RE: Light IS Right: PH Blog

RE: Light IS Right: PH Blog

Sunday 1st May 2016

Light IS Right: PH Blog

Why kg, not hp or 0-62, is the first number you should look at on the spec sheet



Interesting press release from Lotus yesterday detailing the amount of weight it has stripped out of its cars of late. It's claiming to have taken 207kg of flab from its current range, listing some of the ways it's done this. These include a one-piece carbon rear deck for the Evora 410 that saves 10kg over the five-piece standard item, the 3kg saved with the development of the Exige Sport 350's funky exposed gear linkage and the 3.5kg saved on regular Elises by switching to a lighter battery.


All very on-message for a brand once again asserting a reputation for being a lightweight leader, even if the Elise's kerbweight has apparently grown by around a third in the 20 years since the original S1. Unfair to compare an older car with a new one carrying a bunch more tech and safety hardware? If the numbers are to be believed my mum's brand new MX-5 1.5 weighs just 50kg or so more than my own 1993 1.6 Eunos and I know which I'd rather have a crash in. Actually this particular example doesn't work because it wouldn't be the new one. I might survive the impact but it's doubtful I'd live to tell the tale!

We're rightly more sceptical about the numbers manufacturers quote after the whole emissions thing. And without putting each car on a set of scales they will always be playing the system by fair means or foul to publish the best kerbweight possible, be it listing the number AFTER weight-saving cost options like carbon seats or forged wheels have been taken into consideration. Or putting the heavy tech that achieves the performance numbers like dual-clutch transmissions, four-wheel steering systems or fancy locking diffs (potentially plus 20kg per box ticked) on the options sheet so they can quote a low 'standard' kerbweight. As well as expecting the customer to pay extra to get the full package. Yes Porsche, looking at you.


Fundamentally though I'll always look more favourably on the lighter car than the heavier one. Which is why I'd take a Golf GTI over an R any day, Clubsport or not. And am itching to drive a Focus RS back to back with front-wheel drive rivals like the Civic Type R or Megane 275 Cup-S. The Ford wins on attention seeking skidfoolery and on-paper firepower. And it's a hell of a machine. But compared with the Renault or Honda it's carrying an extra 200kg or so. That's a huge amount. Chassis set-up, damping and clever traction management and stability control mitigate. But whether you're factoring in wear to consumables or simply the kind of agility that really counts in 'the twisties' on road or track it's the most significant number for me when comparing these cars. Because - numbers be damned - through the seat of your pants a lighter car is always going to be more fun, more honest in its feedback and less reliant on an electronic smokescreen to deliver the wow factor.


In the supercar league I think McLaren needs to make more noise about the weight advantage it has over the Italian and German rivals. The issue is clouded by the different weight standards used by various manufacturers but if you add a driver and fluids to the quoted 1,313kg dry weight of a 570S it's still going to be at least 150kg lighter than an R8 or 911 Turbo, if not more. Without even driving the cars that number would be enough for me to put the McLaren in pole position, a comparison that extends to the next level up when you put a 650S against a Ferrari 488 GTB or Lamborghini Huracan.

Forget horsepower figures. Never mind the torque output or gizmo count. Don't even look at 0-62, lap times or top speeds. I think when it comes to comparing cars on stats alone the one suffixed 'kg' is the most important one to inform the fun and engagement you'll have at the wheel. On the understanding this sometimes requires a forensic examination of how the number has been reached in the first place to make sure you're comparing like with like...

Dan

 

 

 

 

Author
Discussion

macky17

Original Poster:

2,210 posts

188 months

Friday 29th April 2016
quotequote all
Bloody right, in particular regarding McLaren's impressive kerb weights.

And why everyone should try a Noble.

jl34

523 posts

236 months

Friday 29th April 2016
quotequote all
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.

CTE

1,488 posts

239 months

Friday 29th April 2016
quotequote all
What about an Ultima (950kgs and up to 1400hp!)...the latest versions are not kit cars anymore...

RamboLambo

4,843 posts

169 months

Friday 29th April 2016
quotequote all
Absolutely agree weight is a killer in terms of feel and response. Long gone are the days of sun 1000 kg cars with all the safety features requirements etc these days.
That's why some of the older lighter cars with a lot less bhp are still fun to drive.

In the supercar arena McLaren lead the way with their carbon tub which gives stiffness and rigidity at a considerable weight saving that's why they feel like go karts in comparison to their equivalents from Italy.
Anyone wanting a spider simply has to buy a 650S IMHO for the carbon tub alone

V8RX7

26,765 posts

262 months

Friday 29th April 2016
quotequote all
Weight is certainly one of the stats I look for and light cars are getting harder to find.

Any sportscar over 1250kg isn't that sporty IME they become more a GT, at home on sweeping A roads rather than B roads.

JohnGoodridge

529 posts

194 months

Friday 29th April 2016
quotequote all
And yet The Nissan GT-R is still the boss?

