brake pistons.. a little confused

[FRpilot]

im a little confused.. on brake calipers there's usually a certain amount of pistons right? actually, dont they call them 'cylinders' in manuals, fsms, and mechanic's books?

anyways.. 300zx front calipers have 4 pistons right.. i used to think that 4 piston calipers have 4 on each side.. when they say 300zx calipers have 4 pistons up front is it really 2 on each side..

its kinda of confusing b/c i remember someone saying a stock 240sx had 2 pistons up front and 1 in the rear and so they have a total of 6 pistons all around.. and then they said a 300zx had 4 piston calipers up front and 2 in the rear and they have 12 total..

is this person just confusing me? b/c iirc.. 240s use drum brakes in the rear and have 1 piston up front.. shouldn't it be more like: stock 240sx = 2 pistons all around and stock 300zx = 6 pistons all around?

someone shed some light please.. LoL. i know this is a simple question but im kinda confused.

[mrdirty]

Originally posted by tRaNCeRBoi408
...240s use drum brakes in the rear...

ummmm........now I'm confused :confused:

[uiuc240]

240s have 4 pistons TOTAL. 1 on each corner.

300s have 12 pistons TOTAL. 4 each up front and 2 each out back. 300s have "fixed" calipers, meaning that the pistons move but the caliper doesn't. 240s have "sliding" calipers, meaning that when the piston moves, it pushes on the inboard brake pad, but ALSO pushes on the sliding arm of the caliper, causing the outboard brake pad to be squeezed as well. Make sense?

Sliding calipers are cheaper and easier to fit behind wheels (hence the fact that they are used on EVERYTHING...even NSX's and Vettes and Moosetang GTs)...but fixed calipers give far better feel/response.

Eric

P.S. 240s do NOT have drums in the rear. The closest you'll get to a drum is if you put the 300zx rears on...they have drums integrated into the disc/hub for the e-brake. Super cool.

[AKADriver]

Brake types:
drum (which will still have hydraulic pistons..)
disc w/ sliding caliper
disc w/ fixed caliper

The 240SX has four wheel discs with sliding calipers. Sliding calipers typically have a single piston each. One pad is mounted firmly to the caliper, the other to the face of the piston; when the piston comes out the pads are forced closer together. The caliper is allowed to slide on a bracket to keep it centered on the rotor. Total = 4.

The 300ZX has four wheel discs with fixed calipers. Because fixed calipers can't move, they need at least two pistons each, one for each pad, to clamp down on the rotor. The 300ZX uses four pistons on each front caliper; this way the braking force can be spread more evenly across a wider brake pad, since each pad is being forced against the rotor by two smaller pistons. In the rear it uses the basic two piston design because the pads are smaller. Total = 12.

Is more = better? Well, when you compare fixed to sliding calipers, remember that sliding will need half as many pistons to do the same work. Sliding calipers need a longer-travel piston, however (twice as long) so you tend to lose brake feel, and their braking force isn't quite as even across both pads... this is why performance cars typically use the fixed type. The disadvantage of fixed calipers is cost (of course) and wheel spoke clearance.

When you see big-$$$ exotic cars coming with six or even eight piston calipers, it just means they have really, really big brake pads.

[uiuc240]

haha! Beat you! nyahnyahnyeahnyeahneayhneeeaaaahhhh!

uh.

nevermind.

E

[thelinja]

This is off the subject of S13/14/Z32 brakes. But the new Mercedes Maybach has 32 total pistons. Each front disc has two calipers each with 4 pistons. Out back they have one caliper a piece with 4 pistons each.....Nuts.

[HippoSleek]

Originally posted by thelinja
... the new Mercedes Maybach .....Nuts.

I think that about sums that up.

Mark - who knows someone who's dad is gettin' a Maybach!! and hopes to score a ride in the pimpiest thing 3var :D

Eric and Ryan - great lesson! :thumbsup:

[240 2NR]

Minis have you all beat in the aftermarket. Available 10 piston front calipers!!!:p