Brake Upgrades for a 4 lug, what's available Options

[76-914]

Looking to upgrade my present brake system but I want to keep it 4 lug AND keep the parking brake. Not to mention, staying out of the Poor House at the same time. I'm not opposed to moving up to a larger MC. Is there such an animal? TIA, Kent (IMG:style_emoticons/default/beerchug.gif)

[zach914v8]

I think for 90% of the 914's out there, the stock system working correctly is great. It is us, the 10% that have scary fast cars that need more. Its a strange feeling when your at the end of a drag strip trying to slow down from 115 mph and see the end of the road come up fast and your car wont stop. When you get out of the car and see you rotors glowing, you know that you have maxed out your brakes.

[stugray]

I think for 90% of the 914's out there, the stock system working correctly is great. It is us, the 10% that have scary fast cars that need more. Its a strange feeling when your at the end of a drag strip trying to slow down from 115 mph and see the end of the road come up fast and your car wont stop. When you get out of the car and see you rotors glowing, you know that you have maxed out your brakes.

If you are maxing out your brakes from one drag racing pass you are doing something seriously wrong.
That would barely give them a workout compared to how I abuse my stock brakes on the track.

I brake about as hard as I can from 110 MPH (with 215 Hoosiers) on just one of 10 corners at the track, and do that for 20 minutes without stopping.
I have only detected brake fade a few times

[zach914v8]

I think for 90% of the 914's out there, the stock system working correctly is great. It is us, the 10% that have scary fast cars that need more. Its a strange feeling when your at the end of a drag strip trying to slow down from 115 mph and see the end of the road come up fast and your car wont stop. When you get out of the car and see you rotors glowing, you know that you have maxed out your brakes.

If you are maxing out your brakes from one drag racing pass you are doing something seriously wrong.
That would barely give them a workout compared to how I abuse my stock brakes on the track.

I brake about as hard as I can from 110 MPH (with 215 Hoosiers) on just one of 10 corners at the track, and do that for 20 minutes without stopping.
I have only detected brake fade a few times

It was more than one pass. I was tuning with nitrous, and finally got the car in the 11's. The brakes went south at about the fourth pass, scared myself a bit. A brake upgrade has been on the list since then.

[stugray]

I think for 90% of the 914's out there, the stock system working correctly is great. It is us, the 10% that have scary fast cars that need more. Its a strange feeling when your at the end of a drag strip trying to slow down from 115 mph and see the end of the road come up fast and your car wont stop. When you get out of the car and see you rotors glowing, you know that you have maxed out your brakes.

If you are maxing out your brakes from one drag racing pass you are doing something seriously wrong.
That would barely give them a workout compared to how I abuse my stock brakes on the track.

I brake about as hard as I can from 110 MPH (with 215 Hoosiers) on just one of 10 corners at the track, and do that for 20 minutes without stopping.
I have only detected brake fade a few times

It was more than one pass. I was tuning with nitrous, and finally got the car in the 11's. The brakes went south at about the fourth pass, scared myself a bit. A brake upgrade has been on the list since then.

Then I still say you have something wrong.
Either the brakes are dragging, or you have fronts only working, etc.
One stop from 120 MPH to zero should make the rotors warm to the touch.
Then the time it takes to drive back to the line, restage, and go again and they would be cool to the touch again.
Laps at my track are only about 2.25 minutes so I repeat the 110 MPH to nearly zero every lap, and that is only one corner of 10. My brakes never get to the point of "glowing red hot".

Drag racing over & over as quickly as possible should not overheat these brakes even in 100% stock form.
Unless of course your car has 500 HP, and weighs 4000 lbs.

The physics just doesnt add up.
I'll calculate the energy dissipated and see.

[zach914v8]

I think for 90% of the 914's out there, the stock system working correctly is great. It is us, the 10% that have scary fast cars that need more. Its a strange feeling when your at the end of a drag strip trying to slow down from 115 mph and see the end of the road come up fast and your car wont stop. When you get out of the car and see you rotors glowing, you know that you have maxed out your brakes.

If you are maxing out your brakes from one drag racing pass you are doing something seriously wrong.
That would barely give them a workout compared to how I abuse my stock brakes on the track.