Think you might have already told yourself you're wrong on this one Dan.

wink

Oddball RS

1,757 posts

217 months

Friday 29th April 2016
quotequote all
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.
With the greatest of respect your wrong, all the issues you list are not the result of too light a weight car but other engineering on the vehicle not being up to the job. Your bike engine car taking off, spring and damper rates / tyre choice / aero or lack of, car too light to be rigid enough? badly engineered in the wrong materials. Alloy wheels bending on a pothole, try the council, roads weren't designed to have them, they fact you now blame a car wheel is sad indeed.

CABC

5,533 posts

100 months

Friday 29th April 2016
quotequote all
I know you get it Dan, but sometimes i wonder whether PH is an enthusiast's site.
Not that this blog will raise 20 pages of discussion...


jl34

523 posts

236 months

Friday 29th April 2016
quotequote all
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 ?

Dan Trent

1,866 posts

167 months

Friday 29th April 2016
quotequote all
JohnGoodridge said:
And yet The Nissan GT-R is still the boss?

Think you might have already told yourself you're wrong on this one Dan.
A fair one but I'm not saying a heavy car can't be fun to drive - I loved the Focus RS, the Mustang was a hoot and there are any number of 'heavy' cars I can appreciate. But in the context of cars I've owned/run and enjoyed I can say I absolutely adored the Clio 197 Cup I had as a long-termer. But the 172 Cup I subsequently bought was - IIRC - c. 200kg lighter, a ton more fun AND would do high 30s mpg to the 197's high 20s. The 197 was a much more advanced and 'capable' car. But the 172 was more exciting.

Ta!

Dan

wst

3,494 posts

160 months

Friday 29th April 2016
quotequote all
RamboLambo said:
In the supercar arena McLaren lead the way with their carbon tub which gives stiffness and rigidity at a considerable weight saving that's why they feel like go karts in comparison to their equivalents from Italy.
Anyone wanting a spider simply has to buy a 650S IMHO for the carbon tub alone
Engineering 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?

nickfrog

20,872 posts

216 months

Friday 29th April 2016
quotequote all
The GTR is very clever. It has put all its eggs in the same tractive basket. It's utterly extraordinary that it can be so competent with all that weight. Yet I find it horrible to drive. But I can see why one would like it although I got seriously ridiculed here for daring to say it's probably the last car I would want to track.

jl34

523 posts

236 months

Friday 29th April 2016
quotequote all
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 ?

CABC

5,533 posts

100 months

Friday 29th April 2016
quotequote all
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.
The Lotus bonded tub is incredibly stiff, way more so than most (any?) heavy barge.
Lotus in particular handle rough roads and potholes incredibly well.
Most heavy (and tall cars/suvs) have highly compromised suspension as they attempt to control weight, high cog and owners' desire to corner fast without falling over. The result is not good, imo.

Andy S15

399 posts

126 months

Friday 29th April 2016
quotequote all
jl34 said:
Look how a nissan GTR defies physics!
While also being the poster child for electronic-aided driving and a boring drive unless at 10/10ths.

You cannot quantify feel by numbers, but weight at least goes some way towards giving you an idea, for sure.

JohnS

935 posts

283 months

Friday 29th April 2016
quotequote all
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.


sneddo

6 posts

105 months

Friday 29th April 2016
quotequote all
Agree with this as a high level principle and have been taking weight into consideration for years, but it isn't the be all and end all.

Having said that.. I too would lean towards a light car over a heavy car.. if I have just two options and have to make a choice based on nothing but stats.

On a related note, when is the industry going to stop with all the nonsense and give us figures we can actually trust in, as it is now is just a joke.

jl34

523 posts

236 months

Friday 29th April 2016
quotequote all
Im simply saying that to judge a car as good or bad, or a 'sports car' or a 'GT car' ;simply by looking at a weight statisitic as per (Dans article ) is a poor one. Low weight is great of course but doesnt necessarily mean its a great sports car to drive. I think the article is fundamentally flawed in that respect.

coppice

8,562 posts

143 months

Friday 29th April 2016
quotequote all
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

JohnGoodridge

529 posts

194 months

Friday 29th April 2016
quotequote all
Dan Trent said:
JohnGoodridge said:
And yet The Nissan GT-R is still the boss?

Think you might have already told yourself you're wrong on this one Dan.
A fair one but I'm not saying a heavy car can't be fun to drive - I loved the Focus RS, the Mustang was a hoot and there are any number of 'heavy' cars I can appreciate. But in the context of cars I've owned/run and enjoyed I can say I absolutely adored the Clio 197 Cup I had as a long-termer. But the 172 Cup I subsequently bought was - IIRC - c. 200kg lighter, a ton more fun AND would do high 30s mpg to the 197's high 20s. The 197 was a much more advanced and 'capable' car. But the 172 was more exciting.

Ta!

Dan
Yes. Light cars IMHO are better ownership propositions like for like. But in terms of absolute excitement I'll leave it to the Italians to be the exception that proves the rule: I don't remember a single journo recommending an Alfa 4C over a Cayman S. You've driven both, haven't you? If you're right about weight it makes Alfa's success in finding the right recipe and failure by cooking it so wrong all the more galling.