Dust Boots burning up constantly

[dogunbound]

I've done 4 track days in my Z so far, and have rebuilt my brake calipers twice now. The car is a mostly stock performance manual with just pads and fluids upgrades. My primary issue are the dust boots which prevent dust from going back into the brake caliper and prevent micro tears which can result in brake pressure loss are literally burning up and fraying. I don't want to have to run a BBK and doubt this would prevent this issue. Any ideas on what else I can do? I am considering ducting, but unfortunately, there are no pre-fabbed brake ducting for this car other than seibon's which is expensive and only works with their front splitter. I am currently uninteresting in messing with aero.

 

[FSUZ33]

Are the pistons sticking/seizing or is it just the destroyed boots?
Regardless, and obvious, the main culprit is heat. You can get a couple of off-the-shelf NACA ducts and some hose and fashion your own cooling setup. You can also add the OEM air diverters from the Z NISMO, front only I believe. 2-pc rotors would help dissipate heat. And making sure you have thick pads, as the thinner they are the quicker they heat up. Might help to get some caliper temp stickers to see how hot they’re actually getting.

 

[dogunbound]

Not sticking or seizing, just destroyed boots. I had a couple pistons where I had to sit there and scrub off the burnt rubber with sand paper lol. The fronts are the only brakes that have any issues. I suspect nissan set a heavy front brake bias in this car. As for temps, I should get those temp stickers, but last I checked with a pyrometer at the end of the session was 650F on my rotors. I should have also checked my calipers too . Need more data.

Yeah even you are suggesting ducting. I'm going to wait for them to tear one more time before I pull the trigger, along with getting those caliper temp stickers. Thanks!

 

[alienpoker]

Someone else had mentioned the Nismo swaybar metal air deflectors. They bolt on with U clamps & would make a difference to brake cooling. It’s how Nismo tried to solve the front brake heat problem. So it’s likely to be simple effective engineering that doesn’t effect Aero much.

You might want to revise your swaybar setup for the track. So I think if someone has changed out their genuine Nismo swaybar, they might sell the whole kit. Or fabricate metal brackets / ducts to work in a similar way?

The Nismo air deflectors do not come (nor will they work) with the revised ‘Nismo swaybar’ kit available in the USA. Here’s a thread discussing swaybars with some reference to them.

I also attach a pic showing the OEM parts. Please ignore the red arrow pointing at the bushing. Anything else will likely be a naca style ducting kit with hoses, afaik - and much more complicated.

 

[Koryak]

Some pads conduct more heat into backing plates than others. Manufactures are tight lipped about this but it's worth a try making contact. The good news is your fluid didn't boil which is why I always check pedal feel after heat soak. Both the dust seals & fluid reach really high temps after coming in if you don't do a cool down lap. I'm with the above airflow aid recomendations and really recommend temp test strips on several caliper locations.

 

[OptionZero]

Brake cooling has been an issue with this issue since 2009 and Nissan hasn't addressed it.

As others have said, your options are:
Full race setup, grab AP Racing track calipers with no boots or high temp boots

or (this isn't even mutually exlusive)

Increase airflow to cool the brakes.

I use (on a 370Z) the Stillen brake ducting kit (2.25 diameter) with Z1 ducts that go to my DRYLs
I have also used universal brake inlet ducts made by Revotec like this:

https://www.race-parts.com/revotec-aluminum-air-inlets

You'll need to drill an appropriate hole, and pick the diameter to match your ducting.

Because the RZ34 uses the same front akebonos as all non-base 370Z's, you should be able to use Z1's ducting kit:
https://www.z1motorsports.com/z1-pr.../z1-370z-front-brake-cooling-kit-p-21496.html

I also have titanium brake shims, which theoretically help


final caution:
Brake ducting is simple on the driver's side, but on the PASSENGER side, the windshield wiper reservoir may make routing challenging. If the reservoir is in the same location on the RZ34, you will need to keep this in mind.

I deleted mine as I have a Varis vented hood, but if you want to retain it, you may need to stick to 2.25 inch ducting. I heard more than that is super tight

 

[dogunbound]

Hmmm, I don't know if I like the air inlets chosen. I feel like there might be a better scoop design if I cutout a rectangular hole in the front left and front right of my bumper, but this is promising.

