Suspension/brakes - opinions pls
Discussion
Mav
You're right, Niel certainly must know his stuff - TVR chassis designer, part time race car driver, and sprint champion (in a Griffith, natch).
Unfortunatley, I only got to speak to him after I'd shelled out on Avo shocks - which he doesn't rate - so I'll have to make my own mind up about them. Apparently, money no object, the Ohlins are possibly best, but VERY pricey.
What did he suggest you did?
You're right, Niel certainly must know his stuff - TVR chassis designer, part time race car driver, and sprint champion (in a Griffith, natch).
Unfortunatley, I only got to speak to him after I'd shelled out on Avo shocks - which he doesn't rate - so I'll have to make my own mind up about them. Apparently, money no object, the Ohlins are possibly best, but VERY pricey.
What did he suggest you did?
quote:
YOU ALL SEEM TO BE MISSING THE MOST VALUBLE ADVICE !
Actually it is first work out what the problem is with the suspension so that you can then work out how to tackle it.
The success of suspension mods is very dependent on who is driving, their driving style and what they are doing with the car. If you want the best handling for a circuit, you have to suffer a bit on bumpy roads. If you want to glide over bumps then don't expect to be 100% on a circuit. If you change the springs and shocks, you may need to look at tyre pressures again as the tyres and wheels are a major active component of the suspension. Changing the suspension can change the car's oversteer/understeer characteristics.
I have spent several years developing the 520's suspension and I have won a lot of championships and sprints on AVOs which judging from the comments about them would not be possible... Interesting this suspension stuff isn't it! Still agree that they do not seem to suit Griffs/Chimaeras though but they are many who are happy with them. I'm moving to GAZ this year as I think that I have reached the limits with the AVOs and they are now the weak point.
The most important thing I have learned with the suspension is that it is complex, always a compromise and focus on addressing handling problems and why they are occuring before spending money on sorting them out.
Steve
www.tvrbooks.co.uk
I agree with Steve, suspension is ALWAYS a compromise. Talk to the experts, so much varies with damper & spring changes that can have a dramatic effect on the handling of the car that us mere mortals aren't even aware of. It is very, very easy to get the combination wrong and unless you are prepared to do your own development work with a sympathetic supplier, my advice would be to go with recommendations from others who have done this already with a particular supplier.
Hope this helps, Jas.
Hope this helps, Jas.
This thread always ends up with the same conclusion. "It's really complicated ... best ask someone who has succesfully done it". The problem is finding someone who will say what they did, how it's better, where, when and how much. It's extremely doubtful (IMO) that the majority are actually interested in ultimate track day handling Most would probably appreciate a more sophisticated ride i.e. with more compliant springing but far better damping (like Porsche ... Ducks for cover here). The standard suspension on TVR's seems very similar to standard bike suspension i.e. Very hard to compensate for the low rent components. When I have replaced bike stuff it's usually softer but gives much better handling on both track and road simply by using quality components. Are there any people out there who have a major success story?
Ok what is the problem or deficiency with the car's handling that you are trying to solve? If the answer is I want it to handle better then you will get a load of different answers cos there are so many variables, including the driver! I took one driver out in his car who was complaining his car handled like crap and he came back asking how I had improved the car's handling. Turned out that his driving style was so abrupt that the car never recovered its balance from one part to another. Driving smoothly gave the car time to work and it was fine. So the questions that are need to be asked are:
Does the car roll too much? Does it understeer? Does it oversteer? Does it dive under braking? Does it tramline? Does it get twitchy under power? Is it too bumpy?
Very often these can be cured by small adjustments or changes but you need to know what the problem is before you can fix it.
So what are the problems?
Steve
www.tvrbooks.co.uk
Does the car roll too much? Does it understeer? Does it oversteer? Does it dive under braking? Does it tramline? Does it get twitchy under power? Is it too bumpy?
Very often these can be cured by small adjustments or changes but you need to know what the problem is before you can fix it.
So what are the problems?
