Well then Mr. IThinkIKnowEveruything...

ever since I put on my underdrive pullies, my voltage needle drops when my car is at idle. the problem is that the alternator does not make enough RPM and the voltage regulator shuts off. The only way to avoid this is to NOT install the underdrive pulley for the alternator. When was the last time you sat the two pullies next to each other... did you happen to notice that the alt pulley in the UD kit is actually LARGER in size.. thereby decreasing the number of revolutions it will make.

It all has to do with ratios.... dont make me bust out the micrometer and shove some math in your face.... because I WILL make you look stupid!

 

Well.. Mr. designer of underdrive pullies. What do you you think happens to the "stock" alt pully when you add a smaller crank pulley??? so therefor why do you think they make the alt pully larger.. hmm... gee...

you should call Ford Racing, Mac, Steeda and BBK and tell them they areall idiots for designing a bad product!

 

I have mine alt pully on and it does drop the volt's only when at a light or not revving but it's not at a point where my car shut off or affects the lighting all crazy. I always had it on since my pully swap I haven't heard any thing positive or negative about having or not haiving alt pully on.
You should try it on and if it feels like it affects it try the stock one don't likethe stock one keep the aftermarket one.

 

apartently you like making yourself look stupid....

imagine the crank to alt ratio is 6:1 stock. when you add a smaller crank pulley, you bring it to maybe 5:1 because the new smaller crank pulley must make more revolutions to cover the same amount of belt, you effectivly slow down the accesories.

by adding a LARGER alternator pulley, you would then change the ratio to 5:1.5 which is 3.3:1 which means the alt pulley is moving even SLOWER

so thank you for making my point, now stfu and never doubt me again!

 

cant we all just be friends? lol ur mean. but there is a such thing as an alt overdrive pully to make up for the lost charge

 

sure there is... but unlike what PX429 is saying... an OVERDRIVE pulley is infact SMALLER, so it will spin faster. And that is why the stock pulley is better than the UD pulley... the stock one is smaller and will allow the alt to turn at a higher RPM, thus cancelling the power loss that usually accompanies U/D pullies

 

Obviously!

 

In reply to everyone:

I can't under stand why you guys want to make your water pumps turn slower. Sure... they're easier to turn with a bigger pulley, but you're not keeping your engine cool.