Hydroboost: worth it?: Grassroots Motorsports forum: Grassroots Motorsports Magazine

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March 17, 2011 4:26 p.m. Bench Racer (BowtieBandit) Reader

So with my hunt for a thumpity thump cam, I know a vaccuum booster won't cut the mustard, since there probably wont be enough engine vaccuum to suffice. I know there is a bunch of astro vans in junkyards equipped with hyrdoboost, and another magazine listed it as another option for big-cammed cars. I mentioned it to a friend, who in reply said "yeah, if you wanna strain your power steering pump like that"

Would a hydroboost be worth the trouble for a vaccuum starved engine? Or would I be better off to go with a smaller bore non-power brake master cylinder, and get similar pedal, with same effort?? (Wilwood stuff, $$$)
March 17, 2011 4:33 p.m. Rob_Mopar HalfDork

What kind of car are you working on again? Depending on the weight of the car and your comfort level, I'd go manual brakes. And there are OE based options for the master cylinders. You don't necessarily need to go Wilwood.

My Barracuda is running essentially a stock '75 Dart manual disk brake setup. The car is around 3400 Lbs. The brake pedal is firm but completely fine for my taste.
March 17, 2011 4:33 p.m. Ranger50 HalfDork

Keep your vac booster and get an electric vacuum pump for a Mustang Cobra.
March 17, 2011 4:44 p.m. oldtin Dork

hydroboost worked well on my old bronco with a stupid amount of rotating mass (36" tires on steelies) and about 4800#. Lots of GM/saginaw ps pumps had dual outlets - pretty much all the light/mid duty diesels. You can find junkyard hydros on astros, old lincolns, mercury marquis, a few caddies, gm/ford/dodge trucks. There's not much to go wrong with them - perhaps seals, but the rebuild kits are cheap. That said - unless it's a tank, I'd try unboosted first.
March 17, 2011 6:57 p.m. Bench Racer (BowtieBandit) Reader

Ya know, I had never noticed that Hydroboost was exclusivley on big stuff until now. The car is a late 3rd gen Camaro, so while not tiny, definately not a boat. The car hasn't seen cones yet, but is almsot exclusively a nice-day cruiser, so awesome brakes are not required, I just don't wanna rear-end anyone.
March 17, 2011 8:44 p.m. curtis73 Dork

Hydroboost is excellent and it can make some insane pressures if you need it. My only concern with HB in a performance application is the "feel." With typical manual brakes you get linear feedback - more pressure means more brakes. With most vacuum assist brakes you get kinda singular feedback - it seems like increased pedal travel doesn't give proportional feedback on your foot.

With HB, you kinda get inverse feedback at the edge (depending on how the MC and brakes are set up). On some with smaller bore masters, you get to a point where the pedal "overcenters" and it gets easier to push during extreme braking.

But its bulletproof and very heavy duty. My 24' box truck has hydroboost and its good for 26k lbs GVW... of course it has its own dedicated pump and a 1-gallon reservoir. Many mid-size diesels have them. I drove a 24 passenger chevy van school bus with HB and it was very effective.

effective = yes. overkill = yes. performance braking feedback = no.

I drove a road-race Malibu once with a manual setup. I found it to have increased effort by a little bit, but properly set up a manual master shouldn't have any trouble.
March 18, 2011 7:33 a.m. ncjay Reader

I have an '85 Chevy dually that originally had hydro boost. I never understood why I'd want my steering system involved with my brakes. Took the hydro boost off and the brakes still work great. I also have a Monte Carlo daily driver that I took the vacuum booster off of with no other modifications. The pedal is a hair too stiff, but I can live with it. You can go with a different size master cylinder to compensate for pedal effort if you feel the need. Hydro boost, in my opinion, just adds extra weight and headaches. If most race cars don't need vacuum or any other kind of boosters, why should my car need one. I am a big fan of KISS - Keep It Simple Stupid. Being a Chevy, it should be easy to find a different master cylinder for your Camaro.