Front Brake Upgrades

[260DET]

Messenger/Dan Baldwin/ 240sx, and other folk who are talking bout brakes in here :nervous:

Have read through your coments on the Toyota 4by4 upgrade,

Im curious - what if i put on massive front brakes, like those supplied by HoppersStoppers (300mm slotted rotors with Big 2-Piston Calipers) but kept the rear brakes on the Z stock,

From what ive read, this seems like a fairly unwise idea - as the Z already has a biasis towards the front brakes, this kind of conversion would massively increase this biasis, thus leading to front-brake lockup...........

Is this pretty much right?

And if it is, what can i do to counter-act this?

Put massive brakes on there rear?

Ah, you have pinpointed the dilemma often faced when modifying - how far do I go and where do I stop? One mod leads to another, to another and so on

BTW there is a fairly simple but not very big rear disc brake conversion using Aussie Skyline/Pintara rotors and calipers which does work quite well. Match that with a setup using twin or big single piston sliding calipers on the front.

[Dan Baldwin]

I understand the front end bias issue in theory. But on my car when I get on the brakes about as hard as you would ever possibly be on them the rear end locks first.

It is actually rather scary, I have never had a car that the rears locked up first. The rear end starts to step out.

That *IS* scary. Something's wrong with your brakes for sure, no way the rears should lock first. I'd have a look in there, could be the rears are dragging. Or you have teflon brake pads up front :eek:

[Dan Baldwin]

what if i put on massive front brakes, like those supplied by HoppersStoppers (300mm slotted rotors with Big 2-Piston Calipers) but kept the rear brakes on the Z stock,

From what ive read, this seems like a fairly unwise idea - as the Z already has a biasis towards the front brakes, this kind of conversion would massively increase this biasis, thus leading to front-brake lockup...........

Is this pretty much right?

And if it is, what can i do to counter-act this?

Put massive brakes on there rear?

Yup. But consider that your car's braking system, ancient as it is, was designed and engineered by professionals to ensure proper braking distribution. You will either need to educate yourself on this to determine what is required, or find an engineered and tested setup (and I'm sure there are setups out there that have NOT been engineered OR tested). Don't just throw a "big" brake setup at the back to balance the "big" brakes up front and hope for the best. You need to ensure that the rotor working diameters and caliper piston areas conspire to give proper front/rear balance, while ensuring the fronts lock before the rears.

[Aussie260z]

I just want to be sure that i get enough brakes for a future engine conversion, so i dont have to go back and do them again,

Would the Z-ZX brake conversion (by doing both the front and rears) be able to stop a 190kw Rb25DET powered Z?

[speedyblue]

Ring up and engineer and find out what is required in your state. He will have an idea what will be required and you can base your upgrade around that. It varies from state to state so you will just have to ask.

[TomoHawk]

That's interesting. What kind(s) of variable do you think are involved? brake pad area? rotor diameter? Pad material?

thx

[Aussie260z]

Spoke to a local engineer in Canberra and he said,

If i go with Rb25DE - might not need anything except the stock brakes working well (maybe the 4by4 Toyota truck caliper upgrade),

If i go with Rb25DET (which i will) - would need to increase my braking power more than i'd be likely to get with the 4-spot Toyota Caliper alone,

Just no 100% sure about which way to go,

I've come across alot of different brake upgrades kits over the last few days and im not 100% certain on which way to go...........

Anyone out there in AUS, have tried and tested brake upgrades for decent HP Zeds?

[my_mad_z]

Aussie260z,

I've upgraded to the 4 spot toyota calipers with peugot vented and slotted discs on the front and I've used the skyline/pintara discs and calipers on the rear..... as far as I am aware, the brake tests are done from 60-0kph and 100-0kph; they measure the braking abilty over these ranges. However, with more power, you would want the extra braking force for safety.

I am also heading towards a turbo setup, however I'm sticking with the L28. I had a turbo L28 in my 260Z but didn't do any brake upgrades..... ended up T-boning a van that made an illegal u-turn in front of me, I was doing 60kph and couldn't pull up - brakes locked up; caused $16,000 damage to my Z; so as u can imagine, I'm going for bigger brakes this time! The standard brakes were ok for normal driving, but trying to pull up suddenly or from high speeds was a challenge!

