampers by a well known manufacturer. Country lanes were downright dangerous with the car bumping, skipping and being thrown off line by the slightest irregularity in the road.
I changed back to my Gaz Monos and the problem was solved.
Sounds like your damping is way too hard or your units are shot/useless/ set up very badly.
Seriously, my handling was that poor when I swapped to a new set of dampers by a well known manufacturer. Country lanes were downright dangerous with the car bumping, skipping and being thrown off line by the slightest irregularity in the road.
I changed back to my Gaz Monos and the problem was solved.
Sounds like your damping is way too hard or your units are shot/useless/ set up very badly.
I'm planning on getting the geo done shortly, then will look at the 3mm spacers. What should the tyre pressures be on 18" spiders? The owners manual just states 22psi for 16" wheels!
I'd love the rack to be less sensitive, similar to your Evora, I reckon I could get from A to B much faster in my Mrs' Audi TT, I can have the wheels struggling for grip right up to 4th whilst pushing it round a corner, if I tried anything like that in the Trev I probably wouldn't be here to tell the tale!
I'd love the rack to be less sensitive, similar to your Evora, I reckon I could get from A to B much faster in my Mrs' Audi TT, I can have the wheels struggling for grip right up to 4th whilst pushing it round a corner, if I tried anything like that in the Trev I probably wouldn't be here to tell the tale!
Interesting previous thread on the subject........
http://www.pistonheads.com/Gassing/topic.asp?h=0&a...
http://www.pistonheads.com/Gassing/topic.asp?h=0&a...
Mine was pretty scary when I first got it.
Since then I've done the following...
Re-gassed Nitrons
Changed all suspension bushes
Raised rack 10mm
3mm wheel spacers
Tyre dropped to 22psi
Geo set up
Now it drives like a 3 series :-)
Since then I've done the following...
Re-gassed Nitrons
Changed all suspension bushes
Raised rack 10mm
3mm wheel spacers
Tyre dropped to 22psi
Geo set up
Now it drives like a 3 series :-)
- edit* do the later Sag/Tuscan upper wishbone fit an early chassis and would this make a noticeable difference to the way the earlier car drives? I was advised to stick with the standard upper wishbons when I replaced the bushes - if it hadn't been for this then I would have bought the later, slightly longer top wishbones.
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