slave for manly clutches
01-07-2019, 04:08 PM
#1
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slave for manly clutches
Hopefully this hasn't been covered before. My apologies if it has. If any of you are running a clutch like we are that has manly pedal pressure and lightning quick engagement and would like to make it less manly or otherwise more operable, a slave swap might just be the solution.
The clutch in question is the Comp Clutch/Supermiata double with sintered metallic or ceramic discs. This clutch has been in the car since early 2013. The organics were originally installed but only lasted a couple of years. They weren't appreciably better at modulation. The car has seen about 4k miles a year of street driving with more than half of that highway driving. The other half has been where it has proven it's utter awkwardness as a streetable part. Of course it wasn't installed for its streetability but for its lightweight and indestructibility. When driven in anger, one thing we never have to worry about in this car is the clutch. It's all those other times you have to press the pedal that you start to think, "am I going to stall it in the middle of this 4 way intersection?".
Well my co-driver decided to give a slave swap a try as he was tired of stalling the car every time he drove it. Even after 5 years. I have gotten used to it honestly and liked having it be something as a right of passage to be able to drive the car. You wanna take it for a spin? See if you can get it to the starting line first!
Anyhow, enough babbling. The slave used was from speedway motors. It's just their generic purple anodized push type slave cylinder in 7/8". Stock is 3/4". The bolt pattern needs a little adjustment with a drill bit. My co-driver, whom did all the work, took this opportunity to do a straight-shot braided-hose back to the master cylinder since you will need new fittings at the slave end. Getting rid of that awful curly q hard line is reason enough to do that if you haven't done so already. Man that thing was annoying.
So how did it work? Well after setting the rod length on the slave and adjusting the rod length on the master (which was done so to prevent over travel on the dual disc set-up) it works as planned. The minimal modulation spot turned into a less minimal modulation spot. It's still quick but has been tamed substantially. The other thing is that the pedal pressure is also a bit less so it's just easier to modulate. I'm sure we'll still stall the thing every now and then but the hecklers clapping and cheering every time we stall it will be mostly disappointed! And now even my mom could drive it in the off chance she decides to get her license again and learn to drive a manual.
This is the only pic I have since I know you all like pictures.
The clutch in question is the Comp Clutch/Supermiata double with sintered metallic or ceramic discs. This clutch has been in the car since early 2013. The organics were originally installed but only lasted a couple of years. They weren't appreciably better at modulation. The car has seen about 4k miles a year of street driving with more than half of that highway driving. The other half has been where it has proven it's utter awkwardness as a streetable part. Of course it wasn't installed for its streetability but for its lightweight and indestructibility. When driven in anger, one thing we never have to worry about in this car is the clutch. It's all those other times you have to press the pedal that you start to think, "am I going to stall it in the middle of this 4 way intersection?".
Well my co-driver decided to give a slave swap a try as he was tired of stalling the car every time he drove it. Even after 5 years. I have gotten used to it honestly and liked having it be something as a right of passage to be able to drive the car. You wanna take it for a spin? See if you can get it to the starting line first!
Anyhow, enough babbling. The slave used was from speedway motors. It's just their generic purple anodized push type slave cylinder in 7/8". Stock is 3/4". The bolt pattern needs a little adjustment with a drill bit. My co-driver, whom did all the work, took this opportunity to do a straight-shot braided-hose back to the master cylinder since you will need new fittings at the slave end. Getting rid of that awful curly q hard line is reason enough to do that if you haven't done so already. Man that thing was annoying.
So how did it work? Well after setting the rod length on the slave and adjusting the rod length on the master (which was done so to prevent over travel on the dual disc set-up) it works as planned. The minimal modulation spot turned into a less minimal modulation spot. It's still quick but has been tamed substantially. The other thing is that the pedal pressure is also a bit less so it's just easier to modulate. I'm sure we'll still stall the thing every now and then but the hecklers clapping and cheering every time we stall it will be mostly disappointed! And now even my mom could drive it in the off chance she decides to get her license again and learn to drive a manual.
This is the only pic I have since I know you all like pictures.
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01-08-2019, 08:07 PM
#3
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Join Date: Apr 2011
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Yes, stock master. SCCA SP rules say the slave and line are open. Nothing about the master so you can't touch it.
And while I did not take any measurements of the fork travel, it does disengage fully and I have adjustment left on the master linkage to go wither way. When it initially was put together and bled it did not disengage. After adjusting the slave linkage and still no dice I remembered that the instructions for the dual disc clutch had stated to adjust the master linkage shorter or add a stop to the pedal so as to not overtravel the pressure plate. Once that was adjusted properly, everything was as expected. Softer pedal, more modulation range, less anticipated leg cramps while stuck in traffic.
And while I did not take any measurements of the fork travel, it does disengage fully and I have adjustment left on the master linkage to go wither way. When it initially was put together and bled it did not disengage. After adjusting the slave linkage and still no dice I remembered that the instructions for the dual disc clutch had stated to adjust the master linkage shorter or add a stop to the pedal so as to not overtravel the pressure plate. Once that was adjusted properly, everything was as expected. Softer pedal, more modulation range, less anticipated leg cramps while stuck in traffic.
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01-09-2019, 07:29 PM
#8
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Join Date: Apr 2011
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Yes the speedway item linked is the one on the car. For the record, I didn't do the McGyver-ing. The concept and work was done by my co-driver Oliver. Honestly I didn't think it would help considering the tenacity of the sintered metallic discs but I am glad I was wrong.
1RMDave, I have more info on the slave pushrod. The speedway one was used but it was modified. It was cut to length and the tip was machined to mimic the factory one. My co-driver has a neighbor next door at work that has a lathe.
Mudflap, you drive a Miata and live in Coloroda. Find your nearest gay pride parade and get thyself a slave, a master, a pushrod, some grass, and go drive on the fast lane on the highway of love!
1RMDave, I have more info on the slave pushrod. The speedway one was used but it was modified. It was cut to length and the tip was machined to mimic the factory one. My co-driver has a neighbor next door at work that has a lathe.
Mudflap, you drive a Miata and live in Coloroda. Find your nearest gay pride parade and get thyself a slave, a master, a pushrod, some grass, and go drive on the fast lane on the highway of love!
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