Engine capacities?
Moderator: RichardW
Engine capacities?
There must surely be some knowledgeable folks out there who can shed light on the following:-
Engine capacities, what's it all about eh? Why is my Xantia a 2.1 when it is clearly 2088 cc. Or my old BX 17RD was 1769ccs (which divided by four cylinders = 442.25cc for each one!), nearer to a 1.8! My 2CV is 602cc (0.6!) Of course it's not just the French. My neighbour has a new Polo 1.2 which is 1198cc and my Minis from way back were 1275cc (1.3) and 998cc (1.0)! Is it that car manufacturers just can't be bothered to get it right! I mean why 2088cc? Couldn't they manage the extra 12ccs? I guess that it is all down to taxation brackets (the original 2CV being the French Deux Chevaux, although that didn't last long and in fact the 602 cc ones were in fact Trois Chevaux!) )and I do remember a long time ago reading somewhere that in the days of decoking and reboring there was a margin left so that the rebore wouldn't take the capacity up into the "next" bracket. Or something like that! I'm sure that this will be a can of worms but should be quite fun to see what comes up!
Engine capacities, what's it all about eh? Why is my Xantia a 2.1 when it is clearly 2088 cc. Or my old BX 17RD was 1769ccs (which divided by four cylinders = 442.25cc for each one!), nearer to a 1.8! My 2CV is 602cc (0.6!) Of course it's not just the French. My neighbour has a new Polo 1.2 which is 1198cc and my Minis from way back were 1275cc (1.3) and 998cc (1.0)! Is it that car manufacturers just can't be bothered to get it right! I mean why 2088cc? Couldn't they manage the extra 12ccs? I guess that it is all down to taxation brackets (the original 2CV being the French Deux Chevaux, although that didn't last long and in fact the 602 cc ones were in fact Trois Chevaux!) )and I do remember a long time ago reading somewhere that in the days of decoking and reboring there was a margin left so that the rebore wouldn't take the capacity up into the "next" bracket. Or something like that! I'm sure that this will be a can of worms but should be quite fun to see what comes up!
Be careful!
I suspect the simple answer is that engine designers don't work towards a specific, 'round figure' swept volume. Why should they - it's just one factor amongst a large number of others which they have to juggle? They might just as logically work towards a nice-sounding oil pressure or crankshaft weight!
The naming of engine sizes is undoubtedly the work of marketing departments, who go for a 'snappy' figure which, where it's significantly different from the actual volume, is presumably calculated to appeal to the target demographic.
I don't know how governments arrive at engines sizes for taxation purposes, but I guess that they measure a number of random samples. Provided that these are 'within the bracket' the specification is met. There will, of course, be minor differences due to manufacturing tolerances, but these are very unlikely to be large enough to warrant making the engines a few ccs smaller 'just in case'.
The naming of engine sizes is undoubtedly the work of marketing departments, who go for a 'snappy' figure which, where it's significantly different from the actual volume, is presumably calculated to appeal to the target demographic.
I don't know how governments arrive at engines sizes for taxation purposes, but I guess that they measure a number of random samples. Provided that these are 'within the bracket' the specification is met. There will, of course, be minor differences due to manufacturing tolerances, but these are very unlikely to be large enough to warrant making the engines a few ccs smaller 'just in case'.
- CitroJim
- A very naughty boy
- Posts: 49658
- Joined: 30 Apr 2005, 23:33
- Location: Paggers
- My Cars: Bluebell the AX, Polly the C3 Picasso, Pix the Nissan Pixo, Propel the duathlon bike, TCR Pro the road bike and Fuji the TT bike...
- x 6204
- Contact:
As Kowalski and Dnsey said,
You'll always find the bore and stroke measurements come out at exact figures. For instance the bore and stroke of an XUD9 engine is 83 x 88 mm which gives a capacity of 1905cc. The same goes for the XU5 1600cc engine with an "oversquare" bore and stroke of 83 x 73mm giving 1588cc.
I cannot think of a single engine in any vehicle ever that has precisely the same engine cc as advertised on the tailgate!
You'll always find the bore and stroke measurements come out at exact figures. For instance the bore and stroke of an XUD9 engine is 83 x 88 mm which gives a capacity of 1905cc. The same goes for the XU5 1600cc engine with an "oversquare" bore and stroke of 83 x 73mm giving 1588cc.
I cannot think of a single engine in any vehicle ever that has precisely the same engine cc as advertised on the tailgate!
Jim
Runner, cyclist, time triallist, duathlete, Citroen AX fan and the CCC Citroenian 'From A to Z' Columnist...
Runner, cyclist, time triallist, duathlete, Citroen AX fan and the CCC Citroenian 'From A to Z' Columnist...
- fastandfurryous
- Posts: 1388
- Joined: 07 Jul 2004, 17:57
- Location: On the road, travelling at high speed. Meep Meep.
- My Cars:
- x 4
- CitroJim
- A very naughty boy
- Posts: 49658
- Joined: 30 Apr 2005, 23:33
- Location: Paggers
- My Cars: Bluebell the AX, Polly the C3 Picasso, Pix the Nissan Pixo, Propel the duathlon bike, TCR Pro the road bike and Fuji the TT bike...
- x 6204
- Contact:
I knew someone would know of onefastandfurryous wrote:I can, but only one.citrojim wrote:I cannot think of a single engine in any vehicle ever that has precisely the same engine cc as advertised on the tailgate!
CX 25. 2500cc exactly.
Jim
Runner, cyclist, time triallist, duathlete, Citroen AX fan and the CCC Citroenian 'From A to Z' Columnist...
Runner, cyclist, time triallist, duathlete, Citroen AX fan and the CCC Citroenian 'From A to Z' Columnist...
Sorry, here's another- BL's A series engine in 1275cc form, badged generally as a 1300 on ADO16's, Allegros,Marinas, etc,but when fitted to the 1275GT Mini clubman thats what it said all along the bottom of the doors....MINI 1275 GT....!!
It's strange that they put the actual capacity on the sporty car, but labled it as 1300 on the shopping cars, but that's BL for you!!
It's strange that they put the actual capacity on the sporty car, but labled it as 1300 on the shopping cars, but that's BL for you!!
its not just engines sizes that have been got at by the marketing people. Landrovers used to be '88' or '109' (the wheel base of the vehicle) up until the series III model , but when the (retrospectively named) Defender came out with its new chassis they were named 90, 110 and 130. The 110 was honest, but the 90 has a wheel base of 91.9 inches and the 130 a 127 inch wheel base.
Thats marketing folk for you <loud marketing laugh>
thus ends my useless non-citroen related vehicular trivia for today, Join me tomorrow for more of the same.........
Pete
ps. Yes I am aware that the 130 was originally named the 127, but the marketing peeps got at it........
Thats marketing folk for you <loud marketing laugh>
thus ends my useless non-citroen related vehicular trivia for today, Join me tomorrow for more of the same.........
Pete
ps. Yes I am aware that the 130 was originally named the 127, but the marketing peeps got at it........
French car free zone....
Not quite true.fastandfurryous wrote:I can, but only one.citrojim wrote:I cannot think of a single engine in any vehicle ever that has precisely the same engine cc as advertised on the tailgate!
CX 25. 2500cc exactly.
Its still a rounded up figure from 2499.790407cc
Bore = 9.30cm
Stroke = 9.20cm
capacity = square(9.30/2) x pi x 9.20 x 4 ccm
Anders (DK) - '90 BX16Image