RE: Light IS Right: PH Blog
Discussion
coppice said:
Dunno about GTRs defying physics- the last one I saw at a trackday was ten seconds a lap slower than the Caterfields and the last one I saw at a hillclimb was trading times with an MX5 . Look good in the multiplex car park though, I will concede that
Quite clearly you've not seen or experienced a GTR being driven properly thenjl34 said:
Utter rubbish
Sometimes a heavier car has a much better suspension system, more rigid structure that provides stiffness and control.
Sometimes a heavier car has a much better suspension system, more rigid structure that provides stiffness and control.
I'll be showing this to Gordon Murray next week. Let him know where he's been going wrong all these years.Edited by GetCarter on Friday 29th April 13:41
JockySteer said:
coppice said:
Dunno about GTRs defying physics- the last one I saw at a trackday was ten seconds a lap slower than the Caterfields and the last one I saw at a hillclimb was trading times with an MX5 . Look good in the multiplex car park though, I will concede that
Quite clearly you've not seen or experienced a GTR being driven properly thenJohnS said:
I think there's a fine balance to be had of power, weight, brakes and suspension set-up. On some roads, a 130bhp Caterham would be an absolute blast but a nightmare on others.
The Super Lap Scotland series has different classes based on power to weight, and is proving very successful with increaseing numbers every round. Interestingly, there is a McLaren 650S competing in the series, and it isn't even in the top class of cars.
You also need to question if the £250k car is being pushed as hard as the lower cost competitors...The Super Lap Scotland series has different classes based on power to weight, and is proving very successful with increaseing numbers every round. Interestingly, there is a McLaren 650S competing in the series, and it isn't even in the top class of cars.
I agree, lighter weight is the way to go. I took 170kg out of my ST205 GT4 and added 100bhp over the factory horse power figure. Net result was way more performance in every area (handling and braking too) with MPG that remain identical to when it was standard.
When I drive my Cerbera, I'm always astonished at how well it handles, stops and steers, due, in a large part, to the 1200kg that it weights. I'm also looking into how I might be able to trim a few more KG off without making it horrible to live with.
Taking 1.5kg off each wheel made a huge difference to ride and handling. A 3.6kg fly wheel made the engine feel way more responsive and the Nitron suspension saved another 1kg a corner. Small savings but in the right areas, making a big difference.
Nailed it Dan !!
Weight IS fundamental.
Its basic physics !!
All the other (often great) engineering is just to mitigate an over-heavy base design.
Add in driver feel, control, AND FUN factor and its a no brainer .. unless, that is, you actually enjoy getting barges to change direction :-) with or without any suspension -- oh and a hell of a lot of extra tyre, brake and fuel used up.
Weight IS fundamental.
Its basic physics !!
All the other (often great) engineering is just to mitigate an over-heavy base design.
Add in driver feel, control, AND FUN factor and its a no brainer .. unless, that is, you actually enjoy getting barges to change direction :-) with or without any suspension -- oh and a hell of a lot of extra tyre, brake and fuel used up.
For sports cars and track cars light is indeed right. Anywhere there is lots of acceleration (lateral or longitudinal) then less weight is better, Newton's 2nd law is inescapable.
For motorway barges the case is different, weight gives greater stability and immunity to wind etc whilst not being a downside due to there being little acceleration involved. There is also the factor of load to consider, it is hard to engineer a 900kg car to ride and perform well with both just a 45kg driver or 700kg of passengers and luggage. A 2000kg car is much more likely to cope well with both. Most of us could probably achieve better weight savings by eating less pies than spending thousands on expensive carbon bits to save a kg here or there.
For motorway barges the case is different, weight gives greater stability and immunity to wind etc whilst not being a downside due to there being little acceleration involved. There is also the factor of load to consider, it is hard to engineer a 900kg car to ride and perform well with both just a 45kg driver or 700kg of passengers and luggage. A 2000kg car is much more likely to cope well with both. Most of us could probably achieve better weight savings by eating less pies than spending thousands on expensive carbon bits to save a kg here or there.
GetCarter said:
I'll be showing this to Gordon Murray next week. Show him where he's been going wrong all these years.
I'm sure its GREAT engineering and fabulous handling, AND amazing lightweight (to stay on topic)
But seriously, would even the least style aware, P-Head be seen dead in it ??? :-)
OK Dan - Money where your mouth is - take a set of scales to your next road review and publish "Weight as tested" alongside all the manufacturers' made up figures.
It'd be good if reviewers got better at calling out the massaging of options lists and curb weights (and consequential performance impact) when reviewing this stuff.
It'd be good if reviewers got better at calling out the massaging of options lists and curb weights (and consequential performance impact) when reviewing this stuff.
jl34 said:
Utter rubbish
Sometimes a heavier car has a much better suspension system, more rigid structure that provides stiffness and control, alloy wheel's that dont bend on potholes and have systems that provide safety and comfort.
