Hippo said:

Yes that's correct. The longer the bar (distance from pivot point to where the weight is hanging) and the heavier the weight, the greater the force applied. the greater the force applied, then faster the time.

Torque = weight x gravitational acceleration x (length of weight to pivot x cos Angle)

For a 1.2m bar and 8kg weight:

Torque = 8 x 9.8 x (1.2 x cos Angle) = torque in Nm = 94Nm when the bar is horizontal.

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Yeh I know that, just pointing out that his readings would be higher with a shorter bar, so he may be condeming the VCU when it's OK.

Datatek said:

Yeh I know that, just pointing out that his readings would be higher with a shorter bar, so he may be condeming the VCU when it's OK.

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ok sorry.

Most people do the same thing. They don't want to look into why the test results are high, if they're high. Length of bar and weight being important but also where they put the weight on the bar. The length should be the distance from the point the weight is attached to the pivot point. Sticking handbrakes etc slowing down the test. The best form of further testing would be to try the turnip test. You only need to perform this over a distance of 3 miles to get an indication of what's going on. But many fall into bad practise of running it for over 10 miles which if there is something wrong, will heat it up the vcu way too high and they change the vcu by default because it's hot. This is a great idea if your a reconditioner as the customer happily thinks he vcu is automatically duff. Many would only need to swop tyres over to fix this or buy new tyres. Especially those who measure the temp themselves after returning home only to find their replacement vcu is just as hot. If they want to change it for whatever reason they will. It's their choice. Rant over.

roshe25 said:

Hippo are you a mathematician or just a clever sod,(meant in a nice way)It would take me a month to work all that out.
By the way I did the test with the bar at 90% and let it fall to horizontal the time it took was about 30secs which I think is far to long.

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Many years ago I asked online for the formula as I knew there was one from school days but couldn't remember it. I can do some maths but not all.

In practice holding a brick close to yer chest is easy when compared to holding the same brick at arms length. The brick is still the same weight but feels heavier when it's furthest away from you.

The one wheel up test has the same effect. The force applied when the bar is horizontal (3 o'clock) is greater than when it's at say 45 degrees to the horizontal. Hence why we get peeps to start the test oft just before 45 degrees to take up the slack in the transmission and for it to start turning. Then measure the time the bar turns from 45 degrees to horizontal.


WheelTorqueGraph AcIP2Aa

Hi
I have just put two pictures of my vcu on post,I would like to know if anyone has any idea of the year of vcu all I have done is wipe it with a rag after taking off.It looks very clean and the bearings are in good shape as I don't know the history of the car.I know the vcu is a bit stiff that's why it is staying off.
This is just for curiosity as the car is 02 td4 es.
Thank you for any help.

roshe25 said:

Hi
I have just put two pictures of my vcu on post,I would like to know if anyone has any idea of the year of vcu all I have done is wipe it with a rag after taking off.It looks very clean and the bearings are in good shape as I don't know the history of the car.I know the vcu is a bit stiff that's why it is staying off.
This is just for curiosity as the car is 02 td4 es.
Thank you for any help.

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It's a 2002 VCU - the year is shown as the two digits after GKN-V nnnnnn 02 nnn

How many miles has your TD4 done ?

DTO said:

How many miles has your TD4 done ?

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Hi
Sorry I should have put about 123.000 miles.