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high output small alternator #3049614 06/11/22 10:48 AM 06/11/22 10:48 AM
Joined: Jul 2011 Posts: 781 wine country 8 8urvette OP super stock
8urvette OP super stock 8 Joined: Jul 2011 Posts: 781 wine country	I have a mini denso style alternator on my barracuda, it fits fine, but I do not think I could go with a OE style due to the size. My current alternator puts out 90 amps max. I am running a big electric fan, big dual fuel pumps, electric water pump and holley fuel injection. While the car is running it actually loses charge. My alternator is maxed out and cannot keep up with the demand. It was adequate before I went to EFI, but the addition of the fuel pumps, and water pump and efi has made it unacceptable. I am looking for something small and single wire hookup. Ideally Id like to see 150 amps- mine is mounted to the motor plate, on the passenger side at the bottom of the plate just about the k member. It is an AndyF plate and alt kit. I do not have much room- so i need something small. HELP!!!!!

Re: high output small alternator [Re: 8urvette] #3049622 06/11/22 11:28 AM 06/11/22 11:28 AM
Joined: Jan 2003 Posts: 30,994 Oregon A AndyF I Win
AndyF I Win A Joined: Jan 2003 Posts: 30,994 Oregon	You might have a problem with your alternator since the combined load of what you listed isn't 90 amps. Do you have a clamp meter? Clamp meters are fairly inexpensive these days and super handy to have. I go around the car and check the amperage in every cable on the car to see what is going on. Often times you'll be surprised that one cable is carrying a lot of current while another one isn't. All it takes is a poor connection somewhere to mess things up. Check your alternator output with the engine running and see how many amps it is producing. Check both battery cables as well as all the engine grounds.

Re: high output small alternator [Re: AndyF] #3049654 06/11/22 12:49 PM 06/11/22 12:49 PM
Joined: Sep 2003 Posts: 19,342 north of coder moparx "Butt Crack Bob"
moparx "Butt Crack Bob" Joined: Sep 2003 Posts: 19,342 north of coder	first thing i thought of, was grounds. need to check those closely. also, please tell me you aren't using those elcheapistan "clamp on" battery terminals where the positive and negative cables are retained to the terminal by a strap and two bolts. i hate those things ! horrible connection[s] for sure using those !

Re: high output small alternator [Re: 8urvette] #3049660 06/11/22 01:10 PM 06/11/22 01:10 PM
Joined: Feb 2005 Posts: 20,159 PA. pittsburghracer "Little"John
pittsburghracer "Little"John Joined: Feb 2005 Posts: 20,159 PA.	Originally Posted by 8urvette I have a mini denso style alternator on my barracuda, it fits fine, but I do not think I could go with a OE style due to the size. My current alternator puts out 90 amps max. I am running a big electric fan, big dual fuel pumps, electric water pump and holley fuel injection. While the car is running it actually loses charge. My alternator is maxed out and cannot keep up with the demand. It was adequate before I went to EFI, but the addition of the fuel pumps, and water pump and efi has made it unacceptable. I am looking for something small and single wire hookup. Ideally Id like to see 150 amps- mine is mounted to the motor plate, on the passenger side at the bottom of the plate just about the k member. It is an AndyF plate and alt kit. I do not have much room- so i need something small. HELP!!!!! My local alternator shop told me you can’t get high output out of these small alternators. After talking to him I’d be surprised if yours is putting out 90 amp. 1970 Duster Edelbrock headed 408 5.984@112.52 422 Indy headed small block 5.982@112.56 mph 9.42@138.27 Livin and lovin life one day at a time

Re: high output small alternator [Re: pittsburghracer] #3049774 06/11/22 08:48 PM 06/11/22 08:48 PM
Joined: Jul 2011 Posts: 781 wine country 8 8urvette OP super stock
8urvette OP super stock 8 Joined: Jul 2011 Posts: 781 wine country	Idont have a clamp on amp meter... would be nice. The ground from the battery to chassis is 2/0 with crimp connectors on the batter side a 3/8 lug on the other side. I am also running a 2 ga ground strap from the block back the neg on the battery, it's a double barrel style crimp connector. I have several small 8 ga grounds from various parts of the engine to the chassis, including the alternate and starter case. My battery is a big 950cca 1100 mca battery. My alternator probably isn't putting out the advertised 90 amp, but what can I get that is small that will put out decent amperage?

