Zed Head's logic is right on the money. If you improve the brakes on the rear of the vehicle only, you subsequently alter the balance provided by the factory setup bias. In order to return to the original bias you either have to upgrade the front brakes as well (theoretically in the same proportion as you improved the rears), or introduce an adjustable proportioning valve. 

Edited December 23, 20186 yr by dmorales-bello

On 12/21/2018 at 10:50 PM, tzagi1 said:

To each his own, refer back to post #401.

You have those who been doing it for 30 years + and those who are too busy talking how it doesn't work.

Doing it for 30yrs doesn't necessarily it was done right, now before you get your back up let me try and explain it another way.

Stock brakes are designed to have a balance of 70/30 front to back,  you throw a set of Toyota 4 pot calipers up front and because of the larger displacement now you have a balance of 85/15, you take the car for a drive and slam on the brakes, the front of the car pitches down a lot more than it did before with the stock brakes and feels like the car is stopping faster, but it isn't, it's actually taking you longer to stop because the rear brakes aren't doing the right amount of work and the front brakes are overloaded.

I've had 3 different configurations of "upgraded" brakes, rear discs, larger MC, larger booster, adjustable proportioning valve on my Z and I still can't lock up all 4 wheels at the same time.  It took me a long time and a lot of money to realize that it is called a braking system for a reason. Each braking system is designed specifically for that car if you change any major component on a braking system you will throw the systems balance off.

1 hour ago, grannyknot said:

Doing it for 30yrs doesn't necessarily it was done right, now before you get your back up let me try and explain it another way.

Stock brakes are designed to have a balance of 70/30 front to back,  you throw a set of Toyota 4 pot calipers up front and because of the larger displacement now you have a balance of 85/15, you take the car for a drive and slam on the brakes, the front of the car pitches down a lot more than it did before with the stock brakes and feels like the car is stopping faster, but it isn't, it's actually taking you longer to stop because the rear brakes aren't doing the right amount of work and the front brakes are overloaded.

I've had 3 different configurations of "upgraded" brakes, rear discs, larger MC, larger booster, adjustable proportioning valve on my Z and I still can't lock up all 4 wheels at the same time.  It took me a long time and a lot of money to realize that it is called a braking system for a reason. Each braking system is designed specifically for that car if you change any major component on a braking system you will throw the systems balance off.

It would be fun to take the same car and do some actual empirical testing to show this.

Stopping distance tests:

           with properly functioning stocks brakes

           with stock drums and yota solids

           with stock drums and yota vented

          with rear disc (Maximas?) and yota vented / solid

See what the actual footage is before and after proportioning valve adjustments

I suspect the results would be surprising. I suspect the footage actually gets worse in many of these scenarios at least until the balance gets right.

The biggest advantage to the Yota caliper in my opinion is the vented rotor should run cooler overall. The biggest disadvantage besides longer possible stopping distances is higher sprung weight.

I wonder if any one at HybridZ has done any testing like this?

 

 

Edited December 23, 20186 yr by Patcon

Maybe we should move this to it’s own thread.. Very interesting conversation!

4 hours ago, wheee! said:

Maybe we should move this to it’s own thread.. Very interesting conversation!

Sorry Jeff @Home Built by Jeff

Squirrel!!!

4 hours ago, wheee! said:

Maybe we should move this to it’s own thread.. Very interesting conversation!

I think this is definitely a worthwhile discussion. 

 

6 hours ago, grannyknot said:

Stock brakes are designed to have a balance of 70/30 front to back,  you throw a set of Toyota 4 pot calipers up front and because of the larger displacement now you have a balance of 85/15, you take the car for a drive and slam on the brakes, the front of the car pitches down a lot more than it did before with the stock brakes and feels like the car is stopping faster, but it isn't, it's actually taking you longer to stop because the rear brakes aren't doing the right amount of work and the front brakes are overloaded.

Adding the Toyota callipers on the front increases the braking surface, so on that percentage I could see 85/15, but does that take into account the greater volume of fluid that needs to be moved? I am imagining that the Toyota callipers require more pedal travel to get them to engage than the factory ones, could it even out the balance (as the rears would still lock at the same travel as before) or even send more bias towards the rear?

26% increase in required foot pedal pressure to exert the same psi on the caliper pistons.

Also a 26% increase in volume of fluid to be moved.

1 hour ago, Home Built by Jeff said:

I think this is definitely a worthwhile discussion. 

This first thread is a must for anyone interested in modifying brakes, https://forums.hybridz.org/topic/38592-brake-balance-faq/

These next two threads are specifically on modifying 240z-280z brakes, you can see over the 11 yrs of the thread what people have tried, what worked, what didn't, https://forums.hybridz.org/topic/38499-brake-upgrade-faq/

https://forums.hybridz.org/topic/104910-brakes-who-is-running-what/

Now if you need to occasionally escape all the "fun" of Christmas, these threads will keep you busy.

27 minutes ago, grannyknot said:

This first thread is a must for anyone interested in modifying brakes, https://forums.hybridz.org/topic/38592-brake-balance-faq/

These next two threads are specifically on modifying 240z-280z brakes, you can see over the 11 yrs of the thread what people have tried, what worked, what didn't, https://forums.hybridz.org/topic/38499-brake-upgrade-faq/

https://forums.hybridz.org/topic/104910-brakes-who-is-running-what/

Now if you need to occasionally escape all the "fun" of Christmas, these threads will keep you busy.

The other thing to remember when reading those threads, is some of those guys are racers and know about how to make cars handle and stop.

26 minutes ago, grannyknot said:

This first thread is a must for anyone interested in modifying brakes, https://forums.hybridz.org/topic/38592-brake-balance-faq/

These next two threads are specifically on modifying 240z-280z brakes, you can see over the 11 yrs of the thread what people have tried, what worked, what didn't, https://forums.hybridz.org/topic/38499-brake-upgrade-faq/

https://forums.hybridz.org/topic/104910-brakes-who-is-running-what/

Now if you need to occasionally escape all the "fun" of Christmas, these threads will keep you busy.

So if I am too lazy to pour through 11 years of threads, those who did the swap I have done, what was the result?

Either way I will be putting mine together and checking the actual results I get. We will see. 

I get jaded about some of these long threads as there are so many contradictory impressions, that it is difficult to separate the 'wheat from the chaff'. I just went through something similar headaches trying to work out the best width and offset for wheels to fit ZG flares. You would think that it has been done for years and there would be plenty of info available, but I searched countless threads on different forums and couldn't find anything useful. I ended up manually going through and measuring the width and offset of the factory wheels and then measuring where I wanted them to sit. I ended up getting 15x9 -20 all round which I have just received and they look like they will sit just right.

Hybrid Z site was run by a bunch of wacko's for a long time. I'm not sure if they still run it.  I don't like the site nor trust most data there.

It's the internet. I take it all with a grain of salt unless I know the poster.

It can be hard to sort out reality, especially on HybridZ, because the threads can pinball all over the place