Can a 1050kg car out brake a 1500+kg r34 gtr?

[Intensevil]

Given this situation:

Both cars are neck and neck and doing 100kmh. They both have the same tires. At a predetermined point they both slam the brakes and brake at the maximum possible potential of the tires (just before lock up).

So long as neither car suffers brake fade then I'm pretty sure that the 1050kg car will out brake the gtr. My friend seems to think other wise. Tell him I'm right.

[Leewah]

The only way the GTR could outbrake the 1050kg car is if the brakes were a hellava lot bigger than that of the 1050kg car.

Eg. If a full weight GTR had 8 pot calipers and 16" carbon rotors with formula 1 grade brake pads and the 1050kg car had pissy 2pot calipers with 13" rotors, then I guess the GTR would possibly win.

It's simple physics. It will take a lot more clamping pressure to slow down a heavier object.

[DoughBoy]

Just from a simple F=ma equation the 1500kg car would need 1.5 times the braking force of the smaller car to decelerate at the same rate. It's alot more complicated but that's the general gist of it/

[NuGGeT]

depends if it was a mini, there breaks are shit house (old ones)

depends on the smaller cars breaks

[nmcmahon83]

Hmmm it's been too long, I cant remember the mathematical equation, but you link momentum to impulse and differentiate to get force... hence at the same speed, the heavier car has the greater momentum, and thus requires the greater force or, in the case assuming equal maximum breaking capacity, takes longer to slow down.

[gts4]

This is a very complicated question

To many factors to take into account

EG: Rotor size, Pads, Driver Reaction, Tyres, ABS ect

But if all is equal then the lighter will stop first

[Intensevil]

Keep this in mind though, since both cars have the same tires then this applies:

Cars slow down as a combination of friction between the tires and the road. But before that the tires have to be slowed down by the brakes, have a force applied against them. Small brakes may be able to lock up the brakes, but the way to slow down fastest is by burning off as much energy as possible in the shortest amount of time. The trade off is that the energy is converted to heat. When brakes get heated they become less effective, spongy ish. The brakes have to cool off between slowdowns inorder to remain effective. Smaller brake pads will heat up faster than big ones and become less effective faster. But big brake pads will soak up all the heat and cool down faster in between braking periods, therefore remaining effective for longer. In concluding this, drum brakes suck teh arse if u need to slow down more than once and discs are gooderor. More area and more pots per caliper is better as it spreads teh heat evenly along the pad.

[Fitzpatrick Speed Works]

well i know from driving both that my datsun 1000 at around 80km without locking the brakes, will stop alot faster than my r32 GTR will, and this thing has front drums, try and back up and do it again or do it from a faster speed and the tires are just to sh.ity and the brakes arent up to the task.... the datsun 1000= 629kg, GTR= 1474kg....

[red900ss]

Regardless of the brakes the tyres will provide a given coefficient of friction (Cf).

Consider that this would be an equal force at each set of tyres, to quote Intensevil "(just before lock up).".

Therefore you have two cars going the same speed, but 1 weighing 1.5 times the other. The tyres are providing an equal force to slow each car, therefore the heavier one would take a greater distance to stop.

(ignore increased weight-> increased down force on tyre-> increased Cf for the moment)

[akeenan]

of course........ lighter will stop first..

[Warpspeed]

Impossible to say, not enough information.

Assuming both braking systems are powerful enough to easily lock the wheels at any time during the stop, and do not fade significantly during the stop, the size of the brakes makes no difference. This assumes that front to rear brake bias is correct for the vehicle, and the driver has reasonable skill.

The next biggest factor is tyre grip on the road. What about unsprung weight and suspension rates ? What about wheel camber and toe under heavy braking ? And what is the front to rear weight bias of each car ? What is the centre of gravity height of each car ? Tyre pressures ?

A formula one car with low centre of gravity, very high rear weight bias, and very good suspension geometry is going to easily outbrake a tall front engined production car even with identical total weight, tyres, and brake specifications.

Then there are technical aids such as ABS and 4WD which can make a big difference if traction is very uneven in wet slippery conditions.

[nmcmahon83]

Picture this... One Skyline R33 GTS-t weighing 1360kg, one Skyline R33 GTS-t completely stripped of everything using lightweight panels etc weighing 1050kg (regardless whether its possible or not)... both identical suspension, tyres, brakes and the same driver. The lighter one will stop first.

