Proportioning Valve??
- Thread starter MJP61
- Start date
Ross
Goblin Guru
The Cobalt proportioning valve is what most everyone is using, and it works, but it doesn't use the rear tires to their potential.
Now the goblin does stop faster than most any car on the street, so do you need to stop faster? Of course we do. Autocross rocks.
Pros:
- You can use more rear brakes
- Your power brakes won't be quite so powerful (this is an advantage, as the Cobalt power brakes are too powerful) giving you more brake pedal that is useable
Cons:
- the Cobalt uses double flares on the brake lines, and the 260-12627 Wilwood proportioning valve uses bubble flares, so you probably will be loaning out multiple tools from your local auto supply store, and learning new skills.
Now the goblin does stop faster than most any car on the street, so do you need to stop faster? Of course we do. Autocross rocks.
Pros:
- You can use more rear brakes
- Your power brakes won't be quite so powerful (this is an advantage, as the Cobalt power brakes are too powerful) giving you more brake pedal that is useable
Cons:
- the Cobalt uses double flares on the brake lines, and the 260-12627 Wilwood proportioning valve uses bubble flares, so you probably will be loaning out multiple tools from your local auto supply store, and learning new skills.
Desert Sasqwatch
Goblin Guru
Hydraulic or vacuum proportioning valve? Both have their merits and can be used to set up the 'stock' brake system to fit your individual liking.
The vacuum valve is used to reduce the effectiveness of the too-big-for-a-Goblin brake booster. The brake pedal 'feel' can be adjusted for more effort to activate the brakes - what some refer to as 'using more of the pedal'.
The hydraulic valve, when installed into the front brake line, can help balance the brakes front to rear. With the 'stock' Coblat system, the front brakes over power the rear brakes and have tendency to lock up, the rear brakes don't do much up to that point. Reducing some of the line pressure to the front brakes makes the rear work harder and be more effective for 4 wheel braking, not just front wheel braking.
Dsteinhorst
Well-Known Member
Has anyone made knuckles with caliper mounting bolt holes machined in a smaller bolt circle (closer to center)? This would help with brake feel, f/r distribution, and would also help clear smaller wheels (RPF1s)
Rotors could be turned down if necessary.
Does anyone have a drawing of the knuckles?
Rotors could be turned down if necessary.
Does anyone have a drawing of the knuckles?
JBINTX
Goblin Guru
Three of us in Houston are running this with much success.
dfkitcar.com
Add-on brake proportioning valve
Doing some autocross, I found that you jamb on the brakes and the fronts lock instantly. Unless you are in a panic stop on the street, you’ll never experience this. At autocross, you find out quickly that you cannot jamb down on the brakes. After doing some research, I decided to decrease the...
Dsteinhorst
Well-Known Member
The factory brake proportioning is done within the system design. There isn't a separate proportioning valve like some other cars have.
k.rollin
Goblin Guru
The kit is not configured to use the factory proportioning valve.
For those asking about the stock valve, see here: https://www.ebay.com/itm/Brake-Proportioning-Valve-2-2L-AT-2010-CHEVROLET-COBALT-PRX2-10RM-/402477136614
For those asking about the stock valve, see here: https://www.ebay.com/itm/Brake-Proportioning-Valve-2-2L-AT-2010-CHEVROLET-COBALT-PRX2-10RM-/402477136614
MJP61
Well-Known Member
The car has no ABS. I will take a picture later when I get home.
Dsteinhorst
Well-Known Member
Is your car 4 wheel disc?
I'm currently trying to understand all the different brake packages available on the Cobalt/G5, and I seem to discover a new one each day.
I'm currently trying to understand all the different brake packages available on the Cobalt/G5, and I seem to discover a new one each day.
MJP61
Well-Known Member
Car from factory is front disc, rear drum, NON ABS. The proportioning valve is called “Rear Proportioning Valve” according to the dealer parts diagram.
Dsteinhorst
Well-Known Member
I could swear my donor with the same specs didn't have a proportioning valve, but I just looked through pictures, and sure enough it did.