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65amp Denso FYI #2917077
04/30/21 06:17 PM
04/30/21 06:17 PM
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Anoka County, MN
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Leigh Offline OP
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Anoka County, MN
I just finished the Denso conversion. I used to throw belts before slowing the old mopar stuff down. Given that, I went with a 4.5” alternator (Jones), 5” crank (Doty Eng). Solid 14.5 volts at idle. (1,000 rpm). Just a fyi for not needing supersonic alternator rpm? I’ll report more data, after using it more.

Re: 65amp Denso FYI [Re: Leigh] #2917094
04/30/21 07:12 PM
04/30/21 07:12 PM
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Oregon
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AndyF Offline
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Yeah the Denso alternators that I've been using are always 14 volts at idle, even with a stock pulley setup. I have a Denso alternator on both of my cars and they both go right to 14 volts as soon as the engine starts. No weird blinking lights like with the factory alternator.

Re: 65amp Denso FYI [Re: AndyF] #2917100
04/30/21 07:26 PM
04/30/21 07:26 PM
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Anoka County, MN
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Leigh Offline OP
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What was (is) the ratio? I’m currently at .782 overdrive.

Re: 65amp Denso FYI [Re: Leigh] #2918465
05/04/21 02:34 PM
05/04/21 02:34 PM
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NW Chicago suburban area
Mopar Mitch Offline
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NW Chicago suburban area
Are you comfortable with 14.5V?

I recently did the Denso swap on my SB... new AutoZone. I had a first one... that was reading around 15V.

I've just exchanged it (lifetime warranty)... reading 14.5V ... and when I put on the headlights... 14.0V... heater motor full blast... together (lights and heater)... about 13.5V.

So, is 14.5 OK without any load?


Mopar Mitch "Road racers and autocrossers go in deeper and come out harder!"... and rain never stops us from having fun with our cars... in fact, it makes us better drivers! Check out MOPAR ACTION MAGAZINE, August 2006 issue for feature article and specs on my autocross T/A!
Re: 65amp Denso FYI [Re: Mopar Mitch] #2918476
05/04/21 03:00 PM
05/04/21 03:00 PM
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Western NC
440Jim Offline
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Originally Posted by Mopar Mitch

So, is 14.5 OK without any load?

IMO, 14.4 is perfect with a small load.
The real question is when pulling 30 amps or more, plus whatever the battery is charging soon after starting, what is the Voltage at various rpms?

Re: 65amp Denso FYI [Re: Mopar Mitch] #2918502
05/04/21 03:54 PM
05/04/21 03:54 PM
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central texas
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krautrock Offline
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Originally Posted by Mopar Mitch
Are you comfortable with 14.5V?

I recently did the Denso swap on my SB... new AutoZone. I had a first one... that was reading around 15V.

I've just exchanged it (lifetime warranty)... reading 14.5V ... and when I put on the headlights... 14.0V... heater motor full blast... together (lights and heater)... about 13.5V.

So, is 14.5 OK without any load?


there are some Denso replacement voltage regulators with a 14.9v set point. i got a rebuilt 65amp alt for my old truck and it runs at 14.9v. kinda worried me until i did some research on it. seems 15.2v is about the limit for factory electrical parts so i haven't had any problems with it running 14.9v.

Re: 65amp Denso FYI [Re: krautrock] #2918514
05/04/21 04:14 PM
05/04/21 04:14 PM
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Boise
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Moparteacher Offline
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You can get the Jones alternators with an adjustable voltage regulator if you see the need. And, with a 5" crank pulley and a 4.5 inch alternator pulley the ratio is1.1:1
If crank speed is 1000 rpm then the alternator is cruising at 1100 rpm at idle.

Re: 65amp Denso FYI [Re: Moparteacher] #2918628
05/04/21 08:20 PM
05/04/21 08:20 PM
Joined: Jun 2003
Posts: 52,915
Romeo MI
MR_P_BODY Offline
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Romeo MI
On my HotRod I have been using a Denso 65A with a drag race regulator.. they allow a 14.5A.. this is on my
83 Dodge Rampage.. its been on there like 3 years so far
wave

IMG_20140528_121230181_HDR-w640-h479.jpg
Last edited by MR_P_BODY; 05/04/21 08:28 PM.






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