Re: high output small alternator [Re: 8urvette] #3049798 06/11/22 10:16 PM 06/11/22 10:16 PM
Joined: Jan 2003 Posts: 30,994 Oregon A AndyF I Win
AndyF I Win A Joined: Jan 2003 Posts: 30,994 Oregon	You can buy a clamp meter for $30 from Amazon. I'd suggest buying one before you waste money on upgrading your alternator. You might just have a bad connection somewhere. https://www.amazon.com/Proster-Auto...&hvtargid=pla-570396598205&psc=1

Re: high output small alternator [Re: AndyF] #3049810 06/11/22 10:44 PM 06/11/22 10:44 PM
Joined: Jan 2003 Posts: 20,167 Park Forest, IL slantzilla Too Many Posts
slantzilla Too Many Posts Joined: Jan 2003 Posts: 20,167 Park Forest, IL	Is the fan on a relay? "Everybody funny, now you funny too."

Re: high output small alternator [Re: slantzilla] #3049813 06/11/22 10:58 PM 06/11/22 10:58 PM
Joined: Jul 2011 Posts: 781 wine country 8 8urvette OP super stock
8urvette OP super stock 8 Joined: Jul 2011 Posts: 781 wine country	Fan, water pump and fuel pump are all on relays

Re: high output small alternator [Re: 8urvette] #3049830 06/12/22 07:15 AM 06/12/22 07:15 AM
Joined: Jan 2003 Posts: 2,915 A shed in England Tig master
Tig master Joined: Jan 2003 Posts: 2,915 A shed in England	I was looking at these to upgrade (the 150A ones) but they are pricey. Page 46-47. HTH's http://www.powermastermotorsports.com/catalog.html# EDIT: They aren't too bad price wise.I was looking at the ones with mounting kits on Summit, that bumps the price up some Last edited by Tig; 06/12/22 07:39 AM. '74 Challenger..9.46 @ 145.9 1/4, 6.001 @ 118 1/8 so far. 4023lb !!! # N/A, Marsh performance 655ci, Indy Maxx, T/R, Indy 600-13 X's, Street legal, pump gas, full interior, Cal-Tracs, mufflers, 3:73's and real 10.5 radials. 9.51 @ 142.4 1/4, 6.003 @ 114 1/8 with our old mule KB, 572-13, 580 wedge. RHD '68 Barracuda Fastback 323ci street/strip. Best ET 13.88 @ 99.03

Re: high output small alternator [Re: Tig] #3049831 06/12/22 07:53 AM 06/12/22 07:53 AM
Joined: Mar 2006 Posts: 9,824 MI, usa dvw master
dvw master Joined: Mar 2006 Posts: 9,824 MI, usa	I run a Denso mini as well. Been thru all the voltage drop tests. Sped it up to a 3-1 ratio. Still can't keep up with the fans. The field core just isn't big enough physically to produce enough amperage. The ratings are unrealistic. Doug

Re: high output small alternator [Re: dvw] #3049845 06/12/22 09:24 AM 06/12/22 09:24 AM
Joined: Jan 2022 Posts: 138 Connellsville 7 71Demon528 member
71Demon528 member 7 Joined: Jan 2022 Posts: 138 Connellsville	150 amp alternator is definitely a bigger core, 118mm case. My dad's 75amp alternator is 100mm case and it is a tiny little thing. If you can possibly fit the 118mm, its a good investment. Part# 8148 from powermaster. Can't say enough good things about the alternator.

Re: high output small alternator [Re: 8urvette] #3049969 06/12/22 03:42 PM 06/12/22 03:42 PM
Joined: Jun 2006 Posts: 427 saint paul mn. J johnzgarage mopar
johnzgarage mopar J Joined: Jun 2006 Posts: 427 saint paul mn.	do a load test on your battery.

