Braking advice needed
ste - 5/10/15 at 10:38 PM
Hi all,
Currently building an MX5 engined, sierra running geared Roadster.
I haven't got any brakes yet so what I want to know is which direction to take.
I'd like to keep the weight down so ali 4 pots is my preference.
I have sierra front uprights and the rear is a modified upright with the sierra brackets welded to it.
Options so far are wilwood front http://www.rallydesign.co.uk/product_info.php?products_id=10508
rear http://www.rallydesign.co.uk/product_info.php?products_id=15580
or hi spec
front http://www.hispecmotorsport.co.uk/Sierra%20260mm%20Ultralite%204.html
rear http://www.hispecmotorsport.co.uk/Sie253UL2SVA.html
am i best fitting a balance bar pedal box?
How do i work out what size master cylinders etc?
Thanks
rdodger - 6/10/15 at 08:05 AM
I used the Wilwood set up on my car which like yours is MX5 engine Sierra running gear.
I have 260mm vented Midlite on the front and the drum/disc kit on the rear with the Powerlite hand brake calipers.
13" Wheels
Regarding the Master Cylinder I started with the Fiat M/C which gave great balance but was 3/4 and gave a too soft pedal. I changed to a 13/16 M/c
from a Nissan Stanza and now the feel is great and the balance spot on.
I since found out that the Fiat M/c is 13/16 TRW-PMF182, Fiat part number 71738443, ATE part number 24.2120-0801.3, Delphi part number LM70135
After IVA I fitted an inline valve to reduce pressure to the rear if required on wet track days. To be honest it isn't required but I bought it
during the build so thought I would fit it 
bi22le - 6/10/15 at 06:18 PM
I have Willwoods on the front and boggo standard Sierra calipers on the rear.
If you budget can do it I would recommend going for Willwood (or similar) MC with a balance bar.
When I changed my rear pads from an unknown brand (but crap) to basic level Mintex the rear was locking up easily on track. Something that would of
been difficult to adjust and get right without a balance bar and inboard adjuster.
The first time I have needed to adjust the brakes in 5 years of trackdays but it paid its way in that single track day. Now the car is balanced again
and utilising the new found braking ability to the rear.
FWIW I have solid discs all round and have NEVER seen brake fade. remember the Sierra weighs over twice what our cars do, I would save weight and
money and go for solids.
ste - 6/10/15 at 10:09 PM
Thanks for the advice, i was wanting to go solid anyway as I had vented discs on my last car and you couldn't get any heat into the pads
I'll have a look into the bias pedal boxes
mcerd1 - 7/10/15 at 12:12 PM
there always seems to be a bit of debate about the wilwood rear handbrake calipers and if they are effective enough for the IVA...
the bog std. sierra rear ones should be plenty powerful enough if a little heavy
some folk have used alloy VW calipers (off mk4 golfs or similar) as they were near enough a direct replacement and saved a bit of weight...
https://www.google.co.uk/?gws_rd=ssl#q=site:www.locostbuilders.co.uk+vw+alloy+caliper
The Black Flash - 12/10/15 at 09:42 PM
quote:
Originally posted by mcerd1
there always seems to be a bit of debate about the wilwood rear handbrake calipers and if they are effective enough for the IVA...
the bog std. sierra rear ones should be plenty powerful enough if a little heavy
some folk have used alloy VW calipers (off mk4 golfs or similar) as they were near enough a direct replacement and saved a bit of weight...
https://www.google.co.uk/?gws_rd=ssl#q=site:www.locostbuilders.co.uk+vw+alloy+caliper
Yeah, the handbrake action on the willwoods is very poor. I had to change mine to get through IVA. In doing so I got to compare them both for
weight; while the front sierras weigh a ton and the willwoods are much lighter, at the rear it's a different story. The rear sierras are much
smaller and lighter than the fronts, and not much heavier than the willwoods. Plus the willwoods need larger disks. I didn't weigh them but a
rough "in the hand" comparison convinced me that there is very little difference between the two setups at the rear.
ste - 12/10/15 at 10:02 PM
Thanks for all the replies. I've settled on wilwoods and solid discs on the front and audi aluminium rear calipers and solid discs.
Going to get them ordered this week and update my build thread
mcerd1 - 13/10/15 at 12:58 PM
quote:
Originally posted by ste
Thanks for all the replies. I've settled on wilwoods and solid discs on the front and audi aluminium rear calipers and solid discs.
Going to get them ordered this week and update my build thread
Have you checked the Audi calipers will fit under your wheels?
I'm told they are a little bit bigger than the sierra ones
ste - 13/10/15 at 01:55 PM
They should do. Pro race 1.2 in 15 inch
Ben_Copeland - 13/10/15 at 02:20 PM
quote:
Originally posted by ste
They should do. Pro race 1.2 in 15 inch
It also depends on your offset. I ran et16 with mine, et 38s might hit
ste - 13/10/15 at 03:35 PM
Yes, was in a rush typing that but will be et16 offset