Weight problems

[Steve W]

Weight problems

I'm worried about my weight? Not just me but also the car. I've seen discussions recently about how much lighter a superlight is over a Vx or Zetec. But what are the figures? Am I correct in guessing that my Zetec (supersprint in a past life) minus screen and spare wheel and with comfy seats would be about 580 ish kg's. If a superlight is only 470 kg were does the 100 kg plus come from. I thought the engine was only 30-40 kg more if so were is the rest of it. A couple of bits of carbon fibre can't make that much difference. Am I missing something or is my guess so far out ?

 

 

Edited by - steve w on 28 Sep 2000 17:28:59

[Crudders]

Steve,

 

I've found myself mulling this over also. I can't claim to know the weight of each individual item but my guess is that the following points make up the difference, (very) roughly in descending order:

 

Bullsh*t

 

Engine type: Vauxhall/Zetec/XF/K/motorcycle thingy

 

Gearbox type: 6/5/4 speed/motorcycle thingy

 

Rear diff/suspension arrangement: DeDion/live axle

 

Bellhousing: steel/ali

 

Spare wheel and carrier

 

Windscreen/aero scereen/wind deflector/nowt (very brave)

 

Wheels: steel/ali/mag ali in varying widths and dia's

 

Tyres: road/track based in varying widths and dia's

 

Roll bar type

 

Heater (lots of weight in all that extra water)

 

Seats: leather/bench/carbon/kevlar

 

Exhaust type

 

Carpets, tunnel padding and trim generally

 

General crud - Extinguisher, tools, spare fluids

 

Loose change lodged under seat

 

Toffee wrappers

 

Dead flies

 

3 micron thickness of "Auto Glym" on the paintwork

 

Carbon fibre body panels

 

I hope this is useful (what am I saying!?)

 

Crudders

 

 

 

Edited by - Crudders on 28 Sep 2000 19:47:45

[Graham Perry]

Mainly Engine weight saving. But equally important is the Ali Gearbox casing for a type 9 gearbox and ali bellhousing as well as light wheels and Brakes . Additionally I believe they have a slightly lighter Chassis. The K series even uses a minimal amount of coolant again saving weight . Having said that I bet that when put on a set of scales most weigh closer to 500 kg

[Steve W]

Well it would seem that there's some extra weight somewhere. I was looking for the excuse to buy all that nice carbon but a couple more cream cakes and any saving is gone ????????

[Graham Sewell]

But weoght isn't the real issue here. I guess everyone remembers Gerry Taylor's heroic efforts to get 3rd place after starting from the back of the grid in a cannibalised car. IIRC, he had trashed his superlight R the day before and had to rebuild his car from a roadsport chassis and the superlight engine and transmission. As he hadn't qualified, he got 3 untimed laps during lunch to acclimatise himself to the car and then slaughtered the opposition smile.gif .

 

So much for the supremacy of the superlight chassis. Obviously, the engine, gearbox et al is a useful performance gain though.

 

Cheers,

 

Graham

[Mike Bees]

There's no such thing as a 'superlight chassis', Superlights use the same chassis as other De Dion road cars. It's alleged that the R500 does have a slightly lightly chassis. The race cars (Roadsport & SLR I suspect) use a slightly different variant of the De Dion chassis - so I read in another Blatchat thread.

 

Mike

[John Richens]

Mike, The R500 does use your"slighty lightly"chassis when no windscreen is fitted..there are a number of differences the most obvious being a shortened passenger footwell ..Am I tempting fate in contradicting a God ?

 

Edited by - john richens on 29 Sep 2000 11:52:05

[Mike Bees]

I only said "alleged" because I'd heard it 2nd or 3rd hand, not because I had reason to doubt it.

 

Mike

[Steve W]

Well if the chassis are all very similar and the engine is say 30 ish kg more. Then were is the extra 70-80kg hiding ? Or is my guess of 580 kg for my zetec too high ? How much does an ali gearbox casing and bell housing save you and are they standard on a superlight ?

Even if I had have a superlight as soon as I get into it it would nolonger be a superlight.

[John Richens]

Steve W When we chose the R500 I wanted the lightest possible but then ordered a full Superlight rollcage to give best protection for idiot-driver capabilities (me)...the car officially started at 460kgs...plus rollcage and fat bustard driver weighed in at 593kgs for SVA test ....just one more bacon butty please cheers John

R500 OLE

[spiderman]

Bacon appears to be popular on the technical threads today.

[Matt Prior]

My car was rebuilt this year with a race chassis, because that's what it was before the previous owner stuffed it [long story].

