how do you work out the size of the charger pully

[fozworth]

I have a reduced charger pully and want to know what reduction it is ,can someone help with how to work it out,

[DaFlake]

If it isn't stamped on there, you will have to measure an original pulley and then your pulley and do that math. Welcome back to algebra 101.

[ButtonIt]

Quote: Originally Posted by DaFlake (original)

If it isn't stamped on there, you will have to measure an original pulley and then your pulley and do that math. Welcome back to algebra 101.

Sounds complicated

[Richard Crofts]

The calculation is simple, I think....

If X = original pulley diameter and Y = new pulley diameter then the sum is;

X - Y = Z
X / 100 = A
Z / A = % of orginal

Its that simple ... or maybe I'm wrong

Happy to be corrected as I never did great at Maths ...only achieving a C

[DaFlake]

Yes, but you have to get the diameters!

[hey_psycho]

Quote: Originally Posted by Richard Crofts (original)

The calculation is simple, I think....

If X = original pulley diameter and Y = new pulley diameter then the sum is;

X - Y = Z
X / 100 = A
Z / A = % of orginal

Its that simple ... or maybe I'm wrong

Happy to be corrected as I never did great at Maths ...only achieving a C

X-Y=Z

Z being new pulley.
then you do Z/X multiplied by 100.

eg. if original was 10cm and new is 8cm.
then 10-8=2 and we know that this is 20%.

In here Z=2, and X=10. so 2/10=0.2 and 0.2x100=20%

there you go. very easy.

[DaFlake]

, there you go the formula is out. Actually it is very easy math wise. It is getting the actually diameter that is going to be hard.

[roland2003]

Hi , tbh you cannot measure it properly unless its off the car. Even then you need decent large digital calipers that reach over the centreline of the pulley. Ignore the diameter of the outer lip if your pulley has one (eg stock & JCW), If you have GTT pulley they are usually our -17% version.
Best Regards Roland GTT

[DaFlake]

Quote: Originally Posted by roland2003 (original)

Hi , tbh you cannot measure it properly unless its off the car. Even then you need decent large digital calipers that reach over the centreline of the pulley. Ignore the diameter of the outer lip if your pulley has one (eg stock & JCW), If you have GTT pulley they are usually our -17% version.
Best Regards Roland GTT

That was my point....

Thanks Roland.

[fozworth]

The one fitted is a BBR one but they are totaly unhelpful with any info as to what size it is even when i explained i didnt i want to buy a new 15% pully if theres was indeed that size all they answerd with is dont bother.Well i want to so it looks as if im going to have to shell out regardless .dont like the look of theres anyway

[MINIAC]

Quote: Originally Posted by fozworth (original)

The one fitted is a BBR one but they are totaly unhelpful with any info as to what size it is even when i explained i didnt i want to buy a new 15% pully if theres was indeed that size all they answerd with is dont bother.

They said don't bother buying a 15% reduction pulley because theirs is 19% or 20%

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