4 piston calipers up front for our SVX!

Chicane · #1 07-21-2003, 06:36 PM

Where to get them?

YOU HAVE THEM ALREADY!

Sort of. I was reading an article online a few days ago about sliding calipers (what our SVX has) vs regular calipers. Basically, Sliding calipers DOUBLE the force of a regular caliper, so even though it only has two pistons, it ACTS like it has 4. So yeah. I'm thinking we don't need to upgrade our calipers unless its some of those crazy 6 piston setups.

I'll try to find the article though.

- Rob

Pure_Insanity8 · #2 07-21-2003, 06:45 PM

Quote:

Originally posted by Chicane
Where to get them?

YOU HAVE THEM ALREADY!

Sort of. I was reading an article online a few days ago about sliding calipers (what our SVX has) vs regular calipers. Basically, Sliding calipers DOUBLE the force of a regular caliper, so even though it only has two pistons, it ACTS like it has 4. So yeah. I'm thinking we don't need to upgrade our calipers unless its some of those crazy 6 piston setups. I'll try to find the article though.

- Rob

I'm thinkin' that I'd like those "crazy" 6 piston calipers that Dayle is working on with the 13" rotors.

I think that an actual 4 piston caliper would still probably be better than ours, just maybe not as much as we'd would have thought.

Mr. Pockets · #3 07-22-2003, 12:47 PM

Rob, where's this article? I've only worked with sliding calipers, so I'd be interested to see how anything that didn't work in the same way would work.

mohrds · #4 07-22-2003, 12:55 PM

Quote:

Originally posted by Chicane
Where to get them?

YOU HAVE THEM ALREADY!

Sort of. I was reading an article online a few days ago about sliding calipers (what our SVX has) vs regular calipers. Basically, Sliding calipers DOUBLE the force of a regular caliper, so even though it only has two pistons, it ACTS like it has 4. So yeah. I'm thinking we don't need to upgrade our calipers unless its some of those crazy 6 piston setups. I'll try to find the article though.

- Rob

Well, that depends on the size of the pistons. There could be a two piston sliding caliper that has more force than a four piston fixed caliper.

It all depends on surface area of the pistons, the more surface area, the more pressure (very simplified). For example, if you have two pistons with three square inches of surface area each and compare it to a four piston caliper that has one square inch each, the floating caliper would have more force.

Now we have to take into account the force lost sliding the caliper, or the efficiency differences between moving two pistons x distance or four pistons 1/2x distance, pressure lost because of different size caliper fluid chambers, etc...

It is very complicated, but basically, many pistons is generally accepted as better than fewer pistons.

Doug

Chicane · #5 07-22-2003, 01:40 PM

Sorry Mohrds, but you're wrong here. And god *@#*&$*(@ IT! I can't find the article! But snoop around! Basically, if the piston sizes are all one size (in this example) a 4 piston regular caliper has just as much 'squeezing force' as a 2 piston floating/sliding caliper. So yeah, we have pretty good calipers. The audi S4 also uses sliding calipers, and if you search about that you'll find its a damn good setup and the only thing you'll really gain by converting to a regular caliper would be 'better pedal feedback', but almost no gains when it comes to stopping performance.

- Rob

Pure_Insanity8 · #6 07-22-2003, 04:12 PM

Either way... this heavy beast could still use some better brakes.

#7 07-23-2003, 10:36 AM

My brakes are amazing.

Raceconcepts slotted Bradis, fresh OEM pads and a complete flush using Valvoline Synthetic brake fluid.

40+ decels from 100 on the Cherohala Skyway with no brake fade.. my brakes work just fine.

Remember, the procedure you use to bed in and heat cycle the pads is as important as the components you use. See Stoptech's site for proper bedding procedures for any sport braking system.

elninoalex · #8 07-23-2003, 01:22 PM

Quote:

Originally posted by Chicane
Sorry Mohrds, but you're wrong here. And god *@#*&$*(@ IT! I can't find the article! But snoop around! Basically, if the piston sizes are all one size (in this example) a 4 piston regular caliper has just as much 'squeezing force' as a 2 piston floating/sliding caliper. So yeah, we have pretty good calipers. The audi S4 also uses sliding calipers, and if you search about that you'll find its a damn good setup and the only thing you'll really gain by converting to a regular caliper would be 'better pedal feedback', but almost no gains when it comes to stopping performance.

- Rob

Rob- You offered no explanation of why Doug is wrong. Could you expand on this?

Stephen

svxcess · #9 07-23-2003, 01:37 PM

Quote:

Originally posted by Porter
Remember, the procedure you use to bed in and heat cycle the pads is as important as the components you use. See Stoptech's site for proper bedding procedures for any sport braking system.

I talked to Dean at ART. They use the Bradi rotors as the basis for their cryogenic treatment. However, his bedding procedure is quite different (maybe because of the cryo treatment).

