K is this where i also query your master/slave combo bore sizes! at 14 mil master travel i'd suspect you are NOT using an equal master/slave combination.
the-lada-dude,
May 26, 10:24pm
can you not brake this down into more simple terms
mjde,
May 27, 12:07am
Snoopy, Yep as I said, at the moment I have a 5/8 clutch master pushing an 11/16 slave that gives me the 14.25mm travel that pushes the1 1/16 master. I will be able to get a little more from the setup by adjusting the length of the pushrod that joins the two ( there was a little bit of freeplay before engagement) and also by moving the attachment point on the pedal
skin1235,
May 27, 4:35am
have you put a booster in there or are you relying on leg power to keep a hold of this thing
you're playing with quite a vital life saving or threatening aspect of this rocket on wheels
while I agree get the max travel the master will allow you have to also consider the extra effort or loss of effective effort any adjustment may create, cos I can assure you that when you need to lock it up you will not appreciate the ripped hamstring or archilies tendons it took to save your life also keep an eye on the pedal height and effective travel, there is not a lot of time at 140km plus to lift a boot back an extra 2 inches even to find a pedal when you want it
mjde,
May 27, 5:41am
At this stage just relying on leg power. thinking out loud for a moment. pedal ratio of std 914 = 5:1, mechanical advantage of the 5/8 to 11/16 another 50% would this be more than a normal setup and enough to overcome pushing a larger dia master cylinder without a booster
sr2,
May 27, 8:40am
Hi; just noticed this great thread. Sorry for the late reply, I??
mjde,
May 27, 2:38pm
Good on ya sr2 I think you helped me with my e type brake problem a year or so ago. That's one of the reasons I'm not keen on boosters. Yes there a certainly people on this MB that have offered very good advice. Like you, I'm one of the old school type that enjoy building my own solutions ( read don't have the sponsorship or funds to stock the car full of willwood or tilton) while still moving forward with the project. I'ts hard enough keeping motivated when things stop while you save over a $k for a floor mounted pedal box and cylinders. I know brakes are important as I've circuit raced a couple of cars when i was a younger man. If there was a way of posting some photos it would as they say save a thousand words.
skin1235,
May 27, 7:03pm
hello sr2, theres yourself and a couple of others who I cannot think of their names at the moment that maintain their own track and rally machines far better qual'd than I to be responding Snoop ( who I have met personally a few times) is really a nice guy - and easier to understand in person - and knows his stuff too like you I'd say he has forgotten more than I'll ever learn or words to that effect
surprise re 4000psi comment, never thought it would be that high ( allow it was not a verified comment but obviously a lot higher than I had thought) will be watching this thread for updates and any valid comments as it develops, will try to sit on my hands - not something that comes easy or that I'm known to do often lol not aggressive, I'd like to learn the method and methodology to come up with a safe system that works, if it is diy on small budget even better, No8 wire techno is a particular love of mine so, if you can remember when posting, theres at least me - layman with an interest, hungry for info, -add another line to explain the why if needed, or I may have to lift my arse off my hands and ask
sr2,
May 27, 7:58pm
Hi skin 1235, you??
snoopy221,
May 27, 9:09pm
LOL @sr2.[was wondering why ya hadn't sniffed this thread out]
Yep i recall ya E type suffice to state FACT is **cleanliness is next to godliness **when a piece of crud is in ya system-if i recall correctly.
FACT again is ya just can NOT get the same 2 inches or so of master cyl (1INCH) stroke from astandard 5/8 cyl . The displacement volumes just do NOT add up. You would be better off using what appears to be the 2 tandem feeds of the original porsche master and combining them to a purpose built long travel slave cyl. End of the day you really need a boosted master with your 4 pots AND a RACING PAD situationIMHOand at LEAST 2 inches of master cyl travel.I M HO. i.e. 2 TO 2500 p s i AVAILABLE AT CALIPERS[As sr2 will point out discs are NOT self energising like drums] sr2 will recall glynnJones from *Fast Forward* in Aucks. Again he would be one of N Z's most experienced racing porsche people.[hence link in post#30]
Again IMOI'd head moreto a master/booster behind the drivers seat activated direct from the pedal I.E. visualize a SIMPLE rod on the floor pan connected to the pedal pulling in to a boosted master cyl at the other end. 2 90 degree weak points only-easily strenghened. mount the booster/master solid and there ya are. Giving full travel and low loading on the **homebuilt** rod-andhigh pressure from the boosted master. Or repivot your pedal from the top-and redesign your firewall and convert porsche to basic japper master booster setup.
skin1235,
May 27, 9:49pm
yep, poetic licence applied for and approved lol kinda figured that ergo the not verified part, the rest still stands though, obviously a LOT more than I envisaged
how do you address the issue re volume supplied /volume required! and can you actually achieve sufficient pressure via leg alone - can accept short travel is best possible scenario but that would reduce pressure surely or demand a much stronger leg, neither of which would be desirable at 100km + especially 4 hrs in and the damn corners are still comin fast
skin1235,
May 27, 9:55pm
don't mind me, I'm hobbled to my chair with casters due to a sever nerve pinch mid thigh, screaming agony to move so I'm stuck here rebuilding a couple of old computers and glancing at this one every so often faark I hate being locked down into one place, and hate pain even more - big chicken when it comes to pain - tramadols good, if you can get enough to keep the float going, oxycondin comes a poor second to 4 or 5 trams
mjde,
May 27, 11:10pm
it's absolutely amazing the effect adrenalin has on the amount of pedal pressure applied. Remember my first race at manfield and coming down the front straight with my right knee shaking violently as i lifted off and started to brake at the 200 mtr mark. Hell I'd only just put my foot on it lightly I thought but there seemed to be a lot of rubbery smelling smoke in the cabin.lol!
