What size serpentine belt for an underdrive crank pulley?

[mralbuquerque]

I just received a bigdaves underdrive crank pulley and i'm looking for the right belt length or part number. Any help would be greatly appreciated. Once i install this i'm heading for the dyno to answer a the question how much hp it gives for a gen3 that's stock except for k+n and sct tune.

 

[plumcrazy]

id assume jonB would know since he sold it to you

 

[treesnake]

Dayco Polyrib #7PK1660......

 

[F8L SNK]

Only use this number if you are deleting the A/C system. This WILL NOT work with A/C.

Dayco Polyrib #7PK1660......

 

[csmwiese]

In a lot of vehicles, with just a crank pulley change you reuse the same belt because the tensioner takes up the small amount of slack.

 

[Fatboy 18]

What I did was to get a piece of string and wrap it around all the pulleys, mark the string length then went to my local auto store and found a belt of the correct length. I changed the crank pulley and the water pump pulley so my belt size would be different to what you require. As csmwisesaid, remember to include the travel of the belt tensioner

 

[treesnake]

Only use this number if you are deleting the A/C system. This WILL NOT work with A/C.

OMG... Good point F8L...

I am installing an underdrive pulley also and every one I have talked to about it DID remove AC...

 

[Fatboy 18]

I have Air Con, and am currently running a 7 PK 1980
Here is a pic of my set up

You must be registered for see images