Look how a nissan GTR defies physics! . i once had a 450 KG bike engined westfield that tried to take off after every pothole. Another 250Kg would have made it much better!
I know quite often a lighter car performs better, but you have to look a lot further into the design. The most important statistic is how it performs from a performance and longevitiy and features perspective. we are driving cars we expect to last and perform on crappy roads. If we were talking tenths on a racecar then thats a different matter.
Most of what you're talking about is ride and handling - which is a subjective thing that gets covered by reviews. Weight is one of those statistics that contributes to ride and handling, but also speaks volumes about what the manufacturer has done to achieve the experience the car delivers. The GTR defies physics up to a point, but it still makes some significant compromises to deliver what it does.Sometimes a heavier car has a much better suspension system, more rigid structure that provides stiffness and control, alloy wheel's that dont bend on potholes and have systems that provide safety and comfort.
Look how a nissan GTR defies physics! . i once had a 450 KG bike engined westfield that tried to take off after every pothole. Another 250Kg would have made it much better!
I know quite often a lighter car performs better, but you have to look a lot further into the design. The most important statistic is how it performs from a performance and longevitiy and features perspective. we are driving cars we expect to last and perform on crappy roads. If we were talking tenths on a racecar then thats a different matter.
As well as light lets also say smaller is better. Especially on our best roads which are B roads.
Don't get me going on wheel sizes and how big they are and heavy. Everyone should be made to change their own wheels after a puncture rather than calling out the AA. Peroxide blonde Phoebe has to change the 21 inch wheel on her SUV using muscle power alone.
Don't get me going on wheel sizes and how big they are and heavy. Everyone should be made to change their own wheels after a puncture rather than calling out the AA. Peroxide blonde Phoebe has to change the 21 inch wheel on her SUV using muscle power alone.
Weight is important, one of the most fun handling cars i have ever owned was a 1.4 102 bhp Rover Streetwise 5dr that i had for a couple of years or so at Uni, only weighed a ton and was such fun, lift of oversteer/line trims etc. The lack of weight meant it changed direction so well, straight line performance was ok but it made a good noise and didn't put a foot wrong in 50,000 miles which being a k-series engine I put down to luck and it being taken to max revs at least once every journey it did within reason! the A3 I had after it felt like a lorry in comparison!
However i would much rather crash given the choice in a modern car!!
Ag
However i would much rather crash given the choice in a modern car!!
Ag
So suspension relies on more mass to make it work, I always thought that was a by-product of the quality of the dampers and the valving? Personally I like lightweight cars, they steer and handle 'properly'. They stop better, turn better and accelerate quicker. They don't tend to have the cotton wool between the controls and are more basic. Things like the GTR are brilliant pieces of engineering but take them to a track and they'll eat your wallet whilst being probably no faster and not be half as much fun as a lightweight.
May I give an analogy?
Watch any Premiership football match, and there is a veritable panoply of strikers, eager to do the same job, namely beating the opposition and scoring (hopefully not an own-goal)
Now think of a few as examples;
Andy Carroll and Christian Benteke are both decent enough, and perfectly capable of getting that win.
But they are big, heavy, blunt tools that bludgeon the opposition into submission.
Topically, look at (the suspended) Jamie Vardy; light, fast, incredibly agile and dances around the opposition like they're not there.
And in that, I believe we have the answer, that whilst all of them are capable of doing the same job, the lighter and more manoeuvrable do it with an economy of effort.
Probably goes without saying that I'd favour a lighter car with less bhp than a Behemoth with a big bhp...
Watch any Premiership football match, and there is a veritable panoply of strikers, eager to do the same job, namely beating the opposition and scoring (hopefully not an own-goal)
Now think of a few as examples;
Andy Carroll and Christian Benteke are both decent enough, and perfectly capable of getting that win.
But they are big, heavy, blunt tools that bludgeon the opposition into submission.
Topically, look at (the suspended) Jamie Vardy; light, fast, incredibly agile and dances around the opposition like they're not there.
And in that, I believe we have the answer, that whilst all of them are capable of doing the same job, the lighter and more manoeuvrable do it with an economy of effort.
Probably goes without saying that I'd favour a lighter car with less bhp than a Behemoth with a big bhp...
I think the thing with very Light cars (previous owner of LCC Rocket) are how easy it is to maintain momentum when properly sorted suspension (and this takes time...) is allowed to work with the road unlike heavier cars having to bludgeon the road into submission (so for the road a softer set up can be used than on a heavier car), but as another poster pointed out on motorways they can be a pain and cross winds can really have an effect so there are downsides too.
Tires can also be an issue as no one really makes a road tire for a lightweight car and sidewalls can be too stiff, it might be unfashionable but higher profile tires seem to work better.
