lyndahern

Hello,

I'm restoring my 64 corvette and I'm planning on adding Vintage Air. I'm going to upgrade to the Dewitt radiator with Spal Fan, but I'm not sure what alternator I should go with. I also already bought the new wiring harness to replace in the Corvette as well and I believe this connects to the alternator. I'm looking to find what you guys have used and/or recommend. Also, what gauge wire I should run.

Thanks,
Lynda Hernandez

Viet Nam Vett

I'm running a Power Master 140 Amp alternator plus a DeWitt's Dual Spal Fan system and a Non Vintage Air system. I believe each spal Fan will draw somewhere between 20 to 27 amps when they kick in. Plus the A/C Compressor is some where in the high 20 amp range. Someone here can correct me if I'm off by a few Amps. Either way I would upgrade your alternator as it is running your electrical system and at the same time trickle charging your battery. I can watch my Volt Meter drop when the fans or Compressor kick in and them come back up. I'm running a Digital Dash which uses a Volt meter instead of the stock Corvette Amp Meter.

I'm sure some of or experts will jump in here and make some good recommendations. I have found that The Power Master is a High Quality Alternator

This one shown has a Serpentine pully but the same unit is available with a V pully
. https://www.summitracing.com/parts/p...NBSmjQY0TFkZT0

lyndahern

Thanks for your reply!

SledgeHammer 2.0

I'm running Vintage Air and a Dewitt Radiator with stock fan and shroud and the stock alternator. If you go with a Dewitt Radiator and have a stock or mild engine, you won't need an electric fan.

lyndahern

I already ordered the Dewitt with the Spal fan, that's why I'm thinking I should be running a higher amp alternator. I'm rebuilding the 327 engine and I've upgraded the the cam and lifters, not sure if that matters. I know it is the higher hp engine.

gleninsandiego

Copied from another thread I posted on asking a similar question:

As far as the alternator goes, I had to go through a couple with increasing output to find one that would support all the electric systems I am running, such as an electric fuel pump, Sniper EFI,
Vintage Air, electric radiator cooling fan and a number of electronic instruments, not to mention the stock stuff like lights.

I ultimately ended up with a Powermaster 47293, which is rated at 150 amps

It took me a number of tries to get the wiring, fuses and relays right for running those fans
I think I finally have got it dialed in

Glenn

Chalie M

Lynda, I’ve been on the sidelines with my vintage air install on my 65 coupe (327/365). Sooo I read/research all these post on vintage air installs, alternator upgrades etc.. I think Glenn has just about worked out all the bugs electrically with his set up.. As much as we would like to do the swap & keep it simple it almost forces are hand to upgrade the electrical system when adding that electrical radiator fan/s & a/c compressor. The amp draws need to be addressed.. so finding the correct alternator is only half the battle read up on posts in this forum such as Glenn’s work on his 63.
I would wire that system & copy the way Glenn did his install, relay’s & circuit breakers are the way to go check out his 63 build post’s.. Sorry Glenn don’t mean to put you on the spot, but Lynda finding the right alternator is only the start I wish I had more info for you but I’m still a year or two away.
Good Luck
Happy reading
Chalie

Chalie M

This may be a little help check out this harness conversation from your stock 64 alt. Plug to the needed CS130 alternator plug & 64 v/regulator eliminator..
https://www.zip-corvette.com/63-68-a...lternator.html

Regards Chalie

RatDog

I added Vintage Air and a DeWitts combo radiator and Spal fan to my’67 10 years ago. I rebuilt my alternator to 100 amps at the same time and haven’t had any issues.

Steve

Viet Nam Vett

So your using a DeWitts Rad with One fan? If that's the case then the power drain will be much less. But also keep in mind the AC Compressor Clutch pulls some amps. I think the stock alternator is 63 amps. So when you add up head lamps and the fan and the A/C clutch at idol plus break lights (If not L.E.D.) your working the Alternator. For My $.02 worth ...I'd at least step up to a 100 Amp unit. Plus figure in all the other minor acc's like headlight motors interior lamps Radio Etc...they all draw power at one time or another. Again..just my $.02 Worth. Others here will have there opinion.

There yah go.. The Ratdog says it all...
I added Vintage Air and a DeWitts combo radiator and Spal fan to my’67 10 years ago. I rebuilt my alternator to 100 amps at the same time and haven’t had any issues.

Steve

lyndahern

Glenn, Thank you so much for taking the time to answer my post. I actually started going through your rebuild when I first started mine a year ago! I think I even personally messaged you back then. I too am in So. Cal and would love to personally see your vette. I do know the alternator in the car now is a 10/12si. so not the original, but was not able to find out how many amps, and I don't believe it's over 100. I've seen a lot of people recommending the Powermaster so sounds like that may be the way I'll go. I'll definitely look up any fuses and relay info you have like Chalie suggested. Thanks again!

lyndahern

Chalie-Thank you, yes I was thinking I would need one of those too!

Chalie M

Check this site out for all your electrical needs, purchased some items in past (way before the Covid), no complaints:-)..

https://www.delcity.net/?mkwid=s&cri...SAAEgJyIvD_BwE



Chalie

lyndahern

Thanks, I'll check them out.

gleninsandiego

Thanks for the kind words.

I am running a single Spal fan on a Dewits radiator, and I consistently underestimated how many amps that bad boy would draw
Especially when first kicking in.
Plus the vintage air fan and compressor sucked more as well

We started out with a 30 amp circuit breaker with an automatic reset coming off the battery, which led to mysterious power outages which couldn't be
initially traced because the breaker would reset. It was a crazy maker. LOL

I finally ended up with 80 amp circuit break that didn't reset and it has yet to blow

For the fans we have now two 40 amp fuses running in parallel to just the fans alone.

In fuses for a house air conditioner they use slow response / time delay fuses to get over that initial power draw when it starts up
Automotive fuse tend to be just the opposite. Quick response.

I am looking forward to testing the entire set up in 100 F temperatures. 80F has been the hottest so far.

Viet Nam Vett

Interesting tech this site will answer many questions... I chose this section..

http://www.madelectrical.com/electri...esensing.shtml

Ten go back to the home page for more info

Viet Nam Vett

Yep,
I use #8 gauge wire from the Power Master 140 amp Alternator thru to a 135 Amp Circuit braker to a fuse array which runs to my horn relay then out to the electrical system. If the alternator diodes go to ground then the CB fires off. Extra protection. I use a 30 amp fuse on each spal fan also as well as the A/C Comp. The Power Master is using an internal Voltage regulator and the voltage sense line goes to the Horn relay to control the output of the PM.

one similar to this one except mine is rated at 135 amps. https://shop.advanceautoparts.com/p/...E&gclsrc=aw.ds

suntreemcanic

Not owning a Corvette yet, when you install a larger alternator how does the amp meter handle the larger current flow?

lyndahern

Thanks! I ended up ordering the Powermaster 47293. Just waiting for it to arrive now.

Lynda

Viet Nam Vett

Been Running the Power Master 150 Amp for years. Supports two Spal DeWitts Rad Fans ..... A/C Compressor.... And the rest of the Corvette Electrical system. Good Choice. Just make sure you add a Fuse system either in line or a an auxiliary fuse block for heavy current draw items. Also I added a 8 Gauge ground wire from the Alternator to the engine block even though it the alternator is grounded thru the mount.

Also added additional ground wires to the frame to the engine block. A good solid ground is the best way to go,