pulleys

[3ZHPGUY]

I installed my Turner Under Drive Pulleys in March of 2009 and love them. Turner offered two different alternator sizes. The one was a closer to stock and was recommended for someone running a high power amplifier. I probably picked up over 10 HP and a documented 2.3 miles per gallon. The change was the most significant change I have ever felt. I feel it's a perfect upgrade, completely transparent and does the job nicely.

I did the job myself and the alternator is a royal pain in the ass. You need an impact gun to get the bolt broken free and off the alternator, and if I remember correctly there is a bushing sleeve around the bottom bolt that need to be tapped in or out with a small hammer. I did not unplug the alternator and did everything under the hood. Other than that it's not bad, had her back together in a few hours.

[johnrando]

Good info, thanks!

[kayger12]

Just some related info.

I really wanted an aluminum pulley for the water pump, but wasn't interested in underdrives (or the slightly smaller pulley that ECS sells).

Ended up tracking down a stock sized aluminum one on the Bav Auto site.

It said they were out of stock, but allowed me to order. I ordered it on July 3rd.

It finally just came today.

Did a lot of searching and this is the only place I could find a stock size aluminum pulley.

Just wanted to get the info on here in the event anyone was searching for one.

Droid X. Tapatalk. Use it.

[danewilson77]

Just some related info.

I really wanted an aluminum pulley for the water pump, but wasn't interested in underdrives (or the slightly smaller pulley that ECS sells).

Ended up tracking down a stock sized aluminum one on the Bav Auto site.

It said they were out of stock, but allowed me to order. I ordered it on July 3rd.

It finally just came today.

Did a lot of searching and this is the only place I could find a stock size aluminum pulley.

Just wanted to get the info on here in the event anyone was searching for one.

Droid X. Tapatalk. Use it.

Thanks KG

HTC Thunderbolt+TT

[mikeyb74]

KG what was the brand of the water pump pulley?

[kayger12]

KG what was the brand of the water pump pulley?

URO

[zj96sc]

I've always thought to myself that if another 10HP and 3MPG were so simple, transparent, and free, why wouldn't it come like this from the manufacturer? There has to be a reason they chose to draw the amount of power off the engine that they chose to draw if the change were as simple as a few pulleys.

Dunno....just something that always popped in my head any time i heard someone raving about underdrive pulleys. Certainly not doubting the gains, but just wondering if they may be at the expense of something less obvious.

So on to the case of the weight. It will has no effect on anything. It's all a marketing ploy, lighter is the same as heavy it all spins at the same rate because it's driven from the circumference. It would be a different story if it was driven from the origin of the pulley. I wouldn't suggest TMS because they lighten the ALT pulley, which is unnecessary...just keep it stock. The pulleys from RE were $185 + s&h, no ALT Pulley included.

This isn't entirely accurate - if the pulley weighs less, its rotational inertia will be lower reducing the power required to spin it and to change it's momentum.

[Hornung418]

Understand that the majority of mass is on the circumference of the pulley and that lightening the middle is pointless, because it's not being driven from the center of the pulley.

[echo46]

As preventive maintenance, I just replaced all three pulleys with INA/Dayco. I had trouble locating the AC pulley and ultimately had to go to Advanced Auto and purchase the Dayco pulley. WHen I tried to order the AC pulley from Pelican Parts they indicated that I had to replace the entire tensioner and pulley together? Weird. Anyway, I also did the belts. Never thought about replacing with the aluminum. Maybe next time.

[zj96sc]

where it is being driven from has no impact on the moment of inertia about the pulley center. if the pulley weighs less, it will draw less power to turn. if the weight savings are closer to the center of the pulley this will make the savings less effective, but the pulley will ultimately take less (albeit a smaller amount proportionally) power to spin.

splitting hairs but just trying to be accurate.

/nerdery