Just call me .... Howard Jr.

[Alex]

Since copying his front splitter design worked so well

I figured I'd see what else i could copy from him

Pedals go forward and back now

But this leaves me with a question - the actual positioning of the pedal box.

Obviously the below is somewhere correct

But I was wondering where you guys were positioning your boxes. More specifically, the distance from the centre side beam (A above) and the the distance from the centre centre beam (B above)

 

[Jack]

Alex,
place the padal ass'y in the car with seats installed and see where you want them...

 

[J. Salmon]

Alex,
place the padal ass'y in the car with seats installed and see where you want them...

I would definitely get the seats placed first. Slight changes in the position of the seat get telegraphed to the pedals. Don't drill anything in the floor for that pedal box until you get your body position fixed.

For example, my father and I have the same inseam, and we fit exactly the same in almost any regular car. But, he is two inches taller (6' vs. 5'10") and it is all trunk. I can sit in the SLC with my helmet on bolt upright in the stock seat and clear. He must recline to clear his head. Which means he needs more leg room, because this pushes his hips forward. No way to determine where you want the pedal box until you have the seat IN PLACE with the correct recline and position. You will even want the angle just right, and the side to side just so.

Don't rush the ergonomics!

 

[Alex]

No drilly drilly I guess then .... yet

 

[Alex]

Seat's in

Now working on pedal positioning. Are there any rough guidelines one wants to follow? For example, when you left leg is fully extended you want the clutch pedal to be fully depressed?

I know a lot will be based on feel, but without bolting it down i can't really play around much with it (as when you push the pedal, all you'll do is kick the pedal box around), so I'm wondering if there's any general guidelines to get the rough placement. (e.g., with the steering wheel you typically want your wrists to be able to rest comfortably on the top of it when your arms are fully extended)

With the adjustability I put into the plate I can move it forwards and backwards about 3'' or so, but I'd like to get it right the first time (in the middle position)


Btw, does anybody else find that when you go to push the clutch (i.e., come off the dead pedal and head towards the clutch pedal) your thigh/quad is really close to the steering wheel? I'm just trying to figure out if this applies to everybody, or if it has to do with how I've got my seat set.

 

[Mike]

Well, I can tell you that the PDG GTM has had many numerous drivers in it. 13 different guys in one year! the distance from the furthest back, lowest point on the downsloping back part of the seat to the brake pedal is 44". Tall driver, like myself, 6'3", have their legs a little bent, pretty much anyone can drive the car at 44".

BTW, looking at your brake bias bar setup, it looks like the cross bar will be in bind when the pedal is pushed. The master cylinder usually travel different lengths front to rear, so there need to be some ability of the cross bar to rotate in the brake pedal. What you have there does not APPEAR to allow this.

 

[Dave]

I know a lot will be based on feel, but without bolting it down i can't really play around much with it as when you push the pedal, all you'll do is kick the pedal box around.

Get some cheap adhesive velcro strips/tabs from the local hardware store to secure the pedal box enabling it to be repositioned easy.

Do you want to sit upright (saloon) or laid back (formula)? Since you have a sunken floorpan, you could do either. Look at Howards seat position, his is very upright. I prefer the formula car position because that is all I've ever raced in. J.Salmon dad's car is like this I believe as was the race SL-C iirc.

 

[Alex]

BTW, looking at your brake bias bar setup, it looks like the cross bar will be in bind when the pedal is pushed. The master cylinder usually travel different lengths front to rear, so there need to be some ability of the cross bar to rotate in the brake pedal. What you have there does not APPEAR to allow this.

Hmmm, so right now when I push the brake pedal both rods push forward evenly and the same distance. What are you suggesting I do to correct this?

Get some cheap adhesive velcro strips/tabs from the local hardware store to secure the pedal box enabling it to be repositioned easy.

Do you want to sit upright (saloon) or laid back (formula)? Since you have a sunken floorpan, you could do either. Look at Howards seat position, his is very upright. I prefer the formula car position because that is all I've ever raced in. J.Salmon dad's car is like this I believe as was the race SL-C iirc.

That's a good idea (the velcro)

My seat is uprightish - I tried laid back but I wouldn't be the least bit comfortable driving like that on the road.

 

[Mike]

Hmmm, so right now when I push the brake pedal both rods push forward evenly and the same distance. What are you suggesting I do to correct this?

There is usually a pivot ball in there on the pedal, as well as on the MCs themselves. Did you buy that setup, or make it?

