Suspension and wheel alignment - Center Gravity
Discussion
I hope the information provided helps others to make a decision to get the car suspension set up by an expert.
My Tamora had a full suspension overhaul just before I purchased it in the summer from James Agger. New arms, bushes, and new TVR standard spec Bilstein shocks and Eibach springs with everything set up to standard TVR settings.
The car handled ok, but was incredibly low at the front with only 7cm of clearance under the front lip. The front lip lasted only a few weeks and broke after several impacts on country lanes.
There are limited adjustments on the Bilstein/Eibach shocks but the spring base can be moved up and down in 1cm increments via the machined grooves and C Clips. I had raised the front spring base up one notch which lifted the front up to 10cm. I did that just before I had the front end repaired and resprayed. The car was booked into Center Gravity for a chassis tune, so my alteration was simply to protect the front lip until the experts could get the car set up again.
Before booking the car in I exchanged several emails with the team at Center Gravity and they confirmed that the standard shocks would be fine for road use. I had found that Parts For TVRs sold an adjustable spring base kit for the Bilstein shocks. Center Gravity agreed they could be useful for refining the suspension if they found smaller adjustments were required, and that they could fit those on the day if needed if I brought a set with me.
TVR C0950 - Shock absorber spring seat
TVR C0951 - Shock absorber lock ring
TVR C0952 - Shock absorber adjusting platform
1 of each per shock.
A warm welcome from Chris and Pete on arrival at Center Gravity. The plan for the day was discussed in detail and in a way that allowed me to understand what they do. Pete asked many questions about where and how I drive, what I liked and did not like about how the car handled, how it felt to drive, what other cars I had driven, how they compared and what I wanted the car to feel like.
Although I have been driving for over 30 years, like many normal drivers it is difficult to use the correct words an experienced race driver would use to describe how a car feels, but Pete was able to make sense of my comments "it feels unstable when changing lanes", "it pulls on cambered roads", "driving on country roads is a both hands on the wheel effort if it's damp", "the front end feels a bit more nervous since I put the new types on", "the car cannot be any lower at the front end" etc.
Next step was for Pete to take the car on a test drive. He confirmed all the characteristics I had discussed and pointed out several other things that I had not noticed until he pointed them out.
Car on the ramps for a full check over and alignment to see what the current geometry, ride height etc was. The data gathered was discussed in detail. Pete explained how each of the different settings for the toe, camber, caster, ride height and corner weight contributed to the handling characteristics and how he intended to change things to get the car handling in a way that I had described I wanted for country lanes and to feel more stable, confidence-inspiring but not boring. All of the settings at the start of the day were within the TVR tolerances or would have been before I lifted the car up, but not quite as consistent on all 4 corners as he wanted them to be. It was clear that raising the front spring bases up one notch had contributed to some of the issues I reported.
Pete worked on the car for the rest of the day, fitting the adjustable spring bases which provided the refinement he needed to get the pitch, ride height corner weights set how he wanted them to be to meet my expectations. The same attention applied to toe, caster, camber on all 4 corners, with a few test drives, re-checks, further adjustments and then a final test drive, alignment check and report.
A full set of before and after data was provided and Pete explained what it all meant.
Pete, Chris and Holly made me feel very welcome. Pete took the time to explain everything he was doing on the car, allowing me to watch him work, chatting about the car as he got on with things. I even managed to get some office work done from the waiting room between the time spent in the workshop. Pete found and fixed a few minor issues (slow leak from a tyre and a loose hub nut). Nothing was too much trouble.
The most important thing from the day is the car feels so much better to drive now and is the best upgrade I have done to any car I have had. It feels incredibly stable and balanced, no longer gets dragged by camber changes, no longer hits every bump in the road, and inspires confidence, even though it was wet and just above freezing on the drive home. It feels as good as my 4WD 911 C4 did on the country lanes. I cannot wait for a dry day to really check it out. It did not feel too bad before the adjustments, but the difference is simply incredible.
The full suspension refresh gave a really good starting point for the Centre Gravity work as there were no worn parts to replace. I have spent less money on the chassis tune and adjustable spring bases than it would have cost to buy a new set of gaz golds and I am sure I have a better handling car now than I would have from just bolting on another set of shocks.
If nothing else, those adjustable spring bases make a real difference to what can be done with the standard TVR shocks.
My Tamora had a full suspension overhaul just before I purchased it in the summer from James Agger. New arms, bushes, and new TVR standard spec Bilstein shocks and Eibach springs with everything set up to standard TVR settings.
The car handled ok, but was incredibly low at the front with only 7cm of clearance under the front lip. The front lip lasted only a few weeks and broke after several impacts on country lanes.
There are limited adjustments on the Bilstein/Eibach shocks but the spring base can be moved up and down in 1cm increments via the machined grooves and C Clips. I had raised the front spring base up one notch which lifted the front up to 10cm. I did that just before I had the front end repaired and resprayed. The car was booked into Center Gravity for a chassis tune, so my alteration was simply to protect the front lip until the experts could get the car set up again.
