Rotus Project Build

[Jamie R]

Lol nope it finished airing about 12 months before I was born

[clive]

Ahh, but you knew what film I meant 

[Jamie R]

That's karate kid, i remember that.....

I thought gas shopper was from Kung fu.........

I've just noticed the predictive text on grasshopper and I'm purposely leaving it as gas shopper is funnier lol

[Jamie R]

Here ya go jon.....

..... notes from college on plcs and control functions.....

Saw this n thought, Jon that poor guy !


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[Jamie R]

Good lord !


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[boosted]

Ladder logic is ace!  So much simpler than Siemens. My favourite was Telemecanique literal code...first i learnt....i hardly do any plc work now ..tiny bit of mitsi....

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[Jamie R]

Like I said,  I know you will do your homework

So, contrary to my comments yesterday, the rear M/C is 0.7" not 0.75" I got confused with the clutch M/C, that said the escort one was still 0.75"

Anyway, rx8 front calipers have a piston diameter of 51mm and the rears are 42.9mm. Front M/C has a diameter of 15.875mm and the rears 17.78mm

Pressure applied to the brake pedal will be equal across each M/C, not to be confused with travel in mm.

So using the force ratio formula, if I applied 100 N to the brake pedal, then there will be 51472 N applied to the front discs and 32518 N

Hence more force to the Fronts as you'd expect.

Havnt worked out the travel required on each M/C yet, but I bet the piston travel is probably less than 2mm - 3mm to pull it up to a halt.

[clive]

Please take into account the servo because as you know this greatly increases pedal pressure.

If you have tried to stop a car servo equipped car without the engine running,  the pedal goes rock hard and this is how the race car felt.
In other words without a servo I was unable to apply enough pedal pressure to stop the car!

From memory you need smaller bore cylinders to exert more pressure to the calipers. 
Hope this helps.

[Jamie R]

Yup totally agree, you are correct.

0.625" is the smallest bore available from obp ( I think from most other places) and is generally allocated for the front system.

The only other options are 0.7 (rears) 0.75 (clutch) 0.85 (oooof) and 1" if you have legs like Ronnie Coleman and can leg press 850kgs in the gym.

Another variable in the mix is the amount of weight you're trying to pull up, the same pedal system from your 8 in Jons westy maybe have different results in terms of stopping distance with the same "lack of feel" or excessive pressure required to even slow down.

You have not suggested this but in case of other readers following this thread and wanting to set the record straight.  A popular misconception is servos make brakes better. Nope, the caliper performance, pad compound, disc size remains the same. A servo just reduces the amount of effort required to press the pedal to achieve the same braking performance.

Anyhow, we've mentioned his name.....

Jon? What size m/c's are you running in the westy, and how do find it in a car under 1000 kgs?

[boosted]

Westy brakes are awesome!!! Ill have to look in the lever arch file for the specs. I changed the front calipers and discs when i went done to 13". I gave Wilwood the specs as i run a Tilton floor mounted clutch brake that came with the car. The brake part has  2 masters 1 for front 1 for rear with an adjustable balance bar. 2 seperate systems. Ill get numbers and post later.

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[clive]

As you say, some people would not realise the Servo is for pedal pressure assistance only.
The race car was nothing to do with weight as I couldn't stop the thing properly even at 10mph 
Jon's cylinder specs should give a base but his caliper pistons will be a different sizes so maybe take that into account,   

[Jamie R]

Yup I can calculate that,

Jon if possible can you let me know the diameter of pistons and whether they are 4 pot calipers etc ?


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[Essex2Visuvesi]

[Jamie R]

Indeed


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[Jamie R]

I don’t think that looks too offensive now it’s been levelled off a bit.

Sand a uniform 4mm gap around the perimeter then it’s primer time


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