Project "Payback" - Page 83 - Lateral-g Forums

**GregWeld** · #**821** 10-19-2009, 07:22 AM

I hear ya on the pad knockback....

It may be that the floating caliper is a better application than the fixed (Wilwood) version for THIS application (Auto X)...

I spent a bunch of time with knowledgeable brake people - the factory reps at Brembo - Wilwood and Baer... My questions were always around one factor - DO I NEED A POWER BOOSTER of some kind... given a two ton car... and relatively high power. They all asked me if any of the race cars out there used power brakes... and that answer is NO. So that is why I went with the 7/8" Wilwood manual master cylinder. BUT I have Baer brakes which are floating calipers...

I would think that the larger the rotor - the more knock-back would be applied - as a small movement would be magnified by the diameter of the rotor. So NOW I'M WONDERING if a simple 2 # residual valve wouldn't "help". This would keep 2 #'s of 'pressure' (check valve) on the line...

Maybe the guys at KORE3 would have some ideas??

Vegas69 · #**822** 10-19-2009, 07:28 AM

I agree the floater would be a much better option. I am running a 2# now and it made no difference. It's just not enough to move a caliper piston. I have all this money tied up in these calipers and e brake setup. A hydraboost will be cheaper but will I be happy with it? Guess I better do my due diligence. There has been talk of a 10# residual and that wouldn't bother me on a track car. But I do drive it alot of the street and that worries me a little.

**GregWeld** · #**823** 10-19-2009, 07:31 AM

Makes me wonder what The Pozzi's would run... or what Steve is running on Bad Penny etc.

Vegas69 · #**824** 10-19-2009, 07:35 AM

Quote:

Originally Posted by GregWeld

Makes me wonder what The Pozzi's would run... or what Steve is running on Bad Penny etc.

I was thinking about that the other day....I may be doing a little detective work in a couple weeks. You in?

**GregWeld** · #**825** 10-19-2009, 07:41 AM

I will post this - you might have read it already - but as usual - "others" here may not be as familiar with all of this - and these forums (IMHO) are best used for LEARNING lots of stuff - even if it doesn't directly affect "us"...

This is a link to StopTech - and a page on KNOCKBACK...

In the short read -- they offer some "advice" -- and in the end... their advice for a STREET driven TRACK CAR is to get used to tapping the brakes!!

But here it is - because it offers solutions to think about - and it's a good read.

http://www.stoptech.com/tech_info/wp_knockback.shtml

**tones2SS** · #**826** 10-19-2009, 08:09 AM

Good to hear you had a good day except for the brakes Todd.
Glad the power steering worked out. Your car is sick. It must have felt awesome outrunning those other cars out there!
Keep up the great work.

Vegas69 · #**827** 10-19-2009, 09:47 AM

Thanks Greg.....my problem is that I experience is putting around town as well. Not severe but noticable. I'd say 1 inch pedal change on the street and almost to the floor on the autocross.

**GregWeld** · #**828** 10-19-2009, 01:08 PM

Quote:

Originally Posted by Vegas69

Thanks Greg.....my problem is that I experience is putting around town as well. Not severe but noticable. I'd say 1 inch pedal change on the street and almost to the floor on the autocross.

WOW!! That's just scary....

So here's the 64 dollar question -- if it's the knockback that is 'causing this -- what good would it do you to install a power adder... When going to the floor etc is a fluid / fill / recovery issue rather than not having ENOUGH pressure once you overcome that problem?

Just talking out loud here....

Vegas69 · #**829** 10-19-2009, 01:24 PM

It would allow me to run a larger master cylinder piston needing less pedal stroke to push the caliper pistons back out. I found out Moser changed bearing manufacturers today. I'm going to get a new set from napa and do a little investigating. If I get motivated, I'll pull an axle tonight.

Payton King · #**830** 10-19-2009, 01:54 PM

emails on this very subject. After speaking to Ron after he changed his to the electic/power brakes, all of his problems went away.

I think my problem is my masters are on the verge of being too small so the knockback that I am getting is amplified due to the small volume of fluid. When I go up in size (master) the pedal is too heavy and I can barely get the car to stop to my liking.

I am making the move to power brakes very soon. Going to the DSE booster route as my motor makes plenty of vaccum. Gotta love an LS motor

Maybe I have gotten old and soft, but I love the brakes on my wife's M3 convertible. If I had to do a full 20 minute session on a track that had a lot of braking zones I would be worn out mentally and physically with my car...and I go to the gym. I am on the Corvette Forum almost everyday, and the guys that are tracking their cars are all running power brakes with the factory ABS. They are upgrading to different calipers and pads.

Rupp WAS using the same wilwood set-up with the 7/8's Wilwood master.

On a side note: I purchased a set of Wilwood "B" pads and they were unbelieveable. If I could run those all of the time I would not change a thing, unfortunately, they are noisey, hard on rotors and very dusty. We all know how expensive the Wilwood rotors are...