Pedal box - Page 3 - Saxperience

axsaxoman · 2nd August 2011, 14:24

so are you using pull or push cylinders + what dia pistons on m/c and calipers.
I will be interested to see the final .
i could not see enough space to fit push cylinders with std dash and with other clearance problems with column and things like --heater ducts etc and as the blower motor is other side of pedal box it means no heater ,as far as i could see --not a good idea in uk ,yes you can fit a heated screen (£300)

slammed106 · 2nd August 2011, 19:21

Quote:

Originally Posted by axsaxoman

so are you using pull or push cylinders + what dia pistons on m/c and calipers.
I will be interested to see the final .
i could not see enough space to fit push cylinders with std dash and with other clearance problems with column and things like --heater ducts etc and as the blower motor is other side of pedal box it means no heater ,as far as i could see --not a good idea in uk ,yes you can fit a heated screen (£300)

er.. was that aimed at me??

mine use regular "push" cylinders and as you can see in this pic the ductwork for the screen/dash vents is still in place.. but i was planning on going for a heated screen anyway, if thats still not enough then i was planning on using a small T7design heater and mould some ducting into the dash vents and mounting it off the dash/cage bar:

with regards to the std instruments giving clearance.. i don`t have to worry:

adamskiTNR · 2nd August 2011, 21:52

are those wing nuts i see? lol

slammed106 · 3rd August 2011, 07:14

Quote:

Originally Posted by adamskiTNR

are those wing nuts i see? lol

too right there wingnuts... the colomns been in and out more times than Ron Jeremys schlong during the mock build, gotta make life as easy as possible..

axsaxoman · 3rd August 2011, 14:45

so,no blower motor ,so not any good for a road car --which was what i said in the very first post --there is no simple way for it be done on a std car and work correctly with std dash and heater +ventilation system .
It is just possible to do if you used pull cylinders with remote reservoirs by having cylinders half in engine bay -- but too much money for most people .
If I were you i would still try to get a bigger ratio than 6-1 on the pedal -if look at some of the ready made hanging type pedal boxes they go for 7.5-1--more the better if you are not using a servo .
you didn,t answer me on caliper piston sizes --.
remember you need 80bar of line pressure at least to work well..
If I were you at this stage ,while you are mocking up fit cylinders to a gauge and check it with pedal pressure required

slammed106 · 3rd August 2011, 18:16

Quote:

Originally Posted by axsaxoman

so,no blower motor ,so not any good for a road car

well, thats YOUR opinion.. just because the car doesn`t have the factory ventilation it doesn`t mean there arent solutions to the problem...

moving South may be 1 for you to consider, it doesn`t rain everyday when you get south of newcastle....

Quote:

Originally Posted by axsaxoman

If I were you i would still try to get a bigger ratio than 6-1 on the pedal -if look at some of the ready made hanging type pedal boxes they go for 7.5-1--more the better if you are not using a servo .

but then in using a mega ratio`d setup you end up with a LOT of pedal travel to get the equivalent master cylinder operation.. from the ones i`ve been looking at (wilwood/AP) they range from 6 up to 7.25..

Quote:

Originally Posted by axsaxoman

you didn,t answer me on caliper piston sizes --.

because i dont know what calipers i intend to use at the minute.. depending on the piston size in them, maybe, the twin pot AP items used on the lotus elise/exige/340.. maybe the "peugeot" branded AP 4 pots...

axsaxoman · 4th August 2011, 09:18

very aggresive reply to my post .
coming back with coments like "your opinion".just shows that you have no experience of using a car in th uk --north or south with no demisting system in all weather conditions--even on a racecar --I have to presume you are some sort of "pussy" that doesn,t go out in the rain or cold damp day .
stripped out car = tin box ,
then add cold air outside and hot sweaty driver + you will get condensation on windscreen and all bare metal surfaces,even a sligth drizzle on your race overalls when outside the car+ water on soles of boots will be enough to cause steaming up once you get in.
the work it takes to fabricate a different shaped duct from heater motor to the heater unit will be well worth the time it takes to construct,
you use a stand alone dash ,so remove the original one and you will have plenty of space to reroute the blower duct
I will say no more on the subjet and leave to guess at the important bits --seems its hard to give anybody the REAL information they need to make a good conversion .
you even say ones you have looked at range up to 7.25 ,so your 6-1 is on the very short side ,and piston dia will have a very large effect on pedlal load + travel

this is your first pedal box .it may be well to take some notice of people who have done this many times before on a many different cars + had all the problems you will encounter.

,

slammed106 · 4th August 2011, 12:08

No aggression at all.. as for driving in the rain.. oooh no!! My baby will get wet.. like i said down south we have dry days so its possible to enjoy the car without the inclement conditions...