Sadly with all the modern safety equipment I can't really see how cars can be properly light again, development costs vs. reward just isn't there for manufacturers.
Tires can also be an issue as no one really makes a road tire for a lightweight car and sidewalls can be too stiff, it might be unfashionable but higher profile tires seem to work better.
Sadly with all the modern safety equipment I can't really see how cars can be properly light again, development costs vs. reward just isn't there for manufacturers.
jl34 said:
Weight is just one of many attributes of the design that make a great performing car.
An ultima is a good example. Ultra low weight , bloody awful handling. And how good would a mclaren p1 be with a live axle and cart springs ?
Yes, the Ultima is a poor handling car.An ultima is a good example. Ultra low weight , bloody awful handling. And how good would a mclaren p1 be with a live axle and cart springs ?
https://www.youtube.com/watch?v=PqmDi1m6EB0
Here it only manages to beat the Dunsfold lap record, including Michael Schumacher in a Ferrari FXX. Clearly, its crap...
Well journos have long stopped trusting manufacturers claims on 0-60 times. So why they believe, and expect us to believe, the weight claims (and bhp) is quite beyond me.
How difficult would it be to take a set of scale to accurately weight the car?
Getting a car to an independent dyno might be harder.
How difficult would it be to take a set of scale to accurately weight the car?
Getting a car to an independent dyno might be harder.
I do agree that light weight for a car is part of the 'virtuous circle' the lighter the structure of the car, the lighter the suspension needed to carry the weight, the smaller the wheels tyres and brakes required, and crucially the smaller and less powerful the engine needs to be to power it.
Gordon Murray one of my engineering heros set the weight target of 1000Kg for the McLaren F1 very early on in the project and even dictated to the BMW engineers designing the amazing V12 to 'consider weight in everyhting they did' and the result was an amazing compact, lightweight and powerful engine.
On the flip side of the coin designer of the Nissan GTR Kazutoshi Mizuno is adamant that light weight isn't necessary for good car design...
If you look at other manufacturers efforts, and using Porsche as an example the placement of the flat six in the type 901 car forced them to come up with a light weight solution for this engine, and in the 1960's they even made an engine using magnesium alloy for the engine cases, and won an award for the largest casting of its type attempted. The latest 981 Boxster uses a composite high strength steel and aluminium structure along with the 991, and aluminium is used for the doors and luggage lids, so to single out Porsche for criticism here isn't quite right.
They even used aluminium to keep the wieght down on the 928 with the front wings and the doors being made of it, and polyurethene was used for the front and rear bumper sections. The engine was cast in light-weight Reyonolds 390 alloy to save weight as well.
Having to pay for every bloody option and stuff that should be standard IS a massive piss take by Porsche though.
The increase in vehicle weight has primarily been driven by regulations for crash safety, mandatory air-bags and other such equipment.
I really want to see a future where all car manufactures strive to intelligently engineer light weight into their cars, along with crash safety and decent styling.
Gordon Murray one of my engineering heros set the weight target of 1000Kg for the McLaren F1 very early on in the project and even dictated to the BMW engineers designing the amazing V12 to 'consider weight in everyhting they did' and the result was an amazing compact, lightweight and powerful engine.
On the flip side of the coin designer of the Nissan GTR Kazutoshi Mizuno is adamant that light weight isn't necessary for good car design...
If you look at other manufacturers efforts, and using Porsche as an example the placement of the flat six in the type 901 car forced them to come up with a light weight solution for this engine, and in the 1960's they even made an engine using magnesium alloy for the engine cases, and won an award for the largest casting of its type attempted. The latest 981 Boxster uses a composite high strength steel and aluminium structure along with the 991, and aluminium is used for the doors and luggage lids, so to single out Porsche for criticism here isn't quite right.
They even used aluminium to keep the wieght down on the 928 with the front wings and the doors being made of it, and polyurethene was used for the front and rear bumper sections. The engine was cast in light-weight Reyonolds 390 alloy to save weight as well.
Having to pay for every bloody option and stuff that should be standard IS a massive piss take by Porsche though.
The increase in vehicle weight has primarily been driven by regulations for crash safety, mandatory air-bags and other such equipment.
I really want to see a future where all car manufactures strive to intelligently engineer light weight into their cars, along with crash safety and decent styling.
wst said:
ngineering is typically all about compromise - I don't really know where McLaren is compromising with their tub-based cars. Is using the same basis for all their products the compromise - are they doing so much clever engineering just by producing it in a volume where it starts to become appreciably cheaper?
If it wasn't clever engineering, then surely Ferrari et al would be doing this as well?I mostly agree with this, with the exception of the Nissan GTR and Alfa 4C which seem to buck the trend ie the GTR is heavy but good, whereas the Alfa is light but disappointing (imo).
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