saki,
May 27, 11:47pm
Yes unboosted
saki,
May 28, 12:14am
When I first started racing my RX2 I used volvo (ATE) 4 potters 35 mm pistons from memory and used 5/8 master cylinder about 50 mm pedal travel, good pedal feel and very progressive brakes. My RX3 I used willwood calipers 11/2 pistons and stuck with the 5/8 master cyl. a bit more travel but you didnt end up with legs like Arnie. I always used a duel cylinder pedalbox, Bought the balance bar from kendall racing supplies and made my own pedal box that is modified the standard item, for master cylinders I used the cheap taiwnese items changed them every couple of seasons never gave any problems.
should I be thinking about that clutch slave and the spring they have inside to maintain pressure on the cup seal now not allowing full return of the brake master in front of it so therefore may not allow full fluid return when pedal released!
or have the trams got me fogged out
skin1235,
May 28, 2:12am
but looks very nice, robust enough I'm sure, clean tidy worksmanship, as you say can be mounted anywhere
thanks for taking the time to post the pics
mjde,
May 28, 4:18am
1. Just looking at the first part of your last reply snoopy. the slave has a max travel of 25mm the master has a max travel of 28mm and yes I know that with the current pivot point from the pedal that the 5/8 master only pushes 14.25mm. I will see if i can find an 11/16 dia master to match the slave. 2. Ls1 weighs very close to the same as a flat six porsche see Renegade Hybrids site in the states
3. The body mass will surprise you. fully dressed and ready for action will be well under a ton
yes and back in the day you are absolutley right but now we have available some very efficient brake compounds that would have stopped that little escort all day. Yep i'm useless when it comes to the calculation side of things , thats why I'm here asking you guys
snoopy221,
May 28, 4:44am
Yep i'm useless when it comes to the calculation side of things , thats why I'm here asking you guys
If i were you i'd drop a dime on glyn jones- he knows me personaly as mike from central motoring back in the nineties-when what is now race brakes -0800racebrakes john arkley esquire-was masterparts-next door to glyn at fast forward. porsches are unique.yeah i know em a bit-and i know brakes. glynn may well have been involved with a 914 upgrade- point is as much as i or sr2 or skin can respectivley advise you
it IS a damn porsche.and glyn knows em damn WELL Both me sr2 and yeah skin sorta agree-ya goin a long winded way. Glynn may damn well have the *shortcut* ya need as to calcs-end of the day BOTH me and sr2 WILL tell ya with big bore 4 pots you NEED a boosted system. [As much as afta ya jag-meh e type boosters ain't the norm-like porsches] ya don't like boosters- TIP. End of the day YOU have DECIDED to FIT brakes from a boosted system. why not upgrade the rest of the system appropriatley! or am i wrong in thinking that!
3rd time ya hit the picks at 240 ya'll agree-beyond ANY doubt.-I M H O
snoopy221,
May 28, 4:49am
just to recap.
I am using 5/8master to move the 11/16 slave to move the 1" master
Quotemjde (46 )5:25 pm, Sat 26 May #9
It'll work-and end of the day late model disc[pad setup will prob require a booster master. Gunna be a few damn calcs-and a few redrillins of pivot points to get the right
***FEEL***
Therin is the *BIG Kicker*
Quotesnoopy221 (296 )5:28 pm, Sat 26 May #12
Outside the square maybe! But a pedal box and 2 5/8's tin cans feeding 2 VH40/44 remote boosters could well give ya what ya want-frnt /rear bias vh 40/44 and pedal box bias!44 front 40 rear!
Quotesnoopy221 (296 )5:49 pm, Sat 26 May #22
5/8 master only pushes 14.25mm. I will see if i can find an 11/16 dia master to match the slave
snoopy221,
May 28, 4:56am
just to recap.
I am using 5/8master to move the 11/16 slave to move the 1" master
Quotemjde (46 ) 5:25 pm, Sat 26 May #9
calcs wise i am using a [given x volume] to gain leverage over [xvolume to move=agaain leverage an [x volume] Notwithstanding the fact that the amount of fluid my [initialx] volume can move limits the ENTIRE system to my initial [x] Gor Blimey i wonda why someone suggested going back to the [x5/8 and usin 2 of em!]
snoopy221,
May 28, 5:03am
now we have available some very efficient brake compounds that would have stopped that little escort all day Meh again 0800racebrakes- LOL ask john about the DS-11S in the front of me ole coon in the nineties. LMAO
mjde,
May 28, 5:09am
Yessiree I will give Glynn a call tomorrow. as you say snoopy he may have the definitive answer and fix at his fingertips. So much for the no8 wire then
snoopy221,
May 28, 5:18am
Well he's been around porsches for dam shyte 30 + years! Megan-who used to work at fast forward with glynn was again one of the BEST -she's now a cop in aucks. Incedentaly if ya do talk to glynn-not only say hi from moi-BUT his business partner in fast forward had a VERY unique vehicle. LOL ever had the ocassion to do a warrant on an old genuine original leather coated springs and all BENTLEY! Yip the original [record to 100 k for weight still stands BENTLEY] WONDER WHERE THAT IS NOW! And shyte i'd hate ta think of what it's worth. that was macc man. immacculate
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