I brake about as hard as I can from 110 MPH (with 215 Hoosiers) on just one of 10 corners at the track, and do that for 20 minutes without stopping.
I have only detected brake fade a few times

It was more than one pass. I was tuning with nitrous, and finally got the car in the 11's. The brakes went south at about the fourth pass, scared myself a bit. A brake upgrade has been on the list since then.

Then I still say you have something wrong.
Either the brakes are dragging, or you have fronts only working, etc.
One stop from 120 MPH to zero should make the rotors warm to the touch.
Then the time it takes to drive back to the line, restage, and go again and they would be cool to the touch again.
Laps at my track are only about 2.25 minutes so I repeat the 110 MPH to nearly zero every lap, and that is only one corner of 10. My brakes never get to the point of "glowing red hot".

Drag racing over & over as quickly as possible should not overheat these brakes even in 100% stock form.
Unless of course your car has 500 HP, and weighs 4000 lbs.

The physics just doesnt add up.
I'll calculate the energy dissipated and see.

Maybe the rears were not working? I don't know. I did the nitrous thing back in 2011, then basically right after that I got too busy with other crap and parked the car for a few years. When I got back on it a few months ago the rears were badly locked up and the fronts were draging. I have since rebuilt the rears and put vw fox calipers on the front with brembo pads.

I just always assumed That I was surpassing the ability of the brakes. Now you have me wondering if I have a restriction somewhere in the system?

[stugray]

I think for 90% of the 914's out there, the stock system working correctly is great. It is us, the 10% that have scary fast cars that need more. Its a strange feeling when your at the end of a drag strip trying to slow down from 115 mph and see the end of the road come up fast and your car wont stop. When you get out of the car and see you rotors glowing, you know that you have maxed out your brakes.

If you are maxing out your brakes from one drag racing pass you are doing something seriously wrong.
That would barely give them a workout compared to how I abuse my stock brakes on the track.

I brake about as hard as I can from 110 MPH (with 215 Hoosiers) on just one of 10 corners at the track, and do that for 20 minutes without stopping.
I have only detected brake fade a few times

It was more than one pass. I was tuning with nitrous, and finally got the car in the 11's. The brakes went south at about the fourth pass, scared myself a bit. A brake upgrade has been on the list since then.

Then I still say you have something wrong.
Either the brakes are dragging, or you have fronts only working, etc.
One stop from 120 MPH to zero should make the rotors warm to the touch.
Then the time it takes to drive back to the line, restage, and go again and they would be cool to the touch again.
Laps at my track are only about 2.25 minutes so I repeat the 110 MPH to nearly zero every lap, and that is only one corner of 10. My brakes never get to the point of "glowing red hot".

Drag racing over & over as quickly as possible should not overheat these brakes even in 100% stock form.
Unless of course your car has 500 HP, and weighs 4000 lbs.

The physics just doesnt add up.
I'll calculate the energy dissipated and see.

Maybe the rears were not working? I don't know. I did the nitrous thing back in 2011, then basically right after that I got too busy with other crap and parked the car for a few years. When I got back on it a few months ago the rears were badly locked up and the fronts were draging. I have since rebuilt the rears and put vw fox calipers on the front with brembo pads.

I just always assumed That I was surpassing the ability of the brakes. Now you have me wondering if I have a restriction somewhere in the system?

That is what I would suspect.
I was going to add this to my previous post, but too late:

Assuming a 2500 lb (1135kg) car @ 115 MPH (52m/s).
That is: E = ½*M*v^2 = 1534520 Joules or ~1.5 MegaJoules
1.5 MJ = ~1450 BTUs

So to come to a stop from 115 MPH, the brakes would have to dissipate 1450 BTUs essentially instantaneously.

1 BTU = the heat required to raise 1 lb of water by 1 deg F.
Specific heat of Mild steel is .122, so .122 BTUs will raise the temp of 1 pound of steel by 1 deg F.
914 front rotors weigh ~15 lbs each.
Assuming that the kinetic energy of the entire car is absorbed by JUST the front rotors, then we have:
1500 BTUs into 30 lbs of steel = 50 BTUs per lb.
50 BTUs into 1 lb of steel at .122 (BTU/(lb*degF)
50 / .122 = 409 deg F.
So If the 1500 lb car is travelling at 115 MPH, and comes to an abrupt stop using the front brakes ONLY, AND all of the heat goes into the rotors ONLY, then the rotors would increase in temp by ~400 deg F.
The temp of Steel becoming visibly “red hot” is 900 deg F.