Steve
www.tvrbooks.co.uk
Problems are:
>Front wishbone bushes are shot, so as I gonna have to take it to bits I thought it was an ideal time for a complete overhaul of the suspension (all round)
>Dampers - feel like they've given their best (the cars 6 yrs old/30K). Bump control doesn't feel the best, the car gets 'floaty' over a series of bumps and in v.fast corners (on the track) it seems to 'pogo' around a bit - if you know what I mean.
>Tramlining - but I'm sure a bit more toe-in would cure this.
Apart from general wear in the suspension I'm not trying to correct any problems, 'tho a bit less dive on the brakes would be nice - just canvasing opinion on the best quality/performing components to use in the rebuild.
I've more or less decided to do the rebush etc myself, then go to one of the specialists for a geometry set up. Just can't settle on which dampers to use, Later standard (Mk4) Bilstiens, or Nitrons. The Bilies win on ease of set up & price. The Nitrons from a performance point of view but lose out on more complicated setting up & more to twidle with all the time & muck up - as you say Quinny.
>Front wishbone bushes are shot, so as I gonna have to take it to bits I thought it was an ideal time for a complete overhaul of the suspension (all round)
>Dampers - feel like they've given their best (the cars 6 yrs old/30K). Bump control doesn't feel the best, the car gets 'floaty' over a series of bumps and in v.fast corners (on the track) it seems to 'pogo' around a bit - if you know what I mean.
>Tramlining - but I'm sure a bit more toe-in would cure this.
Apart from general wear in the suspension I'm not trying to correct any problems, 'tho a bit less dive on the brakes would be nice - just canvasing opinion on the best quality/performing components to use in the rebuild.
I've more or less decided to do the rebush etc myself, then go to one of the specialists for a geometry set up. Just can't settle on which dampers to use, Later standard (Mk4) Bilstiens, or Nitrons. The Bilies win on ease of set up & price. The Nitrons from a performance point of view but lose out on more complicated setting up & more to twidle with all the time & muck up - as you say Quinny.
quote:
Turned out that his driving style was so abrupt that the car never recovered its balance from one part to another.
That's funny, I don't *remember* taking you for a spin but you're definitely describing the "handling problems" I had!
BTW re adjustable dampers, think of this as making adjustment possible, rather than necessary. When I bought the Nitrons I told Guy what the car setup was and he fitted the right valving to give a good range of adjustment round the sort of rates I would need, and set them to his best guess based on the numbers I gave him. Similarly when I tried the Gaz dampers, Mark set them to a reasonable rate based on his knowledge and experience. I did adjust them subsequently, but that was my choice trying to fine-tune them, not because I had to. If you get fixed dampers you have to live with the one standard rate, and there's no way it will be right for every car and every driver.
Cheers,
Peter Humphries (and a green V8S)
quote:
Problems are:
>Front wishbone bushes are shot, so as I gonna have to take it to bits I thought it was an ideal time for a complete overhaul of the suspension (all round)
>Dampers - feel like they've given their best (the cars 6 yrs old/30K). Bump control doesn't feel the best, the car gets 'floaty' over a series of bumps and in v.fast corners (on the track) it seems to 'pogo' around a bit - if you know what I mean.
>Tramlining - but I'm sure a bit more toe-in would cure this.
Right I would rebush and see how the car feels first - you may be really surprised as the suspension will start to work correctly and many of the problems you are seeing could go away. If you fit new shocks don't forget to fit new springs because tired springs can cause problems as well.
As for shocks, how much is your budget and how much twiddle factor do you want? If they are shot then almost anything would be better and I would go with some adjustables so that you can play around. If you don't want to play, go for a standard or a sports setup where you get it as is.
One word of advice is that keep them on a setting until you get used to it and don't start changing immediately.
Tramlining can be inherent or made worse by geometry. Camber is normally the main culprit but toe and tyre pressures can all play a part.