Re: high output small alternator [Re: johnzgarage] #3049981 06/12/22 04:47 PM 06/12/22 04:47 PM
Joined: Jan 2003 Posts: 30,994 Oregon A AndyF I Win
AndyF I Win A Joined: Jan 2003 Posts: 30,994 Oregon	Originally Posted by johnzgarage do a load test on your battery. Exactly. Find the real problem before throwing money

Re: high output small alternator [Re: AndyF] #3049997 06/12/22 06:04 PM 06/12/22 06:04 PM
Joined: May 2019 Posts: 712 Lake Villa Il INTMD8 super stock
INTMD8 super stock Joined: May 2019 Posts: 712 Lake Villa Il	What pulley ratio (or just pulley sizes) and idle speed? 69 Charger. 438ci Gen2 hemi. Flex fuel. Holley HP efi. 650rwhp @7250 510rwtq @5700

Re: high output small alternator [Re: INTMD8] #3050001 06/12/22 06:38 PM 06/12/22 06:38 PM
Joined: Jul 2011 Posts: 781 wine country 8 8urvette OP super stock
8urvette OP super stock 8 Joined: Jul 2011 Posts: 781 wine country	ok, it is a new battery- a few months old- 6 at most. I wanted to upgrade it and get some more CCA- I went and bought a new battery figuring ill just use this one in one of my other projects. Start the car up with the new bigger battery and i have 14.4 volts at idle. with the other battery i was seeing in mid 13's.... so maybe i dont use this "old" battery and just return it?

Re: high output small alternator [Re: 8urvette] #3050009 06/12/22 07:32 PM 06/12/22 07:32 PM
Joined: Jan 2003 Posts: 30,994 Oregon A AndyF I Win
AndyF I Win A Joined: Jan 2003 Posts: 30,994 Oregon	So it wasn't an alternator problem after all. Might have been a battery issue or it could've been a bad connection which you fixed when you replaced the battery. You can double check by swapping batteries again and making sure everything is tight. If the voltage drops back to 13 at idle then you know the battery is weak. Last edited by AndyF; 06/12/22 07:33 PM.

Re: high output small alternator [Re: INTMD8] #3050012 06/12/22 07:43 PM 06/12/22 07:43 PM
Joined: Mar 2006 Posts: 9,824 MI, usa dvw master
dvw master Joined: Mar 2006 Posts: 9,824 MI, usa	Originally Posted by INTMD8 What pulley ratio (or just pulley sizes) and idle speed? East coast recommends around 20,000 alternator rpm at max engine RPM. So a 7000 rpm motor is close to 3-1 ratio. Doug

Re: high output small alternator [Re: dvw] #3050036 06/12/22 09:08 PM 06/12/22 09:08 PM
Joined: May 2019 Posts: 712 Lake Villa Il INTMD8 super stock
INTMD8 super stock Joined: May 2019 Posts: 712 Lake Villa Il	^ Suprised 20k doesn't damage the rotor, I thought Denso's were 16k max. I'm at 2-1 ratio, 1150 idle, 7600 max rpm, so alternator speed 2,300 at idle and 15,200 max. 69 Charger. 438ci Gen2 hemi. Flex fuel. Holley HP efi. 650rwhp @7250 510rwtq @5700

Re: high output small alternator [Re: INTMD8] #3050066 06/13/22 12:13 AM 06/13/22 12:13 AM
Joined: Jan 2003 Posts: 30,994 Oregon A AndyF I Win
AndyF I Win A Joined: Jan 2003 Posts: 30,994 Oregon	The small Denso alternators are 20,000 rpm limit. The GM alternators are usually 16,000 or 18,000. Powermaster has the numbers in their catalog.

Re: high output small alternator [Re: 8urvette] #3050072 06/13/22 02:36 AM 06/13/22 02:36 AM
Joined: Aug 2003 Posts: 43,123 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,123 Bend,OR USA	Don't forget about the wire size on the car feeding from the alternator to the battery possibly being a choke, you can only push so many amps through a stock wire One of the Power Master techs. told me to use a # 4 gauge wire from their single wire100 amp alternator directly to the battery after I burnt the original 10 gauge wire up in my old race car by accidently grounding it while trying to use a timing light off of the single wire feed to the battery, the clamp on lead for the 12V feed to the timing light flopped over when i started the motor up and grounded out against the case Last edited by Cab_Burge; 06/13/22 02:36 AM. Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

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