Optima battery/voltage question

Supe

MalibuRacing Junkie
May 21, 2003
15,116
0
36
Charlotte, NC
Here's the scenario guys. An off the shelf optima red top with my electric fuel pump, water pump, msd box, and fan will drop my voltage down to 10.5-11v. I only need to make a few strip passes, but do NOT feel comfortable turning 7k+ with that little voltage going to the fuel pump/MSD box. Do you think the battery would put out more off a fresh full charge enough to get me down the 1/4, or do I have to hunt down a 16v battery until I can find an alternator bracket/mandrel setup? I have no time to install anything other than a new battery, as I'll be getting into town Thursday night and leaving Friday morning.
 

basketcase

MalibuRacing Junkie
Jul 9, 2003
9,600
0
0
Stockton, CA
www.jackstandracing.com
oh, and I can't offer any battery help, my nova went through a red top and 2 ever starts in 3 weeks...The Nova in the garage now needs one, as it has gone through one itself.
 

Supe

MalibuRacing Junkie
Thread starter
May 21, 2003
15,116
0
36
Charlotte, NC
basketcase said:
It's a small block chevy...how can you not have time to mount an alternator? Do I need to part my crap out here?

I can't use a low mount alternator with the 400 block, so I'd have to find a mid mount bracket and drive mandrel setup by Thursday, and I don't know of too many parts stores open in my area to get belts at after 8:00pm...
 

rich

Dragway Regular
May 22, 2003
1,226
0
0
kenniwick wa.
are you sure the battery is fully charged to start with? what size overall is the battery?reserve and cca add up the draw of each peice i wouldn't run the system lower than 11.5 volts
 

540Malibu

Pro Stocker
May 22, 2003
1,432
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Shrews., MA
the alternator in my 55 quit 2 weeks ago, i drove it with all the lights on, electric fuel pump, MSD and fan on for more than 30 miles without the voltage dropping below 11.5, you should be fine.

the msd only needs 8 volts, and as long as its a good size fuel pump, it will run cooler with less voltage, aeromotives pump controller just varies the pump voltage.
 

Supe

MalibuRacing Junkie
Thread starter
May 21, 2003
15,116
0
36
Charlotte, NC
It's one of the smaller red tops with a Holley Blue pump. 50 amp capacity, with a 110 minute reserve. At idle, the fuel pressure at the carb inlet stayed exactly the same. I'll put a fresh charge on it Thursday and see what I come up with, the voltage drop was with it right off the shelf at the parts store.

I'll probably shut the fan off right at the start of the pass and turn it on when I cross the stripe. That seems to be the biggest draw in my system, and the iron heads take a while to get up to temp anyways, plus I have a lot of airflow going through my radiator just from it's positioning, so I'm not too worried about it overheating in 11 seconds time, especially with the electric water pump.

Mitch - That's good to know, I was just worried about the MSD output at higher RPMs with the lower voltage.
 

Wagonized

Dragway Regular
May 25, 2003
1,066
0
0
abbotsford bc canada
www.cardomain.com
with a fresh charge you should be ok.

however for future notice the group 31 yellow and blue tops (odd shaped cells) are a much stronger battery.
 

Supe

MalibuRacing Junkie
Thread starter
May 21, 2003
15,116
0
36
Charlotte, NC
Wagonized said:
with a fresh charge you should be ok.

however for future notice the group 31 yellow and blue tops (odd shaped cells) are a much stronger battery.

If I had planned on running no alternator, I would have run the yellow. I was planning on running an alt, so went with the small red top purely for weight savings. Once it's continuously charged I should have no trouble with it.
 

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