Joe's truck

I've read a little about the under drive pulley kits for the 4.6L and they claim to add about 12 HP. Has anyone done this or do they know much about it? I just don't want to waste $$

atvrider93

they don't "add" power, they just increase driveline efficiency to get more of the crank HP to the wheels. I dont have them so I cant comment on whether they are worth it or not

Mike

from what i read it can mess with the charging system. i also heard takin out the clutch fan frees up like 15 horse too. i have mine out and some other mods and even with over sized tires and stock gears she can keep with or beat other peoples trucks with similar mods and stock tires

VanoFord

Not only the charging system, but also the AC compressor. It makes it work harder, and therefore less efficient, robbing you of gas mileage/fuel. They honestly arent worth the drawbacks. I researched and decided against but do as you see fit. Good luck!

BigRedXlt

how does it make the ac compressor work harder? and how does it hurt gas mileage because everything I have read states that it increases gas mileage by lightening the load on the engine? It just doesnt seem to make sense that by freeing up the engine the gas mileage will decrease. If anything I have heard that the electronic accessories in your truck might suffer (not in terms of damage just a less ample supply of power) but thats about it. Definitely nothing about decreasing gas mileage....

Brandon's07

This is a discussion that takes place in all the forums I have ever joined. From Mustangs to Trans Ams and Chevrolet pickups. I have used the underdrive pulleys and I did notice a difference on the highway when hitting the passing gear. It had a little more jump. At that time I was trying to get as much out of a 6 cylinder as I could and I got quite a a bit when all was said and done. The pulleys decrease the size of your altenator pulley and you do lose a little charge at idle but it is not major. I will say that if you can get a good deal of the pulley set, go for it. If not, determine what you are willing to pay. Do not expect cutting a second off your 0-60 time but there are some power differences to be noticed. Hope some of this helps out.

Brandon

blackbetty

This is a prime example of why forums are a bad place to ask a broad question. The information you get could be good, or really bad like the post I quoted.

The best kit you can get for the 4.6 would be a mustang kit for the 01-04 4.6. Steeda and summit are both good kits, summit is just a non name brand but same quality as the Steeda kit. Stangs get great help from them as far as when your adding the ponies up, and it does help free rev's.

In response to the ac comment, I think he meant to say water pump.

Troyer promotes up to 15 ponies on his in house dyno with his kit, about 300 bucks.

ballistic

from my research.. UD pulleys are suspect in terms of delivering a return your cash. I have opted to not get one at all. Many will agree the pulley should be low on your list, or skip it entirely. As are throttle spacers.
Better prioritys are...

1. custom exhaust system.
2. CAI to go with ^
3. now your truck will run lean so get custom tunes like Gryphon/evo.
4. e-fan

i have done the above 4 items in the posted order. If i did it again i would reverse the order.

VanoFord

Don't just say something is bad, define what is bad in it. I can call BS on posts all day too, unless I back it up whats it matter?

The crank pulley changes size, larger i think. Therefore it will turn all your accessories slower. The Power Steering wont pump as well, AC will probably cool less efficiently at idle/low rpm, Alternator may decrease charging at idle/low rpm. These are not opinions, these are facts. But then again, what do I know? Someone says this is BAD info I am giving so since someone else said so, its gotta be true, huh?
Have fun with the pulleys! Make sure you take note of how all your stuff works now, so after its on, you can tell us what really happened. I personally dont want to effect that many things in my truck just for 15HP (which is probably conservatively a high number).

Franchi

Worthless? Not at all in my opinion. I have them on my Mustang. Would I add it right away? No.

Far as alternator and charging systems, I have Shaker 1000 system in the Stang with the duel 10's inch woofers and there was zero difference in before and after install of the pulleys. If somebody had a MASSIVE aftermarket system drawing a ton of juice, then no I wouldn't add it. But that's really only getting into folks who build custom sound systems for their vehicles.

And I didn't get 12 or 15 rwhp add from the pulleys, I got 8.

And personally, I saw no difference in how the power steering, ac, ect ect ran after installation....