Mr C
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| posted on 14/7/13 at 07:20 PM |
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Braking options for a V-Storm
A couple of us are looking at upgrading our brakes on our v-storms as they are currently next to useless with the fronts doing all the work and the
backs doing nothing.
Current set up is 255 vented discs with AP 4 pot calipers up front, vw mk 4 rear calipers with 253/273 solid discs with a remote tandem master
cylinder 60/40 split f/r
The car is 33/66 weight distribution some research shows that atom go large and equal front and back along with the new Vühl 05 which has a very
similar weight (740kg) and weight disribution to the v-storm. So we are looking to go same size front and back with 280 or there abouts discs and 4
pots all round with some sort of handbrake mechanism also potentially loosing the tandem master cylinder and replacing it with a 50/50 split along
with a brake proporting/bias valve.
We have cortina/caterham uorights up front and sierra XR4 type bearing carriers with mounting points for calipers
Had a look at Wilwood and Hispec, bit of a minefield, looking for any thoughts on a creative cost effective solution.
Girl walks into a bar and asks for a double entendre, so the barman gave her one
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rodgling
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| posted on 14/7/13 at 09:22 PM |
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If the backs are doing nothing then I would think that you should try a bias bar or different master cylinder sizes. Hi-spec do make a caliper which
should be a drop-in replacement for the rear, which might be an improvement, but personally I would start with getting the balance right.
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onenastyviper
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| posted on 15/7/13 at 06:34 AM |
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Doesn't braking balance depend on the dynamic weight distribution of the vehicle?
"If I knew what I was doing then it wouldn't be called research would it?...duh!"
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russbost
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| posted on 15/7/13 at 07:54 AM |
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Don't waste your money changing rear brakes until you've tried a bias valve or similar method of reducing pressure to the fronts. This
will mean you will need more pedal presure, but if you bias the brakes more to the rear then you will get more overall braking effort - it is
obviously very important NOT to push the braking bias too much to the rear as the last thing you want is a rear end lock up.
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
http://shop.ebay.co.uk/furoreproducts/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
|
NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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Mr C
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| posted on 15/7/13 at 03:57 PM |
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Thanks all, Thanks Russ, hope all is well in your neck of the woods. The master cylinder unfortunatley is biased 2:1 which can't be adjusted so
the plan is to find a suitable replacement and add in a bias valve of some sort. Ideally it would be great to add separate mastercylinders and a bias
bar but a lack of installation room makes this difficult. I'm not 100% convinced about the efficacy of the rear callipers, only just scrapping
through the IVA test so this may be the next items to go, possibly for powerlite handbrake callipers.
If anyone has any ideas on tandem master cylinder piston sizes etc as a starting point that would be helpful along with a recommendation for a bias
valve. (I'm presuming a bias valve will only reduce the pressure to the back)
Girl walks into a bar and asks for a double entendre, so the barman gave her one
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rdodger
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| posted on 15/7/13 at 04:09 PM |
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Would it not be possible to change the master cylinder to an equal one then add a wilwood bias valve in the rear line to reduce the rear braking
effort?
Sounds like the cheapest/easiest route. The mk4 Golf handbrake calipers are pretty good and the handbrake element is a lot better than the Wilwood
handbrake caliper.
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rodgling
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| posted on 15/7/13 at 04:49 PM |
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Would think the Hi-Spec option will be much easier to fit to the rear than the Wilwood caliper, as you won't need to make a mounting bracket or
anything, it should just bolt straight on. Golf rears should be OK though.
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jeremy
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| posted on 16/7/13 at 10:01 AM |
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We've found a Wilwood 50/50 master cylinder and Wilwood proportioning valve(s). Next step is to spend more money (!!) and fit them.
I was interested to read about the proportioning valve having a 'knee' in the pressure graph - so at low braking pressures, the front and
rears will get 50% each. Harder braking means more pressure will go to the front as the weight of the car shifts towards the front.
As Mike said, we'd love dual cylinders and a balance bar but it would take some serious surgery of the pedal box to fit.
I guess we're down to experimenting....
