Caliper spring clip delete?

[J30tChumpCar]

I am upgrading to z32 calipers on our j30 track car .
In the interest of better cooling I was looking to delete the stainless spring clip for maximum airflow through the rotor vanes.

Any downside?

[es.biggs]

I doubt taking those springs out will do anything. I don't know if there is any downside to removing the springs, but if they weren't necessary, Nissan more than likely wouldn't have put them in (and left them there). It's been a while since I've done brake work to my car, but if I remember correctly, it looks like they just brace and provide support for the brake pads to help keep them in the right place. Personally, with brakes being something that will keep you alive or kill you on the track, I would absolutely leave the springs there. If you want better brakes on your track car, get a bigger brake system.

[J30tChumpCar]

I am not trying to second guess and get our team killed, the brakes were designed for street use and have to be quiet, I suspect the spring is a anti vibration measure, something a track car can do without.

Anyone have a FSM to see what Nissan calls it?

[es.biggs]

They call it the cross spring.

[AZhitman]

I am not trying to second guess and get our team killed, the brakes were designed for street use and have to be quiet, I suspect the spring is a anti vibration measure, something a track car can do without.

Anyone have a FSM to see what Nissan calls it?

That piece maintains accurate pad alignment and prevents chatter.

Removing it does nothing for "brake cooling". Build some ducts that direct air to the center of the hat if you're that concerned about cooling.

Actually, now that I think of it, there's a hundred other things you can do to prevent brake fade - removing a component of the system isn't the way to do it.

[J30tChumpCar]

The front turn lights in the bumper have been converted into brake cooling ducts to channel air to the rotor hat and caliper,we use high temp fluid and never reached fade even with the factory cast iron 2 piston J30 calipers.
We have run this car at (2) 12 hour endurance events. The 1st event we learned how quickly stock cheap pads wear out and that we really needed better tires.

The second event, Sebring,we stepped up with the stickiest tire allowed and custom made NASCAR grade pads on the original J30 calipers,suddenly we were leaders until the last hour when we found our pads worn out.
Aside from a PCV reroute we wanted a slight brake upgrade.
For the next event (24 hours), we decided the aluminum calipers off a z32 would run cooler and offer us more room to custom order the same grade pad but thicker (j30 rotors are 11in but 2 mm narrower then z32 rotors)
While mocking it up without the cross spring I got used to seeing the rotor vanes looking at me through the top of the caliper, when the real race pads arrived I assembled with the cross spring and it looked as if it cut 70% of the air flow in that area, thus my request to find someone that tracks their car without them.

[DCaff300ZX]

Not an expert on this, but when I got my Z32 the drivers' side caliper was missing the spring while the passenger side was still there. There was a noticeable clicking/rattling sound under braking from the DS caliper, and the pads would wear quicker and unevenly on that side as well until I replaced the spring which made both operate evenly/correctly and removed any noise.
I now have upgraded to a GTR front brake setup which also uses the same style springs, I personally would not go without them track OR street...

[es.biggs]

So that spring allows the pads to come into full, even contact with the rotor. Good to know!

[AZhitman]

Correct.

Your issue isn't there. Your issue is you're trying to increase pad thickness so that it wears for an entire 24 hours.

Here's why that's flawed:

1) Thinner rotor = bad. Heat kills pads (and brake performance). Thinner rotor = less mass = more heat. Get some brackets from SPL Parts, a set of thicker 350Z / G35 TRACK rotors, and keep the aluminum calipers.

2) If you're wearing pads that fast, you're using the wrong compound. "custom made NASCAR grade pads" means nothing to me. What brand? What compound? NASCAR uses over 20 different compounds, depending on which track, ambient temp, and other variables. Use a more aggressive compound, so that braking is more efficient (heating the rotors less).

3) You mentioned seeing the rotor vanes through the caliper. You do realize that the vanes are designed to pump air OUT, correct? The most effective cooling is obtained by directing fresh air at the CENTER (back side) of the hat. See below.



As such, the clip is only blocking air from exiting in a very small spot (remember, the wheel is spinning, so it doesn't TRULY "block" anything).