[R33man]

Given this situation:

Both cars are neck and neck and doing 100kmh. They both have the same tires. At a predetermined point they both slam the brakes and brake at the maximum possible potential of the tires (just before lock up).

So long as neither car suffers brake fade then I'm pretty sure that the 1050kg car will out brake the gtr. My friend seems to think other wise. Tell him I'm right.

I'm probably going to regret saying this but taking in to account all the things that Intensevil has said in his post I believe the heavier car will stop first.

Here are my reasons.

The original post said both cars have the SAME tyres and brake at maximum potential I.E. just before lock up.

Also "So long as neither car suffers brake fade" This tells me that the brakes on both cars are up to the task and heat build up will not reduce performance. Remember they brake all the way to stand still with the wheels verging on lockup. You cannot brake any better than this. Bigger brakes will not stop you any faster, they will just allow you to do it more often before brake fade.

Now the heaver car will have more weight on the tyres. This means that more braking force can be applied before lock up. Therefore the heavier car is capable of more braking force before reaching its maximum which occurs just before lock up. It is because of the fact the heavier car can apply more force that it will stop quicker.

Before anyone tells me, yes the brakes on the heavy car will get a lot hotter than the lighter car but because in this case "neither car suffers brake fade" than this will not be an issue.

Think about it, it takes a lot less force to lock up the wheels on something light like a bike than something heavy like a truck.

[benm]

Interesting theory

[Intensevil]

By that theory a heavier car can also corner faster. That little bit of extra weight on teh front wheels is still not enuff to compensate for the increased momentum. Its like saying that a sumo wrestler can stop quicker from a sprint than a jockey can. Sure theres extra weight on the part thats doing the stoping, but it is neglible

[R33man]

By that theory a heavier car can also corner faster. That little bit of extra weight on teh front wheels is still not enuff to compensate for the increased momentum. Its like saying that a sumo wrestler can stop quicker from a sprint than a jockey can. Sure theres extra weight on the part thats doing the stoping, but it is neglible

I think you have missunderstood my post. I in no way said a heaver car will corner faster. In fact it will corner worse because again assuming two similar cars with differing weights. The cornering ability will be determined by the lateral grip of the tyres. The lateral cornering force of the car is produced by two things, weight and speed. Assuming the lateral grip of both cars is the same the heaver car will reach its limit at a slower speed. This can be linked to the formular Force = Mass X Acceleration.

Now, It is not like saying a sumo can stop quicker than a Jockey. This example has nothing to do with the subject. The key things here are that the tyres are the same, the brakes do not fade, and both cars brake at maximum ability.

What I dont think you are taking into account is that the heavy car will have to dissapate a LOT more heat than the lighter car. This has nothing to do with the maximum coefficient of friction available from the tyres, weight on the other hand does.

Another example would be when you brake in a car with the same tyres on the front and back, if you set up the brakes so there was no bias then you did the 100 to 0 test what do you think would happen? The answer is that the back wheels would lock up. This is because when you brake the weight of your car shifts to the front. This is the reason why there is bias set into a brake system.

I hope this makes sense.

[nmcmahon83]

No offense dude, but you are trying to disprove 200-300 yr old laws of physics... the less mass, the less inertia, the less force required to change its velocity...

Also, by you're theory, we can say that it would indeed take longer for the weight of the heavier car to shift onto the front wheels, since there is more of it, and hence full braking capacity would be reached later than that of the lighter car which means more time to brake etc etc...

All these little things are negligable when compared to the laws of physics.

[pentae]

No offence guys,

But i would like to point out that this thread subject is really stupid.

Not trolling, but honestly.. of course a lighter car given the same brakes, tyres etc will stop first.

[R33man]

Ok. You guys don't have to believe me if you don't want to. But looking at the original post which is very specific to the conditions I am sure I'm right.

nmcmahon83 I agree with you about the less weight, less momentum, less force thing. I am just saying that because of the less weight on the tyres it is not able to apply as much braking force as the heavier car.

But hey its discussions like this which is what a forum is all about.

[BryanB]

intensevil you ask stupid questions you will only get stupid answers.....

r33man you have a good point, though you have to remember the actual brakes themselves have their limits and the actual velocity to weight of the lighter car - the brakes have a lot less force to stop and thus will stop faster due to the actual size of the brakes themselves.... that is my theory anyway, its an impossible situation in this day and age and shouldn't of been brought up haha