I spoke to an engineer in Melbourne and he was quite happy with the brake upgrade I mentioned.....I'm an engineer myself, and I'm confident with the setup. I'm aiming for 200kw+ at the rear wheels and I'm sure that the brakes will be fine. A friend of mine has a 383 chev(stroker) in his 240z (approx 250kw rwhp) and he's using the same brakes on the rear but different on the front (from memory, I think they're toyota corona brakes that are smaller than the peugot/4spot caliper setup I have). His brakes work quite well, pull the car up very nicely, however after a copule of hard braking sessions, he gets brake fade. I believe that with the peugot/4spot setup, the braking force will be sufficient for 190kw.

The setup was fairly cheap too.... $200 for the 4spot calipers, $136ea for the peugot vented/slotted discs(brand new from dba), and $100 dollars for the skyline/pintara discs and calipers (pick a part) - all up, $572. I had to do some machining on the front discs, bracket fabrication for the rear calipers and that was all. I realise that the 4spot toyota calipers are heavier than alloy calipers, however I have no intentions on circuit racing.

Apologies for the long reply.

Marc.

[Aussie260z]

Thanks for the reply my_mad_z,

That sounds like a really good upgrade, probably wouldnt follow the same route as you with the front brakes,

But the rear brakes seem sweet, and more than enought for what im planning,

How did you go about making the bracket?

Is it basically the same bracket as the early 80's Nissan Maxima rear caliper bracket???

What did you do about the hand-brake cable?

Did you do any Master Cylinder upgrades?

[Brett240]

Aussie260z,

i have a decent amount of HP and run my car on the track rugularly. im using Z32 300ZX calipers and discs up front and an old kit for Zed's that uses AU Falcon calipers and rotors on the rear. this comes with a proper hand brake setup as well.

works great and has no problem hauling the car down time and time again from 200mkh plus on a race track with no brake fade or pedal feel difference. i will PM you the details of the shop that can do this for you when i get back to sydney in a few days.

oh and putting huge brakes on the front only WILL make your car stop harder in the real world. The fronts will now lock up easier at lower speeds becouse HEY YOU HAVE BIGGER BRAKES!! they are supposed to lock easier.

what you will notice is your rear's will fade into oblivion, but if you get that far then your old fronts would have too and you'd be out of brakes.

As long as you have those big bad brakes up front stopping it will be fine and the car will be stable

the Z32/AU setup has too much brake bias to the rear so the rears lock first on mine, havent got around to putting in an adjustable proportioning valve yet.

[my_mad_z]

Aussie260z,

I'm not sure about the maxima rear caliper bracket, haven't seen one. All I did was used the original skyline/pintara bracket and made it fit. From memory, I think I had to increase the diameter and drill a couple of holes, was a very simple procedure. The handbrake can be attached directly to the caliper, with very minor filing of the handbrake bracket. I did this initially but found that the cables were a touch too short and would rub on the drive shafts. I have resolved this issue by extending the cables and the handbrake works fine.

In regards to the master cylinder, I tried to get a new 280zx master cylinder but found out that they dont sell them brand new anymore in Aus. So I spoke to a few brake specialists and they said it would be fine to use a 260z master.....one guy suggested I remove the one-way valve for the rear brakes (located in the master cylinder) to compensate for the disc upgrade. I haven't done so yet and the pedal feels fine.

I'll take some photos of the upgrade and post them up as soon as I can.

Cheers.

Marc.

[Aussie260z]

Thanks mate, would love to see pics of your setup, especially like to see the rear brake setup,

This is what i've been thinking............please anyone tell me if what i say can/cant work,

Just a theory...............

Stock 1973-78 Aussie 260z rotors specs are..........

(271mm by 12.7mm) with an overall rotor thickness of 43.5mm,

If you use big brake upgrade as sold by HoppersStoppers for the 260z they use the AU111 front brakes, its specs are (298mm by 28mm) with an overall thickness of 65mm,

Now the thickness of this disc its a hell of alot more than that of the Zed - 21.5mm thicker,

So what im thinking is they would use the 240z hub, which is 17mm (whereas the later 260z is supposed to be up to 25mm, 8mm thicker) than machine it up, but they cant take as much of as would be required to keep the original Zed wheel-offset, that is why it changes 8mm outwards............any opinions???????

BUT...........there is a set of falcon rotors, which has specs of (325mm by 32mm) with an overall thickness of 45.3mm, this rotor would need almost no mod's to fit onto the Zed, depending on what hub you use,

All these ford rotors have a centre diameter of 71.5mm, the original Zed rotor has a centre diameter of 81mm, so just need to machine the rotors out and it would slot right into place,

Of course you would need to also,

16" wheels (for the 298mm by 28mm rotors) &

17" wheels (for the 325mm by 32mm rotors),

and re-locate the caliper mounting holes for the calipers, or use some sort of bracket,

Ok..........how does this sound???????