running a 50% crank underdrive pulley...charging problems?

[ritc]

Now that I basically got my belt routing situation figured out and decided to go with a electric fan/water pump with DC controller, and a/c delete with p/s bracket to move it up, I had a question about running a race 50% on a street/weekend car that will have an electric fan/water pump.

I wont be running a big radio system just a cheap cd player so the biggest concern would be the charging system during idle when the fan and WP are going or even a few min. while there running to cool the engine in the staging lanes and the car is off. Only solution I could think of would be to run a sub 2" alt. pulley but I have yet to find one online, would it be possible to have one pressed in from another application like a similiar tensioner etc?

Also would I not notice much of a HP difference from the common BBK/MAC/March 20%-26% under drive sets comapred to a 50% crank? And would I need any type of spacer to run this crank with the stock balancer? Or will the stock crank pulley just come off and I just need to bolt the new one in?

 

[ritc]

bump....

 

[Daggar]

You're spinning your wheels with the under drive pulley. If I read correctly, you plan to run an electric water pump and an electric fan. So the only thing you're running form the belt drive is your power steering pump and alternator. On the dyno, I'd be suprised if you saw even a 1 HP difference with an under drive and just those two accessories.

 

[Snikt89GT]

I'd want a damn good charging system if I had both electric fan + waterpump. Why even bother with the underdrive?

 

[ritc]

Oh alright if the difference is that little I wont even bother then, thanks for the advice guys.

 

[8950HO]

You`d be better off getting a 3g alternator if you don`t have one already instead of a race crank pulley.
Especially with an electric fan and water pump.

I don`t know if even a 3g would charge at idle with a 1-7/8" overdrive alternator pulley and a 50% reduction race crank pulley.Probably not too well if at all,and certainy not with an electric fan and wp.

 

[Daggar]

I'd want a damn good charging system if I had both electric fan + waterpump. Why even bother with the underdrive?

You`d be better off getting a 3g alternator if you don`t have one already instead of a race crank pulley.
Especially with an electric fan and water pump.

Ditto!