i have had Hydro-boost on for about 2 years now and they are the best brakes i have ever had BUT, still no brakes when the Eng. stalls. so i was thinking how about a Vac. pump to ether assist or provide all braking.
i did a little testing last summer and with the old Vac. booster with the Eng. Vac at 17 inches i was able to generate about 1,640 lbs with a "hard" push on the pedal. then with the hydo-boost i was able to get about 1,730 lbs with the same abount of lag effort.
so there is about 100 lbs advantage to the hydro. but i think the old Vac. was more than enough to get "great" brakes with 35-38 inch tires. at 17 inches of Vac.
so has anyone tried the Vac pump that a few brake companys are selling for the street rod guy's? how much Vac do they provide? can the pump run 100% of the time? provide all assist?

this way i can have great brakes all the time. my motor has a max Vac right at 17 inches. some times stab the throttle and it will drop to near zero. with the Elec. pump Vac. should never drop below ? what ever the pump provides. and being elec. i'll still have brakes when it stalls.

and no i don't want a standard. i like my auto.

steelman

hmmm...
wonder how many inches of vacuum a smog pump can draw?

i would run it of a pressure switch so that normal engine vacume does the work and the pump kicks in when mmhg drops ,or vacume stops all together

http://www.pirate4x4.com/forum/showthread.php?s=&threadid=114152&highlight=subaru

Originally posted by steelman
some times stab the throttle and it will drop to near zero.Not dropping to 0 usually means you have too much restriction in your intake. Only matters if you want a lot of performance.

the pump from s.s.b.co generates 21" vaccume. its rated constant duty, runs $245
im out of them, but can still get them

Originally posted by Old Scout
http://www.pirate4x4.com/forum/showthread.php?s=&threadid=114152&highlight=subaru

Old scout, hmmmmm,
now theres a idea. keep the 100 lbs advantage that the hydro
has over the Vac. system. and still have brakes when it stalls, i like it.

i think the hydro-boost's work more off of pressure than flow so this could work. any idea how many amps it will draw? i take it it is 100% duty cycle seeing how it was for steering. plus this would free up my power steering pump to run just the box and ram.
i'll see if the local auto store has a re-buld for exchange.

thanks Old scout.

steelman

You might want to check around on some diesel boards too. I've heard of some of the owners of older Cummins equipped trucks putting in Ford (powerstroke) electric vacuum pumps (no idea what models that came in though) when the Dodge mechanical one fails. Heard you can get them pretty cheap too.
I don't have first hand experience with this, but thought it might be a lead you might find worth chasing down more info on.

Diesel scouts have a Vacuum pump that is part of the alternator.

or you could just get a wilwood manual master and have the same brakes all the time with minimal pedal effort with 1 ton axels and huge tires, but then again you cant go to PnP for racing stuff, jiMMy

want some real vacuum...? Get a small A/C pump from a samurai or a geo metro... run it from a medium sized 12v dc motor. That will pull like mad... You will probably have to regulate the vacuum with a spring adjustable relief valve.

If you want to get really fancy, set up the small A/C pump to run off the engine via the A/C clutch... then when the engine is off... it could be run by a DC motor with a one way clutch... like this:

http://www.burly4x4.com/images/vpump.jpg


This way the DC motor will not spin when the pump is being run by the engine, and the clutch will be disengaged when the pump is being run by the DC motor.

Some of the mid 1980's GM passanger cars had an electric vacuum pump. Not sure on all of the applications, but the electric vehicle folks always look for them. GM vacuum pump (http://advanceguard.dhs.org/conversion/Conversion100.htm)

A new commercial 12V vacuum pump can be found on the Electro Automotive site vacuum pump (http://www.electroauto.com/catalog/vacuum.shtml) THey get around $385 for the pump, reservior, switch, fittings. They comment on it pulling 20Amps @ 12V... but the reservior only means only for breaking.

Smog (air injection) pumps work good for injecting air, but the long life vanes are not really designed to pull vacuum.

Hmm... why not go with electric brakes. :) I worked with a German Company on a "electric brake vehicle". No master cylinder! No brake fluid... all of it was wired! Pretty cool... but can not find much on it on the web. I can only discuss if I I find the web references. :( Then again hard to find at a pick-n-pull yard! brake-by-wire (http://www.conti-online.com/generator/www/de/en/continentalteves/continentalteves/themes/products/electronic_brake_systems/brake_by_wire/emb_0602_en.html)

Tom :usa:

hows this for an idea

an electric vacuum pump, wired into the same circuit as your brakelights.

that way the pump only comes on when you hit the brakes, and the pump would last a long time.

a vacuum pump should be able to build up enough vacuum quickly enough from the time the switch is triggered to the time the brakes are really applied?

How about using one of those little 12v ass-saver air compressors... us it to suck the air out of a vacuum canister of some kind... you could use a pressure sensor (a map sensor) to turn it on and off according to how much vacuum was in the reservoir. basically like a reversed air compressor...


Also, what about the little pumps that power air horns... they probably have enough pull and volume for brakes? If not how about using two in parallel for more volume or two in serries for more suction.


I think on my own buggy I will modify the booster to use pressure instead of vacuum... This way, I can us a small pressure regulator to drop the pressure from my onboard air system down to power the brakes. If I want stronger brakes, I just turn up the pressure via the regulator. This seems the best way to me for people with onboard air. If you are worried that your engine will die and your air tank would run empty, you could just use an ARB compressor, or one of the other small electric types.

Originally posted by CWToyota



I think on my own buggy I will modify the booster to use pressure instead of vacuum...


How hard is this to do? I'm not familiar with the innards of a booster but that sounds like a good idea.

Travis

Originally posted by The Jerk
or you could just get a wilwood manual master and have the same brakes all the time with minimal pedal effort with 1 ton axels and huge tires, but then again you cant go to PnP for racing stuff, jiMMy


What he said. Keep it simple. Use Wilwood. I promise you wont look back. More parts= more problems. Also you can TUNE the wilwood system. Call Wilwood enginnering, they are very helpful.


http://www.wilwood.com/contact.asp

Good luck, Dan

How hard is this to do? I'm not familiar with the innards of a booster but that sounds like a good idea.

Well, I don't know how hard it is to do as I have never done it... Just an idea that popped into my head about a year ago. I have never seen it done (not to say it hasn't been done).

with a normal booster, the vacuum hose connects to the front and pulls a diaphram toward the master cylinder. With my suggestion, you would in effect be turning the booster around and pressurizing it so that it would push the diaphram toward the master cylinder. I'm not sure if turning the booster around, modifying one or just building a pneumatic ram setup would be the best way to do this... I'll have to check out a few different models of boosters this weekend.

If higher pressure was used (ie 40-120 psi) a small pneumatic ram could replace the booster.

Originally posted by 9V
hows this for an idea

an electric vacuum pump, wired into the same circuit as your brakelights.

that way the pump only comes on when you hit the brakes, and the pump would last a long time.

a vacuum pump should be able to build up enough vacuum quickly enough from the time the switch is triggered to the time the brakes are really applied?

I think it would take to long. Ther is alot of vacume that an engine makes that I dought a little pump can keep up

Originally posted by Old Scout
Diesel scouts have a Vacuum pump that is part of the alternator.

most toyota diesels run a similar setup, the vacuum is hooked through the alt.
edit: but it needs a vacuum canister