Vacuum source for your brakes

[Zuffen]

As part of the instal of the Haltech on my Lancia I need to find a place to source vacuum for the brakes.

The set up is the vehicle has a supercharger feeding through a slide throttle directly into the manifold.

I figure I can't get vacuum before the charger as the intake is 100mm in diameter and will never be under enough vacuum, but if I try after the charger the brake booster will explode when I go on boost.

I'd thought about taking a lline off the manifold with a one valve to stop boost going to the boosted but not sure this is the safest way to do it.

I could run a diesel alternator with a vacuum pump.

Attached is a photo of the engine bay so you can see the problem.

 

[cribbj]

Rod, an electric vacuum pump might be an option if Graeme's idea doesn't work for you.

Here in the US it's a common problem and an outfit called SSBC came out with an auxiliary pump to sort it: http://www.autoanything.com/brakes/69A3151A0A0.aspx

There are also some cars that came straight from GM with auxiliary electric vacuum pumps (P/N: 22034995)

 

[XR8tt]

Use a one way valve off Nissan / Toyota brake hose to booster..
So booster ONLY receives vacuum...There should be a valve on your booster anyway, doesn't hurt to have two...
Then connect to vacuum on manifold when it idles or off throttle..
Usually between throttle body and blower.. Depending where T/B is ??

Yes .. I see the Subaru's have a vacuum pump for what looks like crankcase ventilation ??
Could be used for both ??

Unwanted attachment in above post for some reason!!

 

[Zuffen]

Thanks for the suggestions.

If you look in the 2nd photo the slide throttle is to the right of the taped up blow off port on the supercharger. It's the long "box" between the supercharger and manifold.

No room to get any fittings in and I wouldnt drill a hole for it anyway.

The pump is looking good.

I'm starting to look into a diesel alternator off a 100 series Landcruiser as the existing alternator is only 55AMPS and once all the lights go on it struggles. One advantage of this is I get more AMP's and I wouldn't have the drain of the vacuum pump to contend with.

 

[XR8tt]

55 amp on a rally car ??
Yes one like these would work. Looks like checking with local
auto elect ?? Nearly every turbo diesel runs a vacuum pump..
I'm sure the WRX rally guys use a Mitsi set up ??
A pump like ...I guess serpentine pulley though ...
http://cgi.ebay.com.au/UNIVERSALTRU...ZAU_Car_Parts_Accessories?hash=item27acfcae79

 

[Cobber]

If you have enough room just get a spacer machined up and put it under the throttle body with a port tapped into it. Just make sure there is a check valve in the line as mentioned above and it's done.

 

[Zuffen]

After consulting with my local auto electrician I've decided the electric vacuum pump is the only viable alternative.

A diesel alternator won't live at 7,000rpm and due to the gilmer drive we can't change the ratio's easly.

Running a vacuum line off the manifold is do-able but the engine won't spend all that much time off boost as even a trailing throttle will see it on boost.

The engine doesn't run a by-pass valve so has an atmo blow off valve as original equipment. It also has a pressure relief valve in the manifold to handle any backfires.

 

[XR8tt]

Yea don't get a Toyota one !!! Lol...
Esp a Prius ...

 

[Zuffen]

Purchased a vac pump with cut off switch yesterday.

One more thin to wire in.

 

[cribbj]

Purchased a vac pump with cut off switch yesterday.

One more thin to wire in.

Rod that really sux.

(Sorry, couldn't help myself!)

 

[XR8tt]

Can these be used for crankcase evacuation ??

 

[Zuffen]

Not sure they're designed for 100% duty cycle.

Better choice would be an old air pump off a Corona Starfire engine (Australia only) as it can be belt driven.

I've heard of it being done but never seen it nor met anyone who has done it.

 

[cribbj]

Rod, speaking of duty cycle, are you thinking to use a vacuum bottle/reservoir also?

 

[XR8tt]

Not sure they're designed for 100% duty cycle.

Better choice would be an old air pump off a Corona Starfire engine (Australia only) as it can be belt driven.

I've heard of it being done but never seen it nor met anyone who has done it.

So does this mean the brakes are not 100 % duty cycle ?? Lol...
Or is there a vacuum switch with a reservoir ?? ...

 

[Zuffen]

The pump runs a switch and only cycles when needed.

I think a resevoir would make me feel happier charging down some twisty road in the middle of the night.

I'd always have a nagging thought in the back of my brain saying "will they work?"

 

[XR8tt]

The pump runs a switch and only cycles when needed.

I think a resevoir would make me feel happier charging down some twisty road in the middle of the night.

I'd always have a nagging thought in the back of my brain saying "will they work?"

Yep been there on a club day at Bathurst on Conrod straight.
Approx 270 kph heading into Caltex chase !!! Phew !!!
Thoughts of....
http://www.youtube.com/watch?v=D3xJpt_KpG4

 

[Zuffen]

Nah.

There would be more carbon fibre flying around!