Running an alternator

Robbie Welch · 09-19-2017, 06:19 AM

Do you think running a alternator has any effect on consistency (charging rate changing while racing). Also how much Et do you think it takes if any just been thinking. I've run one for years just never done an A-B-A test with it.

Dragsinger · 09-19-2017, 08:23 AM

Robbie, I think it is a good idea and provides consistent voltage. If you charge the battery as time allows the alternator load is small. In addition, use pulleys that limit the alternator speed to no more than about 20% overdrive.

Ed Wright · 09-19-2017, 10:11 AM

Makes more difference with an EFI car. Voltage level effects how fast the injectors open. I found when my 12 volt batteries were a little low, my logger showed it running leaner. That, of course, effects consistency. I had a button under the accelerator pedal, hooked to a relay, that shut the alternator off @ WOT.
Going to two 16 volt batteries cured all that. With no alternator. Had to lean it down with 16 volts batteries. The injectors opened faster, of course.

Robbie Welch · 09-19-2017, 11:37 AM

I run a 16volt battery and the alternator is a16volt . I charge the battery between rounds also I have a 75% reduction pulley on the crank. Just been thinking about the possibility of consistency issues because the alternator may be changing charge rates while racing. Anyone ever trace a consistency issue to running an alternator? Thanks for the response's

Mike Pearson · 09-19-2017, 03:21 PM

I have never run an alternator. I also have a 16 v battery. I have a lithium battery. They are more stable with the voltage over the charging state. The race car does not run enough to charge the battery with the alternator so I don't see any reason to run one. You still have to charge the batteries between rounds so there is no advantage

buzzinhalfdozen · 09-19-2017, 03:42 PM

My kid runs 12 volt stuff, bracket car, lights, dial boards, ect. He runs an alternator and very rarely charges his battery, lots of times double entering the car. So from my perspective I'd say they do a fair job of keeping up with the demand. Car prints tickets so I'd say an alternator does not cause inconsistent E.T.'s. Merely my observations.

terry1 · 09-19-2017, 03:42 PM

Don't you have to run an alternator in Stk?

Rsmith38 · 09-19-2017, 03:48 PM

By NHRA Rules - you need an alternator in Stock -

Mark Yacavone · 09-19-2017, 05:46 PM

Quote:

Originally Posted by terry1

Don't you have to run an alternator in Stk?

Yes, it has to be in place, and turning with the engine ;-)

Mark Yacavone · 09-19-2017, 05:55 PM

I've used Ed's idea with the micro switch. I also use it to un-ground the fan relay on the run. Not so much as a speed secret, but to keep the voltage consistent during the run.
Does it help? Can't say, but it can't hurt, as long as you charge between rounds.
We are talking about carb'ed combos here.

09-19-2017, 06:19 AM	#1
Robbie Welch Live Reporter Join Date: Sep 2005 Location: Golden Beach Maryland Posts: 1,234 Likes: 55 Liked 262 Times in 124 Posts	Running an alternator Do you think running a alternator has any effect on consistency (charging rate changing while racing). Also how much Et do you think it takes if any just been thinking. I've run one for years just never done an A-B-A test with it.

09-19-2017, 08:23 AM	#2
Dragsinger VIP Member Join Date: Jul 2008 Location: Liberty City [East Texas] Posts: 1,760 Likes: 5 Liked 99 Times in 60 Posts	Re: Running an alternator Robbie, I think it is a good idea and provides consistent voltage. If you charge the battery as time allows the alternator load is small. In addition, use pulleys that limit the alternator speed to no more than about 20% overdrive. __________________ Larry Woodfin 471W

09-19-2017, 10:11 AM	#3
Ed Wright Veteran Member Join Date: Mar 2005 Location: Sand Springs, OK Posts: 8,132 Likes: 896 Liked 390 Times in 170 Posts	Re: Running an alternator Makes more difference with an EFI car. Voltage level effects how fast the injectors open. I found when my 12 volt batteries were a little low, my logger showed it running leaner. That, of course, effects consistency. I had a button under the accelerator pedal, hooked to a relay, that shut the alternator off @ WOT. Going to two 16 volt batteries cured all that. With no alternator. Had to lean it down with 16 volts batteries. The injectors opened faster, of course. __________________ Ed Wright 4156 SS/JA

09-19-2017, 11:37 AM	#4
Robbie Welch Live Reporter Join Date: Sep 2005 Location: Golden Beach Maryland Posts: 1,234 Likes: 55 Liked 262 Times in 124 Posts	Re: Running an alternator I run a 16volt battery and the alternator is a16volt . I charge the battery between rounds also I have a 75% reduction pulley on the crank. Just been thinking about the possibility of consistency issues because the alternator may be changing charge rates while racing. Anyone ever trace a consistency issue to running an alternator? Thanks for the response's

09-19-2017, 03:21 PM	#5
Mike Pearson VIP Member Join Date: Mar 2007 Posts: 2,437 Likes: 611 Liked 1,904 Times in 571 Posts	Re: Running an alternator I have never run an alternator. I also have a 16 v battery. I have a lithium battery. They are more stable with the voltage over the charging state. The race car does not run enough to charge the battery with the alternator so I don't see any reason to run one. You still have to charge the batteries between rounds so there is no advantage __________________ Mike Pearson 2485 SS

09-19-2017, 03:42 PM	#6
buzzinhalfdozen Senior Member Join Date: Sep 2006 Location: Bellevue Ohio Posts: 984 Likes: 0 Liked 11 Times in 8 Posts	Re: Running an alternator My kid runs 12 volt stuff, bracket car, lights, dial boards, ect. He runs an alternator and very rarely charges his battery, lots of times double entering the car. So from my perspective I'd say they do a fair job of keeping up with the demand. Car prints tickets so I'd say an alternator does not cause inconsistent E.T.'s. Merely my observations. __________________ Joe Buchanan SS/BX 3117

09-19-2017, 03:42 PM	#7
terry1 Member Join Date: Sep 2006 Location: Moncton, N.B. Posts: 276 Likes: 24 Liked 24 Times in 13 Posts	Re: Running an alternator Don't you have to run an alternator in Stk?

09-19-2017, 03:48 PM	#8
Rsmith38 Member Join Date: Mar 2011 Posts: 186 Likes: 0 Liked 28 Times in 15 Posts	Re: Running an alternator By NHRA Rules - you need an alternator in Stock -

09-19-2017, 05:55 PM	#10
Mark Yacavone Veteran Member Join Date: Mar 2002 Location: Miles From Nowhere Posts: 7,791 Likes: 2,883 Liked 5,080 Times in 1,936 Posts	Re: Running an alternator I've used Ed's idea with the micro switch. I also use it to un-ground the fan relay on the run. Not so much as a speed secret, but to keep the voltage consistent during the run. Does it help? Can't say, but it can't hurt, as long as you charge between rounds. We are talking about carb'ed combos here. __________________ "We are lucky we don't get as much Government as we pay for." Will Rogers