E36 M3 Porsche 996 front caliper conversion

[E36forever]

BBK'k on our cars are pointless. I have PFC pads front and rear and even with 255 RE11's, the car still has more brake than the car needs.

True, except for one thing (if you recall I'm lazy) with the 996 calipers and alike I can change out my front pads in 15 min. and it's EASY! However as you know with the stock sliding calipers that isn't the case. Oh, I also save 7 lbs per corner to boot

As for pedal feel it isn't much better. Between the slop in the booster and it being over boosted is the main reason.

[aeronaut]

^ oh....I've *thought* about getting rid of that booster...slippery slope for a dual purpose car.

- - - Updated - - -

Now if only it didn't say Perch on the caliper. It needs a decal that say Corvette.

Agree, I would have preferred black calipers, but MUCH prefer 'brembo' red over black Porch.

[RauchenReifen]

In a single piston sliding caliper, the bore bottom is the "second piston", so in effect, a single piston sliding caliper with a 1" bore would equal a two piston (with 1" bores) fixed caliper.

Ah, the doubled surface area makes perfect sense now, thanks for explaining it.

[das borgen]

BBK'k on our cars are pointless. I have PFC pads front and rear and even with 255 RE11's, the car still has more brake than the car needs.

Das, have you ever tried stock set up with the best pads or did you go right to the bbk?

I've probably tried more pads than you

[KnudsonsM3]

What suspension and tire set up do you have?

[1000hp]

soooooooooo...it doesn't feel any better than stock? or does it?

[E36forever]

soooooooooo...it doesn't feel any better than stock? or does it?

Nope, but people will tell you all day long it does.

[das borgen]

I already noted my thoughts in the OP

[aeronaut]

It's not wrong.



For braking torque calculations, yes. Each fixed piston applies a force of (line pressure) x (piston area). So say line pressure is 1 MPa to make this easy (1 MPa * 1 mm^2 works out to 1 newton) . In the case of the 996 calipers:

FPiston(40mm) = 1 MPa * (pi*(40/2)^2) = 1256N
Fpiston(36mm) = 1 MPa * (pi*(36/2)^2) = 1017N

Ftotal = 2*Fpiston(40) + 2*Fpiston(36) = 4546N (or 2273N per pad)

But the trick of sliding calipers is the caliper itself isn't fixed to the mount. So as the inner pad (piston side) applies a force of Fpiston(60mm), it pushes the caliper away from the rotor. But when the outer pad contacts it has to resist with a an equal force as it is what prevents the caliper from sliding further. So:

Fpiston(60mm) = 1 Mpa * (pi*(60/2)^2) = 2827N.

Ftotal = 2*Fpiston(60mm) = 5654N (or 2827N per pad!)

For what it's worth, I agree with the above calculations. (I did my own version of this, starting with the fact that pressure on both sides of the rotor *must* be equal...hence 1 piston or 4 piston design, sliding or fixed caliper, it doesn't matter; total the pressure on one side, and double it. That'll be the total pressure.)

So assuming all things equal (same pads, rear calipers, etc) I take the numbers above, and get 4546/5654=0.8, or 20% less pressure on the front rotor (brembo less than OEM). But we really want brake torque, and the new calipers are paired with rotors that are 325mm/315mm larger = 3% longer lever arm. So, roughly, the brembo calipers will move the brake bias to the rear about 17%. That's quite a bit (if my calcs are right), and doesn't seem like a great idea!

Make sense?

[M3AN]

Standard calipers + good pads + good fluid + good lines + CSL rotors + 345mm caliper adaptors is the least expensive way to upgrade the brakes on these cars.

https://www.ecstuning.com/News/BMW_E...997_1998_1999/

[Foda420]

Standard calipers + good pads + good fluid + good lines + CSL rotors + 345mm caliper adaptors is the least expensive way to upgrade the brakes on these cars.

https://www.ecstuning.com/News/BMW_E...997_1998_1999/

+1 recently did this myself and am very pleased with the results. Even more so having read the calculations done in this thread!

[aeronaut]

FYI, Apex Arc-8 17" wheels will fit over the Brembo/RallyRoad setup without shaving 12mm off the Brembo caliper mounting bosses. Now, do I REALLY want E46 M3 CSL 345mm rotors? I doubt it.

