ST165 brake upgrades?

[RS13]

Mate of mine had his first track outing yesterday in his ST165 racecar, but after a few hard laps the brake pedal started touching firewall!

We're putting it down to bad fluid, as the car had been sitting for a bit, and the brakes weren't really smoking or anything, bit of air in the lines.. but the brakes are standard ST165, so he was considering upgrades.

What would bolt on, that are a worthwhile upgrade? Are ST185 brakes bigger? ST205? Ideally he wants as large as possible, that will bolt up with no modifications.

Cheers.

[flygt4]

i have heard of people using STI brakes before as they share same stud pattern but there is some modification required to get it all right.

i think someone on here put 185 brakes into a 165 a while ago, they may still be around. was fairly straight forward i think.

they have a pretty shitty stud pattern as its quite uncommon.

[sergei]

I use 185 facelift brakes on 165, rotors are 277mm vs 254mm stock, callipers are same, different brackets. Straight bolt-on.

[RS13]

I use 185 facelift brakes on 165, rotors are 277mm vs 254mm stock, callipers are same, different brackets. Straight bolt-on.

So I'm able to use the factory 254mm twin-piston callipers/mounts and simply swap rotors/pads? Do you recommend doing all four wheels or just the fronts?

[sergei]

You will need to get 185 rotors and brackets, rears are very similar sized but will not fit (well the ones I got did not) as they are slightly deeper.

[Prymal]

And youll still kill the update 185 ones in quick time ! they are good for about 5 hard laps then youll loose them .

If your dead serious about a " bolt up " affair - let me know as i know the wherabouts of a st205 front and rear setup available soon , and i also know a few guys in oz who have successfully put 325mm STI rotors/brembo's up front on their Gt4's ..

[Malcolm]

st205 brakes onto an st165 is a pretty simple affair, as far as I know. Have a look for information on putting st205 front brakes onto an aw11 - for an st165 it's almost exactly the same, except you don't have to redrill the rotors. As far as I know, the rears are a straight swap

[strx7]

get some descent pads which dont gas up as much. get some high temp dot 5 fluid and put some ducting into the brakes to cool the calipers

[sergei]

There are a few issues with ST205 brakes on ST165:
the spigot diameter is bigger on 205 by 1mm, solution: 1 machine the rotor hole bigger and use "filler" washer to centre the rotor, another solution is using the spigot(rotating part of the hub) and bearing off ST205 and machining the hubs to receive ST205 bearings, this way rotor replacement would be off the shelf (instead of machining rotors to fit).
Another issue is that rotor has different offset and calliper on ST205 and does not have bracket (due to 4 pot), which means that there is a need of making custom brackets, not a really biggie, just a simple fabrication.
Another problem with ST205 brakes (not really a problem) is that you cannot use anything less than 16" wheels.
277mm rotors are sufficient for rally sprints and hillclimbs and similar small events, if I run out of brakes I will probably go for brembo or other custom aftermarket option. Lots of rally cars run similar sized brakes as people prefer 15inch wheels for gravel (or stuck with them because of regs).
As far as I am aware the advantage of ST205 brakes is from great piston area and really wide rotor, 305mm vs 277mm rotor is not that much bigger.

[Trls250s]

The 205 brakes do not need a braket made at all.

We are currently fitting 205 brakes to a 165 now using 165 struts and hubs.

The disc needs the outside diamater machined down so they fit inside the wheels and the caliper can sit closer to the centre of the disc. The inside diameter does not need to be machined at all, it fits right on to the hub

the disc needs some spacers behind it so they dont touch the ball joint, this only needs to be 5 - 10mm. Use steel as aluminium can break under heating and loading (exactly what happens under heavy braking while racing).

The calipers need to be taped and the brakets need to be drilled out. Its wierd but the 205 works back to front compared to the 165 ones, but they have the same mounting distance from the centre of the wheel.

And vala you have 205 brakes on your 165. For the rears no modification is required. If you can get 205 rear suspension its even a bonus (especially if you get the 205 shocks with adjustable dampening) but not needed.

[Trls250s]

Also i can confirm the 205 discs are monsters compared to the 165 ones. It dwafs them. The 205 discs are nearly 14.5" in diameter compared to the 165 ones which are closer to 13".

I will take photos if needed to show the conversion as we are doing it right now.

[sergei]

so how do you centre rotors properly especially with spacer behind?

[Trls250s]

Will need to double check with the old man as the conversion is being done to his car.

[matt dunn]

get some descent pads which dont gas up as much. get some high temp dot 5 fluid and put some ducting into the brakes to cool the calipers

Yeah, dont under-estimate the effect that heat has on the brake fluid.
I run good race fluid, but still bleed before and once again during the event as you can feel the difference if you dont.
It not tto bleed air, as there is none,
but cooked or overheated fluid gives a spongy feel to the pedal.

[RS13]

get some descent pads which dont gas up as much. get some high temp dot 5 fluid and put some ducting into the brakes to cool the calipers

Yeah, dont under-estimate the effect that heat has on the brake fluid.
I run good race fluid, but still bleed before and once again during the event as you can feel the difference if you dont.
It not tto bleed air, as there is none,
but cooked or overheated fluid gives a spongy feel to the pedal.

Yeah mate, I believe hes' going to tee up some dot-5, am gonna flush the whole system as the car sits a while between outings.