Brake Pads - Page 2

Mike · #21 17th May 2010, 12:44

Quote:

Originally Posted by MartinClan

The brakes on that were equal to any modern car. That's why I suspect the combination of Metro Servo and BMW linings.

Robin

Robin
I am with you on the Metro servo - it only offers 2:1 boost. My A4 has, I beleive, over 4:1 boost, so the effort in the Marlin will be twice that of my A4. I have tried to locate a servo with a bigger boost, but am restricted by the diameter (as I guess the Sportster is)
During my searches I have been told some modern cars are running a pump off the engine to generate a vacuum (I guess to do away with the inlet manifold vacuum and help control emissions better?)

It therefore struck me that if the servo can not change in diameter, perhaps the vacuum pressure could be increased if there is a pump to contol it?

Is anyone aware of a car with its own vacuum pump? - and if so what pressure does it run at? - and could it be increased to offer a greater boost from the same sized servo?
Mike

Simon · #22 17th May 2010, 19:07

Hi Mike,

Most diesels these days have an engine driven vacuum pump. The vacuum on petrol engines is generated when the throttle is shut and because diesel engines dont usually have a throttle they need a separate means of generating vacuum.

The problem will be that they are usually directly driven by the engine (sometimes of the back of the camshaft or an engine ancillary) and therefore will need some type of machining / fabrication to connect up to a different engine.

Simon

Simon · #23 17th May 2010, 19:13

Thinking about it a little more...

Some alternators have a vacuum pump that 'piggy backs' on the rear: http://www.alibaba.com/product/newju...cuum_Pump.html

If you can find one of these types of alternator that fits your engine then the plumbing should then be reasonably straight forward.

Hope this helps !

Simon

GreatOldOne · #24 24th May 2010, 14:09

Posted this on e30 zone:

http://www.e30zone.net/modules.php?n...topic&t=170021

Like I replied, I guess my problem is the amount of force required to get the desired effect. I'm waiting to see what the combined wisdom of the zone (or at least brian) has to say.