[DeTomaso] Booster talk

[Ken Green]

Chris Difani and several of us are working on systems using big Porsche (made by Brembo) calipers.  We have looked at sizes for MCs and it's not black magic.  We should have two or more cars running around in the next two or three months, and can report on the results.
 
We are using dual MC pedal assemblies, and at least the Wilwood and Tilton assemblies use a standard MC.  They are available in 1/16 graduations from 5/8 to an inch or more, so there is plenty of room to get the right size.  I'm not sure that the bolt pattern is on the CNC Racing Pantera duel MC setup, I think CNC Brakes does NOT have a big selection of sizes.  Tilton, Wilwood, AP Racing etc, make a bunch of MCs with the same bolt patten.
 
Also, the stock pedal assembly (designed for boost) is about 5: 1 pedal ratio, and the aftermarket pedal assemblies (designed for NO boost) are typically 6.5:1.
 
And, I think the pads can make a big difference.  
 
We will share what we learn with everyone.
 
Ken
 
 


--- On Fri, 7/17/09, cengles at cox.net <cengles at cox.net> wrote:


From: cengles at cox.net <cengles at cox.net>
Subject: Re: [DeTomaso] Booster talk
To: MikeLDrew at aol.com
Cc: detomaso at realbig.com
Date: Friday, July 17, 2009, 8:01 AM



Dear Mike, 

You wrote:


>The guy who owns the Pantera I drove across Europe had that setup in his
>car, but he's a weight savings fanatic and removed the booster and attached
>the balance bar/master setup directly to the trunk wall to save a few pounds.
>Unfortunately his brakes stopped working as a result
>
>Apparently by changing the master cylinder bore diameters it's possible to
>get big brakes to work without a booster. Geoff has gone through a couple
>of different iterations without gaining proper braking performance back;
>he's going to try one more time, and if that fails he'll give up and put the
>booster back in.

$$$$$$ Very interesting. I have long be interested in running the brakes without the booster. My limited field interviews seem to show that it is possible, but they also show that *not* many people do that modification. I have been told that it is easy to test by removing the vacuum line to the booster to test the "non boosted" condition. 

However, your report about Geoff's difficulty in finding the proper master cylinder to compensate for the big brakes' piston volumes and the need for proper brake "feel" seems to underscore that this isn't a straightforward process. Unless someone has found that perfect iteration of non-boosted master cylinder with big brakes, then it looks like I am committed to vacuum boosting. 

Warmest regards, Chuck Engles 

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