If you want to stop dive then you need a stiffer front suspension to help resist the transfer. The problem is that this can cause the rear to start moving around and before you no it you have a real tail happy car so you then stiffen up the rear. This now makes the car too hard and you feel the bumps. Somewhere in between all this is the best compromise setting. Alternatively simply braking a bit earlier and more gradually can reduce the dive quite considerably. Alternatively you can exploit it and the fact that the rear will go light and break away to trail brake into a corner and use the resulting oversteer to turn in better. Makes a mess of the car when you get it wrong and hit something though.
Steve
www.tvrbooks.co.uk
quote:
By the way I'd like to set the record straight regarding the Avo's after I'd said they were crap. What I should have said is that they were crap on MY CAR.
The set that I fitted to the griff were the second set I'd bought, I'd previously fitted a set to a wedge that I used to own, and they were a massive improvment over the originals and once I'd got them set up I never needed to touch them again. This was the reason I bought another set when I traded to the griff, so you can imagine my dissapointment when I couldn't get them to work. Again I think Steve's right they don't seem to suit the griff for some reason.
Incidently I gave them to a friend with a V8S and he was very happy with them. Is the suspension on a V8S similar to a Wedge (leading link)? If so it might go some way to explaining why they worked so well on these 2 models.
I tried AVOs on the V8S and they were diabolical. I know of several others who have tried them on an S, so far I have not found anyone who liked them. But I have heared good reports of them on Wedges and Cerberas. My experience was a couple of years ago and maybe things have moved on since then. Also I was buying fairly low spec dampers, and I see that AVO do varous types now including some very nice looking competition spec dampers. But as far as AVO are concerned I would need some pursuading before I tried them again.
Cheers,
Peter Humphries (and a green V8S)
If you want to stop dive then you need a stiffer front suspension to help resist the transfer. The problem is that this can cause the rear to start moving around and before you no it you have a real tail happy car so you then stiffen up the rear.
Steve,
I'm confused. If you stiffen the front suspension, you have less weight transfer to the front of the car.
If you have less weight transfer, it follows that the rear of the car will be much MORE stable under braking conditions.
Stiffening the rear aids acceleration and roll rate giving both rear tyres a larger footprint.
Have I got this correct, or am I just being thick? (It is late!)
Jas.
Before you get Wilwoods take a look at these:
www.hispecbigbrakes.co.uk/
Here is a review I found that an Elan owner did:
www.informatica.zen.co.uk/elan/HiSpecBrakes.htm
I'm having some made for my Chimaera hopefully arrive next week.
>> Edited by loadofcods on Friday 1st March 07:55
www.hispecbigbrakes.co.uk/
Here is a review I found that an Elan owner did:
www.informatica.zen.co.uk/elan/HiSpecBrakes.htm
I'm having some made for my Chimaera hopefully arrive next week.
>> Edited by loadofcods on Friday 1st March 07:55
quote:
Alternatively you can exploit it and the fact that the rear will go light and break away to trail brake into a corner and use the resulting oversteer to turn in better. Makes a mess of the car when you get it wrong and hit something though.
Steve
www.tvrbooks.co.uk
Fair enough, I understand what you're suggesting here, but certainly on Griffs, the way the rear wheels lock up under hard braking could really do to be minimised IMO.
Jeffgleed's comments about quality suspension components having softer setting is interesting - my Avo's seem to be far less harsh than the standard shocks, but at the same time give a bit more 'feel'.
Haven't used them on a circuit yet, so I'll have to hope, that as Pete Humphries pointed out, Avo might have developed the shocks to a spec that now suits the Griff.
On Avo's (or the one's I have at least) the only adjustment is for rebound. The ride height can also be varied - though obviously not quickly or easily. Does it follow that, for track use, a high (stiff) setting for the rebound is generally best?
The problem with suspension work is changing too many things at one time can mean you end up no knowing what made the changes.
Ok you save time but you also run the risk of getting spring/shox that may not be the ideal for a correctly bushed car. Not a good idea IMHO. If you are going for a known setup then not a big problem but if you want to get the best, do it in stages so you knaow what each change will do.