I am debating learning how to tig weld for this lol. Instead of just buying the prefabbed part. Thanks for showing me this!

 

[OptionZero]

Do you mean for aesthetics or for air flow?
For aesthetics, there are plenty of different shapes available. As long as you can mate the back end to the duct, i'm sure you can shop around for different inlets. AFAIK, no specific inlet duct has been made for the RZ34 bumpers, unless Nismo's GT4 program has some. I don't know how to get that type of stuff.

For a strictly performance standpoint . . . I'm guessing the absolute ideal airflow would be something like a NACA duct underneath that is shaped so "suck" air up and in, but thats some custom work to integrate it all. Possible, but requires expertise beyond what I have.

As a reference this is what the Nismo Z34 race car uses:

https://www.nismo.co.jp/en/news_list/2011/news_flash/110007.html

Bottom line:
Brake deflectors will help
Brake ducting will help more
Inlet duct, whatever works for you

 

[OptionZero]

I have two front bumpers. One that i use on track, so it can get beat up and cut as needed

I initially had the Revotec duct. Its not 100% flush due to the curvature of the bumper but it works

then Z1 released their DYRL duct so I switched it to that

kept the Revotec duct but it isnt hooked up to anything. In the future ill route it somewhere

 

[dogunbound]

So I decided to get these https://www.race-parts.com/revotec-side-air-ducts and rivet them onto my front bumper. I also went with the z1 brake cooling kit. www.z1motorsports.com/z1-products/z1-motorsports/z1-370z-front-brake-cooling-kit-p-21496.html
Here are the results:
I dremelled the front bumper to create an adequate sized hole.

This is the right side:

This is the left side:

I had to delete the windshield washer reservoir on the left side. As for the right side... it was kind of a pain in the ass due to the water to air intercooler coolant line running through 2 pumps occupying the space. I had to position the right side duct where the outlet passed in the middle of the hose where there was a gap.

I also had to cut up my wheel well, and bottom cover to get it to fit.

Hopefully this solves all of my brake dust boots burning up issues. Also the brakes should last a little longer.

Tools used:
Flat head screw driver for prying
Socket set
Zip ties
Dremel with grinder tip and sand wheel tip
Heat gun for bending the ABS plastic along with shaping the bumper
Phillips screw driver
Breaker bar
1/2" torque wrench

Hopefully I didn't forget anything.

 

[OptionZero]

nice job with the NACA duct

 

[dogunbound]

So update. I did an HPDE with these ducts and the dust boots still cook to shit. Seems like I need a different kind of rubber at this point. Brake ducting is still useful to keep temps down and help longevity of all the parts down there, so I'm not peeved this didn't work. Just that I need a different alternative.

I found this website and it looks promising. https://racingbrake.com/internal-fit-high-temp-blue-boots/

I just need the size of the boots I need for the fronts and rears. I know the fronts have differently sized holes from the top one and the bottom one.

 

[OptionZero]

What power level and tires are you running?

the RZ34 akebonos are the same as the Z34 and I don’t recall anyone burning up the dust boosts at stock power levels

i don’t know what diameter ducting you’re using but some have gone up to 3inches at higher power levels and tire compounds

you can also try titanium brake shims, which resist heat to a degree

full on racing calipers do not have dust boots for this reason, but the tradeoff is the need to rebuild them much more frequently

it seems like more heat capacity boots is only a partial solution, getting more air flow is also needed

 

[dogunbound]

What power level and tires are you running?

the RZ34 akebonos are the same as the Z34 and I don’t recall anyone burning up the dust boosts at stock power levels

i don’t know what diameter ducting you’re using but some have gone up to 3inches at higher power levels and tire compounds

you can also try titanium brake shims, which resist heat to a degree

full on racing calipers do not have dust boots for this reason, but the tradeoff is the need to rebuild them much more frequently

it seems like more heat capacity boots is only a partial solution, getting more air flow is also needed

Everything is stock other than tires and brakes.
Tires are just some "super 200s" (ECF fronts and Dunlop Direzza ZIII rears).
I have 2.5" ducting. I'm not able to put any bigger tbh.

I might just say fuck the boots and rebuild the calipers without them next time. Just more maintenance unfortunately.