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britishtrident
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| posted on 16/7/13 at 10:58 AM |
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quote:
Originally posted by russbost
Don't waste your money changing rear brakes until you've tried a bias valve or similar method of reducing pressure to the fronts. This
will mean you will need more pedal presure, but if you bias the brakes more to the rear then you will get more overall braking effort - it is
obviously very important NOT to push the braking bias too much to the rear as the last thing you want is a rear end lock up.
Fitting a "bias valve" in the front brake circuit is a definite No NO! any valve that cuts off/reduces/proportions the
hydraulic pressure is for the rear circuit only.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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rodgling
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| posted on 16/7/13 at 11:03 AM |
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You can of course adjust brake balance by selecting a caliper with suitable caliper piston area (similar to changing master cylinder area), but
obviously this is expensive if you go through several iterations and caliper choice may be limited.
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jeremy
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| posted on 16/7/13 at 11:07 AM |
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quote:
Originally posted by britishtrident
Fitting a "bias valve" in the front brake circuit is a definite No NO! any valve that cuts off/reduces/proportions the
hydraulic pressure is for the rear circuit only.
Agreed
quote:
Originally posted by rodgling
You can of course adjust brake balance by selecting a caliper with suitable caliper piston area (similar to changing master cylinder area), but
obviously this is expensive if you go through several iterations and caliper choice may be limited.
Indeed, and when we're talking about the rears, there is also the issue of a handbrake solution every time.
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rodgling
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| posted on 16/7/13 at 11:11 AM |
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quote:
Originally posted by rodgling
You can of course adjust brake balance by selecting a caliper with suitable caliper piston area (similar to changing master cylinder area), but
obviously this is expensive if you go through several iterations and caliper choice may be limited.
Indeed, and when we're talking about the rears, there is also the issue of a handbrake solution every time.
Yes, but don't forget you can change the front (I think reducing caliper piston area at the front should make the fronts less effective), as a
way of making the rears do more of the work.
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jeremy
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| posted on 16/7/13 at 11:15 AM |
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quote:
Originally posted by rodgling
quote:
Originally posted by rodgling
You can of course adjust brake balance by selecting a caliper with suitable caliper piston area (similar to changing master cylinder area), but
obviously this is expensive if you go through several iterations and caliper choice may be limited.
Indeed, and when we're talking about the rears, there is also the issue of a handbrake solution every time.
Yes, but don't forget you can change the front (I think reducing caliper piston area at the front should make the fronts less effective), as a
way of making the rears do more of the work.
Yeah - if anything in out application the fronts should be the last thing to change as they are AP 4 pots with proper lug mounts that bolt on
perfectly - so good quality and we have a question mark over the strength/performance of the rears. I would also be nervous about reducing braking
effectiveness
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MarcV
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| posted on 16/7/13 at 11:26 AM |
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I would also suggest getting the balance setup before swapping calipers and discs. Front calipers should be fine items, but are they available with
different piston areas? I would not worry about the VW calipers, they should be up for the job.
First stop would be a proper MC with a (adjustable) pressure reduction at the rear.
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russbost
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| posted on 16/7/13 at 12:16 PM |
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"Fitting a "bias valve" in the front brake circuit is a definite No NO! any valve that cuts off/reduces/proportions the hydraulic
pressure is for the rear circuit only"
Ok, I've never tried it, but how is fitting a bias valve into the front circuit in any way different to fitting it in the rear circuit? In
either instance you'd only be doing it because there is inadequate braking getting to the circuit at the opposite end - I'm not saying
you're not right, but I'd like to hear why it should be such a no no? So far as I can see the only down side is that you'd need more
pedal pressure to acheive the same braking effort, providing you can still get the fronts to lock b4 the rear I can't see how that's a
problem???
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
http://shop.ebay.co.uk/furoreproducts/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
|
NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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britishtrident
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| posted on 16/7/13 at 12:49 PM |
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Yes the car needs about a 50-50 split I would estimate with the current setup has only about 20% the braking done by the rear.
This will be a quick post as I don't have time right at this moment to do Brake balance 101 but almost everything thing is wrong with this
setup even just switching to Siarra 4x4 or MG TF rear callipers would give 20%+ more braking on the rear axle at the expense of a lot of
unsprung weight.
