altenator pulley ratio to crank

Tom keedle · 01-02-2011, 09:38 AM

here's something else to think about,
http://www.decouplerpulley.com/
i see potential...

Tom Goldman · 01-02-2011, 12:23 PM

I tried one on my car when I had a micro v belt system on the car.
Two of them failed ,altho they were OEM units. ... locked up the overunning clutch.
may have been the rpm range , as I was running a small engine at the time and hitting about 8400 in the traps.
The most common application of these pulleys is on diesels ,to help minimize belt screech at shut down. ...They also cut down on belt whip when a automatic tensioner is employed .

Tom keedle · 01-03-2011, 05:47 AM

Quote:

Originally Posted by Tom Goldman

I tried one on my car when I had a micro v belt system on the car.
Two of them failed ,altho they were OEM units. ... locked up the overunning clutch.
may have been the rpm range , as I was running a small engine at the time and hitting about 8400 in the traps.
The most common application of these pulleys is on diesels ,to help minimize belt screech at shut down. ...They also cut down on belt whip when a automatic tensioner is employed .

i was kinda thinking that might help on gear changes...just a thought.

rod · 01-02-2011, 12:33 PM

try to limit the alt. rpm's to less than 20K. and then only for a very short period of time.
let's say U used a 6" crank pulley and a 3" alt. pulley. that would put the alt. turning 14K with the engine at 7K. the engine would only be at 7K at the top of some gears and for a short period of time.
now if U used a 6" and a 2" the alt would go 21K. way to much.
if you have no choice, then 1. make sure you use an alt. than can be easily [meaning not some special alt. which has to be ordered and takes three weeks to show up] and cheaply replaced or 2. have all the windings epoxy coated to keep it from flying apart.

in my case on my 265 i used a nippo denso alt from a 3 cyl chevy something. i used an old smog pump pulley [5" dia] drilled for the chevy three bolt dampner pattern and the original 2 3/4" alt pulley. that runs the alt at just a tad less than 2 to 1. my 265 hit 7K twice. and again only for a very short time.

be careful of some low mount kits on camaro's. the alt. pulley runs into the steering box. i spent 3 ours reconfiguring a friends. ugh.

rod in AZ

01-02-2011, 09:38 AM	#1
Tom keedle Senior Member Join Date: Dec 2008 Location: Berthoud, Coloraduh Posts: 695 Likes: 13 Liked 8 Times in 7 Posts	Re: altenator pulley ratio to crank here's something else to think about, http://www.decouplerpulley.com/ i see potential...

01-02-2011, 12:23 PM	#2
Tom Goldman VIP Member Join Date: Jan 2003 Location: Allentown,PA Posts: 2,474 Likes: 885 Liked 859 Times in 234 Posts	Re: altenator pulley ratio to crank I tried one on my car when I had a micro v belt system on the car. Two of them failed ,altho they were OEM units. ... locked up the overunning clutch. may have been the rpm range , as I was running a small engine at the time and hitting about 8400 in the traps. The most common application of these pulleys is on diesels ,to help minimize belt screech at shut down. ...They also cut down on belt whip when a automatic tensioner is employed . __________________ Tom Goldman 1500 SG , 1506 STK

01-02-2011, 12:33 PM	#4
rod Member Join Date: Dec 2009 Location: Kingman, NW AZ. in the middle of the longest stretch of Route 66 Posts: 314 Likes: 0 Liked 20 Times in 15 Posts	Re: altenator pulley ratio to crank try to limit the alt. rpm's to less than 20K. and then only for a very short period of time. let's say U used a 6" crank pulley and a 3" alt. pulley. that would put the alt. turning 14K with the engine at 7K. the engine would only be at 7K at the top of some gears and for a short period of time. now if U used a 6" and a 2" the alt would go 21K. way to much. if you have no choice, then 1. make sure you use an alt. than can be easily [meaning not some special alt. which has to be ordered and takes three weeks to show up] and cheaply replaced or 2. have all the windings epoxy coated to keep it from flying apart. in my case on my 265 i used a nippo denso alt from a 3 cyl chevy something. i used an old smog pump pulley [5" dia] drilled for the chevy three bolt dampner pattern and the original 2 3/4" alt pulley. that runs the alt at just a tad less than 2 to 1. my 265 hit 7K twice. and again only for a very short time. be careful of some low mount kits on camaro's. the alt. pulley runs into the steering box. i spent 3 ours reconfiguring a friends. ugh. rod in AZ