Thanks again!
Just one question - what on earth is a "turnip test"?!
Actually, 2 questions. Does the FL1 use any "CAN" systems in its electronics? I'm guessing it does - at least for the chassis systems like ABS and Traction Control? On other vehicles, there are often aftermarket CAN readers that you can plug into various "nodes" in the electrical system so that you can harvest data. Do such things exist for FL1? It just struck me that if you can get signals from the front and rear ABS sensors, it'll tell you how much faster or slower one pair of wheels is turning than the other.
Last thing, (and this might be viewed as heresy on my part)! I'm beginning to think that the difference in gearing end-to-end, is not to compensate for a reduction in rolling radius of the front tyres, but simply to take any backlash out of the system and maybe alter the handling characteristics slightly. The reasons I am starting to think this are:
1. If it were the case, it would only really ever work at one particular combination of wear state and tyre pressures.
2. They could easily have compensated for the lower rolling radius at the front by specifying a higher pressure - it's very common with lots of other cars to have different recommended pressures at each end.
3. A new car (or a new set of tyres) would not be the ideal setup and yet, in my handbook, they advise replacing all 4 at once. Replacing two (and putting the 2 new ones on the back) is only their 2nd best option.
4. The manual says nothing about the importance of fitting 4 tyres of the same make (even though there can be differences in rolling radius between 2 tyres of different makes but the same nominal size).
5. The manual doesn't recommend increasing rear tyre pressure when heavily laden or towing.
Discuss!
Yer worrying about this too much. Take the props and vcu oft if it worries you that much.
You can watch live data via obdii on the FL1 but the precision and speed of refresh you need, with 4 value capture and pause, isn't available. The hawkeye will show two at a time but the figures are in whole numbers in kph. So not good enough for precise measurement. You only have the option of going up/down the live data list so limited on which two you pick. It would need someone to write their own interface and display abs pulse counts. That's if its available in the list you can pull out. It may only offer the calculated kph values. The FL1 does recognise pulse counts for use with traction control as it can sense slip with less than half wheel slip. All depends if the raw values can be got at.
The Ternip Test was named after
@Vagrent who is a member on ere who sadly doesn't post anymore. I miss him and his wit. It needed a name and he regularly posted the word turnip on its own on different fred's. So I used that.
The sheering affect in the vcu (how it works) creates heat as a side affect. The more heat the greater the sheering inside. It's a live dynamic test you can do after a drive. 3 miles is enough although I and others tested it over much greater distances over time. Its a valuable test which is free to do with no knowledge or tools. Ambiant temperature does change the results which is part of why this was investigated. The temps measured shouldn't be much different if doing 3 miles or many more. Temps measured with infrared are more accurate.
Theory is if the vcu is cold after a drive of 3 miles then theres little or no difference in prop speed. Either yer very lucky or the vcu is seized or something is not right like pinion gear cut oft, lay shaft missing, rear diff content missing etc. You may have a dodgy recon vcu.
If the vcu is comfortably warm after a 3 mile drive then it's working as it should, with some difference in prop speed ratio, and coping ok with it, it is understood. A further longer drive would confirm.
If the vcu is hot to touch after a 3 mile drive then its working harder than ideal. This points to there being a lot more stress in the transmission which is a concern and should be investigated further.
Over the years a lot has been said on ere about vcu's. Each fred created in the past ended in long drawn out arguments and got no where. We also had trolls chipping in. So anything vcu related was done out of sight of the forum after a certain point in time until the time was right to post up. When I found out about the 1:1 ratio I asked on ere for wheel measurements but didn't say why. The problem is if you post up a result it will be discussed but not investigated. There will be loads of theory but little testing. Peeps just won't do the test themselves or are put oft posting up results. Some can't do the more advanced tests if they're mechanically difficult which is understandable. The work we were doing all lead to the ratio fred which said some of what had been done and asked for teeth counts. As usual it got trashed then cleaned up by mods.
We still don't have conformation one way or the other if the ratio changed on all vehicles. Its difficult to get peeps on ere to check this. I can chalk a gear through the ird filler hole and film the teeth turning to count them with the help of an led inside via the filler hole. Its not easy but possible with HippoRamps (TM) and other lifting kit. When pinion gears have been taken oft members teeth counts could have been taken. LR always superspeed part numbers when parts changed. It wiuld be strange for them to not do this on a different ratio ird. It goes against all their convention for other parts and is also part of their production ordering and component control. So we're stuck which on a personal level is annoying.
@dfossil was the only one to contact me and come forward with his results. Unfortunately they differ from mine. I'd been collecting broken/cheap ird's to gain more teeth counts. Also approached peeps directly when they were swopping out ird's or repairing them but the project was put on one side then shelved. So in the end we never got a definitive answer. I knew about the sweet spot fred before it appeared as it had been discussed privatley. At the time I was hoping to get more results before it was posted. To this date he's the only one who came forward with the same 1:1 result I had found. Nobody else came forward having done the same tests. But as said, once the result is advertised no one is interested in doing the tests. For me that's annoying. Its possible we may never know. Funny to see theres currently 58,000 views of my video of drilling a hole in my old vcu to watch the content come out.
Attention then turned to sacrificing my low miles new gkn vcu. We wanted to know it's limits which included a test to see what temperatures were measured and how fast we could constantly turn it. The results of that haven't been posted. I may do next year.
, then many owners want know why. 