Off the top of my head ISTR golf GTI rear callipers have a 37.5mm dia piston Sierra 2 litre 4x4 rear calliper pistons are about 43mm dia.
Again off the top of my head this gives an effective hydraulic area of 1,100 mm^2 for the Golf calliper. and about 1400 mm^2 for a Sierra 4x4
rear
In contrast a standard Cortina front calliper has an effective hydraulic area of 2,200 mm^2
I don't know any other calliper options for the rear that will give a bigger hydraulic area and have an effective handbrake mechanism.
The master cylinder also needs replaced, provided the front callipers are not enormous the Fiat or early Fiesta or early Polo items used by many
Locosters should do the job if a balance bar is to awkward to fit in the space available.
But still more braking has to be removed from the front unless a balance bar can be fitted that leaves the only option is to fit smaller brakes
to the front not as drastic as it sounds as even without knowing the piston diameters in the front callipers it is obvious the the front is
way over braked both in terms of disc size and effective hydraulic area. I don't the diameters of the pistons in the curent calliper but
I would suggest standard diameter Cortina solid discs (as vented discs are over kill and will result the front brakes being over cooled when the
rears are warmed up also this will save on unsprung weight) and callipers
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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russbost
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| posted on 16/7/13 at 01:57 PM |
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quote:
Originally posted by britishtrident
Yes the car needs about a 50-50 split I would estimate with the current setup has only about 20% the braking done by the rear.
This will be a quick post as I don't have time right at this moment to do Brake balance 101 but almost everything thing is wrong with this
setup even just switching to Siarra 4x4 or MG TF rear callipers would give 20%+ more braking on the rear axle at the expense of a lot of
unsprung weight.
Off the top of my head ISTR golf GTI rear callipers have a 37.5mm dia piston Sierra 2 litre 4x4 rear calliper pistons are about 43mm dia.
Again off the top of my head this gives an effective hydraulic area of 1,100 mm^2 for the Golf calliper. and about 1400 mm^2 for a Sierra 4x4
rear
In contrast a standard Cortina front calliper has an effective hydraulic area of 2,200 mm^2
I don't know any other calliper options for the rear that will give a bigger hydraulic area and have an effective handbrake mechanism.
The master cylinder also needs replaced, provided the front callipers are not enormous the Fiat or early Fiesta or early Polo items used by many
Locosters should do the job if a balance bar is to awkward to fit in the space available.
But still more braking has to be removed from the front unless a balance bar can be fitted that leaves the only option is to fit smaller brakes
to the front not as drastic as it sounds as even without knowing the piston diameters in the front callipers it is obvious the the front is
way over braked both in terms of disc size and effective hydraulic area. I don't the diameters of the pistons in the curent calliper but
I would suggest standard diameter Cortina solid discs (as vented discs are over kill and will result the front brakes being over cooled when the
rears are warmed up also this will save on unsprung weight) and callipers
So, particularly with reference to your last paragraph "more braking has to be removed from the front" so why is a bias valve such a no
no? I can't see the logic???
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
http://shop.ebay.co.uk/furoreproducts/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
|
NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
|
britishtrident
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| posted on 16/7/13 at 02:09 PM |
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quote:
Originally posted by russbost
quote:
Originally posted by britishtrident
Yes the car needs about a 50-50 split I would estimate with the current setup has only about 20% the braking done by the rear.
This will be a quick post as I don't have time right at this moment to do Brake balance 101 but almost everything thing is wrong with this
setup even just switching to Siarra 4x4 or MG TF rear callipers would give 20%+ more braking on the rear axle at the expense of a lot of
unsprung weight.
Off the top of my head ISTR golf GTI rear callipers have a 37.5mm dia piston Sierra 2 litre 4x4 rear calliper pistons are about 43mm dia.
Again off the top of my head this gives an effective hydraulic area of 1,100 mm^2 for the Golf calliper. and about 1400 mm^2 for a Sierra 4x4
rear
In contrast a standard Cortina front calliper has an effective hydraulic area of 2,200 mm^2
I don't know any other calliper options for the rear that will give a bigger hydraulic area and have an effective handbrake mechanism.
