Re: ur-q vacuum brake conversion

[Mike Zamikhovsky <MikeZ755@sprintmail.com>]

David G. Lawson wrote:
> 
> Martin,
> 
> >I use the intake vacuum to operate the brakes.  The only problem is
> the lack of power brakes under left foot braking otherwise it just as
> good as with a N/A engine.  You might want to use a cylinder head out
> of a car with a vacuum pump but you would have to change the valves
> to sodium cooled.  I know someone who has done this to get rid of the
> hydraulic system on their Ur-q.
> <
> 
> Thanks for detailing your install. I was wondering about this. The
> porsche 951 is a turbo and it uses a vacuum booster for the brake
> system so there is nothing stopping me from using it on an ur-q.
> I think of my wrecked GT, the vacuum brake setup and the head with
> the vacuum pump just sitting there. I see another project developing.
> Ditching the ur-q hydraulic brake setup including the bomb and
> hyd booster and base unit and numerous hyd lines seems like a
> step in the right direction. And I have the core for my big valve hyd
> head sitting right there, including the vacuum pump. And those schrick
> cams are designed for the NA cars, so they have the vacuum pump
> cam designed into the camshaft, right folks? Oh, this might just be
> too good to pass up.
> -
> Dave Lawson


Hi Dave. 

My 83 TQC survived break booster falure this year and I did't want to pay 
over $500 for replacement. John Beckus at Sport wheels rebuilt it for me 
for $125 and all is well now. I see a problem with use of coupe head in 
that intake runners are substantially smaller. You may lose some power at 
 top rpm. Also it is too much work. You can take it out completly and 
install manual double master cylinder setup with adjustable bias between 
front and rear. However when I did that on my rally car I found that 
force needed to stop the car is just too great. Bruno does this to his 
rally cars alsow. He however also gets rid of power breaks to get all the 
fluid to his quick rack which requires higher flow rate from the pump.

I hope that you will be able to live with what you chose.
 Mike Zamikhovsky