Underdrive pullys
#1
Underdrive pullys
So im looking into getting under drive pullies for my 96 gt and i came across these:
http://cgi.ebay.com/ebaymotors/1996-...ht_2344wt_1165
So i was wondering if they are an investment thats worth it
thanks!
http://cgi.ebay.com/ebaymotors/1996-...ht_2344wt_1165
So i was wondering if they are an investment thats worth it
thanks!
#4
On a more positive note, the crank pulley does not appear to be of the piggyback type--I sent the vendor a message asking if they have a photo of the backside of the crank pulley.
OTH, it is difficult to tell from the photo of the crank pulley and balancer are separate components with "rubber" dampening (as it should be), or a single part. I would be wary of a single piece balancer/pulley as neither Ford nor any established after market vendor has chosen to go that way...
OTH, it is difficult to tell from the photo of the crank pulley and balancer are separate components with "rubber" dampening (as it should be), or a single part. I would be wary of a single piece balancer/pulley as neither Ford nor any established after market vendor has chosen to go that way...
#5
The vendor sent me a photo of the backside of the crank pulley--which tells me for sure that it is not a piggy-back unit, that the balancer is bonded to the puller hub, and that it appears well made and finished.
Based on this photo and that the crank pulley is SFI approved I'd go for if I had a '96-'01-1/2...
Based on this photo and that the crank pulley is SFI approved I'd go for if I had a '96-'01-1/2...
Last edited by cliffyk; 03-28-2011 at 01:16 PM.
#6
after i looked at that ebay page, seems the seller is SLP - wonder if its the same SLP we know that makes exhausts?
i might buy it just for the crank wheel, i need a new crank wheel eventually, the outter edge of mine is chipped up slightly... the only thing i cant use is the water pump pully right?
i might buy it just for the crank wheel, i need a new crank wheel eventually, the outter edge of mine is chipped up slightly... the only thing i cant use is the water pump pully right?
#7
after i looked at that ebay page, seems the seller is SLP - wonder if its the same SLP we know that makes exhausts?
i might buy it just for the crank wheel, i need a new crank wheel eventually, the outter edge of mine is chipped up slightly... the only thing i cant use is the water pump pully right?
i might buy it just for the crank wheel, i need a new crank wheel eventually, the outter edge of mine is chipped up slightly... the only thing i cant use is the water pump pully right?
However this is not a problem. The stock crank/pump pulley drive ratio is 1.27:1, an overdrive, meaning that the water pump spins 1.27 times faster then the crank. With UDPs the crank/pump ratio is 0.77:1, and underdrive, slowing the pump to 0.77 time the crank speed.
Using the UDP crank pulley with the OEM water pump pulley will result in a 0.95:1 ratio, still an underdrive, but just not as much as using the UDP pump pulley.
Here's a comparison of the OEM versus UDP water pump speeds:
and if using the UDP crank pulley with the OEM w/p pulley:
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I mapped all this out while making the decision to get UDPs--can't help it, I'm a 3rd generation engineer on my father's side; and my mother's father was an engineer as well...
Last edited by cliffyk; 03-29-2011 at 07:12 AM.
#9
This set actually used to retail for $199.95, it was recently discontinued and we lowered the price a few times just to blow them out.