New Accessory Pulley = Better MPG? - Fuel Economy, Hypermiling, EcoModding News and Forum

Tygen1 · 08-31-2009, 01:34 PM

So my Accesory pulleys were makeing a racket, during their replacement I saw the timing belt pulleys were almost dead. Replaced them all and now the motor is much quieter. Anyhow, drving in to work this morning I noticed my SG was reporting a lower GPH than normal on the coasts, around 17 when it is normally around 20. My normal Idle GPH is around 17-18. By the time I got to work I was seeing the idle GPH around 12-13. I'm sure the savings is very small, but the old pulleys must have had quite a bit of friction in the those worn out bearings. I also did about 1mpg better on the way to work, however that is well within the normal variation due to traffic. We'll see if it's a consitant gain. I'm just amazed at the difference in GPH...

cfg83 · 08-31-2009, 01:40 PM

Tygen1 -

Yes, please document your results. I assume the old pulleys were worn out OEMs. Are the new pulleys replacement OEMs or ?!?!?

CarloSW2

Tygen1 · 08-31-2009, 09:56 PM

The old pulleys appear to be OEM, the replacements are Autozone Duralast (Korean). I'm not to pickey on that sort of stuff, the OEMs for this motor are German, but last just as long as the cheaper stuff, they need to be changed with the belt. The old pulleys were all in pretty bad shape.
I wish I could thourghly document this, but I didn't expect such a big change, so I don't have a reliable base line, just observations. The commute back home showed the same results. Runs smooth and quiet now. The Coasting GPH went as low as 0.14, just amazing to me because it never went below 0.17 before...

NiHaoMike · 08-31-2009, 10:21 PM

You could get even more of a savings if you use an underdrive pulley.

yanlapanic · 08-31-2009, 10:35 PM

Quote:

Originally Posted by NiHaoMike

You could get even more of a savings if you use an underdrive pulley.

i dont think its good for me , i have a sound system that can take more than 25 amp ...

underdrive alternator and all accesory is not for me I think . but its a great item !

Christ · 09-01-2009, 12:57 AM

Quote:

Originally Posted by Tygen1

So my Accesory pulleys were makeing a racket, during their replacement I saw the timing belt pulleys were almost dead. Replaced them all and now the motor is much quieter. Anyhow, drving in to work this morning I noticed my SG was reporting a lower GPH than normal on the coasts, around 17 when it is normally around 20. My normal Idle GPH is around 17-18. By the time I got to work I was seeing the idle GPH around 12-13. I'm sure the savings is very small, but the old pulleys must have had quite a bit of friction in the those worn out bearings. I also did about 1mpg better on the way to work, however that is well within the normal variation due to traffic. We'll see if it's a consitant gain. I'm just amazed at the difference in GPH...

Of course it would take less fuel, you're seeing (apparently much) less parasitic losses, thus less load at idle.

Tygen1 · 09-01-2009, 02:08 PM

Yep, I didn't think the load from worn bearings was that great, I was wrong...
I do have a UDP, 40%, and a 30% ODP for the Alt to get it back up to speed. UDP was a minimal, probably not calcuable savings, but the motor runs smoother and rev's more freely.

Tygen1 · 09-01-2009, 02:09 PM

Also, hit 50mpg on the commute to work today! That is a first

Definatly something going on here...

NiHaoMike · 09-02-2009, 08:08 PM

Quote:

Originally Posted by yanlapanic

i dont think its good for me , i have a sound system that can take more than 25 amp ...

underdrive alternator and all accesory is not for me I think . but its a great item !

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