Will there be any major side effects from doing this, as they seem to obstruct the airflow quite a bit?

Second question, in the quest for cooling the inadequate brakes my car has, is there a good reason for not using the lamp washers to squirt water onto the calipers? A bit like the diy intercooler spray setup. (Temporary fix before I can afford some decent brakes)

I had to remove the plate to put my new 308mm kit on, no adverse effects yet

I think spraying water on to the brakes would only crack or warp them.

I think you'll find that the big racing trucks have water cooled disc brakes, however, they're proabaly made with that in mind, I left my sheilds on, cos there's an ABS sensor just behind it, and I wouldn't want to melt that!

I've removed them from the beginning, it is a big improvement on cooling. no problems at all.
When using open wheels, like the oz super T or Legra's it's even better.
Jan-egbert

The only problem you could run into without the splash gaurd on the rotor is if you are under heavy braking and hit a puddle. If that was to happen you could warp the rotors due to the sudden change in temperature of the rotor material. That being said I know lots of people that run without them. Rotors aren't that expensive, and they can be turned.

I don't think that water spray would be a good idea for two reasons. First, the sudden drop in temps could warp the rotor. Second, a the water is applied between the pad and rotor it creates a film which reduces friction (stops slower). After a little bit the water will boil causing a vapor film over the pad. This is part of the reason why rotors are cross drilled and slotted is to remove the outgassing of the pad to increase stopping ability. You'd be better off running brake ducting to the caliper and rotor if you really want to lower temps.

trucks used to have water sprays onto drums (dunno about discs due to less mechanical advantage during braking and differing cooling characteristics) but they were triggered from the brake pedal (obviously ;)) rather than spraying as & when from stalk. also they had thermocouples to measure the temps so that they sprayed on/off only for certain temp ranges AFAIR. seem to remember they went through a fair old drop of the wet stuff... ;)

secondly, if you use washer fluid with soap in that's alkaline, it can be slippery to the touch i.e. not want you want on the brakes...:(

you know when you've gone through a ford and it says test your brakes - do you want that each time ? :( (plus you've got to have a system that'll supply enough fluid equally to each rotor with a decent spray pattern)

not wanting to sound negative but... ;):D

Apple

Taking the back plate off will cause no problems whatsoever , been doing it for years and never had any problem , on the scooby it only covers 3/4 of the disc anyway so water ect can still get on to it , you get more airflow over the discs if you take them off .

Took mine off when I fitted my Godspeed 335mm kit. I've not experienced any ill effect in 14 months.

Steve

Thanks all for the advice, I will be removing the backing plates and avoiding standing water when the brakes are hot!! Shelving the idea of the water spray, but will try to duct some extra airflow onto the calipers.

Ian, are the Brembo calipers off an Evo any good? Do they work with the Godspeed disk/bell upgrade?

G

I dont know I haven't tried them , the calipers we have are radially mounted but the EVO ones have lugs , they are quite big lugs aswell so may be too big to fit a bracket on to them in the space available . If you have a caliper I could always try them , Cheers Ian

Ian, it was just a thought, seem to be lots more spare Evo calipers around than Subaru 4 pots!

So what is the purpose of Subaru fitting this backing plate in the first place?

to make the car heavier?

Best for cooling would be to leave the backplate in place, cut a 10-15cm hole in it near the center and pipe a duct from the front splitter into this hole. Airflow needs to be directed onto the back-center of the disk so it can flow outwards through the disk vains.......