RE: Nissan GT-R: Kazutoshi Mizuno Interview

[Garlick]

Munter said:

Alfa Male said:

Please, more of this!

Indeed. Enough with keeping us in suspenders. Part 2 gad'damnit.

W are just awaiting the videos from the camera guy, hopefully it won't be too long now.

[Godzill-R]

Weight is very very importan for performance make I believe. Formula one car only under 600kg But with 1000 kg down force and this weight making tire grip. But GTR is 1700 kg making tire grip alot. Lighter weight is better all people say but please understanding. If F1 car only 600kg weight if they lun at high speed the car will be sliding and finally crashed. So lighter weighting is better thing for acceleration and bleaking. But lighter weighting dangerous for beena because for about disability so professional driver easily control the lighter weight car but if beena driving high performance car the lighter weight car in that case lighter weight car making suddenly station many many making so for colnerling for bleaking for acceleration so not only weight control tire grip road counter is very very important point so this car is 1700kg is very very important for performance making.

Your's Kazutoshi Mizuno (Mr. GT-R)

[HereBeMonsters]

Godzill-R said:

Weight is very very importan for performance make I believe. Formula one car only under 600kg But with 1000 kg down force and this weight making tire grip. But GTR is 1700 kg making tire grip alot. Lighter weight is better all people say but please understanding. If F1 car only 600kg weight if they lun at high speed the car will be sliding and finally crashed. So lighter weighting is better thing for acceleration and bleaking. But lighter weighting dangerous for beena because for about disability so professional driver easily control the lighter weight car but if beena driving high performance car the lighter weight car in that case lighter weight car making suddenly station many many making so for colnerling for bleaking for acceleration so not only weight control tire grip road counter is very very important point so this car is 1700kg is very very important for performance making.

Your's Kazutoshi Mizuno (Mr. GT-R)

Wow, a reply from the horse's mouth!?

I think I get what he's on about, and I have to say one of the best roadholding cars I've ever driven is a new Corsa. Heavy but with decently designed suspension to take advantage of it, and with an engine to overcome the weight, might make sense?
I certainly felt like an absolute novice the first time I ever drove an Elise...

[Tazio1]

Well done, great to have an insight into his thinking - looking forward to seeing more.

[Garlick]

Part 2 will be live today, stand by.

[RacingPete]

Part 2 - http://www.pistonheads.com/doc.asp?c=52&i=2084...

[Mario149]

I've just come across these vids and haven't read through all eleventy pages of responses, so apologies if this has been said already, but....wtf?!

I've watched the first couple of vids and from a basic engineering physics perspective, his talk about weight makes no sense whatsoever (so much so I'm not going to bother watching the rest). Is he trying to sell the idea that making the car heavier lets it corner faster?! Frictional force between 2 surfaces moving over each other (e.g. a tyre and tarmac) is directly proportional to the force pushing the 2 objects together (i.e. weight of the car). So, roughly, double the weight of the car, double the frictional force (i.e. the amount of grip you get) in a corner. But here's the kicker, the frictional force required to go round a corner is proportional to the weight of the car, so double the weight, therefore double the force required to get the car round the corner, so it cancels out!

Now, there are many other things at play as well (tyre contact patches etc, where his explanation is also dubious), and I don't doubt for a second that he knows this full well. It just seems he's trying to explain a rather complex physical system with enough "pseudoscience" to make it sound convincing to the layman rather than going the whole hog. The problem is what he's saying, at that level, is garbage! I hope it got better in the vids after that, shame I've just been put of watching them.

Anyway, GT-R is a fantastic car and an engineering marvel (if maybe a little on the porky side ) so if someone can explain to me with proper physics how making the GT-R 1700kg instead of say 1200kg makes it go better I'd be very interested to know

Edited by Mario149 on Monday 22 March 22:12

[VPower]

Mario149 said:

I've just come across these vids and haven't read through all eleventy pages of responses, so apologies if this has been said already, but....wtf?!

I've watched the first couple of vids and from a basic engineering physics perspective, his talk about weight makes no sense whatsoever (so much so I'm not going to bother watching the rest). Is he trying to sell the idea that making the car heavier lets it corner faster?! Frictional force between 2 surfaces moving over each other (e.g. a tyre and tarmac) is directly proportional to the force pushing the 2 objects together (i.e. weight of the car). So, roughly, double the weight of the car, double the frictional force (i.e. the amount of grip you get) in a corner. But here's the kicker, the frictional force required to go round a corner is proportional to the weight of the car, so double the weight, therefore double the force required to get the car round the corner, so it cancels out!

Now, there are many other things at play as well (tyre contact patches etc, where his explanation is also dubious), and I don't doubt for a second that he knows this full well. It just seems he's trying to explain a rather complex physical system with enough "pseudoscience" to make it sound convincing to the layman rather than going the whole hog. The problem is what he's saying, at that level, is garbage! I hope it got better in the vids after that, shame I've just been put of watching them.