Steve
Ok you save time but you also run the risk of getting spring/shox that may not be the ideal for a correctly bushed car. Not a good idea IMHO. If you are going for a known setup then not a big problem but if you want to get the best, do it in stages so you knaow what each change will do.
Steve
quote:
If you want to stop dive then you need a stiffer front suspension to help resist the transfer. The problem is that this can cause the rear to start moving around and before you no it you have a real tail happy car so you then stiffen up the rear.
Steve,
I'm confused. If you stiffen the front suspension, you have less weight transfer to the front of the car.
If you have less weight transfer, it follows that the rear of the car will be much MORE stable under braking conditions.
Stiffening the rear aids acceleration and roll rate giving both rear tyres a larger footprint.
Have I got this correct, or am I just being thick? (It is late!)
Jas.
It is not as simple as that. The weight transfer does not change, it is the way that the car responds and balances that does. In other words how the car moves and settles. The tranferred weight is a factor of acceleration and weight. If you have a stiffer front suspension, the front will not move as much so that the rear of the car will try to rise a little to compensate. It's a bit like riding a bike and hitting the front brakes hard. The rear will start to move and flip you over. Look at a video of car braking hard and you will see what I mean. Most people see the front go down and this disguises the fact that the rear rises a little.
So what you want ideally is a stiffer front suspension to stop dive and then you need to stiffen the rear so that it is harder for the rear to move. The real key is getting the balance right. Also driver input is also critical on this so that all the car weight transfer is smooth and predictable. What you are looking for is a suspension setting that keeps the car as level as possible and can balance as quick as possible so that the car can enter the corner smoothly and balanced.
If the car is not balanced by this point, you can't get the power down. Trail braking in some degree tries to make a virtue out of a vice and deliberately causes the car to be ouit of balance in a controlled (usually) manner so that it helps the cornering and not hinders it. It is a very tricky technique to master as get it wrong and its look for somewhere to put the car time. It is faster as it allows you to brake later and carry more speed through the corner.
Steve
www.tvrbooks.co.uk
quote:
By the way Pete do you remember me? I'm the really good looking bloke (no honest) with a bad limp.
Of course I remember you! I also remember you set the fastest speed through the speed trap out of all the TVRs, how come you've traded down from your 4.3 to a 500?
quote:
I used to come to the meets with Chris (Grey V8S). Are you sprinting this year?
Haven't seen Chris for ages. How's he doing? Yes I'm still running the TVR championship and I'll be at as many rounds as possible. Hopefully see you there. Can I persuade you to register this year?
quote:
I notice you didn't make it to the Oulton track day, probably a good job, as the last 2 years I'm sure you went through your pads and wrecked the discs. Take note Leadfoot this guy's giving us advice on brake upgrades!!!! ONLY JOKING. Pete's probably tried every combination of shocks and brakes on his V8S by now and I think he holds the fastest time around Curborough for a modified production car. Well I could'nt get anywhere need it anyway. And I did try believe me.
Cheers,
Quinny.
Haven't done Oulton for a couple of years for one reason and another. Yes the original brakes used to really suffer there and I used to go down to the back plates quite regularly. That was one of the reasons I started the brake upgrades. The 'big brake' upgrade was fine there. But after the next round of power upgrades I fried them at Pembrey, hence the move to the 'monster' 4-pot Wilwood/AP and 300mm discs. Haven't had a chance to try thise at Oulton but I've pushed it extremely hard at other places with no problems. Oulton is one of my favorite circuits, fingers crossed I'll make it this year!
I'm afraid I don't hold the Curborough long course record, I broke last year's record but an Exige had already beaten it my more. Gives me something to aim for I guess! I think I still hold the short course and Loton class records - until Moonie comes back out to put me in my place!
BTW in case you're interested, I published the in-car video of those runs at Roop's web site www.roop.ik.com > Index > Videos. Be warned they're quite big though!
Cheers,
Peter Humphries (and a green V8S)
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