The master cylinder also needs replaced, provided the front callipers are not enormous the Fiat or early Fiesta or early Polo items used by many
Locosters should do the job if a balance bar is to awkward to fit in the space available.
But still more braking has to be removed from the front unless a balance bar can be fitted that leaves the only option is to fit smaller brakes
to the front not as drastic as it sounds as even without knowing the piston diameters in the front callipers it is obvious the the front is
way over braked both in terms of disc size and effective hydraulic area. I don't the diameters of the pistons in the curent calliper but
I would suggest standard diameter Cortina solid discs (as vented discs are over kill and will result the front brakes being over cooled when the
rears are warmed up also this will save on unsprung weight) and callipers
So, particularly with reference to your last paragraph "more braking has to be removed from the front" so why is a bias valve such a no
no? I can't see the logic???
Hint --- weight transfer --- difference between front to rear balance required on wet or slippery conditions and a perfect dry high
friction road surface.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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russbost
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| posted on 16/7/13 at 03:06 PM |
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I'm talking about an adjustable hydraulic brake bias valve, where is the difference between mechanically adjusting brake balance as with twin
pedal box, or mechanically/hydraulically by playing with the piston sizes of calipers/master cyl etc or adjusting with a bias valve reducing pressure
to the rears as is frequently fitted to 7 type cars, or, as we are talking about in this instance, a bias valve to reduce pressure to the front brakes
(which is surely exactly what you are doing when you increase front master cyl dia?)
I'm obviously being exceptionally thick here, but what has weight transfer got to do with it? An adjustable system is just that, adjustable, it
can't be 100% perfect for all road conditions, weight transfer conditions etc. I wasn't suggesting adjusting the front pressure back to
the point where you're locking rears, tho' that could easily be accidentally done with a mechanical system, particularly when braking into
a downhill corner
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
http://shop.ebay.co.uk/furoreproducts/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
|
NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
|
Mr C
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| posted on 16/7/13 at 04:46 PM |
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Jeremy and I know exactly where you are coming from Russ, even with my limited knowledge, and I think the course of action is decided, and the posts
from Russ, Marc, Rdodger supoort the case to change out the master cylinder and fit a bias valve to the rears.
As rodgling states there are other options which are easy said in a sentence but costly in the real world (I think its fair to say both Jeremy and I
have had quite a bit of that during the build of these cars!!) The master cylinder option will get us a step in the right direction is cost effective
and there is scope to improve other componenets as required.
I also spoke to the garage that are repairing my chassis today, anything other than an oem handbrake mechanism is sh!te and the golf calipers should
be up to the job and they are running Hispec handbrake calipers on their kit car!!!! so are in a good position to make that call in my book.
I think one of my rear calipers is faulty which is not helping
I'm not into forum debates and arguing the finer technical details of insignificant aspects, especially just to get my post count up and would
rather the thread didn't go in that direction, so we'll leave the thread there, unless Jeremy or Russ have anything further they wish to
add.
Thanks all.
Mike
BTW nice avatar Jeremy, saw mine today and it looks a total mess 
Girl walks into a bar and asks for a double entendre, so the barman gave her one
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britishtrident
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| posted on 16/7/13 at 06:30 PM |
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quote:
Originally posted by russbost
I'm talking about an adjustable hydraulic brake bias valve, where is the difference between mechanically adjusting brake balance as with twin
pedal box, or mechanically/hydraulically by playing with the piston sizes of calipers/master cyl etc or adjusting with a bias valve reducing pressure
to the rears as is frequently fitted to 7 type cars, or, as we are talking about in this instance, a bias valve to reduce pressure to the front brakes
(which is surely exactly what you are doing when you increase front master cyl dia?)
I'm obviously being exceptionally thick here, but what has weight transfer got to do with it? An adjustable system is just that, adjustable, it
can't be 100% perfect for all road conditions, weight transfer conditions etc. I wasn't suggesting adjusting the front pressure back to
the point where you're locking rears, tho' that could easily be accidentally done with a mechanical system, particularly when braking into
a downhill corner
Give a man enough rope and he will hang himself, you are very keen to display your lack of knowledge to an amazing degree.
