charlie_pank Posted June 28, 2013 Share Posted June 28, 2013 offshoot of Honda s800 thread ... genuinely don't understand, not being deliberately obtuse. Here's a plot of wheel torque against road speed: here There's a different curve for each gear - so you just need to be geared right to achieve the torque you want, so long as you've got the rev-range to allow it. Can you actually show us a plot for a CEC and a similar BEC? Link to comment Share on other sites More sharing options...
MikeMolloy Posted June 28, 2013 Share Posted June 28, 2013 I have a power curve at the wheels for a Caterham Blackbird (not my car, but the same fuel injected lump). Honda claimed 164bhp, but that's at the crank, with "ram air" yadda yadda. The dyno shows 132 bhp peak at the wheels. I took that curve and fed it into excel to create a torque-at-the-wheels vs engine rpm graph. Then factor in the gear ratios, final drive reduction and diff ratio, wheel diameter, and you get torque-at-the-wheels vs road speed for each gear. This basically allows you to see waht the optimum change up rpm for each gear is i.e where the torque in the lower gear drops below that available in the higher gear. Not unsurprisingly it reveals you should change up on the limiter in every gear! Then I searched for a nearest equivalent CEC dyno plot. The closest I could find was 1.8K-Series with 140 bhp at the wheels. Did the same calcs and overlaid the curves for 6th gear (both cars geared for around 130mph top end). It is obvious that the CEC torque spread is a lot wider than the BEC. That's what gives the perception that the CEC "has more torque". The peak isn't higher but the spread (of road speed) is wider. However the BEC has less weight so a drag race would be pretty even. Add a few corners and "add lightness" might well win! 😬 Link to comment Share on other sites More sharing options...
MikeMolloy Posted June 28, 2013 Share Posted June 28, 2013 Oh, and would genuinely love to see a dyno curve for your R1 engine (or in fact any R1 BEC if you can find one...) IMO the R1 is a brilliant choice for a c.300kg single seater in the sub 1100cc hillclimb class. They go like stink. Link to comment Share on other sites More sharing options...
charlie_pank Posted June 28, 2013 Author Share Posted June 28, 2013 I've never dynoed anything, but I will get you a 0-60 time at some point. I'm in no hurry though, too busy with 'project Roo' Link to comment Share on other sites More sharing options...
Klunk Posted June 28, 2013 Share Posted June 28, 2013 Fred is this any use here? Not BEC (or exactly the right CBR) but compares a CBR1000 with an R1 in their original habitat. Regards, Giles Edited by - Klunk on 28 Jun 2013 18:32:34 Link to comment Share on other sites More sharing options...
Ivaan Posted June 28, 2013 Share Posted June 28, 2013 The figures below were recorded by my AIM datalogger at Oulten Park in October last year. This is the first early run, when the track was still wet. I don't really understand the figures, but the Race Analysis software shows curves for both power ( Kw) and Torque ( Nm ). Do they make any sense? The data logger records time, speed, gear, rpm, G's, oil pressure, oil and water temps. So it's easy to see actual 0 - 60 times. I haven't managed below 4 secs yet, either bogging down or spinning the rears, but it should be possible. I've now got a set of slick's to try on track sometime. 😬 Test Name Oulton Park 161012 RPM Power Torque 0 1241.393921 2824.22998 200 0 0 400 435.5489807 3519.248047 600 0 0 800 488.2745667 3727.330566 1000 787.6663208 3617.486084 1200 1201.589233 6600.013184 1400 1598.07251 7679.567383 1600 930.1974487 5157.303711 1800 2020.898682 8336.029297 2000 1971.491333 8508.045898 2200 2325.346191 8906.250977 2400 1706.363037 6835.633789 2600 2504.605225 8779.108398 2800 2566.738281 8160.728027 3000 2288.890137 7504.621582 3200 2545.797363 8125.991211 3400 2731.323975 8242.333984 3600 1625.879517 5188.250977 3800 2750.766113 7639.03418 4000 2513.763184 6470.827637 4200 1874.022583 4951.874023 4400 2299.697998 4744.675781 4600 2362.554443 4786.614746 4800 2320.999756 4624.061035 5000 2354.2229 4326.39209 5200 2581.080078 4566.450684 5400 2825.837646 4843.381348 5600 3418.41748 5608.73584 5800 3997.670166 6342.707031 6000 4646.043457 7102.460938 6200 5075.270996 7568.555176 6400 5365.490723 7871.188477 6600 5900.915039 8301.40918 6800 6016.300781 8291.314453 7000 6479.562988 8587.640625 7200 6703.992188 8721.3125 7400 6929.129883 8854.174805 7600 7340.94043 9034.401367 7800 7502.061035 9069.017578 8000 7736.117676 9074.385742 8200 8132.997559 9250.055664 8400 8574.974609 9609.489258 8600 9622.78418 10408.48242 8800 10125.24902 10806.82227 9000 12501.29395 12286.62305 9200 12277.55371 12402.03613 9400 11532.73438 11688.7666 9600 11435.59375 11274.77246 9800 11803.74023 11392.31543 10000 12498.90723 11746.25684 10200 12785.00293 11853.71094 10400 12965.80176 11880.19238 10600 12929.82324 11713.74805 10800 13256.79688 11558.90039 11000 13347.67676 11546.37305 11200 13012.52344 11080.10742 11400 9181.011719 7751.466309 11600 7506.961914 7101.94873 11800 0 0 Edited by - Ivaan on 28 Jun 2013 20:39:53 Link to comment Share on other sites More sharing options...
