Hi everyone,

Got an Archie SBC setup - I searched and founds lots of usefull A/C info, but nothing like this. Some years ago I had a mechanic remove my a/c compressor because I was eating through belts from the pulleys not being lined up perfectly. So with the new engine in the works, I was thinking about putting it back in and addressing the alignment issue.

The headers I have in there now have cracked on the "firewall side", and from what I was told, those headers have that issue. So I was talking with FieroGuru on other header options, and he pointed out that some header options are eliminated simply because of the accessory locations if you want to keep the A/C. So the idea popped into my head... I already have an electric water pump, so why not an eletric A/C compressor?

It could then be attached almost anywhere that has the room and be able to work. Just might need to get a bigger alternator in there and rig up a relay/wiring for it.

I found this - http://www.alibaba.com/prod...sor_For_Vehicle.html and I'm trying to see if something like that would be powerful enough, or what other options are out there (I know some of the hybrid cars have electric A/C units, too).

Not to mention... since my most recent move, I can't find my factory A/C compressor, and it was sitting in my shed without the ends capped (I think) and alot of other metal things in there got surface rust from remaining pool chemical vapors... so it's probably just a paperweight now. lol

Thanks guys!

I am of no help on this....but it certainly sounds interesting. With that, you should even be able to mount it up front. I did see an issue though...."Input voltage: 24VDC, 48VDC, 72VDC, 96VDC"

Yeah, though in the pursuits of my googling, I ran across a guy who intalled a 12v motor and just coupled the shaft on that motor to the shaft of the A/C compressor. Granted, it was in a totally different vehicle, but that's besides the focus. So I emailed him for more info to see how he rigged it up so that the compressor would "engage/disengage" now that it was driven by this motor instead of by a belted clutch.

So I'll see what he has to say and let you guys know.

Alright,

I did not hear back from the guy who did the electric conversion, so I just started looking into DC 12v motors myself. Needless to say, I found tons of them. So now I have two important questions to help narrow this down:

A) at what RPMs is the compressor running at it's optimum efficiency? 1000? 1500?
B) How much torque does it take to turn the A/C compressor? I don't have a torque wrench and can't seem to find any info on it.

Thanks guys!

quote Originally posted by CowsPatoot: I did see an issue though...."Input voltage: 24VDC, 48VDC, 72VDC, 96VDC"

The voltage is not the issue...the issue is the AMPS. There is no free lunch, you are going to need a second alternator to get enough power to run a motor to drive an a/c compressor. Unless you fill the trunk with batteries and only have a/c every other day while you wait for them to recharge.

A car a/c is roughly as powerful as a home central air, it's not going to be powered by a dinky motor.

I was planning on putting in a higher output alternator, that's for sure. But to really get into it and find out if it's feasible at all, I still need to find out the answers to my A & B questions in my previous post.

Thanks for the input just the same!

quote Originally posted by Trinten: I still need to find out the answers to my A & B questions in my previous post. Thanks for the input just the same!

I've done some reading on the subject from electric car forums... it takes about a 1 hp motor to spin an a/c compressor. 1 hp doesn't sound like a lot but that's 746 watts or 62 amps. As I said earlier the problem is the amps. You are going to need at least a 160 amp alternator to operate the normal car plus this motor (more if you account for losses).

I don't know the optimal RPM of the compressor, but RPM is not an issue with electric motors, they spin at whatever speed is required of them.

Thanks again for the info! Some of the motors I was looking at were 3/4 - 1 HP, but some would only have an RPM of 300 or so, and others would be over 1000, so I was trying to find out what RPM would be best for the A/C.

Doing a QUICK search, the strongest alternator I found on Summit for a Gen I SBC was 200amps. Armed with the info you gave me, I'll need to try to hunt down one closer to 220.

BTW, does anyone know if by moving the alternator down to where the A/C normally is, if you can run different alternator casing styles?

find a guy local to you that rebuilds alternators, and have hib build you a custom one at the rating you need.a buddy of mine had a 200 amp alternator out of an ambulance, he'd toast a battery within 6 months, it would charge the battery while barely being able to crank the engine over, wouldnt need to jump the vehicle as long as the engine would start to turn over.

It might be worth looking at using a V5 compressor rather than the HR6 type. The V5 is always on (when the clutch is engaged) and adjusts itself internally so there's less load on whatever is driving it. With the cycling systems it's all or nothing so not only do you have a high load when it's one but you are continually having to overcome startup resistance every time it cycles on.

------------------
Dave

www.ltlfrari.com

Thanks for the suggestions! I think I have both types... IIRC, when my mechanic took my A/C off a few years back, that compressor was relatively smaller than the one I just picked up last weekend. But I'd need to get them side by side to compare, probably do that this weekend.

Now to hunt down some alternator rebuilders and get some pricing!

Any other thoughts or suggestions, keep 'em coming. If this pans out, I think I'll move the unit up front someplace, so I don't need to worry or mess with those long hoses.

quote Originally posted by Trinten: Any other thoughts or suggestions, keep 'em coming. If this pans out, I think I'll move the unit up front someplace, so I don't need to worry or mess with those long hoses.

I've been kicking this around myself...but to free up a spot for a power steering pump... Or maybe go with electric PS as well.

Ricky refits the corvette power steering into his car. I *think* it was a 2000 vette? It's in his build thread someplace. Though with the room up front, I imagine there's a place to put both! Might as well get some use out of it.

Why not just fix the belt issue and build a custom header? As far as power goes, doesn't the ac clutch unlock at a programmed TPS value anyways?

[This message has been edited by Jncomutt (edited 10-29-2009).]

Heya man!

Yeah, I could try to fix the belt issue, hope that it works out better this time. I got a set of "turbo headers" that just point straight "back" (so to the driver side) that I'm going to use to try to do the exhaust. No idea about if or when the A/C clutch unlocks, my throttle and everything is mechanical, so not sure how that would work. I thought 'on' was 'on' always.

But really, this would make things a bit unique... afterall, that's why alot of guys here mod their cars. Granted, it's not as flashy as Rick or Curly's, but it's something - and, depending on the hype you beleive, an A/C can rob up to 15 HP or so. lol (not that it'd make all that much of a difference since you gotta be careful going into gear anyway! lol)

[This message has been edited by Trinten (edited 10-29-2009).]

quote Originally posted by Trinten: ... and, depending on the hype you beleive, an A/C can rob up to 15 HP or so. lol (not that it'd make all that much of a difference since you gotta be careful going into gear anyway! lol)

Well we just established that it takes from 3/4 to 1 hp to spin the a/c compressor so the 15 hp robbing of power can't be true.

I agree it would be unique and worth doing for that reason alone.

Hey Jscott,

I know, that's why I mentioned the hype.

I did talk to a place that rebuilds alternators - he said it was possible, but with that much generation the unit is going to be creating alot of heat, and might die sooner than a good aftermarket one with proper heat disappation designs built into the casing. I appreciated his honesty, and did a little bit of searching this morning and did find one high-amp alternator maker that said the same thing, the excess heat kills other components and your newly rebuilt alternator dies in months instead of years.

BTW, does anyone have any pics of alternator mounted in the A/C area/position? I don't want to buy an aftermarket alternator and then find out it won't fit/mount properly. :/

Thanks all!

Well I mean if superchargers run off of belts to spin some blades, and turbos run off of exhaust to spin some blades, why not say a current ac is like a supercharger and then redesign a 'turbo' ac compressor that runs off the exhaust gasses??

(kidding of course)

You know... hmm. If it weren't for the exhaust tempatures... hmmm.... stop giving me crazy ideas! I do that well enough on my own!