 

Anyway, Len said they had to lop-out a bar in the passenger footwell because I have adjustable seats and the two aren't compatible, so there are obviously some minor differences between road and race chassis.

 

Weight difference betwixt the two'd be fairly marginal though, I'd guess.

 

[Graham Perry]

The weight saving on the gearbox casing and bell housing from what I remember when I did mine was about 40lb. Mike Bees is right when he says that there is no such thing as a 'superlight chassis'. My comment on slightly lighter Chassis was in comparison to your original Crossflow Chassis that now has a Zetec in it. If you look at the earlier Di-Dion Chassis that were not designed specifically for K power some of the cross member are really quite thick compared to the later cars.

[Mike Bees]

Here are some Caterham-originated figures for how the Superlight saves weight over the standard K-series:

 

leather adjustable seats +10.8 kg

full windscreen + wipers +6.6

hood + full side screens +8.0

paint +2.5

spare wheel including carrier +11.5

tool kit (for above) +2.8

full carpet set +3.3

heater +3.9

tonneau +1.6

 

At that time the claimed weight for the Superlight was 470kg, against 520kg for the standard K-series De Dion. These could well be best-case dry weights.

 

Mike

 

[Anna Rexia]

Is this the Lotus Seven Club branch of Weightwatchers?

[Steve W]

Ok how about this for some creative accounting.

Start with a superlight 470kg

leather adjustable seats +10.8 kg

paint +2.5

full carpet set +3.3

tonneau +1.6

guess +10 kg for chassis differences

guess +30 kg for the zetec (no screen,spare,heater etc)

528.2 kg

That would mean my Zetec is about 530kg ish. That means I don't need to go on that diet after all.Just one more bacon butty please cheers.

 

 

[Graham Perry]

Anna, I reckon I am a bit sad, because I do spend more time worrying about the weight on my much lightened crossflow than I do about the surplus inches hanging around my posterior. I keep convincing myself that its easier to loose 10 Kg of flab than 10 kg off my car, but do you think I ever do anything about the first alternative......... do I heck

[Marius]

Don´t undereestimate the wheels. I switched from 15" Revos to (wider) 13" Image-split-rims with ACB 10 on. I didn´t weigh the wheels but I guess they must be half the weight of the Revos. I used to bend my back when lifting the 15"s, now I carry 2 of the 13"s easily and I didn´t get stronger (my girl-friend sais..). oh, and the 13" look very neat, I forgot.

John Richens, are you out there, I´ve got some pictures of your R500 on my website from Spa, www.mospeed.de. If you want some just let me know.

[Nick]

A while back, somebody posted comparable weights of the fibreglass and carbon fibre bits. The search keeps timing out on me - can anyone remember the post?

 

Thanks, Nick

[Nick]

In answer to my own post...! Bad form, I know, but I had one last go at searching and it didn't time out. If anyone's interested, Dave J in 'Wings and Stuff' said....

 

"I've just stripped the carbon , wings , dash , rear wings and nose off me superlite and stripped the GRP versions from kevins car .

TOTAL WEIGHT SAVING = 237.12 Grams ( after I had washed all the ****e from me rear wings ).

 

This will increase my power to weight ratio by .34 bhp/ ton"

[Steve W]

Damm I knew it all that carbon fibre is just for show no weight loss at all. Ok I admit it does look nice and if it were not so damm expensive I would be tempted. I know there's some weight hiding somewhere. Maybe it's all the water socked into the carpets at the moment from all this rain.

[Peter Carmichael]

We did a comparison on the Cadwell Park weighbridge last year. My Superlight, Nick Dinsmore's Vauxhall and Felix Klauser's Zetec. All are stripped out and all had full tanks of fuel and were ready to go out on the track. My car was probably minus its headlamps but was otherwise in roadgoing spec.

 

SL - 500kg

VX - 546kg

ZE - 580kg

 

IIRC.

 

Only heavier than standard items on my car were the FIA roll bar, Apollo tank and the half doors. Both Felix and my cars were on superlite wheels with 6 inch ACB10s.

 

When it was flat-floored by Arrowstar three years ago with a half tank of fuel my car was 488kg. I think this is pretty close to Caterham's claim for a dry weight.

 

The 6 speed gearbox is very light (29kg I believe).

[Steve W]

Ok stupid question time. The figures for your superlight and the VX sound spot on but how come the Zetec is heavier. I thought that it was lighter than a Vx ???

Ps very sorry for the delay in getting your DiDion tube back to you. Still waiting on some parts for the suspension change.

PPS have you got that new engine fitted yet ?