Before booking the car in I exchanged several emails with the team at Center Gravity and they confirmed that the standard shocks would be fine for road use. I had found that Parts For TVRs sold an adjustable spring base kit for the Bilstein shocks. Center Gravity agreed they could be useful for refining the suspension if they found smaller adjustments were required, and that they could fit those on the day if needed if I brought a set with me.
TVR C0950 - Shock absorber spring seat
TVR C0951 - Shock absorber lock ring
TVR C0952 - Shock absorber adjusting platform
1 of each per shock.
A warm welcome from Chris and Pete on arrival at Center Gravity. The plan for the day was discussed in detail and in a way that allowed me to understand what they do. Pete asked many questions about where and how I drive, what I liked and did not like about how the car handled, how it felt to drive, what other cars I had driven, how they compared and what I wanted the car to feel like.
Although I have been driving for over 30 years, like many normal drivers it is difficult to use the correct words an experienced race driver would use to describe how a car feels, but Pete was able to make sense of my comments "it feels unstable when changing lanes", "it pulls on cambered roads", "driving on country roads is a both hands on the wheel effort if it's damp", "the front end feels a bit more nervous since I put the new types on", "the car cannot be any lower at the front end" etc.
Next step was for Pete to take the car on a test drive. He confirmed all the characteristics I had discussed and pointed out several other things that I had not noticed until he pointed them out.
Car on the ramps for a full check over and alignment to see what the current geometry, ride height etc was. The data gathered was discussed in detail. Pete explained how each of the different settings for the toe, camber, caster, ride height and corner weight contributed to the handling characteristics and how he intended to change things to get the car handling in a way that I had described I wanted for country lanes and to feel more stable, confidence-inspiring but not boring. All of the settings at the start of the day were within the TVR tolerances or would have been before I lifted the car up, but not quite as consistent on all 4 corners as he wanted them to be. It was clear that raising the front spring bases up one notch had contributed to some of the issues I reported.
Pete worked on the car for the rest of the day, fitting the adjustable spring bases which provided the refinement he needed to get the pitch, ride height corner weights set how he wanted them to be to meet my expectations. The same attention applied to toe, caster, camber on all 4 corners, with a few test drives, re-checks, further adjustments and then a final test drive, alignment check and report.
A full set of before and after data was provided and Pete explained what it all meant.
Pete, Chris and Holly made me feel very welcome. Pete took the time to explain everything he was doing on the car, allowing me to watch him work, chatting about the car as he got on with things. I even managed to get some office work done from the waiting room between the time spent in the workshop. Pete found and fixed a few minor issues (slow leak from a tyre and a loose hub nut). Nothing was too much trouble.
The most important thing from the day is the car feels so much better to drive now and is the best upgrade I have done to any car I have had. It feels incredibly stable and balanced, no longer gets dragged by camber changes, no longer hits every bump in the road, and inspires confidence, even though it was wet and just above freezing on the drive home. It feels as good as my 4WD 911 C4 did on the country lanes. I cannot wait for a dry day to really check it out. It did not feel too bad before the adjustments, but the difference is simply incredible.
The full suspension refresh gave a really good starting point for the Centre Gravity work as there were no worn parts to replace. I have spent less money on the chassis tune and adjustable spring bases than it would have cost to buy a new set of gaz golds and I am sure I have a better handling car now than I would have from just bolting on another set of shocks.
If nothing else, those adjustable spring bases make a real difference to what can be done with the standard TVR shocks.
Great post, thank you.
The only thing that I would question is the phrase " standard TVR shock absorbers". The OE shocks on my T350T were Harvey Bailey( red) and were absolutely terrible.They created a jiggly ride probably due to initial " sticktion", in there travel; followed by a soft wallowiness,due to lack of damping once the initial " sticktion", was overcome.
The rear spring" location "at the top of the damper did not actually locate the springs.This allowed the springs to move into a banana shape.
Perhaps some earlier T cars had better "standard", Bilsteins?
Nitrons I fitted, produced a more supple ride ( lack of sticktion?) even with a 100% stiffer spring rate and much better roll / dive control etc.
Sagaris spec springs( 450 front /400rear) and OE Bilsteins were night and day in comparison with Harvey Bailey's with 200 front /175 rear springs.
The only thing that I would question is the phrase " standard TVR shock absorbers". The OE shocks on my T350T were Harvey Bailey( red) and were absolutely terrible.They created a jiggly ride probably due to initial " sticktion", in there travel; followed by a soft wallowiness,due to lack of damping once the initial " sticktion", was overcome.
The rear spring" location "at the top of the damper did not actually locate the springs.This allowed the springs to move into a banana shape.
Perhaps some earlier T cars had better "standard", Bilsteins?
Nitrons I fitted, produced a more supple ride ( lack of sticktion?) even with a 100% stiffer spring rate and much better roll / dive control etc.
Sagaris spec springs( 450 front /400rear) and OE Bilsteins were night and day in comparison with Harvey Bailey's with 200 front /175 rear springs.
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