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Posted by: speed metal army Feb 24 2017, 10:23 PM

Looking for pics of either the wilwood pedal setups or the tiltons.
Thanks guys

Posted by: 914forme Feb 25 2017, 09:18 AM

Not fully installed yet, bit more metal work to do to get this installed.



Wilwood Pedals, with Howe Masters. I pushed the pedals forward so they are closer to the original spot. That means that I cut the foot board out and built a new section.



Need to make the side pieces to seal this up. The back plate will be made to unbolt so you can R&R the cylinders if need be.

Just wish Howe would make 5/8" MC I can change the fulcrum point on the Wilwood pedals so it might not matter.

Posted by: Downunderman Feb 25 2017, 02:21 PM

I'm using an OBP unit which is essentially the same as a Tilton. http://www.obpltd.com/Pedal-Boxes/Pro-Race-V2/Floor-Mounted-Bulkhead-Fit/3-Pedal-Unit-BHF/3-Pedal-Unit-BHF-Hydrulic-Clutch/Floor-Mounted-Bulkhead-Fit-Hydraulic-Clutch-Pedal-Box-OBP0001PR

It goes here:

Posted by: speed metal army Feb 26 2017, 10:48 PM

Thanks guys! 914forme what size MC's are you using? Dual or single?

Posted by: 914forme Feb 27 2017, 11:54 AM

Dual,

Originally 3/4" = ~19mm for brakes and 5/8" for the clutch. I was running 1988 911 Carrera Calipers. I used to use the stock 19mm MC, why change a good thing.

Now that I converted to Boxster S brakes, I am at 7/8" = ~23mm and since I am using Howe's I upped the clutch master to 3/4" hopefully I don't pay for that one. I can change the pedal ratio if need be for the clutch master.

Give me a big enough leaver I will move the world.

Posted by: turnaround89 Feb 27 2017, 12:29 PM

What's the best way to size up a clutch master cylinder for the clutch slave cylinder?

Can you undersize a clutch MC for the slave cylinder?

Posted by: 914forme Feb 27 2017, 07:05 PM

Yes you can! It is a ratio and pressure thing.

So it can be a bit of a math trick. My slave is 3/4" bore, I am not sure of the travel. My master is also 3/4" bore not sure of the travel there. Best case scenario I am at a 1:1 relation ship.

Now for the fun, the clutch slave pushes the clutch fork, and it is a simple lever. The pedal is also a lever, so the trick is to get it so it feels good, while being at a ration that is soft enough to push.

Simplest thing I can relate this to that you might know is the 914-4 brake pedal and master cylinder. Stock -4 size is 17mm, it will stop the car perfectly, yet the pedal feels soft. So most people will upgrade to a 19mm master. It firms the pedal up, and some like that feeling, as do I. IT is a square of the size of the bore, the and the ratio of the two.

So it can get complicated, and a bit of math, with a few variables I don't know off the top of my head.

http://www.buckeyetriumphs.org/technical/clutch/ClutchCalculations/ClutchCalculations.htm

Posted by: Cracker Feb 27 2017, 08:46 PM

Two different markets (for the most part)...Wilwood's for Hot-Rods; Tilton's for Race-Cars. The biggest issue I ran into when I first installed a small pedal plate was the amount of flex in the floor. The fix (for me) was to extend the plate all the way out to the rocker panel. It also made for a nice even transition for the carpet too!

I literally trust my life to this install...

Tony

Posted by: turnaround89 Feb 27 2017, 10:06 PM

914forme - This is great and the link is awesome. I haven't been able to find anything like this yet, while trying to setup the clutch system in my Subaru conversion. Thank you so much!