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Post by Baldrick on Aug 22, 2011 8:43:06 GMT
What is an AOD gearbox?
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Post by enigmas on Aug 22, 2011 11:27:26 GMT
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Post by Deleted on Aug 23, 2011 20:45:14 GMT
Just done a service took the car up the road 3000rpm = 63mph, 3500 rpm = 70 mph on Satnav speedo 6mph too fast I went for a drive today and averaged 60mph for a while and I agree that one further change up would be beneficial. There's plenty of power in reserve and it's a great pity that the BW35 was only 3 speed. Fuel economy would be transformed at, say, 1500rpm at 60mph. My new diesel Focus 1.6 is showing 1800rpm at 60mph in 5th gear so spinning much slower than the lazy old V8
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Post by stevew on Aug 23, 2011 22:09:16 GMT
Thank you for taking on the principle that things we accustomed to can be improved. Technoledgy has improved over the last 40 years in motoring world and it's good to take a fressh look at what we are accustomed too and see if things can be improved. This diff change is a good example
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Post by johnwp5bcoupe on Aug 24, 2011 7:40:00 GMT
I don't think you're going to get the increases in economy that you think that diff is going to give you. It's not the same as having another extra overdriven gear, all you're doing is raising the three gears you already have, which is going to mean higher throttle openings to get things moving in the first place. Having a long think I am with harvey with this one to a large degree worried that the car would bog down under some conditions like hill starts etc motorways and dual carriage ways once up to speed it would be a great improvement I am sure, the proof would be a standard 3.5lt up and running as a trial which will be sadly hard to achieve due to tooling costs for a one off. Don't get me wrong steve you are right to pursue this angle and I hope it comes off and works out ok
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Post by stevew on Aug 24, 2011 8:17:32 GMT
I don't think you're going to get the increases in economy that you think that diff is going to give you. It's not the same as having another extra overdriven gear, all you're doing is raising the three gears you already have, which is going to mean higher throttle openings to get things moving in the first place. Having a long think I am with harvey with this one to a large degree worried that the car would bog down under some conditions like hill starts etc motorways and dual carriage ways once up to speed it would be a great improvement I am sure, the proof would be a standard 3.5lt up and running as a trial which will be sadly hard to achieve due to tooling costs for a one off. Don't get me wrong steve you are right to pursue this angle and I hope it comes off and works out ok It has been done, it works, rover p4 with av8 and bw35 box and 2.7:1 diff- 35MPG proven. Check out the rover p4 site, Mikes v8.
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Post by johnwp5bcoupe on Aug 24, 2011 8:27:02 GMT
I can't see it on the P4 club site steve would the allow it
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Post by Deleted on Aug 24, 2011 9:43:40 GMT
What do you estimate the RPM at 65/70mph?
Are you saying that the improved diff is going to dramatically reduce the RPM at cruising speed?
The engine is definitely looking to change up at 60+
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Post by johnwp5bcoupe on Aug 24, 2011 11:25:34 GMT
Googling! 185x80x15 88.5 % eff Torque Converter 2.81:1 @ 70 = 2783, 60 = 2391, 30 = 1179 3.54:1 @ 70 = 3506, 60 = 3000, 30 = 1485 What are your comments about the revs at low speed Have a play vexer.com/automotive-tools/speed-rpm-calculator
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Post by Deleted on Mar 25, 2012 19:52:37 GMT
Hi Stevew, Just read your thread on CWP's I run a garage in France and I was just having this conversation with a customer who has installed a 4.6 rover into his P5B and was looking at changing the diff ratio. Did you get anywhere with supplier, if so how much and where could we buy!!! Your help would be appreciated. Thanks Andreas Adamou.
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Post by enigmas on Mar 26, 2012 10:22:56 GMT
There are many large Ford sedan final drive units in OZ with a multitude of ratios and also incorporating rear disc brakes that will fit a P5B. (Similar track) just remove the Ford spring perch and weld the Rover one on and change the rear tailshaft coupling. This has been done before on a P5B. Simple cheap and effective. You could easliy have a good 2nd hand unit shipped over.
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