Drag Racing Tech - Racing without an alternator

This isn't exactly LSx or even EFI specific. In fact we are currently working on an 8 second carb'd SBC powered S-10...

This truck has always run an alternator... My friend is changing some things up and wants to go without. We see all kinds of people doing it, but without taking a 45 minute drive to the track, we cannot ask them.

Our question really comes down to battery Amp/hour ratings and how to know what we need.

We've added up the amp draw for all electrical accessories, and come up with the fact that we need at least 95amps to power everything. Where the problem lies is that while all the components have a draw rating in total amps, none specify how many per hour. So how do we know which battery and/or whether we should run two batteries or not?

FWIW, we are going to run 16v either way. It's just a matter of the amp/hr ratings needed to maintain decent voltage all the way down the track.

If 1 16 volt battery keeps the voltage above 14 it should be OK. If not, I'd run an Alternator before I'd run 2 batteries. 16 volt batteries weigh a ton, more than the alternator and bracket would weigh. The alternator should outlast the battery so you only have to replace 1 battery when the time comes. Just my opinion, you'll probably get varying ones.

I've ran The "V" 16 Volt Battery and East Coast 110amp 16 volt alternator for a couple of years and I love it. I rarely ever charge the battery at the track, even at 2 day races. It's over 18 volts when running. I have no voltage step down on anything (not computer controlled) never had a problem, haven't even blown out any light blubs.

I think keeping the alternator is a good idea. Saves you the charging BS, which if you start trying to hot lap or make rounds might get overlooked/not charged up as much.

Derek

I really appreciate all your input. We are going to try a single 16volt battery and no alternator. I brought up all of your points and he had other reasons for wanting to ditch the altenator I guess. With my cars, I will probably always run an altenator.

On a carbed car I wouldnt be scared at all, but I would probably run dual batteries if you are bracket racing just in case you dont have a chance to charge it long.

But on a car like mine that idles and draws nearly 100amps with electric water pump, low impedence injectors, fans, 20 amp fuel pump, COP ignition, two widebands etc running with no alternator wouldnt last long with a single battery.

With a 145 amp alternator on the car I will lose about .1 volts per pass if I cool the car the down with the fans/water pump between rounds and dont have to start and move the car in the lanes a dozen times. I'm good for around 10 passes before it loses a volt or so with the alternator. If I put the car on a 25amp charger between rounds when the fans an water pump are going then it loses nothing, but I can easily go a whole day without a charger if need be.

Why would you want to go without an alternator? I just don't see the point? It doesn't rob any power at all really so why not run one??

I've been thinking about pulling my belt. I have a e/water pump. I pulled the belt before a dyno pull and gained enough that you should see a gain at the track.Haven't heard of any other LS1 nos cars trying it.I was thinking about maybe running a on off switch. No belt would be better. No alt. is even better cause of the weight savings

Why would you want to go without an alternator? I just don't see the point? It doesn't rob any power at all really so why not run one??

I would assume my alternator at WOT is probably taking ~ 20hp to drive at full output with the voltblaster @ 16V, maybe even more. But I'd rather have the extra loss then having to charge the battery or have my ignition and fuel pump get weaker at lower voltage. Same reason I still have power steering on my car, thats 12lbs and and 5-10hp, but I give up a little ET to keep it on the car.

Phil's car has 1 16 volt battery and no alt.has efi,elec fan,intercooler pump,elec water pump.at the top end of the track its about 15 volts.we never have any issues.

I would assume my alternator at WOT is probably taking ~ 20hp to drive at full output with the voltblaster @ 16V, maybe even more. But I'd rather have the extra loss then having to charge the battery or have my ignition and fuel pump get weaker at lower voltage. Same reason I still have power steering on my car, thats 12lbs and and 5-10hp, but I give up a little ET to keep it on the car.

Yeah thats exactly why I kept my alternator on my race car.. The 10hp and 10lb gain from removing it just isn't worth the time and trouble of having to drag a battery charger with me everywhere I go and having to worry about voltage drop on the nitrous. Just isn't worth it in my opinion.. Turn the boost up 1lb or jet it up 20hp and there you go.

