Prob-ably ?
VCU Torque test results
- Thread starter The Mad Hat Man
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GrumpyGel
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- Christchurch, New Zealand
Thanks for the input Rob.As an associate professor at UCL, I too read the second comma as being unnecessary
FWIW lol
My niece is in her 2nd year ay UCL.
Some sort of history degree.
Alibro
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I hope your ashamed of yourself for this!!!
I hope not! lol
Brilliant - hope she is enjoying it!
my daughter has just completed her first year and I can’t believe how quickly it’s gone!!!
GrumpyGel
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Yeh, she's loving it.Brilliant - hope she is enjoying it!
my daughter has just completed her first year and I can’t believe how quickly it’s gone!!!
She's a shy girl and has come out of her shell at UCL.
Her course is 4 years, with the 3rd being overseas. So she's off to Dublin for next year, but regretting it quite a bit as she'd like to be carrying on in her digs with her flatmates. Sure she'll enjoy it though.
My son and his girlfriend flew into London this week, taking 4 months out touring UK & Europe before returning for PHDs and getting married next year. They met at 'summer school' at UC which was a prerequisite for them starting their physics degrees.
She's quite taken by London, and Michael has always hated that we've pulled him away from it (that was until he met a Kiwi girl). So he's asked if you have any PHD funding available?
Alibro
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I take it your kids are like mine, got their brains from their mum.Yeh, she's loving it.
She's a shy girl and has come out of her shell at UCL.
Her course is 4 years, with the 3rd being overseas. So she's off to Dublin for next year, but regretting it quite a bit as she'd like to be carrying on in her digs with her flatmates. Sure she'll enjoy it though.
My son and his girlfriend flew into London this week, taking 4 months out touring UK & Europe before returning for PHDs and getting married next year. They met at 'summer school' at UC which was a prerequisite for them starting their physics degrees.
She's quite taken by London, and Michael has always hated that we've pulled him away from it (that was until he met a Kiwi girl). So he's asked if you have any PHD funding available?
GrumpyGel
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Bejesus NO!I take it your kids are like mine, got their brains from their mum.
Must be the milkman
Hippo
Lord Hippo
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Test temp doesn't seem to effect the results unless you get close to the point where you make the vcu's fluid fail by burning and going much thicker. Or it starts to freeze.Thanks
I completely understand just using this as a comparative test - I was just curious
I did my own spreadsheet: analysis from the data from around your link
If speed was simply proportional to the torque the power of x in the below would have been -1, but its not.
Interestingly (for a geek like me anyway) Hippo's, Chris2000's and Seraphin's values all lie along the same trend line
BUT, MrBlockPaving's are much quicker
He did say he did it at 6 degrees C though
I thought, wait a minute but viscosity usually increases with lower temp so his times should be higher
Then I realised - the whole point of the VCU is that it has a special fluid in that has a viscosity that increases with temp (that's how it works)
So that makes absolute sense
What I think is interesting is that not only are times are obviously strongly linked to test temp (I would probably get long time values on a hot Portugal summer 40 C day) but also that the way the times vary with weight also change, so you cant simply assume a constant relationship between time and weight or length - this effect is confounded with temperature - the effects of two parameters interact - the strength of the effect of varying the weight depends on the temperature.
So, in a nutshell, I would do the test with a standard weight and length bar as designated by Senhor Lord Hippo (what is that by the way?) so that everyone's results are comparable
I would also make sure that the bar is the same weight in each case, or even make sure that the weight of the bar plus the hanging weight was a standard weight
I would also at least note the ambient temperature and try to ensure it was pretty close to room temperature if at all possible
Again, all the above in the spirit of my thoughts, I could well be completely wrong - but I enjoy finding things out and having theories shot down is part of that
Top line is Hippo & Chris2000 & Seraphin's data (top equation is Hippos only, Right equation is all 3 together)
Bottom line is MRBlockPavings data at 6 degrees C
R squared is just how well the line fits the data - extremely well here as its almost a perfect 1.0 (simplifying a bit)
View attachment 320086
PS Maths wont hurt you, dont be scared
The force applied is the focus point of the test. Length of bar, weight and angle it starts at are the 3 key points.
We didn't include the wood weight as it doesn't differ much when comparing what peeps use. The metal bar is near the pivot point so weight is less of a concern as most will use the same sort of bar. But I agree they do factor in, if only by a small amount.
We tried not to over complicate fings to make it a diy test. In the early days of this fred and other freds, it was one massive arguement on ere. It continued over many years. Its difficult to get peeps to do the test and put results up. If you search my posts for the word 'cookie' you will find example results.