Fitting any kind of pressure limiting or proportioning is very different from fitting a valve in the rear circuit because the direction of weight
transfer under braking is always rear to front .
Fitting a valve in the rear works well because under gentle braking (as on slippery surfaces) a greater share of braking can and should be done by
the rear wheels. If the surface is high friction and the driver applies more hydraulic pressure the weight transfer in increases a greater
percentage of the braking can be done by the front wheels but the braking effort that the rear tyres will reach a limit. A brake proportioning
or pressure limiting valve in the rear circuit if set-up correctly on a good dry surface will give a brake balance that will be drivable even on a
slippery surface.
A valve in the front circuit might be set to work in a very narrow band conditions but if set in the dry the slightest hint hint of dampness will it
still suffer bad front locking and if the valve is set for damp conditions the car just won't stop well.
I haven't checked this (someone on the forum will know one way or another ) but ISTR from a thread many years ago in this forum fitting
limiting/reducing/regulating valve in the front circuit is specifically banned.
Fitting a pressure limiting is different from fitting a brake balance bar or changing bore sizes on hydraulic components.
There is no substitute for getting the brake calliper hydraulic diameters in the right ball park as even a balance bar has its limits on how much
it can adjust out.
Once the balance setting is too far off centre it will not work properly, that can be rectified (within reason) by juggling master cylinders
bores.
But in this case the force exerted by the hydraulic pressure is at least twice that acting to the rear and the front brake pad friction is acting
on a larger diameter disc.
Based on real world experience on building and racing rear engine Modsports and Special Saloons which required almost exactly 50-50 brake
distribution in trying to balance a 54mm diameter callipers on the front with 48mm diameter callipers on the rear required one step change in master
cylinder bores in the pedal box ie 0.7" on front and 0.625" on rear to bring the balance bar anywhere near the centre of its'
usable adjustment range.
It is not a question of a Golf rear calliper not being man enough (?) it is the problem of achieving a 50-50 braking force distribution with
front calliper that have at least twice the hydraulic area of the rear callipers.
Not only is front calliper exerting twice the friction force on the disc the rear is but it is exerting it at larger radius on the disc than rear
calliper.---- square that circle.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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Mr C
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| posted on 16/7/13 at 07:13 PM |
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Trident as much as you think you are being helpful I find your posts quite arrogant and insulting to others that try and post in a positive light. If
there was an ignore button for you I would have pressed it long before I posted the initial post in this thread. I try and refrain from posting within
this forum spefically to avoid posts like yours which are unhelpful at best and insulting at worst. I posted knowing that there are some very helpful
and valid views out there that would assist Jeremy and myself in making an informed choice, though also mindful also of responses like yours which I
had hoped would not materialise.
Jeremy's first experience of this forum is this thread, whilst not wanting to break confidentiality, I can tell you that it is not a wholly
positive experience thus far.
I ask that you refrain from knocking Russ, he is one of the most helpful guys in the game which he does with sincerity and integrity two qualities
that your posts are lacking.
I'll also bring this thread to Chris's attention before it get's out of hand
Thank you
Mike
Girl walks into a bar and asks for a double entendre, so the barman gave her one
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britishtrident
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| posted on 16/7/13 at 07:39 PM |
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quote:
Originally posted by Mr C
Trident as much as you think you are being helpful I find your posts quite arrogant and insulting to others that try and post in a positive light. If
there was an ignore button for you I would have pressed it long before I posted the initial post in this thread. I try and refrain from posting within
this forum spefically to avoid posts like yours which are unhelpful at best and insulting at worst. I posted knowing that there are some very helpful
and valid views out there that would assist Jeremy and myself in making an informed choice, though also mindful also of responses like yours which I
had hoped would not materialise.
Jeremy's first experience of this forum is this thread, whilst not wanting to break confidentiality, I can tell you that it is not a wholly
positive experience thus far.
