it never ends... that should be the tag line for anyone that modifies their car...

 

Just for clarity, I've got a custom built forced inductions T4 Billet turbo with a 1.25 exhaust housing and .96 turbine. I cannot believe I'm going through all this to build a little boost. LOL

 

what size? 80mm?

 

Yes

 

 

It's a bit of a no-win.

The ideal rear area is more like 4 x 1.25. Even 4 x 1.375 wouldn't be 'bad' for feel and bias. BUT...you'll give up the clamp force you want with that reduction. All told you'd lose roughly 60% of the clamp force all other things being equal.

 

So is the solution a 1.25" bore manual master ? I drove it today and it actually stops decent but the low pressure out back makes me think I'm leaving clamping force on the table by using the factory power master and booster. I've got a Strange 1.25" bore manual master but I'm still debating installing it. I don't really know what to expect by swapping. I'll probably make a decision after I get a chance to get some VHT on the ground and see how many RPM's I can foot brake the car before the tires push through the brakes.

What should the factory rear brake pressure be ? Now I wish I checked the pressure before I tore it apart..

 

I said for proper brake balance the ideal caliper would be more in line with a 1.25" four pot.

Moving to a 1.25" MC will only make less pressure and require you push harder. Changing a mc won't effect balance ever, just effort.

There's no indication of low pressure out back with the mc you have now. That varies constantly by how hard you push. There is however significant clamp force from the larger bore calipers, which for staging purposes it what they likely intended. Line pressure is not what you're looking for, clam force is the goal. (that's a math deal, not just fluid pressure)

The overall problem (if there is one, it's doing what you wanted) will never go away with out compromise. You can go smaller bore calipers and lose the effect you wanted for staging, or you can live with a soft pedal and extreme rear brake bias- despite it being less than ideal for a dd car.

You might be able to put large bore front calipers of some sort on the car and get the bias/balance back that way. And even increase the staging hold. But beware: you might bottom the piston in the mc trying to do it too! Put in a larger mc to compensate? Might help if you can run up the line pressure pushing hard enough.

My experience is that drag kits are generally just that: drag kits. They really don't work in the conventional world real well. *It's the safety factor I'm concerned with here as well as 'feel'.