Unknown Object

[tractorboy]

Does any one know what the large valve block does on the brake circuit at the rear of the car just before the T connector (next to the diff) It bolts on to a plate..any ideas would be very helpfull...

[Paul V]

Only a guess but it sounds like it could be a pressure regulator to limit pressure to the back wheels.

[tractorboy]

Thanks Paul, I spoke to Tower View Race Services today and they werent exactly that helpful on the subject but I did manage to squeeze out of them that it is the brake balancer... ...Before i post yet another ever hopefull techy question has anyone upgraded their early solid Griff rear disks with a twin disk/caliper set up? ...If so would you happen to know if the original brake balancer is ok to use? ..Tall order but someone must know what im rambling on about...

[shpub]

Unless you have put 300mm discs on the front with really big callipers, don't touch the rears. Upgrading the rears on their own will do nothing except increase the likleyhood that the rears will lock up. Fitting an adjustable balance will help but all that does is reduce the braking power back down to what it was before. Regards Steve www.tvrbook.co.uk

[zertec]

I agree. The Zertec development 4.3 Griffith has the original tiny solid rear discs with uprated pads. The front however has Brembo WRC gravel specification motorsport brakes. These are grooved 300mm fully floating discs with 4 pot calipers (they fit in the 15 inch wheels). You need good front brakes (and these are the best at any price), the rears are only for settling the car down. The better braking at the front, the more weight transfer you get and therefore more braking can be done by the fronts and the less you need the rears and so on. The last thing you want is the rears locking up on you. Hollywood stunt drivers use an additional mechanism to lock the rears to induce skids etc. you don't want this is daily life. On the same thread we recently fitted 4 of these brakes to an Ultima race car (fitted with brake balancer) the owner tells us he can now outbrake Lotus Elises and Caterhams on the track which he couldn't do before. We threw his old Wilwoods in the bin where they should be.... Clive Reed Zertec Limited [e-mail] www.zertec.co.uk

[GreenV8S]

quote:The better braking at the front, the more weight transfer you get and therefore more braking can be done by the fronts and the less you need the rears and so on.

Surely the amount of weight transfer is determined by the laws of physics, i.e. the position of the car's CoG and the amount of grip generated by the tyres at the point of locking. On road tyres you are unlikely to get ever more than about 15% transfer even with the best brakes in the world. Yes if the front/rear balance is miles out you would not get quite the same total braking so you will get slightly less weight transfer, but even really rubbish brakes should get quite close to the 15%. So you are not talking about a big difference. In my experience you probably wouldn't be worrying about changes in weight transfer in this situation, the effect on the car's handling from getting the brake balance wrong can be quite dramatic! (The problems I've seen with TVR brakes have been with overheating on track rather than a problem with the brake balance.)

quote:On the same thread we recently fitted 4 of these brakes to an Ultima race car (fitted with brake balancer) the owner tells us he can now outbrake Lotus Elises and Caterhams on the track which he couldn't do before. We threw his old Wilwoods in the bin where they should be....

That would be James Hall's car I guess? At the time I didn't understand why James was so unhappy with the brakes, it seemed to me that they couldn't have been set up right. What I mean is, as well as physically fitting the brakes and getting the alignment and clearances right, you have to sort out the overall effective leverage of the brakes (how heavy the pedal is), the front/rear balance curve, and the front/rear thermal balance. The first two of these determine how the brakes respond prior to overheating and from his description I suspect they weren't set up right when on James' car. It seems to me that this isn't a problem with the brakes, its a problem with the installation and/or pads. I'm certainly very happy with the 4-pot Wilwood superlights on the V8S and know several others who have them on TVRs and are just as happy. They are also far cheaper than the alternatives from AP and so on. So perhaps you should fish those old Wilwoods out of the bin? (By the way I have no association with Wilwood, other than as a happy customer!) Peter Humphries (and a green V8S)