NBS master cylinder Swap

[kylenautique]

Also, if you do hydroboost, use hoses from a 94 or 95 k2500, and delete the EVO valve. That way the high pressure hose screws directly into the PS pump. No need for the adapter that is prone to leaking. The factory ABS will work with this mod.

 

[Supercharged111]

Also, if you do hydroboost, use hoses from a 94 or 95 k2500, and delete the EVO valve. That way the high pressure hose screws directly into the PS pump. No need for the adapter that is prone to leaking. The factory ABS will work with this mod.

I happen to like my properly functioning EVO on both trucks with hydroboost.

 

[L31MaxExpress]

I happen to like my properly functioning EVO on both trucks with hydroboost.

Mine has not functioned in years but it also does not leak. Even when it worked right, I hated it.

 

[kenh]

Sorry I didn't read the whole thread.

Hydraulics are not complicated. Example.... 1" master cylinder with 1 sq in of surface area with 100 pounds of pressure will generate 100 # of force. Apply the 100# to a cylinder of 2 sq in" and that cylinder will produce 200# of force. Increase the master cylinder to to 2 sq in" and the same 2 sq in' cylinder now only produces 200# force.

It's all about relationship. Cylinder divided by master gives the percentage of increase. IE, 1:1, 2:1 100:1 etc.

So you HAVE to know the master piston size. If you go larger on the piston size you loose pressure at the wheel. If you go smaller, you increase pressure at the wheel BUT you also may loose enough volume of fluid the brake pedal reaches the floor before you can apply full braking force. It's a balance of the two cylinders. I can guess many of you have never driven a car with non boosted brakes!

Ken

 

[kylenautique]

I happen to like my properly functioning EVO on both trucks with hydroboost.

The evo works great until it doesn’t. Once it decides to go bonkers on you, it makes driving quite interesting... not one of GMs best ideas...

 

[Frank Enstein]

Sorry I didn't read the whole thread.

Hydraulics are not complicated. Example.... 1" master cylinder with 1 sq in of surface area with 100 pounds of pressure will generate 100 # of force. Apply the 100# to a cylinder of 2 sq in" and that cylinder will produce 200# of force. Increase the master cylinder to to 2 sq in" and the same 2 sq in' cylinder now only produces 200# force.

It's all about relationship. Cylinder divided by master gives the percentage of increase. IE, 1:1, 2:1 100:1 etc.

So you HAVE to know the master piston size. If you go larger on the piston size you loose pressure at the wheel. If you go smaller, you increase pressure at the wheel BUT you also may loose enough volume of fluid the brake pedal reaches the floor before you can apply full braking force. It's a balance of the two cylinders. I can guess many of you have never driven a car with non boosted brakes!

Ken

My 69 Firebird wannabe road racer with license plates has 4wheel disc brakes using D52 calipers and a 73 Corvette 1 5/16 power brake master. The car has manual brakes.

It's nearly both feet on the pedal to get it stopped. It stops fine but you have to MEAN IT!

 

[Supercharged111]

The evo works great until it doesn’t. Once it decides to go bonkers on you, it makes driving quite interesting... not one of GMs best ideas...

Mine went bonkers so I fixed it with a $40 sensor. . .

 

[L31MaxExpress]

The evo works great until it doesn’t. Once it decides to go bonkers on you, it makes driving quite interesting... not one of GMs best ideas...

Having driven plenty of older GMs the EVO setup felt like crap. I was happy that it gave the older GM power steering feel once the solenoid was unplugged. No more wrestling the steering wheel with no assist at highway speeds while fighting stiff cross winds. In my opinion atleast the vans should have never had the EVO it is boarderline unsafe. Putting EVO on GMs excellent power steering system destroyed the function of the system. I have had some crosswinds hit the thing so hard it takes a quick 180° turn of the wheel to keep it in the same lane. I personally like the being able to steer with 1 finger kind of assist.

 

[Supercharged111]

Having driven plenty of older GMs the EVO setup felt like crap. I was happy that it gave the older GM power steering feel once the solenoid was unplugged. No more wrestling the steering wheel with no assist at highway speeds while fighting stiff cross winds. In my opinion atleast the vans should have never had the EVO it is boarderline unsafe. Putting EVO on GMs excellent power steering system destroyed the function of the system.

I dunno, they seem a bit over boosted IMO bit then again it really depends on the tire. My dually has lighter highway steering than my 1500 with its little ****** sized 225/75/16 tires vs 285/70/17.

 

[Gibson]

The combination valve only exists in the TBI trucks though,

I've sure looked under the hoods of a lot of Vortec trucks.
And there it is, a combination valve bolted to the ABS unit.