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Dihappy Enthusiast

Dihappy

Posted
Posted

Heres an email i received:

 

 

...could you tell me if there are any downsides to using an underdrive pulley?

 

You state that it increases horsepower by slowing down the accessories.

Would this hurt certain funtions of my electrical system or AC, etc..?

 

 

 

quote:

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Sure there are side effects. The truck does not charge at idle. I do make a correction to this and recommend it for the truck. Use the crank pulley pn 549900 for 1960.. and a overdrive alt pulley to speed the charging back up. Pn 540120 is 26.95. This combination will net 11 hp at the wheels with almost no side effects.

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CMNTMXR81 Senior Enthusiast

CMNTMXR81

Posted
Posted
are under drive pulleys worth messing with can you feel a gain in power?

I have them in the Camaro.

 

They'll charge at idle for only a little while.  If you sit at an extended stoplight or are stopped in traffic, they'll eventually not charge enough.  When in this, I occasionally have to bring the RPM's up to keep them charging.  This will happen more frequently at night when the lights are on.  The lights are a huge draw on amperage.  If you are running a lot of stereo equipment, that too can cause a draw issue.

 

What did I notice in return?  The engine revs faster and since it isn't turning as much mass up front on the motor, maybe (note I said *maybe*I gained 1 extra hp at the flywheel).  I think it cut my 1/4 mile times by about a tenth of a second though.

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