In reality, the calipers, pads, and wheels get hot, and a significant amount of heat is dissipated right away via convection.
Therefore “rotors getting red hot by a single drag racing pass is ‘busted’”

Now of course if the heat could not dissipate between runs (and you did repeated runs back to back), then you could certainly overheat them.

[zach914v8]

I think for 90% of the 914's out there, the stock system working correctly is great. It is us, the 10% that have scary fast cars that need more. Its a strange feeling when your at the end of a drag strip trying to slow down from 115 mph and see the end of the road come up fast and your car wont stop. When you get out of the car and see you rotors glowing, you know that you have maxed out your brakes.

If you are maxing out your brakes from one drag racing pass you are doing something seriously wrong.
That would barely give them a workout compared to how I abuse my stock brakes on the track.

I brake about as hard as I can from 110 MPH (with 215 Hoosiers) on just one of 10 corners at the track, and do that for 20 minutes without stopping.
I have only detected brake fade a few times

It was more than one pass. I was tuning with nitrous, and finally got the car in the 11's. The brakes went south at about the fourth pass, scared myself a bit. A brake upgrade has been on the list since then.

Then I still say you have something wrong.
Either the brakes are dragging, or you have fronts only working, etc.
One stop from 120 MPH to zero should make the rotors warm to the touch.
Then the time it takes to drive back to the line, restage, and go again and they would be cool to the touch again.
Laps at my track are only about 2.25 minutes so I repeat the 110 MPH to nearly zero every lap, and that is only one corner of 10. My brakes never get to the point of "glowing red hot".

Drag racing over & over as quickly as possible should not overheat these brakes even in 100% stock form.
Unless of course your car has 500 HP, and weighs 4000 lbs.

The physics just doesnt add up.
I'll calculate the energy dissipated and see.

Maybe the rears were not working? I don't know. I did the nitrous thing back in 2011, then basically right after that I got too busy with other crap and parked the car for a few years. When I got back on it a few months ago the rears were badly locked up and the fronts were draging. I have since rebuilt the rears and put vw fox calipers on the front with brembo pads.

I just always assumed That I was surpassing the ability of the brakes. Now you have me wondering if I have a restriction somewhere in the system?

That is what I would suspect.
I was going to add this to my previous post, but too late:

Assuming a 2500 lb (1135kg) car @ 115 MPH (52m/s).
That is: E = ½*M*v^2 = 1534520 Joules or ~1.5 MegaJoules
1.5 MJ = ~1450 BTUs

So to come to a stop from 115 MPH, the brakes would have to dissipate 1450 BTUs essentially instantaneously.

1 BTU = the heat required to raise 1 lb of water by 1 deg F.
Specific heat of Mild steel is .122, so .122 BTUs will raise the temp of 1 pound of steel by 1 deg F.
914 front rotors weigh ~15 lbs each.
Assuming that the kinetic energy of the entire car is absorbed by JUST the front rotors, then we have:
1500 BTUs into 30 lbs of steel = 50 BTUs per lb.
50 BTUs into 1 lb of steel at .122 (BTU/(lb*degF)
50 / .122 = 409 deg F.
So If the 1500 lb car is travelling at 115 MPH, and comes to an abrupt stop using the front brakes ONLY, AND all of the heat goes into the rotors ONLY, then the rotors would increase in temp by ~400 deg F.
The temp of Steel becoming visibly “red hot” is 900 deg F.

In reality, the calipers, pads, and wheels get hot, and a significant amount of heat is dissipated right away via convection.
Therefore “rotors getting red hot by a single drag racing pass is ‘busted’”

Now of course if the heat could not dissipate between runs (and you did repeated runs back to back), then you could certainly overheat them.

Wow, that is good to know. I guess I need to figure out what went wrong here. So by your math I probably don't even need to fuss with vented rotor/billet hubs.

So at what point will these brakes not work? I have a Lm4 5.3 v8 and boxster six speed going in it. I plan on doing the nitrous thing again with the new motor. shooting for low 10's or high 9's with the next setup. Somewhere near 500hp and maybe 135-40mph in the 1/4 mile. If the stock brakes are good for that, I am done chasing the billet hub dragon.