XT/GT/sti clutch pedal travel

[93Leg-c]

This is going to take some explanation so please bear with me.

First of all, my goal is finding a clutch pedal setup in my ss with the shortest travel from fully engaged to fully disengaged. It would be like having the a short shifter vs the long throw of a factory gearshift lever.

Some history: Back in '05 when the the Legacy GT came out, I had the opportunity to drive the Forester XT, the Legacy GT, and the sti back-to-back-to-back. I found that the XT had the longest clutch pedal travel (I did not like it at all!), the GT had less pedal travel than the XT, and the sti had the shortest clutch pedal travel. When I finally do a AT to 5MT swap, I'd like to have the shortest clutch pedal travel possible.

Does anyone know why the sti has the shortest pedal travel and the Forester the longest travel? Does it have to do with the bore diameter of the clutch master cylinder and/or the slave cylinder? Or are the pedals physically/mechanically set up differently, for example, the sti having the shortest length clutch pedal "arm" and the Forester the longest or is one set of pedals set up with a different mechanical leverage ratio?

Also, can I bolt in the sti pedal assembly in my '93 ss without any doing any mods? Or are the mounting points different? (From searching, I know it's not a simple project to get the 5MT pedal setup to fit but none of the posts indicate the necessity of drilling new mounting holes.)

If the sti pedal assembly will require modifications I probably won't use it. Then the next question is, can I achieve a shorter clutch throw if I used the ss or wrx pedal assembly in conjunction with a wrx or sti clutch master cylinder and/or slave cylinder if they have bigger bores?

Any help is much appreciated! Thanks!

[Legacy777]

There's two separate factors that affect the clutch pedal travel.

The first is the clutch pedal itself and where the push rod of the clutch master cylinder attaches to the clutch pedal. I do not know if these change at all between models, but I kind of have my doubts. You could determine whether they change by checking the part numbers between the different cars. That may not be fool proof method, but would give you some place to start.

The second factor is related to the bore sizes of the clutch master and slave cylinders. A larger master cylinder coupled to a smaller slave cylinder will provide a shorter travel of the clutch pedal, but require more force to depress the clutch pedal. The opposite is true, a smaller bore master cylinder and a larger bore slave cylinder will require more travel on the clutch pedal to get the same output travel on the slave cylinder.

Clear as mud?

[206er]

why do you prefer short clutch pedal travel? I think longer is easier to modulate.

[biggreen96]

This sounds like a good thing to find out. I need to do something about my dying slave, and would like to find the shortest travel too. Shorter may be harder to modulate, but it would take only a few days to get used to.

[93Leg-c]

Thanks, Josh! The "mud" has cleared up my general understanding about the matter satisfactorily!

Now, is there a relatively easy way to find out the bore sizes of the master and slave cylinders? Are the specs listed somewhere?

Josh, you answered my first set of questions. Now, does anyone know if the sti pedal assemblies (like the '04-'07s) will bolt into the ss without mods?


206er, while it's true a longer clutch pedal travel is easier to modulate, if it's too long, then it becomes wearisome for me. And it becomes harder for me to drive with precision and performance. If the XT clutch pedal assembly were in my ss, it definitely would be too long for me to enjoy driving. I would actually begin to dislike driving the ss. I don't mind lifting my knee about 6-8" when using the clutch, but to have to raise my knee over a foot definitely takes away from my driving enjoyment. Whenever I drive a manual-shift car, I ALWAYS double-clutch and rev-match when I downshift and the time it takes me to downshift to a lower gear is equal to or less than the time it takes to upshift. The XT long pedal travel would wear out my left leg. Basically, I like using mostly my ankle when using the clutch pedal rather than having to use my whole leg to shift gears.

Of course, if the short clutch pedal travel will make the clutch really stiff, then that's not good either (for me). So, I'll have to find a balance somewhere.

Oh, and in case you might be wondering, yes, I always install a short shifter too as the factory throw is too long for me to enjoy driving. I like using my fingers, hand, and wrist to shift gears rather than my whole arm.