Anyway, GT-R is a fantastic car and an engineering marvel (if maybe a little on the porky side ) so if someone can explain to me with proper physics how making the GT-R 1700kg instead of say 1200kg makes it go better I'd be very interested to know

Edited by Mario149 on Monday 22 March 22:12

Mario
perhaps this will help?
http://www.pistonheads.com/gassing/topic.asp?f=48&...

Basically I think what Mizuno-Han is saying is that for the specific tyre/wheel size of the GTR, there is no cornering benefit in reducing the weight below 1700kg.
Indeed it could even make the car less forgiving to handle and thus slower for the average driver to handle.

Bit like my Cerbera once you go past the limit with an empty boot and empty fuel tank! bh!

[havoc]

VPower said:

Mario
perhaps this will help?
http://www.pistonheads.com/gassing/topic.asp?f=48&...

Basically I think what Mizuno-Han is saying is that for the specific tyre/wheel size of the GTR, there is no cornering benefit in reducing the weight below 1700kg.
Indeed it could even make the car less forgiving to handle and thus slower for the average driver to handle.

Bit like my Cerbera once you go past the limit with an empty boot and empty fuel tank! bh!

But that's silly - it's putting things backwards (unless you let marketing people design your cars!).

If reducing the weight meant that the intended tyre/wheel size was no longer optimal, then you altered the tyre/wheel sizes. Surely that's the right way to go about things...anyone can see, from watching Minis, Lotus-7s / XIs and Chevrons race, than lighter cars corner far better (& quicker!) than heavy ones.

So I would read that as they didn't have the budget to reduce the weight, so they're now trying to put a veneer of 'science' over why it's such a heavy car. When the reality is that:-
- It IS too heavy;
- But it still performs near-miraculously well for both its weight and its price.

[Blue Meanie]

And so it IS heavier, and yet it can still corner like on rails... maybe the designers of this car know what they are on about?

[Mario149]

havoc said:

VPower said:

Mario
perhaps this will help?
http://www.pistonheads.com/gassing/topic.asp?f=48&...

Basically I think what Mizuno-Han is saying is that for the specific tyre/wheel size of the GTR, there is no cornering benefit in reducing the weight below 1700kg.
Indeed it could even make the car less forgiving to handle and thus slower for the average driver to handle.

Bit like my Cerbera once you go past the limit with an empty boot and empty fuel tank! bh!

But that's silly - it's putting things backwards (unless you let marketing people design your cars!).

If reducing the weight meant that the intended tyre/wheel size was no longer optimal, then you altered the tyre/wheel sizes. Surely that's the right way to go about things...anyone can see, from watching Minis, Lotus-7s / XIs and Chevrons race, than lighter cars corner far better (& quicker!) than heavy ones.

So I would read that as they didn't have the budget to reduce the weight, so they're now trying to put a veneer of 'science' over why it's such a heavy car. When the reality is that:-
- It IS too heavy;
- But it still performs near-miraculously well for both its weight and its price.

I agree, it's putting things backwards. In all fairness to Nissan, they've produced a great car, but if they could have produced the GT-R with that much horsepower weighing 1200kg, trust me they would have found a way to optimise the tyres and make it quicker than it is even now. And that's before we consider the dynamic issues of trying to get 1.7 tons to change direction quickly. If everyone could get away with making sports cars weigh 1.7 tonnes they would. It's easier to add BHP to keep the power/weight ratio up than it is to add lightness.

As an aside, I loathe it when people use pseudoscience and interchange mass with force/weight (i.e. quoting kg instead of newtons), for god's sake that part of physics really isn't rocket science. Rant over Actually, wait it's not, reading things like "1000 volts of power!" is possibly even more annoying....

[VPower]

But reducing the tyres and weight would mean the power cannot be put down on the tarmac.
So reduce the weight and you need less power, or rather the power is wasted because it can't be utilised.

Just like my Cerbera, it will wheel spin in third off the throttle.
Fill it with Le Mans camping gear to the brim, fill the tank and chuck in a mate and it handles much better!

So perhaps that's why Lotus Elise and the Caterham 7 with their light weight, smaller tyres and lower power will beat almost anything on a twisty track??

But the GTR is not intended to be one of them.
Is it not a nice family 4 seater!;)

[havoc]

Blue Meanie said:

And so it IS heavier, and yet it can still corner like on rails... maybe the designers of this car know what they are on about?

It also rides like it's got no suspension. Which makes a big difference.


VPower - not sure I'd want to take a family out in one!

Re: traction - it's got a very good 4wd system and arguably a very sophisticated TC system, so I doubt traction would be any real problem even reducing the footprint slightly. But it's a fair point...Nissan's engineers clearly had priorities / targets, and ones which were very different to e.g. the Lotus Evora's or Porsche 911's engineering teams.




Final point...I'm probably in a minority here, but I don't actually think that mega-power, mega-grip, and statistics-chasing (0-60, N'ring time etc.) necessarily make a good driver's car. Something to brag about down the pub...but how many people here genuinely care about bragging down the pub?!?
(to exemplify this, an amateur-racer friend-of-a-friend sold his 500+bhp Evo VIII and got a 993 C2 wide-body which he enjoys far more despite it being (apparently*) quite a bit slower around the 'ring)


* I say apparently because I was (un?)lucky enough to passenger with him back in '08 and it was far from slow...

