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8th December 2020, 17:31 | #51 | |
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The graph you posted Jamie, suggests a max torque around the 2200 rpm mark, at that RPM in 5th in my auto (without lock up), it is around 70 mph if I recall. I imagine that a manual would be similar RPM. To me, this would be placing maximum torque on the clutch for sustained periods? for motorway driving at least and it wouldnt be required at this point either, as you would be cruising (or at least should be lol). Or do I misunderstand dyno runs? If I am correct, would it not be more useful to have the maximum torque slightly lower down the rev range for reliability, allowing it to be 'switched off' when an upshift took place? Therefore containing its power to shorter use.
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8th December 2020, 17:41 | #52 | |
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8th December 2020, 20:26 | #53 | |
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However I would be somewhat reticent to subject a clutch with a maximum service torque rating of 370Nm to the sort of abuse that exceeding that figure by 60Nm and the resultant damage caused. That is not down to clutch quality although poor quality components will be the first to fail, it is a simple calculation based upon total surface area of the friction material along with it's friction coefficient, and the clamping load of the clutch cover, these are not variables but known figures. Figures that were arrived at during the design of the car to incorporate safety margins of components, the sort of limits that would not have been ever exceeded under normal circumstances. Longer than I have been actively involved in motoring it has been known that tuning cars can result in reduced lifespan of components, back in the 1970's Leyland Special Tuning catalogues warned about the voiding of manufacturer warranties for various tuning products, and these were offerings not of a third party, but the manufacturers themselves. That was of course then, but many of the exact same principles apply to this day, and huge increases in diesel torque output was of course just as possible eight years ago as it is now. The top and bottom of the matter is simple, I drive with a degree of mechanical sympathy, as do many others especially in the case of the demographic of most owners here. But it would be fairly blinkered to view things that way, we are all individuals after all, and there are enthusiasts myself included, who might occasionally wish to make rapid progress by driving spiritedly. This of course is a trade off between functional performance and reliability, and to say otherwise is not true, however it is perfectly possible to enjoy a happy compromise. The decision was made at the time to develop something to further enhance the driveability of the car without compromising reliability and allow the car to lift it's skirts once in a while if required, without creating a trail of unhappy owners with broken cars. The cars themselves were never designed to be anything other than a test mule for the all new Bosch common rail technology, so if it all went horribly wrong it wouldn't reflect badly upon the parent company BMW. Further to this the only reason R40 was fitted with the M47R and the output limited to 116PS and 270Nm as to not make the car a direct competitor for the E46. When BMW divested themselves of Rover Group, the first thing the newly formed company did was to launch a touring version of the car and up the output in some models from 116 to 131PS and up the torque output from 270 to 300 Nm. You can ask anyone who has driven both variants that even this modest increase in power is very noticeable. So why did Rover not increase the power further? there are a few good reasons although it was of course technically possible to do so. The main reason was type approval, it would not have been possible to obtain EU3 emission approval even with the development of a new generation of DDE4 with output greater than that offered by the original XPower diesel tune upgrade. So given that originally an upgrade from 116 to 131 in XPower format cost in the region of £500, it was an option few actually chose. It is a personal choice of course, and there is room for either type of tune, or indeed none at all.......it is not possible to please everybody all of the time, or indeed some of the time, or in extreme cases not at all. Some people will be happy to accept that by effectively "overclocking" a car will result in better performance and accept this will also have a detrimental effect upon reliability, others not so, or others who simply don't care one way or the other as they're perfectly happy with the car as it left the factory. Finally Hodgy's tourer which achieved 170 BHP and 360Nm on the dyno run previously mentioned, had a manual boost controller and the wastegate modified to prevent overboost from popping the intercooler hoses, and was being run in conjunction with a synergy 2. The tune installed in the car was written by Darkside Developments, which brings this post nicely to it's conclusion. Here is a link to explain how to read a dyno printout, something you and I may not need, but will provide valuable insight to people not familiar, the text being especially pertinent LINK Brian |
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8th December 2020, 21:06 | #54 |
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This thread must be leaving people confused about what is possible to safely achieve
on a diesel let alone achieve. May be there should be a meeting between Jamie and one of the 160 remap guys each supplying a diesel car. Both cars have Jamie's remap and then a dyno test and both cars are given the 160 remap we generally talk about and again the cars dyno tested. Video both cars tests and see where we go. I feel silly suggesting it but how else to put this to bed? macafee2 |
8th December 2020, 21:09 | #55 | |
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In all seriousness, if someone with a 160 car does want a dyno run with both maps and is local to the Midlands drop me a PM. |
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