Caterham Seven 485 CSR

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Blue7
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Caterham Seven 485 CSR

Can anyone clarify the designation of the Caterham Seven 485 CSR.  I thought the numbers indicated the bhp per tonne eg:

Seven 270 / 500kg / 135 bhp / 270 bhp per tonne … hence designation “Seven 270”

Seven 420 / 500kg / 210 bhp / 420 bhp per tonne … hence designation “Seven 420”

Seven 485 CSR / 580kg / 237 bhp / 409 bhp per tonne … but designated “Seven 485”?  Where does the 485 come from, why not 409?  Is it a dastardly Brexit trick to confuse the Europeans Confused

David

Roadsport06
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I understand the numbers are now based on a nominal figure of 500kg
Golf Juliet Tango
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Nominal weight for all three different chassis.  Frown 

I suppose it is just a number.

Stephen

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7 wonders of th...
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problem is non of them weigh anywhere near 500kg...... and the weights CC quote are dry weights with no coolant oils or fuel, in the lighteat spec for the car too, with aero etc.

They should use the kerbweight calc that tintops do.

 

7 wonders of th...
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CC quaote the 420 as 560Kg......

....and the 620 at 545Kg

.....bearing in mind the 620 has a significant amount of additional plumbing, coolers lines blower brackets and lubes which adds circa 25-30 Kg the additional weight saving measures CC quote must include the use of a Helium filled chassis....... Whistle 

Mcalvert
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I'm slightly doing this from memory from when I test drove the original 485 for Lowflying (it's in the archive here) but I seem to recall that the reality is a little more complicated. 

As stated above, the model numbers are based on the the power in PS over a nominal weight of 500kg (for all models).  The original 485 made 240PS which would of course have made it a 480R, however the 5 was added to reflect that it had successfully passed EU5 compliance...

 

Michael Calvert

Lowflying Editor ([email protected])

StevehS3
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From now on I am going to consider my 120hp K to be a 243. Much better.

rj
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Yeeeks. If I have to use 500kgs my figure will go down by 12%

That would be a disaster as it surely would make the car slower.

Or... are the BHP & BHP/whatever figures just for bragging?

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Blue7
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Thanks everyone for the replies, especially Mike's which gets close to explaining it. 

First of all 7 Wonders is correct ... confusingly, when I looked at the CC website last night it was showing a weight of 500kg for the 420 but this morning I just can't find that page but I can locate another page that indicates a weight of 560kg.  Your other information regarding the weights being dry as opposed to kerb is also very interesting.

Nevertheless I seem to be getting closer to an answer in that all the designations are based on the bhp of the engine, which I assume is a bench test or maybe in S3 chassis on a rolling road.  Regardless this figure is assessed against a nominal weight of 500kg which is applied to all models in the range.

On that basis 237 bhp against the nominal 500 kg weight results in 474 and maybe there is now a EU compliance reg. EU11 so add 11 to result in 485?  However, I hate mysteries so further research reveals a further complication in that sometimes CC quote bhp and other time ps, which is pferdestärke (German), sometimes referred to as metric bhp, which is about 98.6% of a single bhp ... now we're getting closer.

So another calculation could be that CC quote for CSR 485 is 237ps, which would be 240 bhp, which using the nominal but incorrect 500 kg dry weight (that doesn't relate to a CSR because it is SV only), would be 480 bhp per tonne plus EUC5 and voilla ... 485 voilà !!  Clap

Talk about confusing Confused

The reason I posed the question is that I attend and enter a lot of static car displays during the year and display a CV for my CSR, which previously indicated that production ceased in 2016.  I have now modified the CV to make reference to the (none Cosworth) European variant CSR 485.  There are always al lot of questions about CC and the variants and what the numbers represent, which I could explain ... apart from the CSR 485 ... but now it is all quite clear ... as Mud! Biglaugh  Thanks again, it has been a very useful exercise for a 70 yo brain Thumb Up

David

PS ... I am going to fit a couple of additional heavy duty battery cables to the bulkhead so that I can claim to comply with EUC 100 "the approval of vehicles with regard to specific requirements for the electric power train" ... and rebadge my CSR 260 as a CSR 360 Hehe

Ivaan
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The BECs out there with an electric reverse should claim to be Hybrid. Reduction in VED anyone?

BECs Rule !
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What is different about the 485 Duratec that gets it to 237bhp?  Assume must have higher rev limit, the roller barrel throttles and different ECU?  Be nice to get all those on my 420 :)