4) Lastly, are your rotor vanes correct (left to right)? You may have the wrong rotor on the wrong side - common problem (I know, because I did it myself - oops). See below:




I ran my 400-hp G35 Coupe for over 5 hours STRAIGHT (quick stops every 20 laps to switch drivers) on Miller's main course, in the heat of the summer, at speeds reaching 140mph (burned 2 entire tanks of gas). Brembo rotors and Ferodo DS pads were still in great shape - drove it from SLC to PHX.

[car nut]

I am not trying to second guess and get our team killed, the brakes were designed for street use and have to be quiet, I suspect the spring is a anti vibration measure, something a track car can do without.

This is exactly what this spring does. The only advantage to not running them is that it's one less step to do when you're changing pads. The only disadvantage would be vibration or chatter under light breaking but you'll never notice it in a track car (assuming you have stainless lines and a high temp fluid).

So that spring allows the pads to come into full, even contact with the rotor. Good to know!

No, if you're pads are wearing unevenly it's a problem with your pistons being misaligned. All that spring does is prevent chatter.

[J30tChumpCar]

Thanks for the replies I know I am grasping straws here but every little bit counts .The race series, brakes and especially our team are budget limited.

Rotors were already available, stock, in spec,J30 units with non directional air vanes.
Brake pads are by Carbotech RP2 endurance formula,made thicker to take up the extra room available by using our existing rotors.
I was waiting for someone to call out nascar..more like Grand Am/SCCA/NASA pads
Our duct work is focused on the center of the hat spilling to the caliper.

This combo before the caliper upgrade consistently out broke most everyone, never faded and gave us too much confidence to understand we were asking a little more then we should have.
A less aggressive technique for this upcoming event and better rotors scheduled for 2011

The car in question has only a forced CAI and free flow X exhaust, so figure its 225hp?
We ran continuously for 12 hours only stopping for fuel and a driver change every 100 minutes. By the end of the day we were only 45 min short on pads.

[AZhitman]

225 hp? Not likely.

The VG30 in the J made 210 at the crank when it was brand new and in optimal condition.

Intake / exhaust MIGHT give you 10-12 hp if it's done right. I'm betting a tired VG might make 170 at the crank, 140 on a dyno.

Anyhow, hope we've addressed the brake clip issue. Leave it in place.

Rather than grasping at straws: Reductions in unsprung weight will pay off tenfold (in acceleration, handling, AND braking), so get creative!

[J30tChumpCar]

Trust me when I say we have been plenty creative, weighing all the spare wheels, removing dust caps,shields, removal of every single e-brake component etc.

Whom said anything about running with a clapped out VG30DE ? And trust me again when I say, a VG in a J30 is very choked with quiet mufflers/intake plumbing, ditch all that ,force air down its throat and you too will say it is a whole different engine. (the competition actually accused us of that).

Rather then start a new thread has anyone a pic of their Z32 NA exhaust manifold from the side and a outlet shot?
We are not allowed headers and it sickened me seeing the J exhaust manifolds had a 1.75 outlet mated to a 2.25 exhaust system.

Anything else I am missing? engine? brakes? rear suspension ideas(mostly z32 stuff)

[AZhitman]

I'm plenty familiar with the VG. Unless you're running forced induction, you're only seeing atmospheric pressure, so you're not "forcing air down its throat".

Unless it's been rebuilt, it's tired. If it's been "massaged" or modded, you might just be bumping up against the $500 rule.

However, that matters not. You asked for ideas, we're here to offer them. I like the Z32 exhaust manifold idea.

If you've removed all interior insulation / sound deadening, get radical and take the soda blaster to EVERYTHING. Paint has weight, and the undercoating weighs a lot as well. Not much you can do suspension-wise unless it's OEM. Z32 lowering springs and shocks would be a start. Sounds like you're well past that point though.

[J30tChumpCar]

Fortunately j cars lead a easier life, ours apparently had frequent fluid changes and shows no abuse, something a Z can rarely boast. Ours runs strong.

We used dry ice and chipped the sound tar out,gutted EVERYTHING, cut the hood/roof/doors/trunk down to their skin and refastened everything to the roll cage. Factory weight was 3500, current weight 2850.No easy feat.

Cut the springs and modified for more positive camber.There is no aftermarket shock to be had, they would likely be shunned anyway.

I guess what I am looking for is more bolt on model to model swaps,nothing internal. Are there any larger stock throttle bodies that fit? Stuff like that. I only have a month for this run of upgrades.
This weekend I hope to complete the PCV reroute to stop smoking on right turns.