New vs old R400 weight

[RobM77]

I've heard Chris Harris from Autocar regularly say that the new Duratec engine in the R400 is lighter than the K series it replaces. I'm sure that I've also read that the new car is considerably heavier than the old one (525kg vs about 480kg?). What are the reasons for this? Can anyone elaborate on these snippets of disjointed information that I've heard?

[SimonY]

The metric chassis is quite a bit heavier than the old Arch one, but at the same time is meant to be stiffer. I think the Duratec is heavier than the K as well, it is the Sigma that is supposedly lighter (although I haven't noticed much difference between the 2007(K)/2008(Sigma) Academy cars in weight)

[RobM77]

SimonY said:

The metric chassis is quite a bit heavier than the old Arch one, but at the same time is meant to be stiffer. I think the Duratec is heavier than the K as well, it is the Sigma that is supposedly lighter (although I haven't noticed much difference between the 2007(K)/2008(Sigma) Academy cars in weight)

Thanks. That's pretty much what I guessed, and I suppose we have to ignore Chris' comments about the Duratec being lighter (check out "Chris on camera" on the Autocar website videos section. He drives the new R400 around Cadwell and chats to Ansar Ali).

That new R500 weighs a whopping 76kg more than the old R500! That's a vast amount (17.5% of the weight of the old car), or the same as an old R500 with me as a passenger and a suitcase in the boot...

[Piers917]

I thought the old R500 weighed 460kg's and the new one 506kg's?

[atom-ick]

RobM77 said:

SimonY said:

The metric chassis is quite a bit heavier than the old Arch one, but at the same time is meant to be stiffer. I think the Duratec is heavier than the K as well, it is the Sigma that is supposedly lighter (although I haven't noticed much difference between the 2007(K)/2008(Sigma) Academy cars in weight)

Thanks. That's pretty much what I guessed, and I suppose we have to ignore Chris' comments about the Duratec being lighter (check out "Chris on camera" on the Autocar website videos section. He drives the new R400 around Cadwell and chats to Ansar Ali).

That new R500 weighs a whopping 76kg more than the old R500! That's a vast amount (17.5% of the weight of the old car), or the same as an old R500 with me as a passenger and a suitcase in the boot...

I make 506kgs - 460kgs = 46kgs heavier?

As i understand it, the original R500 was maybe weighed without any fluids, washers etc. From what i have heard, most were more like 500 kgs.

[RobM77]

atom-ick said:

RobM77 said:

SimonY said:

The metric chassis is quite a bit heavier than the old Arch one, but at the same time is meant to be stiffer. I think the Duratec is heavier than the K as well, it is the Sigma that is supposedly lighter (although I haven't noticed much difference between the 2007(K)/2008(Sigma) Academy cars in weight)

Thanks. That's pretty much what I guessed, and I suppose we have to ignore Chris' comments about the Duratec being lighter (check out "Chris on camera" on the Autocar website videos section. He drives the new R400 around Cadwell and chats to Ansar Ali).

That new R500 weighs a whopping 76kg more than the old R500! That's a vast amount (17.5% of the weight of the old car), or the same as an old R500 with me as a passenger and a suitcase in the boot...

I make 506kgs - 460kgs = 46kgs heavier?

As i understand it, the original R500 was maybe weighed without any fluids, washers etc. From what i have heard, most were more like 500 kgs.

Sorry, I thought it was 430kg. 46kg is still an awful lot! Still, that makes the weight gain easier to explain with the Metric chassis and engine weighing a bit more each.

Car weights are usually quoted by the manufacturer as "dry", so that's without battery, oil, coolant and petrol. Strangely, they then go and measure the 0-60 with a full tank of fuel and a fat passenger..

Most people that I know who've weighed their 7s have weighed them at about 500kg "wet". I think mine was about that without the ballast in when SimonY corner weighted it recently. We run at 600kg with driver on board in Roadsport A, and most of us carry lead (so with me that's about 35kg of lead).

So far as I know, the R500 lost most of its weight through lighter wheels, nose cone and wings; so I'd expect less than my car's 500kg for a wet weight. 460 dry is quite believable.

[rubystone]

RobM77 said:

atom-ick said:

So far as I know, the R500 lost most of its weight through lighter wheels, nose cone and wings; so I'd expect less than my car's 500kg for a wet weight. 460 dry is quite believable.

R500 had magnesium bell housing as well as carbon/kevlar seats in addition to the full carbon pack and magnesium wheels. The tyre were also filled with nitrogen which made them lighter and the rollbar was constructed from Beryllium (OK so I made the bit up about Nitrogen).

[adamh]

RobM77 said:

So far as I know, the R500 lost most of its weight through lighter wheels, nose cone and wings; so I'd expect less than my car's 500kg for a wet weight. 460 dry is quite believable.

Hmmm . . . never believed the 460kg dry weight myself. Even with the stuff you mention plus light ACB10 tyres, carbon bits, mag bits and no seats or weather gear. I suspect that 460kg figure came from the marketing dept. My guess is more like 475/480 which is still light for a car engined Caterham.

[RobM77]

adamh said:

RobM77 said:

So far as I know, the R500 lost most of its weight through lighter wheels, nose cone and wings; so I'd expect less than my car's 500kg for a wet weight. 460 dry is quite believable.

Hmmm . . . never believed the 460kg dry weight myself. Even with the stuff you mention plus light ACB10 tyres, carbon bits, mag bits and no seats or weather gear. I suspect that 460kg figure came from the marketing dept. My guess is more like 475/480 which is still light for a car engined Caterham.

It does seem very light. My Caterham is 500kg wet, and I suppose the dry weight of mine would be about 480kg (say 4kg battery, 7kg oil, 2kg coolant & 5kg petrol?). I'm not sure how much you'd lose with the R500 bits, but I think another 20kg is just about possible; though you'd be stretching it.

Of course, I'm assuming that the 1.8 isn't much heavier than the 1.6 I've got in mine - it was just stroked wasn't it, and certainly the R500 has some lighter internals as well.

[subirg]

Re old vs new R400 - I believe the k-series car had a dry sump (extra weight) whereas the new one does not.

[RobM77]

subirg said:

Re old vs new R400 - I believe the k-series car had a dry sump (extra weight) whereas the new one does not.

Aha. I presume the Duratec's oil system is more resilient to lateral g force when mounted longitudinally then? I know the old K always needed at least an Apollo tank for any reasonable track use.

Does the R500 have a dry sump?

I think the new Sports 2000 Duratec cars have dry sumps.

[SimonY]

Yes R500 has dry sump, is mounted just in front of the engine

[rubystone]

SimonY said:

Yes R500 has dry sump, is mounted just in front of the engine

Simon, is it behind the radiator then? I forgot to ask Mick

Old R500 had a dry sump of course...

[SimonY]

It is a tall tank in the triangle between front of engine and the chassis tubes. The tank is triangular as well, looks very neat. IIRC the rad is a combined oil/water cooler, assume this is something new as well?

Edited by SimonY on Tuesday 15th April 20:32