James Saunders Posted January 12, 2002 Share Posted January 12, 2002 Does anyone know, if the BHP figures Caterham quote for their cars, are at the flywheel or wheels ?? James (Formerly Jimmy07) CATERHAMWEBid=black> Link to comment Share on other sites More sharing options...
kenny. Posted January 12, 2002 Share Posted January 12, 2002 I would assume its estimated at the flywheel James. My HPC 175bhp when standard made 160ish bhp on rollers when new, and 135bhp x/flow showed 112bhp Kenny HPC Link to comment Share on other sites More sharing options...
James Saunders Posted January 12, 2002 Author Share Posted January 12, 2002 Do you think most manufacturer's quote the flywheel BHP figures or power at the wheels ?? Reason being is I just read CCC and a nova with a 2.0 vx engine has 189bhp at flywheel and 157bhp at wheels and will accelerate from 50-70mph in 3.1 secs .. James (Formerly Jimmy07) CATERHAMWEBid=black> Link to comment Share on other sites More sharing options...
Jason Plato Posted January 12, 2002 Share Posted January 12, 2002 The measurement is taken at the wheels then the transmission rolling losses are calculated = estimated flywheel bhp whilst also compensating for atmospheric pressure and air temperature . This is why you can "gain" 10bhp by going to another rolling road , or pumping the tyres up to silly pressures or if you have people sat on the back of the car to maintain traction during the power run , if they leap off when calculating the coast down transmission losses then the bhp figure will increase compared to previous . A synic would say that a dubious rolling road operator could distort the figures using the above to justify his cost of work . This is why a sound comparison of power with caterhams and a like is done at Emerald in Brixton , Dave Walker knows his beans and has demonstrated consistent results which when compared to other reputable operators are very acurate . And he is good value , plus the caff across the road does a top breakfast !! teeth.gif Dave Link to comment Share on other sites More sharing options...
dalec Posted January 12, 2002 Share Posted January 12, 2002 Caff across the road is the first stop with Dave! I can vouch for the good value and he keeps the records of each car on his r/road for comparison, so you can see how yours compares to the best in bhp and torque across the rev range. Link to comment Share on other sites More sharing options...
Red SLR Posted January 12, 2002 Share Posted January 12, 2002 Kenny, was that at RR in Congleton???? X777CAT Link to comment Share on other sites More sharing options...
oilyhands Posted January 12, 2002 Share Posted January 12, 2002 Agree with all the comments re Emerald and DW, but I believe the K in normal and supersport forms was calibrated in house by Rover on a dyno . I think the figures given will be those acheived during the dyno runs and wil *most definitely* be at the flywheel. The RR figures back these up pretty well. Oily Link to comment Share on other sites More sharing options...
kenny. Posted January 13, 2002 Share Posted January 13, 2002 Simon, The last rolling road I used when I modded the VX was Pip Gardeners at Northwich..really top bloke. Kenny HPC (Thought shortly to be SLR but now fly in the ointment as usual!!!!!!) Link to comment Share on other sites More sharing options...
James Saunders Posted January 13, 2002 Author Share Posted January 13, 2002 Oily, Do you think that most manufacturers will quote flywheel BHP figures in their brochures ? Reason I ask is I was looking at a new GSXR1000 motorbike and suzuki claim 160bhp but magazines claim 140bhp, the latter being at the wheel so 160 must come from the flywheel... James (Formerly Jimmy07) CATERHAMWEBid=black> Link to comment Share on other sites More sharing options...
oilyhands Posted January 13, 2002 Share Posted January 13, 2002 *All* manufacturers quote flywheel/crank horsepower in their brochures. Oily Link to comment Share on other sites More sharing options...
Tony Wright Posted January 13, 2002 Share Posted January 13, 2002 Wonder if I could get away with quoting the BHP at the wheels of my car rather than the flywheel, as my German insurance policy is on horsepower rather than engine capacity.question.gif Link to comment Share on other sites More sharing options...
elie boone Posted January 13, 2002 Share Posted January 13, 2002 There is also a difference between DIN and SAE figures for horcepower. I think SAE is without waterpump, alternator and other external bits. Link to comment Share on other sites More sharing options...
Steve Robinson Posted January 15, 2002 Share Posted January 15, 2002 James, Suzuki do indeed quote BHP at the flywheel not the back wheel. Not that it matters in the case of the GSXR1000 as it is still the quickest thing on the road. I sold mine in June as it was downright leathal. i just didn't have the self control to ride something that will hit 140 in 11 secs! Beautiful handling bike, but felt more at home in France than on our crappy roads. Robbo Link to comment Share on other sites More sharing options...
Tony Martyr Posted January 15, 2002 Share Posted January 15, 2002 There is some degree of control over manufacturers methods of determining engine power within the test cell, as Elie states there are methodologies and calculations produced by DIN and SAE that are intended to compensate for atmosphic conditions at time of test and other variables such as fuel. I know of no such controls for the after morket and there are many ways in which optimistic figures can be and are produced. Nobody complains when the figures are too high but will disparage the workshop that produces figures consistanty lower than others whether they be right or wrong. Rover did a lot of work some years ago for the VHPD and SS K series engines in a cell at Longbridge that I visited a couple of times, I think, it was called the racing cell. Any figures from that cell would have been produced with a proper power curve test sequence programmed into the controller and should have been published as corrected power. I'm not sure if they used DIN calculations, some companies use their own versions but all are similar. The engine would have been fitted with water pump but probably not alternator. The rules are a bit unclear in some areas. Most modern engines have complicated multi-drive belts so you have to test with units such as steering pumps and sufficient circuitry to protect them from damage. The k series can be run without the alternator and probably was. Link to comment Share on other sites More sharing options...
James Saunders Posted January 15, 2002 Author Share Posted January 15, 2002 Thanks for your replies chaps.. Robbo, I was thinking of changing my 2001 GSXR600 for the 1000 or 750 .. Do you have any views on this ?? some people say the 750 is quick enough, just lacks the torque of the 1000... James CATERHAMWEBid=black> Link to comment Share on other sites More sharing options...
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