clutch pedal pressure reduction

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Hanns Per
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clutch pedal pressure reduction

in the Caterham CSR 260 I have the original AP Racing clutch cover with the red dot and the AP racing master cylinder with Dia 15mm and the SBD standard slave cylinder. The pressure needed to press the pedal is very very high. Has anyone a solution to reduce the pedal  pressure?

7 wonders of th...
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you can swop the clutch master cylinder for a smaller one, 

.7 or .625 are readily available and a striaght swop, you will need to reset your clutch stop too though.

 

 

7 wonders of th...
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OldAndrewE
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.7 and .625 are both larger than the original 15 mm (17.8 and 15.9 respectively) so will increase pedal pressure

Andrew

1985 S3 1700 XFlow.  Undergoing full restoration

James B
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CSR fitment is different configuration/orientation.  Not easy to find alternative m/c's.

James

 

revilla
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Also remember that by simple conservation of energy, whatever you do, to get the same action at the clutch plate, force * distance at the pedal will remain constant. So reducing the force will require a longer travel. Unless of course you go power assisted, which I think is unlikely.

SV VVC 170 - 170.4 bhp @ 7100 rpm - 142.4 ft.lb. @ 4900 rpm

7 wonders of th...
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are forgot is was a CSR..... Banghead 

If its the same as the race version on the CC site then AP list a 14mm option here:

https://apracing.com/race-car/master-cylinders/flange-mounted-types/offset-flange-type/cp4623-type

 

7 wonders of th...
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or does the LHD use remote reservoirs...? in which case you should be able to buy a bare one and take the connecter to your reservoir form your current one.

Hanns Per
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I have the 14mm master cylinder and tried it but as mentioned by revilla I am stuck within the law of physics it does help a little  but results in longer pedal travel. For the clutch if I am not wrong I need 6-7mm travel minimum. One thing I have not checked yet would is the possibility to increase the diameter and to change the proportionof pedal length to master cylinder pushrod connection or would this accoridng to the law of physics have no impact on pedal pressure?

SM25T
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The lever ratio of the pedal arm would make a difference to the effort needed.
revilla
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Yes I'm afraid it doesn't matter how you do it with combinations of the hydraulic diameters at either end, the leverage at the pedal etc. it will work out the same. 10% less pressure, approximately 10% more travel!

SV VVC 170 - 170.4 bhp @ 7100 rpm - 142.4 ft.lb. @ 4900 rpm