Cosworth Power Package/Parts Teased

[ProjectGT86]

Originally Posted by Guillaume

Pulleys don't add a single horse power... This voids any point you might be trying to make.

Can you read??? I said Pulleys decrease rotational mass.... decreasing rotational mass FREES up horsepower, leading to less parasitic loss.

[Guillaume]

Originally Posted by ProjectGT86

Can you read??? I said Pulleys decrease rotational mass.... decreasing rotational mass FREES up horsepower, leading to less parasitic loss.

Well you're still wrong. It does decrease rotational mass, gives better engine response too. That's a similar effect to reducing the the overall weight of that car by several lbs, if you will.

It doesn't "free" or "add" any power whatsoever.

[ProjectGT86]

Originally Posted by s2d4

It doesn't work like that.

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Oh really? With just a CAI and an exhaust set up in addition with the stage 2 tune you get an additional 20whp, http://ft86speedfactory.com/ecutek-s...cable-457.html its basically the same thing you get from cosworth for about half the price, and probably with pulley upgrades (decreasing rotational mass doesnt add power but allows more power to reach the wheels) and some additional bolt ons im sure you get close to 40whp, and you its still cheaper than this cosworth rip off

[Guillaume]

Originally Posted by ProjectGT86

(decreasing rotational mass doesnt add power but allows more power to reach the wheels)

Again, no. Gee, what's so hard to understand? Inertia does not cause powerloss.

[ProjectGT86]

Originally Posted by Guillaume

Well you're still wrong. It does decrease rotational mass, gives better engine response too. That's a similar effect to reducing the the overall weight of that car by several lbs, if you will.

It doesn't "free" or "add" any power whatsoever.

Are you trying to be stupid? If the crank has less resistence while spinning that means less power is being loss, which means more of the power at the crank is going to go to the wheels...

[JerryMichaels7]

Yes it does? If the motor has to spin said object how is it not wasting enery spinning said object? Taking and item out of the equation say going to an eletric water pump instead of manuel, or reducing drivetrain wheight thru pulleys/FW/DS. It frees up the motors wasted energy.

[JerryMichaels7]

^^beat me to it.

[Guillaume]

We're talking about a light weight pulley with same gear ratio, yes? Not an underdrive pulley.

Then it does not "free" power that would be other wise consumed by a heavier pulley. Inertia affects transitory phenomenons (accelerating or decelerating). It doesn't cause energy loss (friction does, aero drag does, not inertia).

That's why people often say "Every pound of rotation mass is equvilent to 10 pounds dry mass.". Yes the car will accelerate faster with a lighter pulley, no the whp won't change.

[DatApex]

Originally Posted by Guillaume

We're talking about a light weight pulley with same gear ratio, yes? Not an underdrive pulley.

Then it does not "free" power that would be other wise consumed by a heavier pulley. Inertia affects transitory phenomenons (accelerating or decelerating). It doesn't cause energy loss (friction does, aero drag does, not inertia).

That's why people often say "Every pound of rotation mass is equvilent to 10 pounds dry mass.". Yes the car will accelerate faster with a lighter pulley, no the whp won't change.

Bingo. When you see companies selling a lightweight pulley they will often have a marketing spiel along the lines of "equivalent of a 10whp increase!"

This is nothing but clever marketing to confuse the ignorant.

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[s2d4]

Originally Posted by ProjectGT86

Oh really?

Yes. They don't add up that way.

[Lawn_Mower]

Originally Posted by Guillaume

We're talking about a light weight pulley with same gear ratio, yes? Not an underdrive pulley.

Then it does not "free" power that would be other wise consumed by a heavier pulley. Inertia affects transitory phenomenons (accelerating or decelerating). It doesn't cause energy loss (friction does, aero drag does, not inertia).

That's why people often say "Every pound of rotation mass is equvilent to 10 pounds dry mass.". Yes the car will accelerate faster with a lighter pulley, no the whp won't change.

This.

The belt is still turning whatever device (alternator, water pump, AC, ect...) those are what are causing the parasitic loss, not the pulley themselves.

[Jason@DSG]

Originally Posted by Guillaume

Pulleys don't add a single horse power... This voids any point you might be trying to make.

Dyno result on a WRX before and after with OEM versus lightweight crank pulley, 10whp freed up:

http://forums.nasioc.com/forums/show....php?t=1868471


I completely agree you aren't ADDING any power perse, but the engine requires less work when running lighter pulleys (or other lightweight drivetrain parts) freeing up power that was lost due to heavier drivetrain components getting more power to the wheels that was just being lost spinning heavier OEM parts.


Another really popular example, 3000GT's and Stealth R/T switching to PST Carbon or Aluminum Driveshafts. This is pretty much the first mod any of these guys do and as you can see here, 381whp OEM driveshaft and 413whp after (post #4):

http://www.3si.org/forum/f1/pst-1-pi...t-dyno-631730/

[Guillaume]

It's the effect of the dynamic load on the dyno.
http://forums.nasioc.com/forums/showthread.php?t=873912

Straight to the point :

The rate of acceleration on the dyno (controlled or uncontrolled) will directly effect the measured power.

[Jason@DSG]

Originally Posted by Guillaume

It's the effect of the dynamic load on the dyno.
http://forums.nasioc.com/forums/showthread.php?t=873912

Straight to the point :

I agree, but the increased rate of acceleration is directly correlated to the increase in efficiency in the drivetrain by freeing up weight. It's one of those things, we're saying the same thing but in a different way. You actually don't increase any power by doing lightweight drivetrain parts but it increases the rate at which the engine "works" which results in higher performance (on a dyno, this translates to more power because of the way dyno's measure power)