First full tank after the underdrive pulley install... noticed literally a 40-50km extra per tank increase.

Used to get 270-280 km per tank.. yes ver very very ****ty i know... still need to recalibrate my speedo its prolly a bit off, and im sure i got other problems with the damn truck.. but ran it down to empty today and the trip gauge read just over 320 Kms to that tank.

Havnt driven the truck any less hard then i usually do

Guess these things help a bit... figured 4 months its basically paid for itself if my truck keeps up this mileage.

One problem im noticing tho... i THINK the belt is slipping a bit now after the install. didnt do it for first few days but now under heavy acceleration sounds like a turbo spooling up lol definately think its the belt... but who would it go so early its brand new. And apparently these trucks have automatic tensioners or something?

 

The belt does have a spring loaded tensioner.

 

You sure you got the right belt? If not.. I'd bet it's your tensioner. They are cheap and REALLY easy to replace in our trucks.

I also just got my UD pulleys installed, and I just filled up, but so far based on my ultragauge, I'm averaging about 1.5-2 mpgs more after about 100 miles. I haven't recalibrated after putting 33's on either, but according to my odometer I get around 250ish a tank... will let you know later what I get after the UD's.

 

You weren't supposed to see any increase... lol now I'm going to have to buy one too! My belt does the same but only at very high rpm!

 

Haha, I'm glad I am seeing it so far. I would be upset if I didn't get at least 1 mpg out of it all. Slowly it will pay for itself. I can definitely feel a little more pep in my step, lol.

Next week I will probably install my taurus 2-speed e-fan... so that should increase it a little bit more. Then I will get a tuner soon... With gas at 3.99/gal in California, I need all the help I can get with mpgs.