Jonathan@Tick

iTrader: (5)

Been digging around on here for info on 16v batteries and what is necessary to run one. I've found a lot of info, but no deffinate answers. We're trying to squeeze every last hundredth out of our cam only car and it would seem that ditching the alt. might pick up a few hp while dropping 10 or so lbs. at the same time.

Basically, without an alternator it should be ok to run the 16v battery with the stock computer correct? It would only be a difference of a volt or so when running. Charging between rounds right now is not an issue...we're not bracket racing the car.

Has anyone done this?

5.3LJimmy

iTrader: (10)

I've never tried, but I remember reading a thread where someone did and it fried the PCM. I would definitely hold off on installing it until you get some proof that it can be done.

PowerTalk

I've read about people running a EWP and pulling the belts off for dyno and track runs with standard systems.

You need a step down box. This thread might help>>>
https://ls1tech.com/forums/drag-raci...v-systems.html

Jonathan@Tick

iTrader: (5)

Well, if I were running a 16v system with alt. that was making 17 or 18 volts running I would think the step down box would be needed. Without an alt, there wouldn't be much difference. In other threads I've searched, there have been guys run 16v batteries with no alt and usually see around 15 volts at the top of the track...but none were running the factory pcm.

I guess if nobody actually chimes in to say they have done this I'm gonna try it anyway. I just want to run a 16 volt battery to keep the voltage in the same range as the 12v system with an alt.

KP has posted in a few threads that he fed the factory pcm 18 volts before to increase the coils output...he has also posted that removing the alt could be good for 15 hp and he doesn't think what I'm asking would be an issue. I do know that removing the alt is worth some et...even old school guys will tell you its worth about 5 hundredths off.

waltsfastz

iTrader: (4)

I can' see where it would hurt anything. as you said while the alt is charging it will run around 14.5 volts. With a 16 volt battery not charging and the load put on it by the car, It would probably drop it at least a volt(probably more like 2) So your right around 14 volts anyways.
Id go for it.

5.3LJimmy

iTrader: (10)

I did some searching on this last night after my post and ran across some of the same threads you guys are quoting. I also stumbled upon the one that I recalled seeing. In it JL-WS6 said "Eastside tried a 16 volt battery and as soon as they hooked it up it fried the factory PCM". I read through a bunch of threads where folks say you can run a 16 volt battery and(with the exception of KP) they all had aftermarket engine control systems(Fast,BS3, etc.).

I'm not saying you can't do it Jonathon, but I would get confirmation from a couple people who have done it successfully before trying and cooking the PCM. I was hoping there would be a few success stories chime in already. So far in my searching I have not come up with a definitive answer to your question.

promod1955

iTrader: (44)

I've been wanting to do this for awhile considering I already have the battery, but I don't want to be the one who finds out the hard way it killed the pcm. Then I could get rid of the factory alt which is pretty heavy, as well as the 4 gauge wire i have running to the back.

The car gets charged between rounds anyway and w/o a huge electrical load on the car, I wouldn't need a 16 v alt to put it up in the 17.5 volt range and increase the chance of an issue.

JFM-jr

iTrader: (23)

A mini alternator (5-6lbs)will weigh about half what the factory unit does(13lbs) and still charge the battery. I have not confirmed this yet but my friend who is an A GM certified mechanic "claims" the factory ECU shuts the alternator off at WOT in much the same way it does the A/C compressor.

Roger Blackmore

Bringing this back to life. My question and situation is the same as the op's. Will it work with a stock PCM ? Race only application. Charging between rounds

Ed Wright

iTrader: (1)

Yes it will I've done it. No problems.
Btw, the PCM does not shut off the alternator @WOT. Logging voltage will show you it does not. Nor does it shut off the AC compressor clutch @ WOT.
Unless, of course I tell it to. :-)