jesseanson Posted February 5, 2009 Report Share Posted February 5, 2009 ok just a quick question you said that the 250 amp rhino series alt for my 95 jimmy would put out 150 amps at 800RPM why does the dyno test sheet say it only puts out 26.9 amps at 1600RPM?? Quote 2004 gmc Yukon 270 amp mechman alt. 1 odyssey PC1500 up front 6 kinetik HC2400's in the back 2 18" BTL's fully loaded 2 saz-3500d's strapped 155.7db @ 38hz sealed MY YOUTUBE!!! Link to comment Share on other sites More sharing options...
rusty959 Posted February 5, 2009 Report Share Posted February 5, 2009 Im not mechman, but the 150 amps at 800 rpm is your engine's speed. The dyno sheet shows the actual alt speed. The alt will always be turning much faster than the engine. Im thinking ive heard 4 times faster? Don't quote me on that. No matter what the ratio is, you will still be good at idle when the alt is actually in your car Quote 2013 Subaru BRZ12" Orion HCCA on AQ 22001967 mustang restoration project: http://www.stevemeadedesigns.com/board/topic/110765-mustang-restoration-build-2011-edition/ Youtube: https://www.youtube.com/user/therusty959 Link to comment Share on other sites More sharing options...
jesseanson Posted February 5, 2009 Author Report Share Posted February 5, 2009 Im not mechman, but the 150 amps at 800 rpm is your engine's speed. The dyno sheet shows the actual alt speed. The alt will always be turning much faster than the engine. Im thinking ive heard 4 times faster? Don't quote me on that. No matter what the ratio is, you will still be good at idle when the alt is actually in your car thanks man, i was just wondering haha i figured it would be something like that Quote 2004 gmc Yukon 270 amp mechman alt. 1 odyssey PC1500 up front 6 kinetik HC2400's in the back 2 18" BTL's fully loaded 2 saz-3500d's strapped 155.7db @ 38hz sealed MY YOUTUBE!!! Link to comment Share on other sites More sharing options...
rusty959 Posted February 5, 2009 Report Share Posted February 5, 2009 Anytime. Im sure he will chime in here at some point and give you the official rundown, but I figured I could atleast take the worry off your mind for now. Quote 2013 Subaru BRZ12" Orion HCCA on AQ 22001967 mustang restoration project: http://www.stevemeadedesigns.com/board/topic/110765-mustang-restoration-build-2011-edition/ Youtube: https://www.youtube.com/user/therusty959 Link to comment Share on other sites More sharing options...
rusty959 Posted February 5, 2009 Report Share Posted February 5, 2009 I was just glancing through some stuff.... read the last part of the first post http://www.stevemeadedesigns.com/board/ind...showtopic=32548 Quote 2013 Subaru BRZ12" Orion HCCA on AQ 22001967 mustang restoration project: http://www.stevemeadedesigns.com/board/topic/110765-mustang-restoration-build-2011-edition/ Youtube: https://www.youtube.com/user/therusty959 Link to comment Share on other sites More sharing options...
MECHMAN Posted February 6, 2009 Report Share Posted February 6, 2009 I was just glancing through some stuff.... read the last part of the first posthttp://www.stevemeadedesigns.com/board/ind...showtopic=32548 With the pulley supplied, your alternator will turn aprox. 3.2 times engine speed. In other words, 800 engine RPM x 3.2 = 2560 rpm at the alternator. thanks Matt Quote 1-888-MECHMAN www.Mechman.com [email protected] Link to comment Share on other sites More sharing options...
8Deuce Posted April 20, 2009 Report Share Posted April 20, 2009 (edited) With the pulley supplied, your alternator will turn aprox. 3.2 times engine speed. In other words, 800 engine RPM x 3.2 = 2560 rpm at the alternator.thanks Matt What would the ratio be for the smaller diameter pulley that you have? Edited April 20, 2009 by 8Deuce Quote Link to comment Share on other sites More sharing options...
MECHMAN Posted April 20, 2009 Report Share Posted April 20, 2009 What would the ratio be for the smaller diameter pulley that you have? Your crank pulley should be about 6.5" in diameter. Our ultra over drive pulley is 1.75" in diameter. 6.5 / 1.75 = 3.71:1 ratio. The only thing to remember, is that you might run into belt slip issues running a pulley that small on a 250+ amp alternator. The decreased surface area, and increased gearing makes it harder for the belt to grip an alternator that strong. You will need to run a slightly smaller premium serp. belt, and keep an eye on it to make sure that it isn't slipping under full load. Quote 1-888-MECHMAN www.Mechman.com [email protected] Link to comment Share on other sites More sharing options...
8Deuce Posted April 20, 2009 Report Share Posted April 20, 2009 Your crank pulley should be about 6.5" in diameter. Our ultra over drive pulley is 1.75" in diameter. 6.5 / 1.75 = 3.71:1 ratio. The only thing to remember, is that you might run into belt slip issues running a pulley that small on a 250+ amp alternator. The decreased surface area, and increased gearing makes it harder for the belt to grip an alternator that strong. You will need to run a slightly smaller premium serp. belt, and keep an eye on it to make sure that it isn't slipping under full load. Got cha, but I meant was, if the pulley supplied turns the alt 3.2x's faster than the engine, what would the smaller pulley turn the alt compared to the engine? Quote Link to comment Share on other sites More sharing options...
E a r t h Posted April 20, 2009 Report Share Posted April 20, 2009 you quoted it bro Quote Link to comment Share on other sites More sharing options...
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