The V8 Owners Forum -

Does anybody no how much vacuumed is produced by the V8
I think I need to fit a 12volt vacuume pump to improve the brake servo/master cars braking
Thanks for any advise
fordpop52@aol.com

Pretty well all production vehicles fitted with the RV8 managed with a vacuum brake servo run from the inlet manifold.

I used to run with twin servos,with a high lift cam on a blown rv8 with no problems

redm6gtr wrote:Does anybody no how much vacuumed is produced by the V8
I think I need to fit a 12volt vacuume pump to improve the brake servo/master cars braking
Thanks for any advise
fordpop52@aol.com

That very much depends on the engine.

But I can see very few applications needing an electric pump.

If you are having problems you then need to look at the plumbing to the booster (do you have it off the right takeoff - the pipe/outlet is about 10mm in size) or you have a booster problem.

If the problem persists you could always put in an alternator from a TDI or TD5 which has a inbuilt vacuum pump.

But there is no issues in an RV8 providing enough vacuum

Garry

redm6gtr wrote:Does anybody no how much vacuumed is produced by the V8
I think I need to fit a 12volt vacuume pump to improve the brake servo/master cars braking
Thanks for any advise
fordpop52@aol.com

A Rover V8 in good condition (like pretty much all petrol engines) will pull an almost total vacuum under overrun conditions.

Chris.

Guys
The rover is fitted with a fast road cam the inlet is an Offernhouser fitted with a pair 45 Weber carbs also a Mallory dist
The brakes were a 7 inch servo with a mark 2 jaguar master
They both needed replacing so I fitted a new servo with a 1 inch bore master
A mistake it should have been a 7/8 bore
There is a one way in the servo pipe
So now I have another master on order and will fit a 12 volt power servo pump from a BMW/VW for extra vacuum
So we will see how it goes

are you sure your existing servo is fitted/adjusted correctly and actually holds vacuum ?

Whatever level of vacuum that may be

I'm with stevieturbo here... are you sure the Booster is good? You shouldn't need additional gubbins if it is all good.

The only difference a bigger master cylinder has is more pressure required on the pedal, boost is not affected by the M/C.

Brand new servo just fitted

Others reading this may well know better but to raise a point - Would a leaking inlet manifold not play a part of the problem, or even be it?

You could measure the vacuum........

Chris.

mike-b wrote:Others reading this may well know better but to raise a point - Would a leaking inlet manifold not play a part of the problem, or even be it?

I'd have thought you'd notice that by poor engine performance before the brakes?

DaveEFI wrote:

mike-b wrote:Others reading this may well know better but to raise a point - Would a leaking inlet manifold not play a part of the problem, or even be it?

I'd have thought you'd notice that by poor engine performance before the brakes?

Possibly...but I dont think there has been a proper explanation of what is even wrong with the brakes ?

Yes - is the booster connected to a small bleed port in the manifold or a proper large bore bore specifically the size for a booster? Also the brakes seem to be a mish mash of components that may not be compatible with each other.

I doubt a vaccum pump will fix the issue if the same size plumbing as is in place now is used.

The RV8 develops plenty of vacuum - as evidenced by the hundreds of thousands of setups around the world that are working fine - so there is something wrong with the OPs set up not the vacuum.

garry