BB-GT

Could someone please explain what Underdrive Pullies are? And what they do?

firefox7

The standard pullies on a car take a certain amount of power to drive them and this also affects the rpm, similar to the way a supercharger will draw power from the engine to drive it.The smaller the pulley....the less work the engine does and the quicker it will rev. Their are also advantages and disadvantages to be gained by this. One disadvantage, is the flow rate from the water pump pulley is decreased and hense the car could overheat in summer.





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Known around town as the Roundabout King.........All those who have tried.....Have Fried...

Proud Owner of a Tickford TE-50 T3 No 033.....13.62 @ 102.07mph..0-100-4.988 secs

BB-GT

Is this the only disadvantage? What if you fitted one of those Craigh Davies electric water pumps that are always advertised in the Mags?
Who make the pullies and where do you get them?

May 2004 Envy GT Stripes,Leather,FPV Wheel, Prem Sound, Tint, No mods Yet!

Fordy

http://norcom.net.au/~bpt/products.htm Give Barry a call.

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Hypnodoc

Mate I have had them on my car for 6 months and all thats happened is the engine revs faster. None of this waffle about alternators not charging or water pumps not turning fast enough. JUST A CONSTANT 10 RWKW INCREASE THROUGH THE ENTIRE REV RANGE

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F6 Typhoon's Numbers 333.
Shockwave, Pedders Shocks & Springs,Whiteline Swaybars, Manta Exhaust System, Twin 3 inch High Flow Cats & 4 inch Dump Pipe, Injectors and High Vol Pump, FPV Mats, Tinted Glass
Whhoooosssshhh
350rwkw XTREME EDIT
The Real Performance Thing
HSV What ?
and 013, Lightning Strike: Twin 2.5 Mandrel Bent Exhaust, High Flow Cat, CAI & Pedders Suspension

BB-GT

Thanks Hypnodoc!
Did you happen to have your car dynoed before you did any mods?

Hypnodoc

BB-GT The underdrives were the first real mod I put on and if the bumometer is anything to go by then they work well. Be warned though that if you start making more than 310 engine kWs and you drive a manual your gonna get clutch dramas. Redhawk put them on his car and got clutch probs because they let the engine rev much freer and the pressure plate can't handle it. I had the same prob, hard soft pedal etc. rang Mal Woods in Qld and got a real clutch now I have no probs.

__________________
F6 Typhoon's Numbers 333.
Shockwave, Pedders Shocks & Springs,Whiteline Swaybars, Manta Exhaust System, Twin 3 inch High Flow Cats & 4 inch Dump Pipe, Injectors and High Vol Pump, FPV Mats, Tinted Glass
Whhoooosssshhh
350rwkw XTREME EDIT
The Real Performance Thing
HSV What ?
and 013, Lightning Strike: Twin 2.5 Mandrel Bent Exhaust, High Flow Cat, CAI & Pedders Suspension

firefox7

Waffle.....I'm sorry but it is true. Maybe not on the GT/P....Maybe not even on a Corvette....but it does happen. I think it really comes down to the design and engineering of the specific manufacturer. The Underdrives you have (for the GT/P) , are most likley very well designed & you will gain more than lose from this modd. I was speaking more on the broader scale. Underdrives are a fantastic way of getting more Kwts.....I will not dought that fact. But as with ANY modd, there are always..,,,always...Pro's & Con's associated with any deviance from the manufacturing specification.


Deviance from the manufacturing specification:wgaf: I want a Supercharger.







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__________________
Known around town as the Roundabout King.........All those who have tried.....Have Fried...

Proud Owner of a Tickford TE-50 T3 No 033.....13.62 @ 102.07mph..0-100-4.988 secs

XRFPV8

Battens underdrive pulleys are good stuff.
i was one of the people who was worried about charging effects etc:..
i can tell you BB-GT there a good quality product that has been tested by many now, i havn't seen or heard one compliant ...like the Doc said

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PHANTOM BA XR8 UTE, AUTO, UNICHIP, APS TUNED 229 RWKW ET:13.47.

Rods Rocket, Boss n/a 290 Unichip Tuned by APS et:12.6@110 Mph
We are all inclined to judge ourselves by our ideals; others, by their acts.

Hypnodoc

I think perhaps its because (dare I say it) as we all know the mighty Falcon is commonly used as a taxi in its base model and the altenators would have to be able to stand a lot of low revs at full load, e.g city traffic with A/C and lights going at low revs for extended periods of time. I have noticed that the lights will dim a little at idle, but then again so did my XR6T and that didn't have them. As for the BPT Underdrives. SUPERB in my book.

__________________
F6 Typhoon's Numbers 333.
Shockwave, Pedders Shocks & Springs,Whiteline Swaybars, Manta Exhaust System, Twin 3 inch High Flow Cats & 4 inch Dump Pipe, Injectors and High Vol Pump, FPV Mats, Tinted Glass
Whhoooosssshhh
350rwkw XTREME EDIT
The Real Performance Thing
HSV What ?
and 013, Lightning Strike: Twin 2.5 Mandrel Bent Exhaust, High Flow Cat, CAI & Pedders Suspension