We run 2 cars. Mine has a single battery and an alternator, I charge it every round but I'm sure I don't need to... I'm just used to it and have a generator so it's no big deal.

My dads has 2 batteries and no alternator, it does just fine but it only runs ignition, water pump, brake lights, delay box and it can run the fans no problem we just normally don't have to. If you're asking if you can make one pass without problem (then charge when you get back), I say don't worry. I know tons of people who do so every weekend.

Batt charge between rds and no alt... batt gets a surface charge only. Check volts before restarting, and going to staging...
Burnout, stage, and run, then look at batt volts...
As for HP to run an alt?? AIRC, it goes something like this:
95 A x 18v = 1710 watts. Converting to HP=W x .001341, which equals 2.293HP....Worth it to mess w/ inconsistent voltages, and battery chargers/generators??

we lose less than 1 volt from startup till the car is back at the trailer,that includes driving to the staging lanes,warm up time in the staging lanes,the pass,and driving back the retun road to the trailer.the other thing is the volatage varies about .1-.2 from pass to pass.Sometimes other things come into effect beside hp,like having space to put an alt

we lose less than 1 volt from startup till the car is back at the trailer,that includes driving to the staging lanes,warm up time in the staging lanes,the pass,and driving back the retun road to the trailer.the other thing is the volatage varies about .1-.2 from pass to pass.Sometimes other things come into effect beside hp,like having space to put an alt

It all depends on the situation, batteries have a finite reserve capacity and do not like to be drained heavy and short charged. Yours is a heads up race car and doesnt hot lap or have to start and move 10 times in the staging lanes like a bracket car, and if it does I'm sure it gets pushed or towed. No right or wrong way to do this one, whatever works for you and your use of the car.

Why would you want to go without an alternator? I just don't see the point? It doesn't rob any power at all really so why not run one??

We had to change a few things around to meet regulations and to update a few things. With a new motor plate setup (the old one was damaged at the engine shop), the current altenator, or even a new one, would have needed lots of custom fabrication and modification to fit again. He wanted to go to a 16v system in the first place, and has already bought a new battery.

He would not mind needing to go to 2 batteries either, as it could replace 150# of ballast weight that is now currently needed to make class weight.

We've gone ahead and re-did the battery wiring, delted the altenator, and installed one 16v battery. We're gonna try a few passes down the track to see if the 2nd battery would be needed or not. Though it sounds like the 2nd will not be needed.

Thanks for all the input guys!

>> On 2nd thought <<
For those of you EFI guys running 16v systems... With this carb'd setup, there really wasn't anything that required the voltage to be stepped down. What would be different with an EFI car? Specifically, FAST XFI equipped.

I know my MSD ignition system will handle the added voltage, and it seems that most of the gauges will not be affected. Not sure about the ECM, the alky control kit, and all the stock lights and accessories.

Without a 16V alternator the running voltage wont be high enough to hurt anything IMO. Most OE electronic devices can handle it, bulbs will burn out quicker and thats about it. Since its a drag car its short duration anyhow, not like you are taking a 10 hour cruise on the highway at 16V.

Without a 16V alternator the running voltage wont be high enough to hurt anything IMO. Most OE electronic devices can handle it, bulbs will burn out quicker and thats about it. Since its a drag car its short duration anyhow, not like you are taking a 10 hour cruise on the highway at 16V.

So with the altenator as well, it could be too much?

So with the altenator as well, it could be too much?

Na, modern electronics are made to work with a big voltage swing, only thing is your bulbs will burn out quicker, since drag racing is short duration the heat generated wont be a big issue anyhow,

I use a voltblaster and at WOT I run at 16V, the fuel pump and ignition love it..

Just finished looking around at that Voltblaster and it seems really cool. Not too expensive either. I think I would conisder that before I would consider going to a full on 16v system.

<<EDIT>>
Just got the S-10 up and running on the 16v battery. We can run it for quite a bit of time before we start seeing any serious voltage drop.

Thanks for all the input guys!!!