Its a 240z - drums in the rear....
Thanks guys - confirmed my interpretation and gave me perspective...
Its a 240z - drums in the rear....
Thanks guys - confirmed my interpretation and gave me perspective...
ugh.. sorry dude. you're fooked. Actually the drums aren't that bad on those things, all things considered.
Put a 10psi residual pressure valve on the line going to the rear brakes and it'll save you a LOT of hassles.
You didn't buy Troy's old Z, did you? No way that thing would ever be legal for IT.....
Houston Region
STU Nissan 240SX
EProd RX7
No - this was a stripped car.
Thanks for the tip on the residual valve...
I run Porterfield R4 shoes on my ITS 240Z. Never had a problem with them overheating. I tried the Carbotech shoes for a while, but they swell when they get hot. Your biggest problem will be the front brakes. You need to get 2 ducts to each side, one on the rotor, one on the caliper/pads, and the highest temp brake fluid you can afford.
David Plott
Atlanta Region #289721
#54 1973 Datsun 240Z
Mount Juliet, TN
What Dave said. We have run both R-4s and Carbotechs in the back. Never had the issue with the Carbotech's swelling in the rear, and they used to give us a much more pronounced bite, but I think Carbotech may have changed the shoe. Doesn't seem the same. When you get the rears working right you should be blueing the drum friction surface. Definitely get two ducts up front and stay on top of your calipers. Ours had needed rebuilding about every 3 weekends. We run SRF fluid and bleed after every couple sessions on track. Brakes are by far the biggest maintenance issue on a Z.
Chris Carey
Central Florida Region
ITS/Vintage Datsun 240Z
Favorite tool to remove undercoating---- A curb!
"Understeer is when you hit the wall with the front of the car and oversteer is when you hit the wall with the rear of the car.
Horsepower is how fast you hit the wall, torque is how far you take the wall with you."
Not trying to brag, but I've probably got more time and effort in brake development and in making a fast ITS car with solid discus up front, rear drums actually work. Here's what I've learned over the years after a lot of trying various things. First, note that my front discs (Triumph TR8, 2011 SARRC champion) are slightly smaller than a Z cars, and the pads the same, slightly smaller. Rear drums are about the same size as are the shoes, but your drums are ally while mine are heavy metal. So, onto my experience:
1. You MUST get the rears to work for the fronts to have a chance of surviving at CMP, Road Atlanta or VIR. To do that, you simply must you race shoes and right now, in my view, there is only one option: Porterfield's new race compound (LS something I think). R4 does not work. You need LS and it's magic. Good friction coefficient, and it lasts. I'm on season two of my FIRST set of shoes and the shoes still look good, and the rears work.
R4 can't handle the heat. Carbotech has discontinued their race shoe material while trying to solve the swelling issue, which was terrible. Shoes would swell on the first use so bad that the car would not roll. Would create enough drag to cause a measurable 10 hp loss on the dyno. I love the Carbotech guys but that material sucks.
Porterfield went all out to help the burgeoning vintage scene and this new compound they have is awesome. Handles heat, no swell.
2. You must duct the rears. I think the main reason is to keep the wheel cylinder alive. I've seen it happen to Z cars and to my car, the cylinder gets crusty hot and just disintegrates. Hell, I've seen fires on Z cars from this happening. You can't cut holes in the body to get air to the drums, so I just drill the backing plates for "exit" and then add a three inch duct to the backing plate and run a hose under the body of the car. It's not ideal but it gets some air to them and I've not had a wheel cylinder failure since I did this.
3. Pad choice for the fronts is crucial. After trying everythign under the sun, I've settled on Raybestos ST-43s. Wear hard. Don't kill rotors. Can handle heat and keep stopping. Expensive though, $275 a pop. But last much longer than the Blues and HT-10s I was using before. I've never had much luck with Carbotech on the front although I love the guys. Have a pair of Ferodo FS3000s thta I've not tried but will report when I do. Still, hard to see it being any better than the ST-43s (do NOT get the 41s...they generate too much heat).
4. Get a good duct to the rotor. Make it as straight (the duct) as possible, and have the intake as close to the centerline of the car as possible. Caliper ducts can't hurt but in my experience they don't help much either. Coating the back of the pads iwth heat treatment will make the caliper seals last longer (I generally go a half season now without changing calipers).
5. Use SRF. $70 a bottle that you use once in a season is still better than a $20 bottle that you have use 4 of due to boiling and bleeding fluids.
NC Region
1980 ITS Triumph TR8
Jeff,
Really appreciate the information - very helpful....
Q: The new Porterfield race compound - is that R4-S ? They said no such thing as LS....
They said "RD-4 is better for race vehicles that do not generate a lot of heat. R-4 is better for high heat race vehicles and the R4-S is for street use."
They quoted me $249 for RC114 ST-43's....
My first impression: Porterfield is extremely responsive to their customers.....
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