Aem Vs. Unorthodox

[bc4g]

Which makes better pulleys/frees up most hp?

Thanks
Chad

[b16b bomber]

getting pulleys wont make any difference, but if you want them get the unorthodox ones

[crxlvr]

pulleys will give you a noticble increase in performance, get underdrive pulleys which are lighter, and smaller then stock. they will provide around 7-10hp.

[Frostbyte]

Originally posted by b16b bomber
getting pulleys wont make any difference, but if you want them get the unorthodox ones

Dude what are you talking about? According to Dyno on my car I will gain 2.7 horses for every pound that I lose off of my crank. I am getting the Unorthodox Full Race pully that only pushes the Alt. which weighs 9.9 Oz. insted of 4 pounds and 9 oz. I will be gain about 10.8 horse of of the pulley. On top of that I also ordered a Unorthodox Race Cam Sprocket. Dude if you get a cam sprocket get the full race one. They are like $200+ they are sweet though. The reason why I ordered this stuff is because I needed the change my timing belt and alt belt. Also that dyno that I gave you for that pulley increases when you use F/I apps.

[GSteg]

also it will reduce drag and your engine will have to work less just to drive your alternator, ac, starter, etc...

[strodda]

sorry if this is a stupid question but i dont know much about the engine yet. if i get the aem tru-power pulley, the belt it comes with, is that a timing belt? cause i need to replace mine anyways.

if not, what part can be replaced that is connected to the timing belt? i have a 91 AT if that makes a difference

thanks.

[RickDaTuner]

Originally posted by strodda
sorry if this is a stupid question but i dont know much about the engine yet. if i get the aem tru-power pulley, the belt it comes with, is that a timing belt? cause i need to replace mine anyways.

if not, what part can be replaced that is connected to the timing belt? i have a 91 AT if that makes a difference

thanks.

not sure what you mean, if you want to get a performance part wich will bring another Timming belt on it, then your not gonna find anything, unless you get one of those stupid run of the timming belt superchargers, but im pretty sure you dont wnat that
if you need a new timming belt, get a new timming belt there no that expensive the only problem is the installation,i htink its like 400-700 hundred buck to get it done but not to sure, you might want to consider changing the water pump on your car while your at it, i think this just saves you a big headach later on, and if your prone to dropping your tranny into 1st wil crusing at 45mph then you might also want to chang you oil pump too,

[ivymike1031]

Originally posted by Frostbyte
According to Dyno on my car I will gain 2.7 horses for every pound that I lose off of my crank.

You won't actually gain horsepower directly as a result of an inertia reduction (ever), but you can get better acceleration from a given power output. Still, "2.7 horses" seems like too much of an acceleration change for a single pound of mass removed from the crank, especially if the radius isn't specified. Did you read this in an article talking about a lightweight flywheel?

I am getting the Unorthodox Full Race pully that only pushes the Alt. which weighs 9.9 Oz. insted of 4 pounds and 9 oz. [/b]

4 pounds and 9 ounces? You aren't replacing the TV damper+pulley with just a pulley, are you?

[Frostbyte]

Originally posted by ivymike1031

4 pounds and 9 ounces? You aren't replacing the TV damper+pulley with just a pulley, are you?

Here you go buddy this is from www.unorthodoxracing.com which talks about thier Ultra R Race Pulley


"For the current Ultra Race lineup, gains of 6 to 14 HP and 5 to 12 lbs.-ft. on normally aspirated engines and 10 to 18 HP and 7 to 14 lbs.-ft. on forced induction engines can be seen. These are average gains. Higher gains can be realized on any modified engine.

These power gains are obtained in a few ways. First, and most important, is the weight loss. There is an average of 2.7 HP gained from every pound lost off the crank shaft. 85% of our gains are from weight loss."

This is the weight comparison for the Ultra R Race Pulley as apposed to the stock for my car.
030610500 1992-1995 Honda Civic/Honda Del Sol SOHC STOCK "4lbs 3.4oz" Ultra R "9.9oz "

If you have ever held a Harmonic Balancer in your hand those things are pretty heavy they are like made out of cast iron they are very brittle if you drop them they will crack very easy.