Ivaan Posted June 28, 2013 Share Posted June 28, 2013 I think the above may all be U/S. Because I'd swapped to my track day wheels, I didn't have the magnet on the rim for the sensor to pick up speed. So the logger recorded 0mph for the whole day Link to comment Share on other sites More sharing options...
Ivaan Posted June 28, 2013 Share Posted June 28, 2013 These results were recorded on the road Test Name CWB310812 RPM Power Torque 0 460.4709778 3005.060059 200 0 0 400 0 0 600 0 0 800 0 0 1000 678.0872803 5465.87793 1200 883.2959595 5136.958008 1400 2107.214111 9762.416016 1600 1527.709839 7986.796387 1800 2697.761719 11755.2041 2000 2713.812256 11620.52051 2200 2677.206299 11023.38574 2400 2372.029297 8903.616211 2600 3036.291748 10417.08105 2800 3403.06958 11015.45117 3000 3346.823975 10172.12402 3200 3816.94165 11158.51074 3400 4115.277344 10877.68945 3600 4706.754883 11599.11816 3800 5712.958496 13424.41504 4000 6711.192871 15052.83887 4200 7645.591309 16384.39453 4400 6883.274902 14481.87988 4600 8387.387695 17207.76367 4800 8822.111328 17377.3418 5000 8871.079102 16829.87891 5200 8444.170898 15462.17871 5400 7483.234863 13314.84668 5600 6249.685059 10595.80762 5800 7257.983887 11497.04492 6000 7803.041504 12132.61621 6200 8956.074219 13356.30273 6400 9543.680664 13929.04004 6600 10120.96387 14464.39746 6800 11228.71191 15363.22461 7000 11572.27441 15512.57617 7200 11582.94629 15234.36035 7400 11237.01074 14518.69238 7600 9911.774414 12200.01563 7800 10662.02344 12718.70605 8000 11105.98438 12948.0127 8200 11494.1377 13116.89063 8400 11871.10156 13266.0791 8600 11953.03125 13225.7373 8800 12189.23633 12946.58008 9000 12487.68555 13057.04004 9200 12689.30566 13096.10742 9400 12197.97559 12403.43457 9600 13488.78125 13158.86133 9800 14116.2998 13536.2832 10000 14517.70898 13644.93066 10200 14528.64063 13570.85254 10400 8099.549316 7477.64502 10600 0 0 10800 0 0 11000 0 0 11200 0 0 11400 0 0 11600 0 0 11800 0 0 Link to comment Share on other sites More sharing options...
Violet Elizabeth Posted July 1, 2013 Share Posted July 1, 2013 Quoting Fred Gassit: This basically allows you to see waht the optimum change up rpm for each gear is i.e where the torque in the lower gear drops below that available in the higher gear. Why do you need to do this for torque ? Won't power do the same job ? Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted July 1, 2013 Member Share Posted July 1, 2013 *arrowup* *arrowup*I think that power and torque at the wheel at any given road speed carry the same information... it's when you vary eg transmission ratios that they carry different information. Jonathan Link to comment Share on other sites More sharing options...
MikeMolloy Posted July 1, 2013 Share Posted July 1, 2013 Torque is a measurable quantity on a dyno. Power is calculated from that. Torque is the force that accelerates the mass of the car, so it's the thing I use for comparison. Link to comment Share on other sites More sharing options...
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