DoubleZero4x4

That's not my understanding. The power is gained by removing 8 lbs. of weight off the crank pulley not by using a smaller pully. The lower weight gives the engine less rotational mass to have to spin around. You will bleed off less power to turn the crank pulley leaving more power to go to the wheels.

If I had an extra $300 I would buy it and take it with me when I get my timing belt done.

Willcipher

This is NOT an under drive pulley; it is significantly lighter though-

Substantial weight reduction 2 lbs 10 oz down from 10 lbs stock.

? Freed up acceleration horsepower and torque.

? Snappier throttle response.

? ***********Stock belt drive diameters.***********

? Maximum traction URD SuperGrip design on the supercharger belt drive.

mastacox

A lighter pullley will not give you gains of 20hp, only in your throttle response and how fast the engine revs up. For a given RPM between a stock engine and one with this pulley on it, the HP will be the same.

EDIT: OK, so i did the calculations my self, because that's the only thing I trust

The horsepower gains are seen in less rotating mass, but only when you ENGINE is accelerating. The faster it is accelerating (I.E. RPM/s) the more gains you will see. So when you're going 4000rpm/s, at 5000rpm (approaching red-line in 1st gear) you will see about 19HP (by my calculations anyway). But what about 3000rpm at 2000rpm/s? You gain 6hp (more realistic driving conditions). Basically, you may see some gains if you drive like a bat out of hell all of the time. Otherwise, the gains are pretty small. It's important to note that the higher the gear you are using, the less gains you see because your engine is accelerating more slowly.

Willcipher

I understand this doesn't give you any more horsepower. But I do want to know what the 'seat of the pants' feel is with this thing installed and you're trying for a nasty 0-60 launch I, like others, am waiting for someone to come along and say "After I installed my pulley, I felt an instant difference in acceleration!"

mastacox

My guess, you'd see an average gain of about 0.25-1 Hp, and a maximum "instantaneous" gain of perhaps 5-6 HP right off the line, based on my calcs... The "maximum gains" of 19 Hp don't seem feasible for a 4Runner, maybe a Corvette or something. As I said before, to gain 19Hp you would need to be doing 4000 rpm/s at 5000rpm! Can anyone's 4Runner do 1500-5500 rpm in one second, while accelerating? That sounds pretty darn fast to me...

EDIT:
How fast is a standard Taco or 4Runner going in 1st gear at 1500rpms and 5500 rpms anyway? Anyone care to test? What about timing how long it takes to go between the two?

mastacox

Also, the "seat-of-the-pants-o-meter" is not a very reliable way to measure gains IMO... I want to see Dyno-tested results of actual gains on a 4Runner or Taco, or maybe 1/4 mile times (but those are difficult to repeat exactly). A Dyno tests in top gear, which means engine acceleration will be comparatively slow, nullifying the addition of this pulley since it's gains are best at very high engine accelerations.

The Dyno tends to be a real heartbreaker that way

I think this pulley will mainly have gains in engine throttle response, and MAYBE a little in top-end 1st gear acceleration.

QSVeilside

Anyone install this yet?

kevin444

hahaha were all waiting, i think gadget needs to have n/a dyno on the 3.4 with the pulley. to maybe boost sales. ahah

Bennito

There are too many pages on CT to read through during the day - especially when the install hassle (not to mention cost) will keep me from going this route. I don't think anyone has posted numbers. but reading all the threads will give you anecdotal evidence to reliability and seat of pants feel.

NX Tacoma

TRDOLMAN,
Did you install the URD pulley yet?

I was think about buying the pully but I am not 100% convinced that it worth it!!

I guess we all just need proof on how the pulley did before we shell out $290

4biker

I'm definitely in Mastacox's camp (even though I'm a noob). If you think about all of the parts that the engine drives, including internal and external engine, running gear, and tires, a weight change of one component of "the mass that the engine turns" just isn't going to register on the fun-o-meter. Add big tires and tall gears and the excitement of a new mod would just wither away...

The sheer mass of the system requires hundreds of pounds of rotational acceleration (or is it angular velocity?) before you even add the weight of the vehicle. Maybe not - not a physics major I'd still buy it, but only if I start excreting money