ART's procedure is to take the car up to 60-65 mph and apply the brakes with your left foot while trying to maintain speed with the accelerator. Keep your foot on the brakes for 8-10 seconds, off for 15 seconds, on for another 8-10 seconds for a dozen times, then park the car and let the brakes cool down for half an hour and you're done.

They are now using the better quality Axxis pads instead of the PBR Metal master pads

$600 for rotors and pads all around plus $50.00 shipping

mohrds · #10 07-23-2003, 01:45 PM

Quote:

Originally posted by Chicane
Sorry Mohrds, but you're wrong here. And god *@#*&$*(@ IT! I can't find the article! But snoop around! Basically, if the piston sizes are all one size (in this example) a 4 piston regular caliper has just as much 'squeezing force' as a 2 piston floating/sliding caliper. So yeah, we have pretty good calipers. The audi S4 also uses sliding calipers, and if you search about that you'll find its a damn good setup and the only thing you'll really gain by converting to a regular caliper would be 'better pedal feedback', but almost no gains when it comes to stopping performance.

- Rob

I'm not sure where you got your AUDI info from, but I know first hand that the S4 has four piston fixed calipers in the front. I helped my friend install new CF pads and slotted rotors on his 2001 S4.

Unless the previous owner replaced the calipers with four piston ones that happened to have the Audi symbol cast into them, they are stock.

As for the sliding caliper debate, Pressure is the force acting perpendicular to a given surface area. P=F/A or in our case, Force is Pressure times the surface Area F=P*A

If the master cylinder produces the same pressure in the brake fluid, the piston area determines the force. The more surface area, the greater the force for the same fluid pressure.

With a sliding caliper, all the pressure is exerted on the pistons and the caliper slides to equalize the force on the inboard and outboard pads. Basically the force is cut in half for each side, half on the inboard side, half on the outboard side. Plus you lose some energy moving the caliper on the slides, so there is no way based on our laws of science that the article you read was accurate.

You didn't happen to read that in the NY Times, did you

Doug

oab_au · #11 07-23-2003, 06:04 PM

Yes, the clamping pressure on the disk, is the same regardless if the calliper is double opposed pistons or a twin piston sliding calliper.

The main difference is in the sliding section. If the slides are free and lubed, the application of the brakes will be the same.
It is when you let the brake off that the difference is realised.

The four opposed pistons will be retracted by their seals, that distort when it is applied, to pull the pistons back from the pads. The disk run out will knock the pads back along with the boundary layer of air that forces the pad from the disk.

The sliding callipers piston seal will pull the piston back from the pad and run out will knock the inside pad back. The outside pad and the sliding calliper mechanism has no seal to retract it, it relies on the disk run out to knock the whole assemble back from the disk.

Also when applied, the pads have to follow the the disk run out to keep contact. This is better with the opposed piston as they only have to move fluid from the pistons on one side to the other side. The sliding calliper has to move the whole mechanism from one side to the other to follow the disk run out. This is where it is inferior to the opposed piston calliper.

Harvey.

cdigerlando · #12 07-28-2003, 02:47 PM

I got very very very noticable improvements with my system. Basically I installed steel braided lines, flushed with hi temp fluid, rebuilt the calipers, installed carbon kevlar pads (from KC), and used cross drilled rotors. The pads and rotors were cryo treated locally. I really don't see the need to improve them. I also painted them for asthetics

Paisan · #13 08-10-2003, 11:21 PM

I dunno about you guys, but I'm with Porter here. I know Porter has actually done some good testing. I too have done some testing with these brakes. I've tracked my SVX 5 separate days. Axxis Ultimate Pads in the Front, Axxis Metalmaster rear, Raceconcepts.net dimpledrilled/slotted all around. Delphi Dot 5.1 fluid flushed, SS Lines.

The only issue I had was that I cooked the drilled rotors @ Jefferson Circuit on our 2nd day there. Cracked all 4 rotors. I will be replacing with the Bradi blanks shortly.

The pads and rotors are the same size used on the Nissan Pathfinder and the Nissan Pickuptrucks. I'm not sure how they could NOT stop our cars efficiently, we are about 500-1000lbs lighter than those vehicles. Only difference could be the calipers or the booster is different.

-mike

Chicane · #14 09-24-2003, 02:30 PM

http://www.sportcompactcarweb.com/ed...212scc_techno/

HAAAAAA!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Told you so, suckers.

- Rob

mbtoloczko · #15 09-24-2003, 03:16 PM

Quote:

Originally posted by Paisan

...

The pads and rotors are the same size used on the Nissan Pathfinder and the Nissan Pickuptrucks. ...

-mike

I knew the front pads are the same as the Nissan Pathfinder, but I was unaware of the interchangeability of the rear pads and the front and rear rotors. Could you be a little more specific about the interchangability? What model/year Nissan corresponds with which of these items?