TR... I'm also looking for improved calipers... I'm wondering if the brake mounts are the same as the Trooper..
When I test drove my VX the brakes were VERY squishy, the pedal was nearly to the floor before they started to grip and the feedback was horrible, they worked through, and I could even slam them hard enough for the ABS to kick in.
As part of the purchase agreement he replaced the rear rotors and pads, and greased the sliders on the front calipers... the results where much improved braking feedback. Still not as good as it could be though.
Under hard braking I can feel the front end "pulse" a bit which I'm assuming is a result of carbon build up on the rotor, or maybe some slight warping.
The calipers look horrible too they're all rusty and dirty...
If there is one thing I've learned about brakes it's that you can fit pretty much any caliper to any car so long as the mounting points are the same or you're willing to make an adapter. I know a lot of people in the 240 crowd have started adapting the 4 piston STi Brembos to their cars, all it requires is a little hunk of metal with some holes in it to adapt the STi mounting pattern to the Nissan mounting pattern. I've personally got a set of 4 piston 300ZX calipers on my car... Nissan used the same bolt pattern so they fit right up, and make an awesome and cheap upgrade.
I think it would be worth looking to see if there are direct fit replacement calipers for the VX from another vehicle... a good place to start might be looking at what trooper people have done... I'm definitly going to look into SS braided lines, and at least new rotors and pad... if the calipers aren't too bad and there are no good direct replacement options I'll probably have them sand blasted, painted and rebuilt.
As for the best rotors to use
here are some basic concepts about the different features of brake rotors (I seem to be writing a lot of these lately)
-rotors with no slots or holes will have the best stopping performance because stopping performance is all about the surface area of the pad in contact with the rotor... holes and slots reduce that contact area.
-drilled rotors add holes that act as gas expansion chambers, depending on the pad material (typically only older organic based racing pads) the friction on the pad will cause it to releases gasses under lots of hard braking a thin layer of gas between the pad and rotor will obviously reduce braking performance... that is why holes have been provided so the gas has some place to escape to since the reduction of the gas layer more than makes up for the loss of contact area in racing applications. This is not something you'd have a problem with in normal street driving, nor with OEM or similar pads.
-slotted rotors the idea of a slotted rotor is that it wipes the pad clean to ensure that the contact area of the pad is even. The reason a pad might not be even is once again the result of hard braking in racing applications. In a race environment the brakes are going from nothing to full clamp back to nothing back to full clamp and the constant cycling of heating and cooling can cause unevenness on the pad surface. The slots actually remove a thin layer of the brake pad to "clean" them. As a result you'll actually dramatically reduce the lifespan of the pad since you're removing a substantial amount more of the pad material with each pass of a slot. Not an issue in racing where the pads get replaced every race, but for street driving meh. If you track your car on the weekends or do something where you're doing a lot of heavy braking then some rotors with a light amount of slotting might be good (maybe 3-4 slots across the entire rotor). Leave the crazy slotting to the race cars.
-Vented Rotors are essentially rotors with a hollow center. The rotor looks like 2 plates with spokes between the two to add structure. These rotors are really good no matter what your application. They wick away heat from the rotor very well which improves braking performance no matter what your application.
--Picking the Right Rotor--
if you're buying drilled/slotted rotors you can calculate the reduction in clamping force based on how many holes and slots are available, knowing the area of the pad simply subtract the area of each hole and slot that is over the pad at any given time (if the rotor is designed properly then the number of slots and holes under the pad should be constant at all times).
--Dangers of buying cheap drilled/slotted rotors--
Depending on the process used to manufacture the rotors having holes in the rotors could go from being something unnecessary to something quite dangerous. Higher quality name brands such as Brembo actually build the holes and slots in the original cast, these are, of course, cleaned up in the final machining, cheaper brands build a plain rotor and drill the holes and mill the slots after the fact... the problem with the latter is that the drilling/milling process causes uneven heat stress at certain spots in the rotor, at a microscopic level the rotor is no long even and it can lead to cracking of the rotor, around the holes and slots... which is never a good thing.
In short:
-for street driving get vented rotors with no holes or slots for the best performance
-for light track or off road use consider a rotor with minimal slots
-if you're building a race only rig... consult your brake tech
-If you're going to buy drilled/slotted rotors for looks, make sure they're manufactured properly less you risk more than just the rotor braking.
a friend of mine wrote up a good overall brake primer that's worth reading if you're interested in more details: http://forums.240sxone.com/viewtopic.php?f=16&t=89
It has a few 240sx specific references but it's mostly generic brake info, covers pads, calipers, lines, fluid, and bias as well.
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Originally Posted by twistedsymphony
Bart
, did your ABS crap out before or after you left Chi?
