master cyl sizes

jess · #1 (**permalink**) 04-18-2005, 05:00 AM

heya all do any of you guys that have the cr chassis running running std brake setups i need to know what master cyl sizes to run i will be running the braided lines as ive been told pedal travel can increase by up to 4 mm between rubber and braided but the engineers at work think im crazy they rec i should run 1inch bore with booster with a prop valve as i would not be able to achieve full preasure with unboosted brakes
so if theres any of you out there that are driving around with the twin cyl setup i would be intrested in your opinion on how they stop and feel would be much appreciated as i gotta put something in there soon
also what size are you guys running for cluth master cyl

confused
jess

blykins · #2 (**permalink**) 04-18-2005, 05:15 AM

I'm running a 3 master cylinder setup .....unboosted.....3/4" master cylinders all across the board....

Clois Harlan · #3 (**permalink**) 04-18-2005, 05:22 AM

I too am runnng un-boosted brakes and they work quite well. Willwoods on the front and Lincoln Mark V on the rears. Be sure and run 3/16" lines to both front and back calipers.

Clois

trularin · #4 (**permalink**) 04-18-2005, 07:43 AM

I do not have a booster, would like one, but there is metal in the way. Clois is right, make sure you run the same size lines.

The rest is a matter of pressure, and pedal. You will need to do the hydraulics math to determine your best master cylinders.

This is why Tilton provides something like eight different ones.

Hope this helps.

RallySnake · #5 (**permalink**) 04-18-2005, 11:59 AM

Jess,

I've been working on this for the last few months. I removed my MasterPower remote brake booster and went with manual brakes to get more consistant feel and to get that ugly lump out of my engine compartment.

Ron Butler recommends a balance bar pushing a 3/4 inch cylinder for the front brakes and a 5/8 inch cylinder for the rear brakes. This is based on a mix of Dodge Dart calipers on Chevy rotors on the front and Jaguar XJ6 brakes on the rear. I believe that the different sized cylinders are based on using smaller front tires. I have 275/60/15 tires all around and with this set up the rear brakes tend to lock up first. I actually spun the car while testing because of this.

So, I changed the front MS to a Tilton 7/10 inch inch unit and that helped some. But, if I hit the brakes hard while cold, the rears lock up first. The next thing I tried, was replacing the front pads with Porterfield Autocross units to give them more grip. This was better, but only when they get hot. Then, I changed the rear pads to a less agressive compund. I removed the Ferodo's and put in Axxius Quiet Stop. This helped a little more. Now, if the brakes are hot the ballance is very good, with a little front bias. If you stab them cold, however the rears lock first. I am not happy.

The balance bar adjustment does not seem to make much difference. I have tried adjusting to the rear but that only made the situation a little worse. So, it's set to full front bias. My next options are: 1. Buy a proportioning valve to reduce the pressure to the rear brakes. 2. Buy smaller front tires. 3. Buy Porterfield pads for the rear so they take longer to heat up. 4. Replace the front MS with a 5/8 inch unit.

I hope this helps you and I am open to suggestions,
Paul

coyled · #6 (**permalink**) 04-18-2005, 12:15 PM

Paul, go up in size on your rear master. It will give you a higher pedal and less line presure to the rear. I would also run the same pad on all 4 corners. I have run a number of different pads and they all act and feel differently. Some work better when hot and others better when cold. The torque curve is also different between pads. Some pads have a flat curve, meaning they have more bite based only on peddle presure. Others tend to increase bite, the harder you press on them. Bottom line, use the same pads all the way around. Scott

pneall · #7 (**permalink**) 04-18-2005, 02:58 PM

Jess,

I am running the dark side set up and that slave cylinder needs a 1" master.Yours could be different with the 302.

There are other guys running the Jaguar front and Ford rear so I will let them speak on that as I am runing Wilwood in front and that needs a 1" cylinder.

Recommend you stick with the dual cylinder set up and bias bar.This way you get all the adjustment you want and wont lock up brakes. After driving boosted cars it takes a bit of getting use to the hard pedal. You can always fit a remote adjuster for the bias bar after rego.

Phil.

Tenrocca · #8 (**permalink**) 04-18-2005, 03:15 PM

Hey Jess,

Ill be running standard brakes. Just ordered my master cylinders from a place in the US. Went Wilwood 3/4 for front, 5/8 for rear and 1" for clutch. I believe these are the sizes Ian recommends. Price was pretty reasonable, all up $206US delivered.

Cheers,
Andrew.

jess · #9 (**permalink**) 04-20-2005, 12:59 AM

thanks guys an opinion from people that actually have tried unboosted brakes makes me fell more comfortable as long as they stop and dont have to stomp on them like crazy
so im going for the same comb as you andrew
thanks heaps
jess

boxhead · #10 (**permalink**) 04-20-2005, 01:29 AM

I will need the same sizes as you aswell Andrew, can you let us know who the supplier is?

I ordered my wiring harness today, also ordered dash panel, pedal assy and handbrake cables.

The wiring will be here early next week but the other items arent in stock and could be a few weeks away.

Barry Nelson · #11 (**permalink**) 04-20-2005, 02:14 AM

Boxhead how did you go wifh the wiring plugs
Bazz.

boxhead · #12 (**permalink**) 04-20-2005, 02:45 AM

I havent had a chance to go and see the guys at Race motorcycles yet.

I will try tomorrow as I normally have a little spare time on Thursdays.

RallySnake · #13 (**permalink**) 04-20-2005, 07:00 AM

Scott,

Thanks for your suggestions. I worry most about one of my son's driving the car someday and not being ready for the rear bias issues. So, I want to make SURE this is not a problem in the future.

Paul

Tenrocca · #14 (**permalink**) 04-20-2005, 03:20 PM

David,

Sent you a PM re the supplier. If anyone else is interested let me know.

Cheers,
Andrew

GAV MILDURA · #15 (**permalink**) 04-28-2005, 04:05 AM

Hey Andrew would you redirect that PM my way?
Thank you, Gav

boxhead · #16 (**permalink**) 04-28-2005, 01:36 PM

Andrew, do you realise these master cylinders have remote reservoirs?

Tenrocca · #17 (**permalink**) 04-28-2005, 03:03 PM

David,

Im pretty sure they can be configured in a few different ways including having the reservoir attached to the cylinder. Theres a package at the post office waiting for me so once I get em Ill make sure for you. The part numbers were what the manual recommended, apart from the clutch where I went 1".

Cheers,
Andrew.

Tenrocca · #18 (**permalink**) 04-28-2005, 04:10 PM

Dave,

heres a link to the page on the wilwood web site with the details of these kits.

Cheers.

willwood

PS. This is my 100th post so should now be "senior". Whooo hoooo

CowtownCobra · #19 (**permalink**) 04-28-2005, 05:18 PM

I recently converted from seperate unboosted MC's to power brakes. I tried a number of different MC's until I found one that seemed to work the best, from a 70 mustang. I couldn't be happier, stops very clean and straight with a lot less pedal force. A small knotch in the fender well was all that was required. Go with whatever you feel comfortable with and have confidence in. In these cars you have to trust your brakes.

BMK · #20 (**permalink**) 05-12-2005, 06:29 AM

Cowtown Cobra

Dave,

Not to get off the "Thread' topic..

..but...

Did that blonde in your gallery photo on page 1 ever find what she was looking for..

If she is a relative bring her along to the London Ohio event.

Would like to help her find it..

...or get her advice on the master cylinder....

Bernie