Mickrick Posted May 22, 2009 Share Posted May 22, 2009 Hello, I could do with some advice on gearing. Do these ratio's/speeds look right? I've been playing around on Peter Ogdens gear calc prrogram, using the ratio's available for the Drenth DG400 box, and the Hartley H1 rpms, and power curves. The 170mph top speed is thoretical of course, and I know a Seven will never get much above 160 due to the non aerodynamic nature! Also I want to use CR500's which are only rated to 148mph. But I'd like the car to top out near it's max rpm in 6th. Does anyone think I've got this all wrong? or am I close. It seems to me that the rev drop in each gear puts the H1 back onto the tourque curve for the next gear. It does look a bit hectic though! Any suggestions/advive would be apreciated Gear set: Manually entered values Gear 1 2 3 4 5 6 Final Ratios: 2.604 2.148 1.736 1.406 1.136 1.000 3.920 RPM Limit: 10000 RPM @Peak Power: 9500 Tyre Size: 245/40 x 15 Tyre Diameter: 22.40 in Tyre Circumference: 70.37 in Gear Mph per 1000 RPM Mph @9500 RPM Mph @10000 RPM -------------------------------------------------------- 1 6.53 62 65 2 7.91 75 79 3 9.79 93 98 4 12.09 115 121 5 14.96 142 150 6 17.00 161 170 Mph RPM (in Gears) ---------------------------------------------------------- 1 2 3 4 5 6 ---------------------------------------------------------- 5 766 632 511 414 334 294 10 1532 1264 1021 827 668 588 15 2298 1895 1532 1241 1002 882 20 3064 2527 2042 1654 1336 1176 25 3829 3159 2553 2068 1671 1471 30 4595 3791 3064 2481 2005 1765 35 5361 4422 3574 2895 2339 2059 40 6127 5054 4085 3308 2673 2353 45 6893 5686 4595 3722 3007 2647 50 7659 6318 5106 4135 3341 2941 55 8425 6949 5616 4549 3675 3235 60 9191 7581 6127 4962 4009 3529 65 9956 8213 6638 5376 4344 3824 70 8845 7148 5789 4678 4118 75 9476 7659 6203 5012 4412 80 8169 6616 5346 4706 85 8680 7030 5680 5000 90 9191 7444 6014 5294 95 9701 7857 6348 5588 100 8271 6682 5882 105 8684 7016 6176 110 9098 7351 6471 115 9511 7685 6765 120 9925 8019 7059 125 8353 7353 130 8687 7647 135 9021 7941 140 9355 8235 145 9689 8529 150 8824 155 9118 160 9412 165 9706 Gear Change RPM drop (change @9500) RPM drop (change @10000) ------------------------------------------------------------- 1 -> 2 -1664 (to 7836) -1751 (to 8249) 2 -> 3 -1822 (to 7678) -1918 (to 8082) 3 -> 4 -1806 (to 7694) -1901 (to 8099) 4 -> 5 -1824 (to 7676) -1920 (to 8080) 5 -> 6 -1137 (to 8363) -1197 (to 8803) Edited by - mickrick on 23 May 2009 12:21:37 Link to comment Share on other sites More sharing options...
Support Team Shaun_E Posted May 22, 2009 Support Team Share Posted May 22, 2009 If you put [ code ] and [ /code ] (but without the spaces) either end of the text then it should look more like how you typed it. Yellow SL #32 - member of Drowned Rat Racing Link to comment Share on other sites More sharing options...
Mickrick Posted May 22, 2009 Author Share Posted May 22, 2009 Cheers Shaun, I'll give it another go over the weekend. Just got in from work, need to eat and sleep! Link to comment Share on other sites More sharing options...
OliverSedlacek Posted May 22, 2009 Share Posted May 22, 2009 What's your peak power? Are you running with a windscreen or not? If you've got 250 BHP ish, then you may get to about 155 MPH, so you need to set your gearing to give 9500 rpm at 155 MPH, or 16.2 MPH / 1000 RPM Link to comment Share on other sites More sharing options...
Willie. Posted May 22, 2009 Share Posted May 22, 2009 Think your final drive should really be 3.92, assuming you're using a Sierra diff and not a 3.89 English Axle 😬 Nothing wrong with being geared for 170. Seems perfectly sensible to me (Mine's something similar) Willie Link to comment Share on other sites More sharing options...
Mickrick Posted May 23, 2009 Author Share Posted May 23, 2009 Oliver, peak power is around 400 at 9500, with a nice flat tourque curve of 250 ft ibs starting at just under 7000rpm. I'm running with a screen, so I recon top speed would be a tad over 160 before hitting the wall. (metaphoricaly speaking!) So I think 165mph at 9657 rpm is about right? But all this may be out of the window, since OP has just pointed out I put the wrong ratio in for the diff! Doh! Off to have another play with gear calc. Link to comment Share on other sites More sharing options...
Mickrick Posted May 23, 2009 Author Share Posted May 23, 2009 O.K I had another go, and at least this time it came out almost legible! The columns are a little bit wobbley but I also changed 4th gear ration from 1.458 to 1.406, as there seemed to be a lot more drop in rpm when changing from 4th to 5th, it's now evened out a bit better. The rev drop in each gear seems to be all within about 20rpm. ! Except 6th which would seem more like an overdrive. Edited by - Mickrick on 23 May 2009 12:28:58 Link to comment Share on other sites More sharing options...
MADMALC Posted May 23, 2009 Share Posted May 23, 2009 I have a spread sheet to calculate rpm/diff ratio/gear ratio/tyre/mph. It may be of use as you can do 'what ifs' quickly. Blatmail me your email and I will send it. S7MAD Link to comment Share on other sites More sharing options...
Mickrick Posted May 23, 2009 Author Share Posted May 23, 2009 Cheers Malc! Had a bit of correspondence with Dennis Palatov, and he's confirmed my suspicions about the ratios being a bit "Hectic". "Too tight" was his comment. Got some good advice though. Top bloke! BM on its way. Link to comment Share on other sites More sharing options...
MADMALC Posted May 23, 2009 Share Posted May 23, 2009 Mick It should be with you now. Regards Mad Malc S7MAD Link to comment Share on other sites More sharing options...
Mickrick Posted May 23, 2009 Author Share Posted May 23, 2009 Cheers Malcolm. YHM back. Link to comment Share on other sites More sharing options...
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