eric Posted December 26, 2010 Share Posted December 26, 2010 If all the components are the same, same cam, pistons, head, carburators ... on a road goindg engine, what would be the expected power with a 1600, 1660, 1700, 1760 or perhaps a 1800 crossflow ? A very theorical question but as everybody knows that a 1600 K supersport is 122HP and a 1800 K supersport 140 HP, I have no idea with a Kent eric Link to comment Share on other sites More sharing options...
CageyH Posted December 26, 2010 Share Posted December 26, 2010 I thought the 1.6k supersport was 132bhp Only dead fish go with the flow....! Link to comment Share on other sites More sharing options...
Area Representative Paul Richards Posted December 26, 2010 Area Representative Share Posted December 26, 2010 as everybody knows that a 1600 K supersport is 122HP And there was me thinking it was 132 bhp. Paul Richards Area Representative - L.A.D.S. (Lancashire and District Sevens) LADS Website Growing old is compulsory - Growing up is optional Link to comment Share on other sites More sharing options...
eric Posted December 26, 2010 Author Share Posted December 26, 2010 so if it is 132 200 cc give 8HP which is not a lot. 100 cc will give 4 HP and 50CC 2HP and it is better not to rebore max but only the size needed eric Link to comment Share on other sites More sharing options...
Area Representative Paul Richards Posted December 26, 2010 Area Representative Share Posted December 26, 2010 8bhp but what about torque? bhp is not the only thing. Paul Richards Area Representative - L.A.D.S. (Lancashire and District Sevens) LADS Website Growing old is compulsory - Growing up is optional Link to comment Share on other sites More sharing options...
CageyH Posted December 26, 2010 Share Posted December 26, 2010 Don't forget though - a bigger bore allows for bigger valves. Only dead fish go with the flow....! Link to comment Share on other sites More sharing options...
eric Posted December 27, 2010 Author Share Posted December 27, 2010 I found a formula in a book : Increase of power = Cubic efficiency x increase of capacity x 0.8 For a 110 HP Sprint Caterham, the cubic efficiency is : 110/ 1.6 If the increase of capacity is O.1 l For a 1700, the increase of power would be in theory (110/1.6) x 0.1 x 0.8 = 5.5 HP eric Link to comment Share on other sites More sharing options...
eric Posted December 27, 2010 Author Share Posted December 27, 2010 A Supersprint which is 135 HP is different from a sprint : -increased capacity (1700) -compression ratio raised by the use of a smaller combustion chamber from the 1300 pistons (not far from 10 but I don't know exactly) - head (but I don't know if the valves are bigger) - Cam a 234 instead of an A2 eric Link to comment Share on other sites More sharing options...
cskip Posted December 27, 2010 Share Posted December 27, 2010 My Sprint was 100bhp not 110bhp. Link to comment Share on other sites More sharing options...
eric Posted December 27, 2010 Author Share Posted December 27, 2010 due to a GT cam and not an A2 eric Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted December 27, 2010 Share Posted December 27, 2010 So .... Same old story. .......... It's not just the size ....... It is what you do with it !!!! Link to comment Share on other sites More sharing options...
Roger King Posted December 29, 2010 Share Posted December 29, 2010 If you leave the spec identical and change nothing but the capacity there will be only a minimal increase in power as the engine gets bigger. But torque is a different matter and will increase significantly with capacity. As a general rule, manufacturers who made varying capacity versions of the same engine (e.g. Crossflow, Kent) would fit a bigger cam to the larger versions. The extra torque of the larger engines would ensure that driveability was maintained, but the cam would allow the extra power to be produced. Link to comment Share on other sites More sharing options...
eric Posted December 29, 2010 Author Share Posted December 29, 2010 Thanks Roger On the driveability side, can we say that a 1600 with a 234 could be compare with a 1720 or 1760 with a 244 ? eric Link to comment Share on other sites More sharing options...
PAC Posted December 29, 2010 Share Posted December 29, 2010 My 1800 Xflow was measured at 175BHP, with 45's and a 264 cam. It doesn't even think about going until 4.5k RPM! Drivability is not too bad, but only because the car is relatively light, compared to other Caterhams it's Cr@p. I was told by a race engine builder that the holy grail is to divide the cc's by 10, and you get a rough estimate of the maximum possible power............ Probably a load of old carp but is about right for mine. I'm sure I've heard of 200BHP Xflows tho Edited to answer my own question: Probably 2.0L X-flows!! P Edited by - PAC on 29 Dec 2010 23:42:53 Link to comment Share on other sites More sharing options...
eric Posted December 30, 2010 Author Share Posted December 30, 2010 I am used to think than after 100 HP / liter begins the hassles So I do prefer 20HP less as a limit for my peace of mind eric Link to comment Share on other sites More sharing options...
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