I ask that you refrain from knocking Russ, he is one of the most helpful guys in the game which he does with sincerity and integrity two qualities
that your posts are lacking.
I'll also bring this thread to Chris's attention before it get's out of hand
Thank you
Mike
I don't suffer fools who keep pushing dangerous advice, the laws of physics are the laws of physics I didn't make them up.
My advice is based on a heap of real world knowledge, training and academic study, if you care to look search on my very many posts particularly on
brakes over very many years on this forum you will find I have pretty good track record on diagnosing sorting out problems and more importantly give
no advice that is potentially dangerous.
Let me put it this way he pushed some pretty silly ideas got corrected then kept coming back.
[Edited on 16/7/13 by britishtrident]
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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russbost
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| posted on 16/7/13 at 09:08 PM |
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I have no wish to get into a childish slanging match, I did say I've never tried this, but I've certainly never heard that a pressure
reducing valve is banned from use on the front brakes, if so by what, construction and use? I'm not aware of it being mentioned in IVA,
tho' quite happy to be corrected on that. It obviously isn't the ideal solution, selecting the right size of cylinder & caliper bores
in the first place is the best starting point.
As you were adamant it was complete no no, I was interested to know the reason why, which I don't believe you have offered an adequate
explanation of, I would have expected a civil reply, not a tirade of abuse. I do only have an HND in engineering & I did my training a long time
ago, but I've also spent over 20 years at the sharp end of the motor trade & fixed more brake probs than you've had hot dinners. I
have of course also designed a car from scratch which does handle & stop properly, so presumably I'm doing something right. I would still
love to hear a proper explanation of how a pressure reduction by one method is so very different to a pressure reduction by any other method, I can
imagine that the quality & accuracy of the valve could play a part but my gut feeling is still that if setup correctly in damp conditions it would
still work in dry conditions, albeit requiring increasd pedal pressure.
I am not suggesting to anyone they should dive into any braking problem without due diligence, however I cannot see the harm in trying something
providing it is undertaken in a careful, sensible & constructive way. Obviously if you are correct that it is for any reason banned then I
wholehearthedly agree it is a complete no no!
Incidentally, I see no reason to bother Chris re this thread, it takes a great deal more to properly annoy me! 
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
http://shop.ebay.co.uk/furoreproducts/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
|
NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
|
onenastyviper
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| posted on 17/7/13 at 06:50 AM |
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The problem using a proportioning valve on the front circuit is that it changes the linearity of the system and introduces a "knee" point
where increased pedal effort does not translate into an equivalent braking effort.
To use a pressure device on the fronts is, in my opinion, not correct and potentially dangerous although 10 out of 10 for lateral thinking .
One thing that has been stated here, and I will reiterate, cars are designed to have natural understeer - it is more stable for 99.99% of drivers who
do not want the car swapping ends on them. It is the same with braking.
I would suggest that if there is a suspicion that the front brakes are doing "too much" then the entire braking system should be looked
at. To not look at it holistically is missing the point that it is an "entire car system".
As is it a kit car, it should be relatively straight forward to go from pedal to pad noting the system component details and their connections, ratios
etc.
Of course you can swap and change components but you have to be sure what you are trying to achieve?
If you want more rear braking and you have a fixed range of line pressure, you have to either increase caliper piston area (more force but requires
more fluid) or increase the effective radius of the pad (more torque).
Again, I will suggest that you need to decide what you want the extra braking for?
If it is just to have more efficient brakes then I stand by my statement - you have to look at the entire system.
If it is to "have a play", say on track then go for it - swap/change to your hearts content but tread carefully.
In either case, beware the consequences - a supposedly simple change can result in brakes that no longer function as intended - increased/decreased
pedal effort/travel, brake fade, overheating etc.
Just to "make it similar to a similar car" should not be the only reason unless you know exactly how you cars compare in all the relevant
operating conditions.
My one final piece of advice - if you make a change, for your own safety and the safety of others, make sure that you thoroughly test the results in a
safe manner and location. Attempting a 70-0mph stop would not be the greatest idea for a first test 
"If I knew what I was doing then it wouldn't be called research would it?...duh!"
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