I'm thinking of putting a underdrive pulley on my 2001 ranger xlt 3.0 for my first modification. Is this a good first mod or should I save money and do somehting different?

 

Here's a test I found, might be of interest to you... Note these Underdog Pulleys were tested on a Saturn, but it just might hold true for other makes and models, I have no idea.......

cut and paste


With various aftermarket manufacturers claiming up to 15 horsepower gains with their underdrive pulleys, we set out to the dyno to find out how much power WE could expect on our 1999 ITA-prepped Saturn twin-cam powerplant. The results might surprise you, but here they are.

Because there were no pulleys available at the time, we went to the extreme and actually REMOVED the accessory drive belt (only for one run, of course) to see what the impact would be to ZERO drag due to the accessory drive – sort of pulleys with infinitely small diameters. We figured that if we saw a big gain without a belt, that the pulley gains would be somewhere inbetween, right?

We fired up the dyno and low and behold, removing the belt netted a whopping 3 HP (and we’re rounding UP). That's it. The number was repeatable, and even correlated to data run earlier on the doomed BMW motors - they saw similar results in their application.

So, in light of the fact that 3 HP was completely without a belt, we estimated that the best we could do was to underdrive a few components by 20% - or a theoretical 0.6 HP gain (3 HP x 0.2). After that, it hardly seemed worth it to try to custom fabricate pulleys for less than a 1 HP gain.

I know, I know – stock pulleys, like stock suspension bushings, aren’t sexy, and you can’t brag about them in the pits…but in racing horsepower talks and marketing BS walks. We chalked up this exercise as yet another learning experience in the quest for REAL horsepower. Maybe someday we’ll find some.

http://www.teamscr.com/pulleys.htm

 

The udp is a great first mod for the price, the guy's that have them say you can feel a real difference, I know I could on my 4.0. The real hp gains are more like 4-6 hp, thats not bad for 80 bucks, it frees up some torque on the bottom end as well. Alot of guy's will do the udp and e-fan together. I can trusfully say, that the bama programer and the udp's are the best to mods I've done as far as power, The gibson was the best as far as sound hee hee. www.jusnesmodified has the udp's for a good price and he's a sponser here. Check out his site, he has bama and alot of cool stuff. They cost alot more for the 4.0 because of the built in harmonic balancer, the 3.0 is cheap in comparision.

 

what kind of mpg should i see from this mod. I'm not really after HP of course a little more would be nice but I'd rather save on gas than have 4 extra horse.

 

The Saturn data posted earlier is worthless, because running an engine under power for even 45 seconds without any water circulation is going to hurt the power output - the data is meaningless.

I suspect Wendell is slightly optimistic w/ his number of 4-6 hp, but everyone I know that has put on an underdrive pulley swears that they can tell the difference. Like Wendell said, the udp for the 3.0 is not expensive, so it seems like a good place to start, since the 3.0 needs all the help it can get.

The only downside may be lower voltage (lights dimming) at idle under high load conditions (headlights on, a/c on, stereo blaring, etc), which can be fixed by just a little pressure on the gas pedal.

 

I've never seen a car get up to operating temp. in 45 sec...

What ever you want to believe in your little mind buddy......... I would believe in what they say compared to you....... I believe they have a little more experience and personal at their disposal..... Oh, I guess you have a dyno in your bedroom..................
I really think they know what they are talking about............ This is a great place, but it has some really closed mined people that think they know EVERYTHING......

 

Another thing that needs to go into this equation is the fact that these underdrive pulleys are usually considerably lighter than the stock pulley. This also would free up some power, not to mention letting the motor rev faster. I don't have a dyno, but I know that it seems like these things work. I've got friends that have them and their cars seemed faster after the instalation. I would have one myself, but I'm already putting a strain on the charging system with 2400 watts of pure sonic bliss. If you decide to go through with it Pappa let us know what you think. Even if it does nothing your engine will enjoy a new belt.

 

I got my hp numbers from Bob Jusnes, I guess they dynoed a 4.0, or somebody had. Don't know about mpg, everone only talks about the power. I can't tell from mine, because I did alot of mods at once, but I was 18/21 and after all the mods and synthetic fluids, I'm getting 22/24, but I do no real city driving as I work and live in the country.

 

LOL! That was really funny!

I didn’t say that the engine would get to operating temperature in 45 seconds. What I said was that running an engine at full power for even 45 seconds without coolant flow would result in a loss of power. The statement is accurate.

An engine at full power is only around 30% efficient. That means a 200 hp engine will waste around 1 million BTUs/hour. All that heat needs to get carried away from the cylinder, and the coolant and oil do that. If the coolant isn’t flowing, it can’t carry away the heat. The over-temperature of the combustion chamber will result in a loss of power.

Regular dyno procedures require cooldown periods between runs – some dyno operators will do 2 or 3 runs before a cooldown, others will require a cooldown every run. This is because automotive engine cooling systems are not designed to carry away all the heat that is generated by full power operation steady state. Even with fans running and coolant flowing, if you run 4 runs back to back, you will see power loss because the cylinders are too hot. This is why you see guys at the track and at the dyno icing engines between runs.

BTW, I have over 20 years as a licensed professional engineer, and I’ve dyno’d more than a few engines, so I know a thing or two about engines. But, if you don’t believe me, demonstrate your open mind and ask an engine designer.