350Z N/A with +1,000WHP and on stock internals!!!
05-10-2006, 04:59 AM
#1
350Z N/A with +1,000WHP and on stock internals!!!
Impossible ? From the engine, hardly… 
That’s 1000 WHP from the brake system of course… Aha, gotcha !
I was bored and decided to figure out how much HP the brake system has to consume to slow the Z down. So I loaded my MidOhio telemetry and ran a power analysis, inverting the longitudinal accelerations, compared that with GPS speeds and using the car’s + me weight of 3413lb (weighted at MidOhio 20 minutes before that data was taken).
The power figures peaked at 1,336HP. Small wonder these things get hot! I figure that the aero drag was probably less than 50HP (speed at that peak moment where near 60mph on a slight up hill – The keyhole entry)
And just for the fun of it I looked at engine breaking. In forth gear at 93 mph, including aero drag, lifting from the throttle will translate to only 128HP.(Note that this figure has more aero drag in it than the 1336HP on, since speed where lower then. 93 vs 60mph)
128HP vs 1300HP for braking. That should convince pretty much everybody to forget about engine braking to slow down fast(er) and concentrate on the brakes themselves.
Cheers!
That’s 1000 WHP from the brake system of course… Aha, gotcha !
I was bored and decided to figure out how much HP the brake system has to consume to slow the Z down. So I loaded my MidOhio telemetry and ran a power analysis, inverting the longitudinal accelerations, compared that with GPS speeds and using the car’s + me weight of 3413lb (weighted at MidOhio 20 minutes before that data was taken).
The power figures peaked at 1,336HP. Small wonder these things get hot! I figure that the aero drag was probably less than 50HP (speed at that peak moment where near 60mph on a slight up hill – The keyhole entry)
And just for the fun of it I looked at engine breaking. In forth gear at 93 mph, including aero drag, lifting from the throttle will translate to only 128HP.(Note that this figure has more aero drag in it than the 1336HP on, since speed where lower then. 93 vs 60mph)
128HP vs 1300HP for braking. That should convince pretty much everybody to forget about engine braking to slow down fast(er) and concentrate on the brakes themselves.
Cheers!
Last edited by Kolia; 05-10-2006 at 05:04 AM.
05-10-2006, 05:04 AM
#2
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Brakes are the most powerful thing on a car. I once heard that the brake pedal is designed to be the strongest thing on the car. It has to stand up to alot of force in those "jab the brakes and pray for dear life kind of stops."
05-10-2006, 05:27 AM
#3
Nah, the pedal is not the most reinforced part of the car.
The suspension mounts are pretty beefy. And the impact structures also.
Much more than the brake pedal assembly, which is basically bolted to the firewall. You can actually see the thing flex.
The suspension mounts are pretty beefy. And the impact structures also.
Much more than the brake pedal assembly, which is basically bolted to the firewall. You can actually see the thing flex.
05-10-2006, 05:31 AM
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Originally Posted by Kolia
128HP vs 1300HP for braking. That should convince pretty much everybody to forget about engine braking to slow down fast(er) and concentrate on the brakes themselves.
That's some hella braking power though. Do you have a bbk or the stock brembos?
05-10-2006, 06:12 AM
#5
LOL!
No, not directly aimed at that one
This is with stock Brembos with track pads and Toyo RA1s.
I was pretty far from threshold braking since I was running with no ABS for the first time. Didn't want to lock up the wheels... I got similar deccelerations with the Falken Azenis RT615.
No, not directly aimed at that one
This is with stock Brembos with track pads and Toyo RA1s.
I was pretty far from threshold braking since I was running with no ABS for the first time. Didn't want to lock up the wheels... I got similar deccelerations with the Falken Azenis RT615.
05-10-2006, 06:16 AM
#6
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i always laugh at the people who post in here saying "i hit a _____ today in the Z". and when asked how it happened they say they were trying to downshift a couple of gears to help them brake. just stomp on the pedal!