Search results for query: cookie
www.landyzone.co.uk
The origional problem was ird's and rear diff's cracking. Vcu being the main cause of the problem. Over worked vcu's thought to be the cause. We monitored vcu temps in use. Also ird and rear diff temps. If the transmission is under strain due to a stiffening vcu, the ird and rear diff should in theory be hotter. Temp results didn't differ much but they gave a good driving comparison for other fault finding.
The result graph for my genuine gkn land rover origional supplied vcu is the comparison datum we use. The graph is made up of a straight line and curve. Above 90Nm of torque the vcu provides a near linear straigh line of results. This is where the force applied is enough to turn the vcu. Its important to note the test is only valid if enough force is applied to turn the vcu in the linear zone. A good vcu will turn with 94Nm from a 1.2m bar and 8kg weight. We're testing to see if it turn and by how quickly.
Below 90Nm the vcu doesn't have enough force applied to turn it. The lower the applied torque, the less it turns. More importantly, you're testing below the linear line so your result will never tell you if the vcu turns with enough force to give a result on the linear line. A point which is often misunderstood.
Our main aim of the investigation was to come up with a comparson test, easily repeated on a diy basis, by anyone who could safely jack up one wheel. Owners could regularly test their vcu without the need to remove it from the Freelander, to spot signs of failure. They could also compare test times to others. Theory being we could detect failure early on before it caused transmission damage. Hence why we use 1.2m and 8kg, which applied enough force to regularly turn a vcu with the same result time. Key point being, if the test result time creeps up the curve on the graph, its a warning the vcu is resisting the applied force more than it should. A cause for concern. Hence why we test the vcu in linear mode, looking to see if the result is on the linear line or creeping up the non linear curve, which indicate an early sign of the vcu seizing up.
The test can be slowed down by brakes or hand brakes catching/rubbing. If a vcu gives a slow result then lift the rear wheels to see if they spin freely.
Hippo
Lord Hippo
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What was the length of bar and weight on the end? Did you let go just before 45 degrees?
120cm bar, 5kg, let it go way before the 45 degrees, but only took time for the 45 degrees. (Between 1:30-3:00 on a clock)
andyfreelandy
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Others will have different views but my rules of thumb are :
20 to 30 secs is as new or recon.
45 secs is monitor and keep an eye pending change.
60 secs is replace within 6 months.
Over 60 secs replace immediately.
With 120cm.and 5Kg
20 to 30 secs is as new or recon.
45 secs is monitor and keep an eye pending change.
60 secs is replace within 6 months.
Over 60 secs replace immediately.
With 120cm.and 5Kg
I have seen videos of others, and concluded as well that mine was too stiff, also felt it when making tight turns it felt like it was braking a bit.
So I already ordered a reconditioned
GrumpyGel
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Going by what people report, that doesn't sound to far off the mark.
Bife
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Hi
I have now got a working VCU for the first time for me!
I'll do the test this week sometime
I saw here, but just checking benchmark setup is still same:
- One rear wheel up (I will do the RHS one, nearside for me, offside for most of you guys)
- 32 mm socket on hub nut with ratchet or bar
- Cable tie wooden length to ratchet or bar
- 8kg Weight suspended at 1.2 from centre of hub nut
- Position just before 45 degrees angle (2 O'clock, say) and release
- Start timer at 45 degrees
- stop timer at horizontal
Could you tell me if that is all correct, anything missing etc, please?
I plan to use masking tape with marker pen lines on (and on bar) and video it to get accurate times via frame by frame with VLC
I will do a few repeat tests, 6 is usual in my kind of material properties testing
I may repeat on other side of vehicle if I can be @rsed
Then I'll post results and repeat periodically (probably erratically)
Cheers
I have now got a working VCU for the first time for me!
I'll do the test this week sometime
I saw here, but just checking benchmark setup is still same:
- One rear wheel up (I will do the RHS one, nearside for me, offside for most of you guys)
- 32 mm socket on hub nut with ratchet or bar
- Cable tie wooden length to ratchet or bar
- 8kg Weight suspended at 1.2 from centre of hub nut
- Position just before 45 degrees angle (2 O'clock, say) and release
- Start timer at 45 degrees
- stop timer at horizontal
Could you tell me if that is all correct, anything missing etc, please?
I plan to use masking tape with marker pen lines on (and on bar) and video it to get accurate times via frame by frame with VLC
I will do a few repeat tests, 6 is usual in my kind of material properties testing
I may repeat on other side of vehicle if I can be @rsed
Then I'll post results and repeat periodically (probably erratically)
Cheers
Hippo
Lord Hippo
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That's how to do it.
Hippo
Lord Hippo
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If applying enough force (1.2m and 8kg) to test the vcu in its linear zone then it can be quite accurate. One full turn of the vcu is enough to mix the fluid round so its even. If you repeat the test continuouly after this, results will be the same.