The MC side looks OK with the clevises, but I thought you may have put those aluminum bushings in for setup reasons on the pedal or something and were going to remove them? The cross bar definitely needs to pivot in the pedal assembly for everything to work properly.

Again I can't tell from those pictures. Maybe it will pivot and those aluminum pieces are just there to "seal" the pivot ball or something, but it is definitely something you want to check out, otherwise there will essentially be no bias bar adjustment at all...if it is all tight.

 

[Doc Kaler]

Alex,

What Mike was implying is that IF your brake bias is not correct once you are on the road AND you need to make an adjustment, it looks like the balance bar is not allowed to pivot on the pedal's axis. It is the ability of the balance bar to pivot that allows different amounts of travel for each master cylinder. If you have different size front and rear masters, you may or may not need to adjust the travel by way of the balance bar.

 

[Mike]

Alex,

What Mike was implying is that IF your brake bias is not correct once you are on the road AND you need to make an adjustment, it looks like the balance bar is not allowed to pivot on the pedal's axis. It is the ability of the balance bar to pivot that allows different amounts of travel for each master cylinder. If you have different size front and rear masters, you may or may not need to adjust the travel by way of the balance bar.

Not only different size MCs, but if you run varying size front and rear piston size calipers, or varying size rotors front and rear, or if you run mixed types of pads, or if you just want to get maximum braking out of the system, then an adjustment of bias to, usually, front is required. If that bolt is solid accross the pedal and snugs up the MC pivot points against those pieces of aluminum and/or there is no pivot in the pedal itself, then no biasing can take place and, given the MCs, calipers, rotors, and pads are all the same, then brake pressure will be equal at all four wheels. Due to weight transfer under braking, even with a much better balanced mid engined car like the SLC, this will most likely not be optimized for the best braking. On the PDG GTM we DO run everything equal as far as hardware, but still run about 56% front bias.

 

[Alex]

I put those spacers there in order to keep the rods even with the master cylinder. Without them one of them goes into the cylinder crookedly. Like this

Are you suggesting what I'm referring to as "crooked" is actually desirable and the proper function of the balance bar?

 

[Mike]

They end up crooked because you are tightening them down too far. It looks like RCR built this piece? I think you should have a talk with Fran as to how the design is supposed to be adjusted. Tight is NOT right. When done correctly and the pedal is actuated, it will look really wierd with one MC travelling a lot more than the other, but that is how the system is supposed to function.

HTH

 

[Mike]

If no one chims in, and I remember, I will take a picture of a race car that is in my shop right now with this particular setup. It ends up looking like the MC pivot points are loose, but that's how it's supposed to be.

 

[Jac Mac]

Alex, remove those 4 fat flat washers and replace them with one thin washer on each side of the pedal sleeve, this allows the balance bar to function as intended.... you should be able to pivot the balance bar in the sleeve until it just contacts the sleeve..just and no more with the 'new' thin washers installed... this will/should give you brakes [ albeit with a long pedal ] if one half of the system should ever fail....... Yes its supposed to look crooked!!! IE when it looks wrong its right which should be easy for you to understand...

 

[Alex]

Okay, i'll remove all but 1 of the thin washers on each side of it.

So with how it was setup, would that mean that (using same size master cylinders) i've got 50/50 bias? Would it have braked okay, or would it have bound up as Crash was indicating?

I just can't see it binding because if I push down on the pedal both rods start pushing at the same time and stop pushing at the same time....how can something that's pushing evenly bind?

 

[Jack]

Alex, you will need only a very slight front bias with the brakes & rotors/master cylinders on your SL-C. Use the thin washers and all will be well.

 

[Doc Kaler]

Alex,

It would have been near 50:50, not binding, but not bias adjustable.

 

[Howard Jones]

I don't know how far along you are but there really isn't much point in trying to finalize the peddle box position and brake bias until the car is running. Brake bias adjustment is the first thing to do once the car will move under it's own power but you will need to drive the car to do so.

I have put together the entire brake system but will leave it dry and as new until I am ready to begin driving the car. Filling up the brakes with fluid and letting it set for a year isn't a very good idea. You may need to remove something like a master cylinder and the fluid will just create a mess. Brake oil will become contaminated with water over time and you might just as well wait until you need it in the system to fill it.

The bias bar does look wrong until you fill the masters with fluid and bleed the system. The travel of the masters is way to much dry to get any idea how the bias system works.

 

[Jack]

Alex, what Howard said!