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05-10-2006, 06:49 AM
#8
Originally Posted by undercat
why did you have your abs disabled? and what size tires are you running?
255/40R17 front
275/40R17 rear
About the reasons behind turning the ABS OFF, I’ll start a new topic in the MotorSport section. Basically, the car handled terribly with these tires and a stock suspension…
05-10-2006, 07:02 AM
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that's interesting, i definitly have to check that out when you post it up.
I imagine with those sized tires, you have much higher maximum breaking ability than on stock size tires.
also, i didn't know 17s would fit over brembos.
I imagine with those sized tires, you have much higher maximum breaking ability than on stock size tires.
also, i didn't know 17s would fit over brembos.
05-10-2006, 08:17 AM
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Originally Posted by njsho
Brakes are the most powerful thing on a car. I once heard that the brake pedal is designed to be the strongest thing on the car. It has to stand up to alot of force in those "jab the brakes and pray for dear life kind of stops."
This means that they are majorly over-designed compared to the worst case loading conditions, they should not fail in any case.
05-10-2006, 08:19 AM
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Originally Posted by Kolia
Impossible ? From the engine, hardly…
That’s 1000 WHP from the brake system of course… Aha, gotcha !
I was bored and decided to figure out how much HP the brake system has to consume to slow the Z down. So I loaded my MidOhio telemetry and ran a power analysis, inverting the longitudinal accelerations, compared that with GPS speeds and using the car’s + me weight of 3413lb (weighted at MidOhio 20 minutes before that data was taken).
The power figures peaked at 1,336HP. Small wonder these things get hot! I figure that the aero drag was probably less than 50HP (speed at that peak moment where near 60mph on a slight up hill – The keyhole entry)
And just for the fun of it I looked at engine breaking. In forth gear at 93 mph, including aero drag, lifting from the throttle will translate to only 128HP.(Note that this figure has more aero drag in it than the 1336HP on, since speed where lower then. 93 vs 60mph)
128HP vs 1300HP for braking. That should convince pretty much everybody to forget about engine braking to slow down fast(er) and concentrate on the brakes themselves.
Cheers!
That’s 1000 WHP from the brake system of course… Aha, gotcha !
I was bored and decided to figure out how much HP the brake system has to consume to slow the Z down. So I loaded my MidOhio telemetry and ran a power analysis, inverting the longitudinal accelerations, compared that with GPS speeds and using the car’s + me weight of 3413lb (weighted at MidOhio 20 minutes before that data was taken).
The power figures peaked at 1,336HP. Small wonder these things get hot! I figure that the aero drag was probably less than 50HP (speed at that peak moment where near 60mph on a slight up hill – The keyhole entry)
And just for the fun of it I looked at engine breaking. In forth gear at 93 mph, including aero drag, lifting from the throttle will translate to only 128HP.(Note that this figure has more aero drag in it than the 1336HP on, since speed where lower then. 93 vs 60mph)
128HP vs 1300HP for braking. That should convince pretty much everybody to forget about engine braking to slow down fast(er) and concentrate on the brakes themselves.
Cheers!
No wonder acceleration (decceleration) experienced in braking or cornering usually overshadows the engine powered accleration.
What gear were you in when you used engine braking to slow down? Most of the everday situations wont ever demand the need to use the extreme braking that you probably calculated, so engine braking is not braking per se, but more speed control. I wouldnt dismiss the use of engine braking completely.
Last edited by spacemn_spiff; 05-10-2006 at 08:22 AM.
05-10-2006, 08:29 AM
#13
Originally Posted by spacemn_spiff
No wonder acceleration (decceleration) experienced in braking or cornering usually overshadows the engine powered accleration.
What gear were you in when you used engine braking to slow down? Most of the everday situations wont ever demand the need to use the extreme braking that you probably calculated, so engine braking is not braking per se, but more speed control. I wouldnt dismiss the use of engine braking completely.
What gear were you in when you used engine braking to slow down? Most of the everday situations wont ever demand the need to use the extreme braking that you probably calculated, so engine braking is not braking per se, but more speed control. I wouldnt dismiss the use of engine braking completely.