[HereBeMonsters]

What I don't understand is how he says downforce is equivalent to mass. Surely that's total toss?

Basically he's saying because an F1 car can produce 1000kgs of downforce, it weighs that much, but can obviously corner very well. Surely that's because it has force pushing DOWN but has a much smaller mass to move around the corner?
Making something weigh 1700kgs so it will corner like something that weighs 700kgs with 1000kg of downforce is just bad science, surely?

[Trommel]

I'm not sure why this generates so much discussion.

There are two options - either something is lost due to the language barrier, or he doesn't want to say it's heavy because it's compromised due to platform constraints or whatever.

[Mr Whippy]

HereBeMonsters said:

What I don't understand is how he says downforce is equivalent to mass. Surely that's total toss?

Basically he's saying because an F1 car can produce 1000kgs of downforce, it weighs that much, but can obviously corner very well. Surely that's because it has force pushing DOWN but has a much smaller mass to move around the corner?
Making something weigh 1700kgs so it will corner like something that weighs 700kgs with 1000kg of downforce is just bad science, surely?

The F1 car is quids in because it has X mass to accelerate (cornering is accelerating the mass), but has X + downforce amount of tyre load to make grip.

The GTR isn't quids in because it has X mass to accelerate (cornering), but has X amount of tyre load to make grip.


Adding mass does give you more grip, but you need more grip to accelerate the mass when cornering. Fortunately, aero force isn't the same as body mass when changing a cars direction.



All they appear to have done is optimise the loads vs tyres vs power really nicely, but they make it sound like something really clever. I'm sure Porsche do this as well as they can considering a rear engine, for example, as will anyone making a sports car.

Not knocking the car, but there does seem to be some feeling that they have to explain away the weight. It's heavy yes, but they engineered it as best it can be with that in mind.
Why they can't just accept it's heavy and that is a consequence of the needs of the rest of the car, rather than say that they made that weight a target is beyond me.


Dave

Edited by Mr Whippy on Thursday 25th March 15:11

[VPower]

HereBeMonsters said:

What I don't understand is how he says downforce is equivalent to mass. Surely that's total toss?

Basically he's saying because an F1 car can produce 1000kgs of downforce, it weighs that much, but can obviously corner very well. Surely that's because it has force pushing DOWN but has a much smaller mass to move around the corner?
Making something weigh 1700kgs so it will corner like something that weighs 700kgs with 1000kg of downforce is just bad science, surely?

Could it be he is considering the laterial G forces involved.

F1 700kg X 5 G = 3500kg.
GTR 1700kg X 2G = 3400kg.

[HereBeMonsters]

VPower said:

HereBeMonsters said:

What I don't understand is how he says downforce is equivalent to mass. Surely that's total toss?

Basically he's saying because an F1 car can produce 1000kgs of downforce, it weighs that much, but can obviously corner very well. Surely that's because it has force pushing DOWN but has a much smaller mass to move around the corner?
Making something weigh 1700kgs so it will corner like something that weighs 700kgs with 1000kg of downforce is just bad science, surely?

Could it be he is considering the laterial G forces involved.

F1 700kg X 5 G = 3500kg.
GTR 1700kg X 2G = 3400kg.

So because it can't pull more than 2G in cornering they decided to make it weigh more?

[Godzilla]

HereBeMonsters said:

VPower said:

HereBeMonsters said:

What I don't understand is how he says downforce is equivalent to mass. Surely that's total toss?

Basically he's saying because an F1 car can produce 1000kgs of downforce, it weighs that much, but can obviously corner very well. Surely that's because it has force pushing DOWN but has a much smaller mass to move around the corner?
Making something weigh 1700kgs so it will corner like something that weighs 700kgs with 1000kg of downforce is just bad science, surely?

Could it be he is considering the laterial G forces involved.

F1 700kg X 5 G = 3500kg.
GTR 1700kg X 2G = 3400kg.

So because it can't pull more than 2G in cornering they decided to make it weigh more?

This calculation is just utter bks, not least because the GT-R cannot pull even close to 2g lateral.

But even if it could, what do those numbers mean?

[Niffty951]

Godzilla said:

HereBeMonsters said:

VPower said:

HereBeMonsters said:

What I don't understand is how he says downforce is equivalent to mass. Surely that's total toss?

Basically he's saying because an F1 car can produce 1000kgs of downforce, it weighs that much, but can obviously corner very well. Surely that's because it has force pushing DOWN but has a much smaller mass to move around the corner?
Making something weigh 1700kgs so it will corner like something that weighs 700kgs with 1000kg of downforce is just bad science, surely?

Could it be he is considering the laterial G forces involved.

F1 700kg X 5 G = 3500kg.
GTR 1700kg X 2G = 3400kg.

So because it can't pull more than 2G in cornering they decided to make it weigh more?

This calculation is just utter bks, not least because the GT-R cannot pull even close to 2g lateral.

But even if it could, what do those numbers mean?

I suppose he may be talking about downforce, pressure on the tires? Saying it puts as much force on the tires as a formula one car so you get more grip?

Does look a bit fishy though?!?