I'm getting close to wrapping this project up so I thought I would post a couple of photos since things have been pretty quiet on this forum for a while. I tested it out the other day in the neighborhood and the caliper mounts that I concocted seem fine so far but I think I need a larger master cylinder since the pedal has too much travel and is a bit soft. I can still lock them up easily however so I may not be that far off. I will hopefully get a response back from Tilton tomorrow.
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I nailed the master cylinder size (check the earlier posts on this topic for details), I can lock it readily and pedal pressure just feels so right that I don't even think about it.
Bias adjustment on the fly is not set up on my car, I have to do it manually between sessions. I probably should set something up one of these days but honestly it has not been much of an issue so it is down the list of upgrades a bit.
I intercepted the brake line to the rear, and spliced in a Wilwood hydraulic knob...an attenuator.
I run excessive pressure to the rears with the threaded rod pulled out to the left (at the pedal). I had to cut off several threads to get enough clearance.
Then, it's a simple matter of twisting the dash knob in to keep the rears from locking.
I brought the tubing inside the cockpit running it along the frame outside the 4" tube. I ran it out the cockpit via the shifter boot hole.
The lever to the left of the bias knob (above the starter button) is a pressure cut-off that's plumbed in series with the bias knob. To keep the car from rolling, I put pressure on the brake pedal, and move the lever down<--this holds pressure in the rear circuit so I can hop out.
Well I installed the new Tilton 7/8" master and it worked like a champ. Pedal is just about perfect now that the pads are bedded in. I ran it though its paces on the track last weekend and after the first half of the first session I was at 100% confidence in the brakes. I can probably tweak the bias a bit more but at this point the swap was successful.
If I read this right, you went from 5/8" to 7/8" up front...bypassing the 3/4"...a pretty big jump. Based on your feedback, it looks like you nailed it. Congrats.
I'm sure the pedal pressure took a huge step up, too. No problem with a shot of adrenaline, right? :)
Yep you have it right. It was a big jump in size but then again the caliper pistons were a lot more surface area as well over the stock configuration. Really the thanks all go to Tilton who did some good calculations to get me the right answer. Pedal pressure is much higher than what I was delaing with using the old 5/8 master with this setup but really not much different than what it was like prior to the new calipers. Perhaps a little more pressure.than stock but not enough to really notice and rely on adrenaline.
Ed - Adrenaline definitely helps, along with all the body weight transfer as you apply the brakes.
Anyway the new front master cylinder is ordered and on its way. Not really a huge newsflash but it was not exactly a simple task. Seems like nothing is simple anymore. Appears that I may have got the only 7/8" Tilton 75 Series master cylinder left in the country! They are back ordered everywhere, and I do mean everywhere. A lot of online web stores have them listed as available but after getting a couple of, "sorry we don't have that in stock" responses back from my online ordering, I started calling first and it took a lot of calls today. Anyway a happy ending and it should make its way to me in about a week.
Here is the reply that I just recieved back from Tilton.
The calculations predict requiring 7/8” front and ¾” rear. That would be for a hard, usually preferred by a spry young man, road racing setup. And older gent might prefer something a little lighter. In that case, 13/16” front and 7/10” rear might be the way to go.
Results are not guaranteed since calculations require estimates for the vehicle center of gravity height, tire grip, brake pad friction coefficient, how hard this particular driver prefers to push on the pedal, and other factors.
Looks like the current 5/8" front master cylinder is way off for this size caliper/pistons and explains the soft pedal. Remember the smaller the master cylinder piston size the more pressure that it generates for the same applied foot pressure and if too small requires even less effort, not to mention the reduced volume available. Now I just need to decide how "spry" I am and order up a new master cylinder.
I did this same scenario for my Lister when I went with the remote bias lever on the dash. I had the same long pedal you described with it juuuuust able to lock 'em up with the pedal just millimeters off the floor. I went only ONE size up, and I hit it right on the nose.
Yes, the pedal got harder, but you'd be surprised how much adrenaline helps out on the track. The increase in effort was a bit disconcerting immediately after installing it, but now I love it. Around town, no big deal.
My original pedal assy didn't allow remote adjustment while out on the track, so I added a TON of rear bias (had to cut the adjustment rod to clear the clutch pedal), then I taper the pressure with the dash lever....works great.
Replies
One size up makes a HUGE difference in travel/effort. If you're at the point where you can lock 'em up, you're real close.
What are you doing about bias adjustments on the fly?
Thanks for the update.
Bias adjustment on the fly is not set up on my car, I have to do it manually between sessions. I probably should set something up one of these days but honestly it has not been much of an issue so it is down the list of upgrades a bit.
I run excessive pressure to the rears with the threaded rod pulled out to the left (at the pedal). I had to cut off several threads to get enough clearance.
Then, it's a simple matter of twisting the dash knob in to keep the rears from locking.
I brought the tubing inside the cockpit running it along the frame outside the 4" tube. I ran it out the cockpit via the shifter boot hole.
Parking Brake:
http://listercorvette.com/Pages/PhotosVideos/ListerCorvetteV3Galler...
The lever to the left of the bias knob (above the starter button) is a pressure cut-off that's plumbed in series with the bias knob. To keep the car from rolling, I put pressure on the brake pedal, and move the lever down<--this holds pressure in the rear circuit so I can hop out.
...works like a dream.
I'm sure the pedal pressure took a huge step up, too. No problem with a shot of adrenaline, right? :)
Anyway the new front master cylinder is ordered and on its way. Not really a huge newsflash but it was not exactly a simple task. Seems like nothing is simple anymore. Appears that I may have got the only 7/8" Tilton 75 Series master cylinder left in the country! They are back ordered everywhere, and I do mean everywhere. A lot of online web stores have them listed as available but after getting a couple of, "sorry we don't have that in stock" responses back from my online ordering, I started calling first and it took a lot of calls today. Anyway a happy ending and it should make its way to me in about a week.
The calculations predict requiring 7/8” front and ¾” rear. That would be for a hard, usually preferred by a spry young man, road racing setup. And older gent might prefer something a little lighter. In that case, 13/16” front and 7/10” rear might be the way to go.
Results are not guaranteed since calculations require estimates for the vehicle center of gravity height, tire grip, brake pad friction coefficient, how hard this particular driver prefers to push on the pedal, and other factors.
Looks like the current 5/8" front master cylinder is way off for this size caliper/pistons and explains the soft pedal. Remember the smaller the master cylinder piston size the more pressure that it generates for the same applied foot pressure and if too small requires even less effort, not to mention the reduced volume available. Now I just need to decide how "spry" I am and order up a new master cylinder.
Yes, the pedal got harder, but you'd be surprised how much adrenaline helps out on the track. The increase in effort was a bit disconcerting immediately after installing it, but now I love it. Around town, no big deal.
My original pedal assy didn't allow remote adjustment while out on the track, so I added a TON of rear bias (had to cut the adjustment rod to clear the clutch pedal), then I taper the pressure with the dash lever....works great.
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