Underdrives

[Mark351]

The 20% underdrives for the BA-BF have proven to be a worthwhile mod, including the NA guys.

Any reason why it wouldn't work for the AU? How many would be interested in one if they were developed?

[Casper]

I think AU I6's are already factory under driven (I could be very wrong to) but, if something was developed, I'd be very interested of course.

[Mark351]

I thought it was just the V8s?

[Casper]

Originally Posted by DeathXR

I thought it was just the V8s?

could be.. I'm not 100% sure. I thought it was the I6's too but I'm hoping I'm wrong.

[loxxr6]

Originally Posted by Casper

I think AU I6's are already factory under driven (I could be very wrong to) but, if something was developed, I'd be very interested of course.

I'm pretty sure that was the explanation posted in another thread on this too.

[FS5]

i was told by repco that ba and au's run the same balancer,they said the part numbers were the same .
i haven't seen a ba balancer up close so i can't they are the same forsure or not .

[stiddy]

casper was right, they are underdriven from factory.

[OED666]

best place to contact would be Ross Tuffbond Balancers... They are in Sydney.

I fitted one of their wiz bang balancers a few months ago. But mines an EL balancer. I should have got an EF or AU one, just incase I wanted to run coil packs in the future. Oh well.

[Mark351]

According to Precision parts (who makes the Powerbond BA balancers), the AU balancers have a different ring offset and other dimensional differences from the BA balancer.

[xr8 007]

i would definantly be interested if developed

[Lukeyson]

im up for it

[GK]

What the hell's a jiggawatt?

Ok, that't the Back to the Future gag out the way?

Pardon my ignorance, but what is an underdrive? How will they increase performance?

GK

[Dauphin]

I did a little research to fully understand the concept myself. This is from Wikipedia:

An Underdrive pulley refers to an aftermarket crankshaft or accessory pulley (such as an alternator pulley) that is designed to drive a vehicle's accessories at a slower rate than stock. Underdrive from the crankshaft pulley means the pulley is smaller that the original pulley it replaces. Underdrive from the accessory pulley means the pulley is larger than the original pulley it replaces. Originally they were invented for race cars in the 1950s and 60s, whose engines had been modified and ran at higher RPMs for longer periods of time than the manufacturers had intended. It was therefore necessary to underdrive the belt-driven accessories (among other things like the water pump) to keep the accessories from burning out and the engines running reliably. Underdrive pulleys did not become mainstream until the mid to late 1980's with their introduction from March Performance for fuel injected 5.0L Mustangs, Camaros & Trans Am's. They also appeared for small displacement engines in the mid-nineties with the entry into the market of Unorthodox Racing.

These pulleys are marketed as performance enhancers that actually produce additional torque and horsepower by reducing parasitic drag caused by belt-driven accessories but more importantly by being lighter and reducing rotational mass.

click here

Sounds like a good mod for some small performance gains and to protect accessories from the power generated by modified high-power engines.

[GK]

Good info Dauphin!

GK

[StealthAu]

I'd be interested, whats the BA system worth? and who developed it?

[Soundwarp]

I've been wondering about this for a while now, I'M DEFFINATLEY IN!
LMK

[feebs]

Guys.. the smaller pulley is the best thing since sliced bread on a ba 6.. and would no doubt be as good on any earlier 6.

FWIR the au xr8' do have a smaller pulley that the base model 8, not sure about the xr6 tho, I guess if the serpentine belt is the same length on the xr6 as it is on the forte's, then the pulley must be the same.

BPT wangara have been selling them for a while, and would be a good point of info.

[Soundwarp]

Well i'm in for sure if there is any gain?