Here is the link that talks about the Ultra R.
http://www.unorthodoxracing.com/ultrar.html
Here is the link that talks about the weights.
http://www.unorthodoxracing.com/weights.html

[ivymike1031]

"For the current Ultra Race lineup, gains of 6 to 14 HP and 5 to 12 lbs.-ft. on normally aspirated engines and 10 to 18 HP and 7 to 14 lbs.-ft. on forced induction engines can be seen. These are average gains. Higher gains can be realized on any modified engine.

These power gains are obtained in a few ways. First, and most important, is the weight loss. There is an average of 2.7 HP gained from every pound lost off the crank shaft. 85% of our gains are from weight loss."

Well what can I say... they certainly seem to be giving out incorrect information on their website. I can't say whether they're intentionally misleading you or just mistaken, but the information isn't accurate. Think about it this way: reducing crankshaft inertia is basically the same as reducing mass anywhere in the vehicle (except that the effect is magnified by the crankshaft speed). Can you affect power by eating less food when you stop at McDonalds? By wearing lighter clothes? By taking the spare tire out of the trunk? Of course not. All you'd change is the vehicle acceleration. You can calculate an amount of horsepower that would be required to produce the same change in acceleration, but that doesn't mean that you're actually producing that amount of extra horsepower.

Even if you give them the benefit of the doubt, and assume that they just mean "equivalent horsepower," their rule of thumb is incorrect. The place where you remove the mass from the crank is far more important than how much you remove - so to say that there is some given amount of horsepower for every pound removed is just silly. The farther the mass is from the crank axis, the more important it is. If they were talking about changes to crankshaft inertia, in lbm*in^2, the statement would make more sense, because then they'd be including the all-important radius, but they aren't.

Furthermore, if we consider "equivalent hp" gains due to reduced inertia, the number doesn't depend on baseline engine power. If you look at accessory drive power (the place where they actually do see improved power instead of just acceleration), again there is no change due to baseline engine power. So the claim that engines that are more powerful initially will see a bigger benefit seems completely bogus.

If you have ever held a Harmonic Balancer in your hand those things are pretty heavy they are like made out of cast iron they are very brittle if you drop them they will crack very easy.

I have held a "harmonic balancer" (more accurately: torsional vibration damper). What isn't clear from your statements or the documentation on the site is whether or not the tv damper is removed when you install this pulley, but it sounds to me like it IS removed. I don't remember whether or not the tv damper is integrated into the crank nose pulley on your vehicle - is it?

The reason that it is important is fairly simple. The TV damper is used to reduce the amplitude of torsional (twisting) vibrations along the crankshaft. The loads that the crankshaft sees due to these vibrations (when the damper is working properly) are typically about four times the "static" (no vibration) loads on the crank. If you get rid of the damper, these vibratory loads will get worse, possibly resulting in the failure of the crankshaft (a broken crank). The stiffness of the rubber portion of the damper, and the inertia of the ring attached to the rubber portion, are picked during engine development to give desireable damping behavior. It's not guaranteed that in every application removing the damper will result in crankshaft failure, but I have trouble imagining an application where the damper is superfluous.

[Frostbyte]

Originally posted by ivymike1031

I have held a "harmonic balancer" (more accurately: torsional vibration damper). What isn't clear from your statements or the documentation on the site is whether or not the tv damper is removed when you install this pulley, but it sounds to me like it IS removed. I don't remember whether or not the tv damper is integrated into the crank nose pulley on your vehicle - is it?

The reason that it is important is fairly simple. The TV damper is used to reduce the amplitude of torsional (twisting) vibrations along the crankshaft. The loads that the crankshaft sees due to these vibrations (when the damper is working properly) are typically about four times the "static" (no vibration) loads on the crank. If you get rid of the damper, these vibratory loads will get worse, possibly resulting in the failure of the crankshaft (a broken crank). The stiffness of the rubber portion of the damper, and the inertia of the ring attached to the rubber portion, are picked during engine development to give desireable damping behavior. It's not guaranteed that in every application removing the damper will result in crankshaft failure, but I have trouble imagining an application where the damper is superfluous.