I was refering to panic stop situations where maximum braking is needed. Many people on this forum (and others) firmly believe that down shifting will help.
05-10-2006, 08:35 AM
#14
Originally Posted by spacemn_spiff
You probably are right, in engineering world, its called Factor of Safety and is fairly high number (2-5) for all critical parts & sub-assemblies. These parts are brakes, suspension, steering etc not just one part such as the brake pedal etc.
This means that they are majorly over-designed compared to the worst case loading conditions, they should not fail in any case.
This means that they are majorly over-designed compared to the worst case loading conditions, they should not fail in any case.
Pretty much everything has to deform enough to dissipate the impact energy. A part too stiff will just transmit the energy to the next element.
For pedals, they have to yield to the weight of the driver to minimize leg fractures.
05-10-2006, 10:00 AM
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Originally Posted by Kolia
Specifically to the automotive industry, we don’t want a super thought part in the car. We need to control the behavior of the various element of the car in the case of a crash.
Pretty much everything has to deform enough to dissipate the impact energy. A part too stiff will just transmit the energy to the next element.
For pedals, they have to yield to the weight of the driver to minimize leg fractures.
Pretty much everything has to deform enough to dissipate the impact energy. A part too stiff will just transmit the energy to the next element.
For pedals, they have to yield to the weight of the driver to minimize leg fractures.
I assume you are talking about crumple zones or crash safety, then that is a different design criteria. What I was referring to was mainly operational or fatigue - reversal or cyclic loading failures? A particular component can be designed independant or dependant failure modes based on either design criteria. That means that car crash failure could be different than operational failure.
05-10-2006, 10:33 AM
#16
It’s not engineering terminology because we’re on a car guy forum and I don’t see the need to loose every body (including myself) in techno gibberish. I’d rather get the idea across than try to amaze the reader with fancy words.
Pure engineering forums exist for these kinds of discussions…
So, in keeping in with the context of us car guys I wanted to outline that the car is not designed to be as though as possible. It’s rather built as stiff as possible while still doing its job of keeping its occupant whole and alive in the case of an accident. Although the specific criteria varies from one manufacturer to another, for many of them safety comes first, even if performance has to suffer. This is true for the car’s white body at least. We don’t use safety factors either. We make it right, returning to the drawing board if simulations and tests shows our design to be inadequate.
Pure engineering forums exist for these kinds of discussions…
So, in keeping in with the context of us car guys I wanted to outline that the car is not designed to be as though as possible. It’s rather built as stiff as possible while still doing its job of keeping its occupant whole and alive in the case of an accident. Although the specific criteria varies from one manufacturer to another, for many of them safety comes first, even if performance has to suffer. This is true for the car’s white body at least. We don’t use safety factors either. We make it right, returning to the drawing board if simulations and tests shows our design to be inadequate.
05-10-2006, 10:58 AM
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Originally Posted by njsho
I once heard that the brake pedal is designed to be the strongest thing on the car.
Originally Posted by Kolia
Specifically to the automotive industry, we don’t want a super thought part in the car. We need to control the behavior of the various element of the car in the case of a crash.
Originally Posted by spacemn_spiff
I have to think harder to understand your terminology, its definitely not a engineering terminology that I am used to.
05-10-2006, 11:11 AM
#18
Originally Posted by undercat
Some brake pedals are designed to yield but I think that it's the whole brake system attached to the brake pedal (safty system sorta like when an engine drops down). It's kinda hard to design high strength steel like that found in a brake pedal to yield before human bone breaks. I did a quick search and saw that new Impreza's have this kind design.
Ah, were we talking at the actual arm of the brake pedal?
That would be a more accurate description!
05-10-2006, 11:50 AM
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Originally Posted by njsho
Brakes are the most powerful thing on a car. I once heard that the brake pedal is designed to be the strongest thing on the car. It has to stand up to alot of force in those "jab the brakes and pray for dear life kind of stops."
