Underdrive Pulleys

[Guest]

Feels good to see the same results on another well respected dyno on another Team N/A vehicle.

Let us all know how your air con feels and what its done for your drive.

Thanks for the post.

[NA-06-XR]

only thing for me to check out now is when I go to Simon, is if I can crack that 9rwkw off a my engine. See if I can crack the 200rwkw...

The challenge is on Greg...

Are you really sure the spark p-lugs will make that much of a difference? do You think I should "suggest" this to Simon and see if He'll talk me out of it or consider it? anyways that another point altogether...

GREAT WORK falconute! its awesome to see that people are still seeing awesome results from the Balancer. And Lawsy is right. The best improvements we N/A guys will find will be the simple ones with easy early gains. the problem isn't top end power, the porblem is getting there and in an effective and efficient manner.

Chow guys.

[aiboart]

If your model is correct, it yields some interesting results.

If, (as per your quote above) the accessory's torque load is variable and it's power input is fixed, then it the speed at which the accessory is driven is irrelevant (to power consumption).

In other words, the underdrive pulley will spins the accessory more slowly, and, the accessory torque load simply goes up to compensate.

The model predicts that the drive of the underdrive pulley (strictly speaking), frictional losses aside, will have no effect on driveline power output.

(It also may predict that the slower running speed of the accessories will have no effect on the accessories themselves.)

Either the model needs some modification, (ie the accessory power consumption and performance is essentially a function of drive speed), or, something else is responsible for the gains being reported from the use of underdrives.... which is interesting.

If the model is correct (accessory power consumption is fixed as a function of drive speed) and the reports of power gains from fitting the underdrive are correct then something from the 'underdrive' pulley is providing the extra torque into the driveline and it is not the 'under drive'. The reported performance gain is therefore the result of the reduction of the polar moment of the pulley; its lighter weight and smaller diameter is releasing the extra torque. Of course the underdrive effect and the smaller pulley diameter are related, but the model predicts that a pulley of the same diameter as the factory original will yield the same power gains as an underdrive pulley, provided that it's polar moment is the same as the underdrive.

Regards,

aa

[falconutebeast]

NOSXR I drive everyday with the aircon, not always at full, cos it gets so damm cold. I havent had anyproblems with it.

[Guest]

NOSXR I drive everyday with the aircon, not always at full, cos it gets so damm cold. I havent had anyproblems with it.

that's one of the question that always follows any good under drive kit,

"what will happen to my air con?"

From what I can tell, its why theres a 10% under drive and a 25% under drive for the Boss engine.

Some (not all) Boss owners who install the 25% kit cry about their air con having no balls after the fitting.

I think its crap but Ive never com across one yet, its just what the guys at Brad Garlic told me, and one of Herrods guys said the same.

So its a big issue of this Balancer for your XR6's that the Air con has no problems after fitting.

[G6ET8U]

Nice results for an N/A!!

Good work guys

Jack

[shirvo]

I was just wondering where is the best place to get an underdrive kit for my ba na ute.

[Gavin.K]

I was just wondering where is the best place to get an underdrive kit for my ba na ute.

PM nos xr he can get them for you.

[SCRIBR]

I don't really understand what the underdrive pulley does?

Is it just because it's lighter or is it actually smaller?

[senna_T]

My understanding is it uses smaller pulleys that don't drain as much power from the engine to drive ancilliaries like power steering pump etc

someone correct me if I'm wrong!