[M3AN]

FYI, Apex Arc-8 17" wheels will fit over the Brembo/RallyRoad setup without shaving 12mm off the Brembo caliper mounting bosses. Now, do I REALLY want E46 M3 CSL 345mm rotors? I doubt it.

Depends what you're trying to achieve of course.

I have 18" rims so no problems with clearance either way. And if I read Foda420's comment and signature correctly he's using 345mm rotors with 17" Apex ARC-8's and stock callipers. All other things being equal, his car should stop faster than yours.

[aeronaut]

Depends what you're trying to achieve of course.

I have 18" rims so no problems with clearance either way. And if I read Foda420's comment and signature correctly he's using 345mm rotors with 17" Apex ARC-8's and stock callipers. All other things being equal, his car should stop faster than yours.

Why?

[M3AN]

Why?

Because the retardation torque is directly related to the diameter of the rotor. The bigger the rotor, the more stopping power.

[aeronaut]

And if there's enough "stopping power" with the OEM sized rotor? (And, there is.)

[M3AN]

And if there's enough "stopping power" with the OEM sized rotor? (And, there is.)

Breaking on the limit down a steep incline is an example I can think of. Needless to say, it seems we both agree that a BBK isn't going to make a significant difference to your stopping power.

However, for those that feel the need to upgrade there are less expensive options.

[das borgen]

I estimate the weight drop at around 8lbs per corner with the floating E46 M3 rotors over a bone stock E36 M3 setup

[flyfishvt]

I'd like to see some test results on these brake upgrades. Shouldn't be too hard to set something up to test stopping distance. Stop watch and you can test stopping time.

[aeronaut]

I doubt these will change stopping distance any at all (except for POSSIBLY after multiple high speed stops). I expect results will be subjective....brake feel, trail braking, etc. Ease of changing pads, brake pad longevity, etc.

[M3AN]

I doubt these will change stopping distance any at all (except for POSSIBLY after multiple high speed stops). I expect results will be subjective....brake feel, trail braking, etc. Ease of changing pads, brake pad longevity, etc.

^ This.

No improvement in stopping distance (same size rotor), stopping distance is determined by your tyres (and ABS software), not your brakes (almost any brake can lock a wheel) BUT:

1. Pad changes are easier with a 'proper' BBK
2. Unspring weight is less with a refined caliper
3. Maybe better pad choices (?)
4. At the absolute heat limit (!) you may get more consistant performance
5. Looks good

Brake feel should be the same if the systems are set up properly but a 'proper' BBK might be easier to set up for more consistent feel.

Detractions are:

1. Brake bias is changed and this may not be for the better
2. Cost
3. Pad choices may be limited (?)

Personal choice - but it's an expensive choice. Just make the decision for the right reasons.

[breakfast]

a stiffer fixed caliper definitely has better feel.

I was glad to get rid of the slider set up.

[joenationwide]

FYI, Apex Arc-8 17" wheels will fit over the Brembo/RallyRoad setup without shaving 12mm off the Brembo caliper mounting bosses. Now, do I REALLY want E46 M3 CSL 345mm rotors? I doubt it.

FYI
I have Apex ARC-8 17x9.5 and they wont fit over my front Brembo/RallyRoad setup with 12mm shaved off the Brembos and running OEM E46M3 rotor.
They hit the spokes.

Maybe with the E46M3 CSL 345mm rotors they would fit since the calipers are moved out 12mm radially where the wheel spokes have moved far away enough from the caliper.

[aeronaut]

Ahh....I test fitted with 12mm spacers.

[Inflame]

FYI
I have Apex ARC-8 17x9.5 and they wont fit over my front Brembo/RallyRoad setup with 12mm shaved off the Brembos and running OEM E46M3 rotor.
They hit the spokes.

Maybe with the E46M3 CSL 345mm rotors they would fit since the calipers are moved out 12mm radially where the wheel spokes have moved far away enough from the caliper.

Ahh....I test fitted with 12mm spacers.

Whoa, so this works huh? I have 17x9.5 +35 Apex Arc-8's and I'm running an 15mm spacer due to suspension clearance. I don't need to shave off 12mm huh? This is awesome, I'd like to run the larger rotor also.

Whoa... Competition Package rotors are $211 on rock auto... yikes