I have made this its own thread so more people can contribute there opinions. Basically I am saying that since I have a efan and underdrive pullies I will get more hp rather from someone that has just one of each for example:
Efan = 3 hp / underdrive pullies 7 hp
I have them together and I claim I get get 12 hp becuase they are working together giving each other more hp. Hp is not exact just example.
Kyle seems to disagree with my theory. What does everyone else think of this?

 

I'm just going to sit back and see where this goes. My view can be found in the "projected gains" thread.

*EDIT* - I will throw this in:
SuperChevy.com - Pumping Losses

 

That was a great link Kyle. What does a electric water pump have to do with anything we are talking about? [sm=WTFsgign.gif]

 

It talked about the underdrive pulleys too.

Personally, I think that if you got 8 hp from the two combined that would be astonishing...

I don't think the two would compliment eachother more than if you just added the two together.

For example, take two cars that are factory identical. Give one an efan and the other some pulleys and dyno them separately. Let's say the efan got 4 hp and the pulleys got 7. I have learned from experience that when upgrades drastically improve one system (they're essentially freeing up power from the same "area" of the engine) you reach a point where further improvements actually make less power than the two combined "should" make. This would be like, using the example above, putting on the efan and pulleys and getting 9-10 hp instead of getting the sum of the two products (which, in this case, would be 7 HP + 4 HP = 11 HP). This is because you have already freed up the "majority" of the power from that one area.

I think it would be the same thing as getting an ebay cold air intake, measuring hp increases (let's say 5 HP), and then putting on a K&N Filter and expecting to gain the full advertised 7 HP. That 7 HP is assuming you are coming from stock. In this case, as in the case above, you are not coming from stock, and therefore (I believe) you will not get the sum of the advertised HP increases.

One exception to this, of course, would be the intake/exhaust relationship. But the difference here is that they are improving on two separate systems that compliment each other. In the efan/pulley case, you are essentially improving on the same system (belt-driven accessories).

Anyways, that's my take on the subject...

 

I understand your point but I still think it has benefited more cuase they are combined. I think of it like this. The pullies frees up horses with the clutch fan there (It weight like 20 to 30 pounds). Then you take the heavy fan off the pullies are able to free up more hp than it would with the clutch fan still on. Basically the engine get more hp from both combined. I stongly believe this and will test my theory out by placing the clutch fan on one day and seeing the difference with it on and off. I still would like more people's opinions and hearing your theory on this.
[sm=repost.gif]

 

See but I see it as there being x amount of power than can be freed up by reducing the engine's drag on the accessories... Once you do the underdrive kit, you're already spinning everything slower, so there isn't much left of that x amount to be freed. Even if you free up the rest, it wouldn't add up to what you'd get on two cars doing each mod separately.

Let's say there's 10 hp than can be freed up. Now let's say one guy puts on an efan and frees up 5, and the other guy puts on a pulley set and frees up 7. Combined, these upgrades would still only free up 10 hp because that is the total loss that can be freed up by reducing drag on the accessories. You can't get 12 hp from accessories that only draw 10...

(numbers are, of course, for ease of explanation only)

 

The link I posted just goes to show you that the WP even OVERDRIVEN at 124% only draws 11ftlbs/10hp peak (7ftlbs/6hp average) in that application. Driven at stock, the difference would be smaller. The purpose of the electric waterpump was to see the ACTUAL pumping losses of a waterpump. The electric pump was driven from an external voltage source as to NOT impact the performance of the motor by adding drag to an alternator for a complete control test to see the actual hp lost on a belt driven WP. In fact, if you look at the pictures, the WP is the ONLY accessory on the motor. So it is a true test of how much power a waterpump actually draws.

The link was meant to show you that the gains from your 10% underdriven pulleys (if you were to extrapolate the data) would be somewhere below half the results from OD to UD on their results table or 3ftlbs/2hp peak --> 2ftlbs/2hp average when factoring in the smaller 10% difference factory to your UD pulleys. But then again, that is a different engine and all (*snicker*). And this is in terms of the WP only and not the other belt driven accessories.

I just thought it was a very pertinent article for this discussion.