Fitting 280 disks and 4 pot calipers to the race car and have mk3.5 rear discs and calipers. Which master cylinders do I require for each end? I am wanting modulation in the feel if that makes sense? Cheers in advance
Surely you have the same cylinders but you have a balance bar and bias valve to set the system right ?
But I have no idea what the correct one is for them brakes as at present only have 239mm discs and appropriate cylinder so jumping to 280 4pots surely will require a different size? Also back had drums on it now discs so that must be a different cylinder again so question really is then what servo is required for 280 4 pots ie 22m???and what is required for rear discs. I am presuming back will be smaller??
A few of questions: 1. What pedal box? 2. What pedal ratio? 3. What size are the pistons in your new calipers? 4. What calipers are you running now? 5. Are you running the bias now? 6. What size MC's do you have now? 7. Do you like the pedal feel/travel as it is now? 8. Is the bias bar centralised or biased to the front or rear? Answer those and I should be able to steer you in the right direction..
Edit I'm not going crazy the question mentions bias box lol Mickey's asked all the difficult questions , you've got to fill in the blanks of what you do know and the it can be discussed better Copy Nige For some reason I thought you were fitting a peddle box must have got my threads crossed ? With 280's you want a 9" servo and the 24 mm master cylinder maybe a stuby focus one if you're tight on clearance ? How much does the car weigh and what power are the things to think about . My car weighs 895 kgs without me and is about 150 bhp running standard 16 v setup with yellow stuff pads and ATE blue fluid stops the car no problem I've got a bias valve to reduce rear braking force as I've removed the rear compensator I've seen your build thread but you need to give the whole picture when asking a more technical question It's the easier for people who know to answer without trawling through your build thread
Cheers Sirg I don't have a build thread so maybe 2 of us with similar name,( I maybe should do one though as car evolves every month from race to race for xyz reasons) but I get where you are coming from regards more information....Il add to yours here and Mickeys next I am fitting a pedal box and looking at comprake and will be removing the servo Car weighs approx. 900kgs and runs around 170bhp 280s are willwood kit and going to be using ds3000 pads..may use ds2500 at rear
Cheers Mickey Comprake pedal box http://www.ebay.co.uk/itm/271417325400?_trksid=p2060778.m1438.l2649&ssPageName=STRK:MEBIDX:IT not fitted yet Ratio 5:1 Piston size unknown looks like they list several on the willwood site?? these are the items for reference though http://www.ebay.co.uk/itm/Wilwood-V...-4-Pot-Calipers-280-x-20mm-Disc-/381078557674 8v 239 standard calipers and discs now we have fitted a small manual in line bias to reduce the back end current mc looks original factory item..no idea what size it is everything is pants at mo hence upgrading the lot 8. not applicable at present cheers
Do you need Wilwoods ? Nige's car weighs about a 1000 kgs with 350 bhp and he has standard g60 brakes ie 280 discs girling single pot calipers He feels it only now getting to a point where he'd upgrade money allowing I think sparrow runs Wilwoods on his turbod mk2
I really liked my Wilwoods. You'll need to either measure the pistons in your calipers or check the part number on the caliper as without the piston diameters we're shooting in the dark. Have you considered the HRP pedal box?
I have retained std servo and MC on my (Corrado) race car with dual line bias valve to proportion the rear braking. I ran 4-pot Wilwood Superlights with std rears and pedal feel was good with no need to change MC, although the calipers weren't up to the job for racing, IMO, too much flex.
As Mike says, I run Wilwoods on my track car. Mine are are Dynalites. Standard servo, 24mm master cylinder, Mk4 rear calipers with smaller piston. I did have to fita bias valve and pressure reducer as the rear is so light. Not sure the reducer is needed, but can't be bothered to test by removing and bleeding at a track day. 900kg and 350bhp. I changed to Carbon Lorraine pads recently, and the brakes are now awesome.
Right Mickey Looks like the cylinders measure inch and an eighth in diamater..website only states inch and a quarter as smallest so must be them?? I have them on my desk if I need to measure anything else....be nice to get them off the desk and on the car
Hmmm thats pretty small for a non assisted brake system. That only gives a total piston area of 3177mm. Considering the stock mk1 GTI caliper has 3470mm and the Girling54 used on 16v's and G60's is 4580mm. (the Midilite with 1.5" pistons gives 4561mm!) When I help people spec MC's for use HRP pedal boxes I usually recommend a 0.625" master cylinder with stock calipers and 6:1 pedal ratio and thats what I would consider the limit, you have smaller piston area and 5:1 pedal ratio,so I suspect a 0.625" master cylinder will take quite a push and be quite a solid pedal. You should probably consider using an AP Racing 14mm cylinder, but you need to factor in the cost of AP Racing when deciding on pedal box options as they are about 125 each. For the rears, on a race car I'd go for a 0.700".. rears are tricky as front/rear bias is much more dependant on driver.. if you find yourself winding the bias heavily to the front with a 0.700" then consider a 0.750" for the rear to try and centralise your bias bar. Personally if they are 1.25" pistons I'd probably sell them and buy some 1.5" versions.
I agree, I doubt they are 1 1/4 if they are for rthe front, that should be on the back, they should be 1 1/2 Traditional start point for race car is 5/8 front and 3/4 rear Remember, you don't actually move the pistons that far, but the small master gives the feel