As for taking your advice, im sorry but i choose whom i listen to carefully.. im in no doubt you have vast knowledge but tbh.. you deliver most of it on forums as a patronising arrogant man.. and when i phoned to discuss an engine build many many many years ago your phone manner seemed identical..

Gareth_R · 4th August 2011, 12:26

just get a heated windscreen. The standard heater system is pretty poor and not that great at clearing the rest of the car anyway. As long as you can see out the front, jobs a good'un

heated screen isnt much dearer that a standard one and then its just a wee bit of wiring and a relay

AlexB^p · 4th August 2011, 12:58

Quote:

Originally Posted by Gareth_R

just get a heated windscreen. The standard heater system is pretty poor and not that great at clearing the rest of the car anyway. As long as you can see out the front, jobs a good'un

heated screen isnt much dearer that a standard one and then its just a wee bit of wiring and a relay

Or if you have polycarbs pull the wiring for the rear screen to the front

adamskiTNR · 4th August 2011, 21:03

an easy solution to most conditions is anti fog rain x on the inside of the screen. works for us at all the rainy races so far this season.
The m/c piston size can easily be worked out with a few formula's so i would do those sums as soon as you decide on your calipers to make the design and development stage of the project far shorter

slammed106 · 4th August 2011, 21:20

adamski- definatly, ive asked a couple of people what size the lotus AP twin pots are and some say 42, some say 44mm

the reason i initially thought of these was that the lotus doesn`t come with servo assistance..

i`ve been reading thru a few peoples blogs recently (mainly the 205 boys as a few of them run bias boxes..

i saw a couple running .625 M/c`s on the front and .7 for rears (at least thats what they said) so assuming my skinny pins can provide 150lb`s of force on the pedal??

150x6 = 900lbs of force @ cylinders..

assuming valve is central...

front : 450/0.3 =1500 psi of line pressure (103bar) - (0.3 is the m/c area in sq/in)
rear : 450/0.385 = 1168 psi (80.5bar) - (0.385 is the m/c area)

like i said i dont know what calipers they were using so ned to find a few more things out...

0.625 seems small though.. maybe compensating for a lower pedal ratio? small pistoned calipers??? was led to believe i`d be looking more towards 0.75" front cylinder.....

axsaxoman · 5th August 2011, 08:59

here we go again --patronising as usual
-if you wish to see common sense that way.
150lbs pedal pressure ?????
you think that pedal pressure is attainable repeatedly on a lap ?
thats like going to the gym + bench pressing near 70kgs with one leg
half of that is a better figure to aim for

a lotus elise is a rear engined car ,so brake set up+ balance will need to be totally different as weight distribution is totally different .
braking on fwd car will be around 80/20split to the front .

If anyone is being arrogant it is you in thinking everyone looking at this before you has got it wrong and you have the miracle cure-
-that is a far better description or arrogance .
all I have done is offered information to help you find the correct answer to your problem .
If i came accross as arrogant when you asked about engine mods it is probably due to me not aggreeing with what you were proposing ,same as with this project.

slammed106 · 5th August 2011, 10:11

Arrogance and confidence are 2 very different traits..

adamskiTNR · 5th August 2011, 20:04

this thread is quite an interesting read with the opinions added. but try and keep the opinions on the technical side if you can

axsaxoman · 8th August 2011, 10:32

I have done nothing else .
i consider it of technical importance to be able to see where yuor going on a wet day --which could be half the year in the uk

slammed106 · 9th August 2011, 19:41

Quote:

Originally Posted by adamskiTNR

this thread is quite an interesting read with the opinions added. but try and keep the opinions on the technical side if you can

apologies fella....

ok! finally got some replies from the 205 peeps... Spiky runs with the lotus Elise 2pots up front but has recently swapped back to a servo unit.. from looking at his photos it looks like his DIY unit was approximatly 5:1 ratio.. (its tricky to scale from a photo though lol...) he did a few track days in it so it obviously worked to a degree but not perfect.....

the other lads i spoke to and got pics from were happy with there setups.. from looking at the pics they had more pedal ratio but also used 0.625 and 0.7 cylinders...

the OBP 205 unit is listed as a 6:1 ratio..

i also caught up with Dean on facebook a whileback asking him about his floor mounted OBP unit (i was considering 1 of these but cant loose any legroom as the seat wont go back with the X in the main hoop of my cage).. he`s had a play about with master cylinder sizes and is now happy with it on road an track and again that unit is listed as a 6:1 pedal ratio...

slammed106 · 23rd September 2011, 21:03

adamskiTNR · 24th September 2011, 10:58

Nice one. Have you tried it with some pressure yet?

slammed106 · 24th September 2011, 20:41

No mate.. im still faffing about with reservoirs and mounting the bulkhead fittings once thats done i can get the pipes made up..

Finally got some calipers but need to get some 300mm discs for them and get the bells/carriers machined.. sooooo much to do lol!!