Pulley size

[SD_T]

Hey fellas 

Pardon my ignorance once again... But regarding pulleys size, I've read that the stock pulley has an outer size of 75mm.

Not having dealt with the previous owner directly, but a dealership, I don't know what pulley I had on, so I grabbed a caliper... and the measurement gave me this:


Am I measuring the right pulley? It's the one ON the G-lader, right?


Thanks in advance!

[NeilG40]

Yes, it's the one on the charger you need to measure.

[SD_T]

So, contrary to my liking I'm running a 64/65mm pulley instead. No wonder I was getting mad belt slip.

I want to keep my car as healthy and reliable as possible. You think a pulley with this size will compromise reliability much?

I had planned a visit to VW tomorrow to change my belts, since they need to be changed and one is not original anyways. But now I am wondering If I shouldn't throw in a stock pulley to the work hour.

[Alexiskayak_7]

You think a pulley with this size will compromise reliability much?

That will be a 68mm one...

[SD_T]

Will it decrease reliability significantly?

I'm not a mad driving type of guy, but it is my daily driver... so I need it to work at all times.

[Puncharado]

Going by other posts, 65mm is the generally accepted safe minimum size, 6500rpm is your engine limit with a 65mm pulley, above this the small bearings on the charger are outside their design rpm limit. PeteG40 has posted some calcs on here somewhere with engine rpm and charger rpm for different pulley sizes.
As for reliability, a good condition charger will be fine, but will need more regular rebuilds. Also wise to change engine oil frequently, although the small bearings mentioned aren't oil fed. Plenty of people are running this size pulley though.
With that size pulley on the car it's quite possible thet the charger has been uprated with an ECU chip to suit.

[SD_T]

Do you think I can visually acknowledge if its been replaced or not?
I recall seeing the original Bosch box, but I don't know if that whole box is swapped or just the chip itself..

[hayesey]

just the eprom chip inside, you will be able to tell if you open the ecu up.

best off with 10k service intervals on the charger if it's on a 65mm pulley.

[SD_T]

Cant thank you enough guys.. and Hayesey once again. I'll open the ecu up to get a clue of what I got.

But anyways, I'll be changing to stock pulley. I rather be a bit down on power and have alot more reliability.
I was fortunate enough to buy the very last original pulley from VW!

I wouldn't mind having the 65 pulley, and eventually a higher revving chip, but it's hard to find someone to service Chargers in Portugal, as I don't know if VW can do that themselves anymore, due to the lack of parts in stock.
If I need to service my charger every 10k, I will have a hard time trying to convince my dad not to trade him for a Bora...and although I like the Bora alot, my heart stays with mighty Polo. Hence my quest for a reliable(ish) G40.

[hayesey]

VW wont service it no, they'll just try to sell you a new one!

If you open the ECU casing, there is a metal cover inside which needs removing, the eprom is under there.  If it's a standard one then it should have a silver sticker on it with VW part codes on it.

[PeteG40]

with a larger pulley it will be slower but last longer between service intervals.

[SD_T]

Thks again Hayesey, I will look into it!

Pete, I'm aware of that, but that's what I'm looking for!