That is what this part is. It is a TV damper replacement. So you are saying that there noway to gain horse from reducing weight of the TV damper causeing the crank shaft to spin less weight? It works like this. Take a pole and put a 4 pound disc on the end and spin the pole then take a 9.9oz disc and spin it on the pole which one is going to be easier for you to spin? the lighter disc of course but when they made the 9.9oz disc it is the same size but made out of a diffrent type of metal (aluminum) this would allow the part to still keep the balance on the crank shaft. Which also puts less strain and stress on the crank shaft. Do you agree with this? You know more about it then I do but this is my understanding on this. am I wrong?

[GSteg]

so you won't increase horsepower by reducing the drag on the engine?

[ivymike1031]

(frost)That is what this part is. It is a TV damper replacement. So you are saying that there noway to gain horse from reducing weight of the TV damper causeing the crank shaft to spin less weight? It works like this. Take a pole and put a 4 pound disc on the end and spin the pole then take a 9.9oz disc and spin it on the pole which one is going to be easier for you to spin?

Here's where you might be getting caught up - the pole with the higher inertia will be harder to accelerate, but maintaining the speed of the poles will be equally difficult. If you apply a drag load to the spinning pole (like you're pulling a car down the road), you'll see the following difference between the two:
* at startup, the heavier pole is harder to spin
* after you get both poles up to speed, there is no difference in how hard they are to spin <-(here's the point I'm making)
* if you get tired and stop trying to spin the poles, the light one will stop faster than the heavy one (for a given rate of slowing down, the heavier pole will require less power input from you)

If you put the engine on a dyno with the lower-mass pulley and make a rapidly accelerating dyno run, you will erroneously measure a power increase vs baseline. If you put the engine on the dyno and run steady-state power measurements, you will find no difference vs baseline (the correct result). If you put the engine on the dyno and make a rapidly decelerating dyno run (from full speed back down to idle) you will erroneously measure a power decrease vs baseline.

(frost)when they made the 9.9oz disc it is the same size but made out of a diffrent type of metal (aluminum) this would allow the part to still keep the balance on the crank shaft. Which also puts less strain and stress on the crank shaft.

That's not correct:
* If the part were designed to balance some rotational imbalance on the crankshaft, then maintaining the shape while reducing density (and thus mass) would render it ineffective
* But... the harmonic balancer is not intended to balance the rotating components. It is intended to cancel out harmonic vibrations
* Changing the inertia of the harmonic balancer will affect how well it functions at its primary job (reducing vibrations) and will likely result in increased crank stress (assuming the balancer was designed properly in the first place)

Also, the pulley shown on the unorthodox site can't be considered a harmonic balancer at all, as it's missing the elastomeric portion (rubber ring) that separates the hub from the inertia ring. On a harmonic balancer, there is an outer portion that can vibrate back and forth with respect to the hub, and this is necessary to its function. (assuming I'm seeing what I think I'm seeing in the pic)

See this site for more info on TV dampers:
http://www.fluidampr.com/torsional_vibration.html
http://www.fluidampr.com/problem.html

(GS) so you won't increase horsepower by reducing the drag on the engine?

Sure you will. The inertia of the crankshaft doesn't affect drag. Inertia only affects acceleration (although it seems that half of the "tuner" community confuses acceleration, or lack thereof, with drag). Underdrive pulleys DO reduce drag on the engine - by slowing down the accessories (as discussed previously).

[Frostbyte]

SO in turn when someone is saying that it is increasing horse power that statement stands true. When looking at the Dyno you will notice a higher increase in HP in the lower rpm range to the wheels.

[ivymike1031]

Looking at inertia changes only: For an accelerating dyno run, that's what the results will show, but they are not an accurate reflection of what is happening. An acceleration dyno is measuring acceleration of a drum, not the actual engine power output. As I've said before, power has not changed, but acceleration has. Just like when you eat less at McDonalds- a lighter vehicle accelerates faster for a given amount of power.

Looking at reduced accessory drag: an underdrive pulley will reduce the drag on the engine, and thus increase power output, but this has nothing to do with the change in inertia. That is my biggest complaint about what the unorthodox site says - they attribute a power change to reduced inertia. They even say that the drag reduction is only about 15% of the power benefit - which is incorrect. Reduction in drag accounts for 100% of the increase in engine power, but may only account for a small portion of the increase in acceleration.