56 replies to this topic

[Graeme Lambert]

Going to be using four pots on front, and two pots on rear, of the car so been advised I need a brake bias valve.

 

Before I go spunk my money on a new one, does anyone have a new but not used or nearly new valve they'd like to sell me instead please?

 

G

[oggster]

I am doing the same and will be following this post with interest

[chris_uk]

You dont need one.

[Graeme Lambert]

Because Chris? I'm just going by what I was told, so if there's a valid reason to save money and not do it I'm all ears mate!

[Pidgeon]

1, You canna change the laws of physics and pressure in the system will always be equal.  All these things do is limit flow, so the pressure downstream increases more slowly than the upstream pressure, but will still reach the same pressure.  To do it properly, you need a bias pedal box with two MCs, hence two systems, two pressures.

 

2, Don't we have a diagonally split system, so you're either repiping or fitting two?

[chris_uk]

Well other than its the way my car has been for years with zero problems i cant really elaborate any more. Who said you needed one? And in particular why?

[Graeme Lambert]

Well other than its the way my car has been for years with zero problems i cant really elaborate any more. Who said you needed one? And in particular why?

Lee #becauseracecar? Or #becausehesgoodatspendingmymoney?

[chris_uk]

Right.. Save your money.

[Wreelybro]

How's your pedal travel with the 4 pots Chris?

[GeorgeBC]

You need to find two sets of pads that will work well together though. I tried loads of different pads and found a lot of the time the rears would lock first. Ended up using Pagid RS14 pads on the front and Pagid RS42 (not so good) on the rear to even it up. Works well and allows you to be confident on the brakes. CLRc6 front and Rc5 rear may work as well but didn't test that combo.

[chris_uk]

Pedal travel feels fine, pedal goes hard before full travel, its just further along the travel over standard. its not quite as sharp as standard but its NOTHING like as bad as mikes if you can remember. I use cl5+ and i never lock my rears first, its always the fronts which lock first.

[Gedi]

The problem with different pads is that they'll fade differently. They might be great for normal running, but on a track session the fronts might display different characteristics than the rears, and if they fade first then you'll lock your rears at a time when you have confidence in them. This is what happened to SteveA, and he lost his car

 

Why are you changing the rears Graeme? I'd be very wary about improving rear braking without having a bias valve and having it set up properly by someone who knows what they're doing.

 

Jimmy did quite a bit of work in this area, might be worth asking for his advice.

[SteveA]

Ideally you should look at sorting your brakes out before you fit a valve so they are working most efficiently in the dry. A valve is mainly there to allow quick adjustments when required (surface changes etc).

 

My car has one and at full forward it basically has no effect and gives me the original force of all four calipers. On full back it essentially turns off the rear brakes so only front locking is possible (for very slippery braking zones)

 

Cliffies car had too much rear bias IMO (I had a bit of a rear wiggle in the dry in it) but he had four pots all round and I believe it was set up with a plenty of rear bias as Mike liked it that way  

Edited by SteveA, 07 January 2015 - 03:55 PM.

[vocky]

if you have removed the ABS unit you will have to fit one.

[leevx2.2]

I didn't have a problem with cl6 front and cl5 rear but changed to pagids and had to much rear braking it's a cheap mod and doesn't take that long so I think worth doing I will take a pic

[Graeme Lambert]

if you have removed the ABS unit you will have to fit one.

I'm keeping the lotus 4-chan abs.

[Graeme Lambert]

I didn't have a problem with cl6 front and cl5 rear but changed to pagids and had to much rear braking it's a cheap mod and doesn't take that long so I think worth doing I will take a pic

Planning on using pagids also. What did you use lee - 42 and 14 or a full set of 42 or something? You still have your abs or turned off?

[leevx2.2]

Abs turned of always I will have to check I think it was 42 and 14's

[leevx2.2]

Pedal travel feels fine, pedal goes hard before full travel, its just further along the travel over standard. its not quite as sharp as standard but its NOTHING like as bad as mikes if you can remember. I use cl5+ and i never lock my rears first, its always the fronts which lock first.

Chris you don't run 2 pots on the rear standered Brembo calipers and 4 pots should be ok that's why you have no problem .

[fezzasus]

Greame, have you worked out the piston area ratio? I was under the impression it was approximately the same as OEM and therefore no need for the bias valve.

 

I'll have an answer about you Z22SE water pipe soon, just need to get hold of someone at home.