MECHMAN Posted July 25, 2011 Report Share Posted July 25, 2011 Is there any chance I could send my alt back to you guys and increase the amperage at all and what would the cost be? In your unit increasing the amperage would actually cost you low speed power for a slight high speed gain. I would recommend against it as it would not be a good use of your money. Quote 1-888-MECHMAN www.Mechman.com [email protected] Link to comment Share on other sites More sharing options...
NightmareImpala Posted July 25, 2011 Author Report Share Posted July 25, 2011 Ok thanks for the info. I appreciate the honesty guys Quote TEAM DISTANT THUNDER Link to comment Share on other sites More sharing options...
08tahoe Posted July 25, 2011 Report Share Posted July 25, 2011 Does it do it all the time, even when your not playing your system? Does it steadily drop to 12.5 or just kinda spike down there. You know, I had the same issue with my DC alt. I called and talked to them and they said that my truck (2006 yukon) has a feature which if 14 volts is not required, the ECM will drop the voltage slowly to 12.5v for fuel economy. I thought they were full of shit, until a friend of mine looked into it some more and sure enough DC was right. I also run two xs3400's on a crescendo 3k at .5ohm, and i still sometimes drop to 12.5. after say 1-2min, the voltage will start to increase slightly until it stabilizes around 14.3ish. This may also be the same for your impala. I'm glad I read this post because I have the same issue and I thought there was something wrong with my dc alt but now I feel better. When it happens in my car I have my radio down so I know its not my system causing it, but when it happens I just turn my a/c on low and my voltage jumps back up to normal, but now that I know what it is then I don't gotta worry bout it. Quote Link to comment Share on other sites More sharing options...
NightmareImpala Posted July 25, 2011 Author Report Share Posted July 25, 2011 I am glad I am not the only one lol Quote TEAM DISTANT THUNDER Link to comment Share on other sites More sharing options...
Swaggasaur Posted July 25, 2011 Report Share Posted July 25, 2011 I am glad I am not the only one lol does yours drop to the low 12's when you stop at stop light and stuff? Quote BHE Wall Build TEAM DC Audio TEAM XS POWER1986 Monte Carlo KMC Nova's 20"4 DC XL's W/ PSI Recones2 DC 5k'sPioneer PRS 8010 Audio Technix 6 XS Power D3100's 1 XS Power D3400 Mechman 220a Alternator Link to comment Share on other sites More sharing options...
NightmareImpala Posted July 25, 2011 Author Report Share Posted July 25, 2011 Not at all. Only with system at full volume @ idle rpm. Quote TEAM DISTANT THUNDER Link to comment Share on other sites More sharing options...
MECHMAN Posted July 25, 2011 Report Share Posted July 25, 2011 That's due to the low idle speed of your car. More battery capacity will fix that. Quote 1-888-MECHMAN www.Mechman.com [email protected] Link to comment Share on other sites More sharing options...
NightmareImpala Posted July 25, 2011 Author Report Share Posted July 25, 2011 That's due to the low idle speed of your car. More battery capacity will fix that. Me? Quote TEAM DISTANT THUNDER Link to comment Share on other sites More sharing options...
UnderLoK Posted July 25, 2011 Report Share Posted July 25, 2011 (edited) Another option is to make 100% sure your pulley is the correct size. Measure (or look up) the size of your crank. Then measure the pulley on your alt. Divide crank by alt pulley, then multiply that by your max RPM (engine RPM). That number should be close to the manufacturers MAX suggested RPM for your alt. Say your crank is 5" and your alts pulley is 1". You divide 5/1 which gives you 5. You then multiply 5xMAX ENGINE RPM which will give you the MAX alternator RPM in your current setup. The reason for doing this is to make sure that you have the smallest pulley you can. If at max engine RPM the alt is only doing 17000RPM then you have room for improvement. Some of these guys (alt manufacturers) say 19000, some say 22000, some say 26000... Depends who you ask, but the only one you care about is what Mechman tells you. Just note that the alt will blow apart if you just randomly put on a smaller pulley, be sure it meets spec. Edited July 25, 2011 by UnderLoK Quote If at first you do not succeed, you are doing it wrong! -ARSCheck out my walled TBSS build over here4 Fi Team 18s on 2 Cactus K9 DS18 doors on 2 MBQ 1Ks, Vifa pillars on a STL4.500 Pioneer X8500 6 XS Power D7500, 1 3400S Second Skin 2 270a Mechman Alts Link to comment Share on other sites More sharing options...
MECHMAN Posted July 25, 2011 Report Share Posted July 25, 2011 (edited) The other considerations with pulley size are belt traction, it's less with a smaller pulley, and idle control issues. Then there's heat, loading the alternator excessively at low speed will burn it out. It needs to spin fast enough for the fans to cool it or it won't work properly. Edited July 25, 2011 by MECHMAN Quote 1-888-MECHMAN www.Mechman.com [email protected] Link to comment Share on other sites More sharing options...
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