Please identify my calipers!!!

Yellowbird RS · 02-08-2006, 04:27 PM

please identify this calipers.
front:

rear:

thanks!

Steve Marshall · 02-08-2006, 06:53 PM

What are they on? Look like A calipers with 3 inch spacing? Anyone? Bueller?

Bill Verburg · Bill Verburg's Garage

The rear is an M

if the vernier reads 3 the front is also an M

if 3.5 an A

Yellowbird RS · 02-08-2006, 10:19 PM

thanks! Bill.
Now what is the easy caliper update for repalce the M calipers?

Steve Marshall · 02-09-2006, 05:18 AM

I always get those cornfused. Seems like the smaller ones came first so they should be A.

cmcfaul · cmcfaul's Garage

I don't believe there is an easy caliper upgrade for M's other then more agressive pads.

To upgrade you need different struts with 3.5 spacing.

Chris

73 911 E

Steve Marshall · 02-09-2006, 08:32 AM

Hey Yellowbird,

This photo was taken in your home town, Aguascalientes.

Laneco · 02-09-2006, 08:46 AM

Our 550 spyder replica has the 3" spacing and we were scrounging for a upgrade. The WERE adaptors to go from 3" to 3.5" but those seemed to be hiding from us and the suspension swap to get the 3.5 was going to be difficult, expensive yadadayaa...

One of the fellows on the 914 forum had a solution. It involves using BMW calipers (320 or 318, can't remember which). A little clearancing, but it did work. Steve built a spacer for the caliper to clear the ventilated brakes on the spyder (had our discs been solid they would have cleared with no issues). The piston on these calipers is HUGE. Its bigger than the 3.5" spaced alloy "S" calipers that we have sitting in a box. Very good and powerful upgrade that was cheap. The spacers between the caliper halves seem to be universal, a little scrounging might find an existing one that is perfect in lieu of fabricating one.

Of course, now I have a pair of rebuilt aluminum 3.5 calipers sitting unloved on a shelf...

angela

Laneco · 02-09-2006, 09:03 AM

Thought I would throw in a few pictures to help you see what Steve did (and again thanks to the 914 forum guys for the idea).

*Note: Please IGNORE the wood in the suspension. We have the coil-overs out for overhaul and the wood allows us to roll the car around until the coil-overs return to us (warranty repair).

angela

Yellowbird RS · 02-09-2006, 09:21 AM

Steve, Did you ran the Pan-American Race? When you took the photo? So why you did't call me?

Angela, So you have 318-320 (????) calipers in stock Porsche Rotors????

Laneco · 09:48 AM

Yes, BMW 320 (I double checked) to stock porsche 3". Look on the 914 forum, search for "brake improvements" or "brake upgrades". That's where we found the information.

**for vented rotors - find or make a spacer**

Never would have thought this would work, but the 914 guys have been doing it for a while and they are RIGHT. It does work.

The difference from the M caliper to the BMW was amazing. The brakes went from pretty darn good to absolutely retina detaching while still easy to modulate. I would recommend this upgrade on any 3" spacing car.

angela

Steve Marshall · 02-09-2006, 09:50 AM

Yellowbird,

That was from the LaCarrera. I didn't know you then. If I do it again I'll hook up with you.

cmcfaul · cmcfaul's Garage

Wouldn't the bigger BMW brakes in the front change the brake bias resulting in the fronts locking up way before the rears?

Chris
73 911 E

cmcfaul · cmcfaul's Garage

Laneco:

Is that the BMW caliper or an M caliper painted red (looks like an M)? Where would the spacer go (split the caliper halfs an in the middle)?

Thanks

Chris

randywebb · 02-09-2006, 10:53 AM

Didn't BV post on the BMW caliper a few months ago?

Bill Verburg · Bill Verburg's Garage

Quote:

Originally posted by randywebb
Didn't BV post on the BMW caliper a few months ago?

No, but I will now.

Quote:

Wouldn't the bigger BMW brakes in the front change the brake bias resulting in the fronts locking up way before the rears?

Chris's comment is at the heart of the matter, I have no idea as to the size of the BMW caliper pistons but if they are larger then, yes, the bias is moved forward. If that was your goal then you have successfully upgraded your brakes.

But.......

That is not what most people are after most of the time.

Most people are after greater thermal performance, the operational definition of improved brakes might go something like this, I have improved my brakes because they no longer go spongy on me and/or no longer glaze pads etc.

To do that you want to increase cooling air flow, increase thermal mass(i.e. bigger rotors, increase the operational temperature of the pads etc.

a caliper change alone has little or no effect on that.

Laneco · 02-09-2006, 11:43 AM

We had the M brakes on the front end originally, the M brakes and corresponding correct pads did not cover the rotor surface. I couldn't dig up a pic, but probably better than 1/2" of rotor surface was NOT in contact with the brake pad at all (actually left a 1/2 rust ring around the center).

The S brakes and pads would cover the entire rotor surface, but NUTZ they didn't bolt up being 3.5"

Now we have the BMW 320 brakes on the front and correct pads which cover the same surface of the rotar as the "S" brakes if they had fit the bolt pattern. (see above pics - previous post).

The pic here shows the "S" porsche brakes and the BMW 320 brake side to side, just for comparison before being painted red. The BMW brake is ferrous metal and the porsche brake is aluminum. The BMW brake is heavier. Pic shows the spacer Steve built to clear the vented rotor.

Both the 911 and BMW brake are stamped ATE. Makes me wonder if ATE actually makes a variety of european brakes with same bolt patterns. Seem to remember this being on a volvo I fixed up for an old boyfriend. Good to get rid of that project. (both the car and the boyfriend...)

angela

Yellowbird RS · 02-09-2006, 11:55 AM

[QUOTE]Originally posted by Laneco
[B]
Both the 911 and BMW brake are stamped ATE. Makes me wonder if ATE actually makes a variety of european brakes with same bolt patterns. Seem to remember this being on a volvo I fixed up for an old boyfriend. Good to get rid of that project. (both the car and the boyfriend...)

angela
[
just found this Volvo caliper with the correct pattern 3"

small 4 pistons

also the MB 190 ('70) use ATE 3" 4 pistons

Bill Verburg · Bill Verburg's Garage

Quote:

We had the M brakes on the front end originally, the M brakes and corresponding correct pads did not cover the rotor surface

The swept area doe affect brake torque in the same way that bigger pistons do i.e bigger means more torque at that end.
the A pad has ~20mm greater height giving it that much more swept area than an M

Quote:

Makes me wonder if ATE actually makes a variety of european brakes with same bolt patterns.

They make a wide variety of calipers w/ varying mounting bolt patterns

Bill Verburg · Bill Verburg's Garage

Quote:

Originally posted by Steve Marshall
I always get those cornfused. Seems like the smaller ones came first so they should be A.

The early calipers came in

L - licht or light
M - mittel or middle
S - sport alloy
A - or Alfa Romeo caliper which is where they came form