Superformance clutch slave

[eschaider]

Something you want to keep in mind as you do your slave selection and replacement is slave cylinder diameter. Your SPF very likely uses a 0.875" clutch master cylinder like mine. Your slave ought to be a minimum of 0.875" or better yet 1". The slave I used in my car is 1.0625".

When you go to a 0.750" slave from a 1" slave you pedal pressure required to depress the clutch will increase. Here is the impact of changing slave cylinder diameter on pedal pressure. The model uses a 0.875" diameter slave and master as 1.0

• A 0.750" diameter slave will increase felt pedal pressure by 36%
• A 1.000" slave will decrease felt pedal pressure by 23%
• A 1.0625" slave will decrease felt pedal pressure by 32%

To put this in perspective;

• If you had a clutch with a 2400 lb plate, a 0.750" slave cylinder would produce a 36% increase in felt pedal pressure and is what you might expect to experience if you put in a clutch with a 3200# plate load. If you have never driven a car with one of these clutches, they give you cramps in your left leg and cause it to tremble uncontrollably in stop and go traffic.
  
• If you had the same clutch with a 0.875" slave cylinder your clutch would feel like a heavy duty but tolerable clutch for many but not all drivers.
  
• If you had the same clutch with a 1.00" slave cylinder it would feel like a light pedal in a showroom stock automobile and be possible for mere mortals to drive.
  
• If you had the same clutch with a 1.0625" slave cylinder it would feel like a clutch in some proletariat euro import and be drivable by anyone (read your wife).

Choose wisely ...


Ed

[sn8ke2]

Originally Posted by eschaider

Something you want to keep in mind as you do your slave selection and replacement is slave cylinder diameter. Your SPF very likely uses a 0.875" clutch master cylinder like mine. Your slave ought to be a minimum of 0.875" or better yet 1". The slave I used in my car is 1.0625".

When you go to a 0.750" slave from a 1" slave you pedal pressure required to depress the clutch will increase. Here is the impact of changing slave cylinder diameter on pedal pressure. The model uses a 0.875" diameter slave and master as 1.0

• A 0.750" diameter slave will increase felt pedal pressure by 36%
• A 1.000" slave will decrease felt pedal pressure by 23%
• A 1.0625" slave will decrease felt pedal pressure by 32%

To put this in perspective;

• If you had a clutch with a 2400 lb plate, a 0.750" slave cylinder would produce a 36% increase in felt pedal pressure and is what you might expect to experience if you put in a clutch with a 3200# plate load. If you have never driven a car with one of these clutches, they give you cramps in your left leg and cause it to tremble uncontrollably in stop and go traffic.
  
• If you had the same clutch with a 0.875" slave cylinder your clutch would feel like a heavy duty but tolerable clutch for many but not all drivers.
  
• If you had the same clutch with a 1.00" slave cylinder it would feel like a light pedal in a showroom stock automobile and be possible for mere mortals to drive.
  
• If you had the same clutch with a 1.0625" slave cylinder it would feel like a clutch in some proletariat euro import and be drivable by anyone (read your wife).

Choose wisely ...


Ed

Thanks for your reply. Seems like a logical explanation; do you know of any 1.00" units on the market?

[eschaider]

Originally Posted by sn8ke2

Thanks for your reply. Seems like a logical explanation; do you know of any 1.00" units on the market?

Here are a few 1" bore Dormans I dug up a while ago;

CS19097, CS33723, CS36170.

Get a Dorman catalog or go to Summit and check out the listings there.



Ed