adjustable brake bias, easy fit?
Discussion
I have upgraded front brakes, and think I need an adjustable brake bias switch. Why, because the factory setting between front and rear is fixed, based on the original installation and that has been changed.
Anybody experience/tips to finding/fitting one?
Is it as straight forward like installing a fuel pressure regulator for example?
I know that setting it up later is the "tricky" part, but I like to tackle problems one stage at a time.
Regards,
Rob (1987 350i)
Anybody experience/tips to finding/fitting one?
Is it as straight forward like installing a fuel pressure regulator for example?
I know that setting it up later is the "tricky" part, but I like to tackle problems one stage at a time.
Regards,
Rob (1987 350i)
The 520 has a Wilwood lever type adjuster bolted to the inside wing near the master cylinder. Biggest headache was getting the right fittings to take the pipes and bending/flaring the pipes. Worth buying a flaring tool for about £20 because there are quite a few pipes and flares to do. Also ended up using a pressure bleeder to get rid of any air as the normal pump method wasn't up to it. .
Steve
www.tvrbooks.co.uk
Steve
www.tvrbooks.co.uk
Two types you can use.
The in dash twiddly knob type and the flow reducer type as per SH.Jeff Stathem has the former on the factory racer. It's a twin cylinder set up bolted to the existing/standard servo. Kits can be got from Demon tweaks but would need 'feckling'. Best route is as per SH for any use other than for a rally car i.e. Road, Sprint or track days. Look in DT catalogue as you can get the under hood type or the one you can fit in the car - looks cool but a pain in the A*** to fit!!.
GW
The in dash twiddly knob type and the flow reducer type as per SH.Jeff Stathem has the former on the factory racer. It's a twin cylinder set up bolted to the existing/standard servo. Kits can be got from Demon tweaks but would need 'feckling'. Best route is as per SH for any use other than for a rally car i.e. Road, Sprint or track days. Look in DT catalogue as you can get the under hood type or the one you can fit in the car - looks cool but a pain in the A*** to fit!!.
GW
Thanks for the info, the project path becomes "clearer".
Had thought already that making the pipes up would be the biggest headache. And I have an immobiliser working on the front brakes as well to make this an even more complex task.
It looks like some steps to this project are added....
Would like to see an installation to a wedge before I start as well. For example yours Steve (and not only for the brake bias), but living in Belgium won't make that an easy one.
Rob
Had thought already that making the pipes up would be the biggest headache. And I have an immobiliser working on the front brakes as well to make this an even more complex task.
It looks like some steps to this project are added....
Would like to see an installation to a wedge before I start as well. For example yours Steve (and not only for the brake bias), but living in Belgium won't make that an easy one.
Rob
There are actually two different things being talked about here. Many race cars have adjustable brake balance. This usually takes the form of two brake master cylinders side by side, the two pushrods are connected by a beam and the pedal pushes in the middle of the beam so the pedal pushes both master cylinders. By screwing the pivot point sideways you can adjust the balance between the front and rear brakes, and you can fit a remote adjuster somewhere where the driver can reach it. I think this is what Jeff has, and it allows you to adjust the static brake balance for example to cope with changes in the fuel load, aerodynamic effects, condition of the tyres and brakes and to tweak the understeer/oversteer characteristics of the car under braking. You very rarely see these on road cars because they require complicated dual master cylinders and are relatively expensive and difficult to fit.
The second type of valve is a brake bias regulator aka pressure limit valve. This is just a gizmo placed in the brake line to the rear brakes, every production car has one of these. What this does is reduce the amount of extra braking at the rear as you brake harder and harder, the idea being that the ratio of braking front/rear needs to match the weight distribution, and weight transfers forwards under braking. There are two common types, the first sort senses acceleration and the second sort senses hydraulic pressure. The V8S came with the acceleration sensing sort, yours may vary. The aftermarket adjustable ones tend to be of the pressure sensing sort. If you're fitting one, you just need to locate the existing bias valve, and basically plumb the new one in in its place. You will probably need to bend the pipes to line up with the new valve, you may need to replace the end fittings too unless you can match the end fittings with the new valve. The valves are directional, make sure it is plumbed in the right way round!!! Final problem is to find the best setting for the valve. This is done by trial and error, adjust it until front and rear brakes lock at about the same time under heavy braking. If your static balance is wrong you'll find that the best bias setting for slippery conditions is different to the one for very grippy conditions, there are ways round this but no easy ones so find a compromise if you can.
The second type of valve is a brake bias regulator aka pressure limit valve. This is just a gizmo placed in the brake line to the rear brakes, every production car has one of these. What this does is reduce the amount of extra braking at the rear as you brake harder and harder, the idea being that the ratio of braking front/rear needs to match the weight distribution, and weight transfers forwards under braking. There are two common types, the first sort senses acceleration and the second sort senses hydraulic pressure. The V8S came with the acceleration sensing sort, yours may vary. The aftermarket adjustable ones tend to be of the pressure sensing sort. If you're fitting one, you just need to locate the existing bias valve, and basically plumb the new one in in its place. You will probably need to bend the pipes to line up with the new valve, you may need to replace the end fittings too unless you can match the end fittings with the new valve. The valves are directional, make sure it is plumbed in the right way round!!! Final problem is to find the best setting for the valve. This is done by trial and error, adjust it until front and rear brakes lock at about the same time under heavy braking. If your static balance is wrong you'll find that the best bias setting for slippery conditions is different to the one for very grippy conditions, there are ways round this but no easy ones so find a compromise if you can.
Look on www.thinkauto.com
Came across these brake balancers whilst looking at their Silicon hoses etc.
Came across these brake balancers whilst looking at their Silicon hoses etc.
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