Who's going fast with AC? need advice........

Here goes.............

Who has gone quick with AC? I am really wondering about the difference between an AC car vs non AC car for 1/4 mile times. I have a 69 hardtop (gonna be my stage 1 clone) that I want to build to have fun with.

The car already has the aluminum drums up front and I was wondering about aluminum in the rear too............ or should I change over to disc all around? The money isn't an isuue, I kinda want to go really fast and look old school and mostly stock.

Here's my set up so far:

12 bolt - 3.73 posi new upper and lower control arms (boxed)
stock big block springs on 4 corners
manual steering, manual brakes
built th400 w/ 3200 tci stall
455 .038 over w/ flat tops (thanks to grandsportsedan)
- 67 tall port heads built to stage 1 specs and ported
- b4b
- 800 cfm holley
- I have a gs113a cam, but will probably go with gs112
- headers 1 7/8 and 3 1/2
- full 3 inch exhaust with dynomax mufflers
- TA front cover
- msd distributor and 6al
- new romac balancer
- holley blue pump (but might want to put in the stage 1 mechanical anyways)

considering the TA roller rockers .... any thoughts? should I bother?


The point is, I have my convertible with AC and I never really use the AC. The original stage 1 I have doesn't have AC. I am wondering wether I should keep the whole AC thing in the car I have and deal with it (it still had pressure when I pulled the front clip off) or should I get rid of the whole deal. I have seen the AC delete stuff on eBay, but I wonder how hard it would be just to put the car to appear like a stock skylark with no AC (because I have a parts car I can change stuff over from)

Will leaving the AC stuff really slow me down?
Whats your thoughts on the brakes?
Any thing else I should consider?

 

Anyone ever have a similar situation?

 

Everyone I knew with a street car that removed the A/C for weight/power/fuel economy figured out about two years later that it was a huge mistake.

Pass 'em in comfort.

 

My car has a/c. You'd only be stripping about 100 lbs. from the car, worth maybe .1 in the quarter. Just take the belt off the compressor at the track if you have to. That's what I've done. I'm also running the 113A cam.

 

Nigel,
I think most if not all tracks will not allow front alum drum cars to race.

 

ac

I am still deciding on my 72', I just put a 455 in and had to remove have of the condensor housing out to get the wide mama in. (Tall TA valve covers.) Then I found out that it is just about as much work to take it out as it is to leave it in, also the same amount of money to get it recharged or buy the replacement cover? This is issue is split 50/50 Vets say keep it, newbies say junk it. I think I am still going to take mine out just cause it just takes up too much room and looks ugly. (keep all the parts for a rainy day or when you settle down.) I don't like to cruise with my windows up anyway! :3gears:
Good luck, can't wait to hear what you decide.

 

George -

I'd like more info on this. I've never had a problem at any of the tracks in Michigan, Ohio, Illinois. Where did you get your information? And what reason is given for not allowing aluminum drums?

 

I believe someone told me in the NHRA rule book that alum front drums are not allowed. They are known to have cracks radiating from the wheel studs and coming apart under hard braking (high heat loads). I believe this was also the reason why GM mandated disc brakes on BBB in 71-up.

 

Thanks for the info George :TU:

I think I'll end up going with a complete disc brake set up front and rear. I've seen a few of them on eBay for a pretty decent price. I've seen a complete rear set up with the master and all the hardware for 499 and the front for 599 so it's not all that bad. Do you know of any complete kits for less that you have had some experience with? Thanks in advance..........

 

I had better tell my buddy that has been bracket racing his car like this for eight years at 129+ mph maybe that black paint has fooled them o No:

 

A/C to remove or not

When I got my '70 skylark in 87 or 88 it had A/C which was still charged and blowing nice and cold. My decision on removing it came when I started swapping engines and of course this got misplaced or that got misplaced or vacuum lines were disconnected and never put back correctly. So once the motor came out the A/C became non functioning although it was charged. When I put in the big block it was just in my way as I was breaking rocker arms and valve cover clearance was tight. I had a non A/C parts car so I removed the heater set up from that car, should have cut out the firewall too. I removed the A/C from my skylark, cut a patch panel from galvanized aluminum to patch the firewall hole then installed the non A/C setup which worked fine for me. Now I have the motor out for a rebuild and will be splicing in a non A/C firewall that I finally got so it will look like an original non A/C car.

Now for my opinion on A/C. If I could buy a '70s type muscle new and option it they way you could way back when, I would not have gotten A/C. Too me a car like that is made to go fast, the less options the better even if a bit of comfort was sacrificed. If I had the money to buy a restored car I would avoid A/C models. Just my preference and believe me I do feel the heat in summer time with the black vinal interior and heat from the headers coming throught the floorboards.

Allen

 

I also have a non-ac firewall, maybe I should cut it out just in case I get some crazy idea in the future. I love the convenience of AC but hate the look.

Anybody got any pics of their engine compartment with the AC hooked up and functional? I'd be interested in seeing how pretty people have been able to make it look............ :bglasses:

 

Allen,
Why go thru all the labor of making your ac firewall to non-ac when you can buy the American Graffiti ac-to-non/ac firewall blower motor cover?


Nigel,
I have an article on our site about a new rear disc brake set-up that uses 80-85 Eldorado/Seville, Toro, Riv calipers with Explorer rotors. Kit was very simple to install and you can get more details from Skip at www.tsmmfg.com
For front disc brakes, I would go with a stock set-up. KSPLynch is selling such a set-up here for $250-275.
The rear disc brake article is www.buickperformance.com/rrdisc.htm

 

I yanked my AC four years ago. It didn't work at the time, I never saw myself fixing it so I pulled it. Pretty easy actually, however I wouldn't pull it with the idea that it would help me go any faster. I say if it works or you want to get it working leave it in, like Phillip said, the .1 can be made up in other places. Although it would increase fuel economy by yanking it...

 

I like to ride in comfort so the A/C on my car stays. I'd rather add more power than lose the a/c for the weight. Number 8 spark plug and especially the rear outer valve cover bolt is a bear to get to but for me it's worth it. Also, a lot of women don't want to sweat while they ride in the car. FYI, you will not see a difference in mileage between the a/c off and a/c removed. Removing the a/c lowers the value of the car. It all comes down to personal preference. Here's a photo comparison of two restored GSX's and a customized engine compartment.

 

There would be an increase in fuel economy actually. Removing 10% of the weight of a car would increase fuel economy by 8%. Removing 100lbs on a 4000 lbs car is 2.5% so it would be an mpg increase of about 2%. Not a big deal at all, but still an increase. That isn' even allowing for the drag the compressor would create even if the AC wasn't turned on.

 

if your serious about going fast,throw the ac and the power sterring on the shelf.if your just cruzing, keep'em on.just my 2 cents.

 

Tell me more about the increase in fuel economy. At least at highway speed, I think you lose more to crappy aerodynamics (windows open) than to compressor drag. Weight is not an issue at steady speed, some guy named Newton figured that out.

 

You are right, weight wouldn't be an issue at steady speeds unless you of course allow for the increased weight on the wheels which would increase the rolling resistance, but damned if I know the numbers for that. I don't even know the numbers for how much it would lower your fuel economy if you had the AC hooked up and never used it, all I know is increase drag and decrease fuel economy.

 

Assuming 15MPG and a 2% increase comes to .33 MPG. 10MPG would be .20 increase. I agree that in theory there would be an increase in MPG. I'm pretty sure you'ld have a hard time seeing/measuring it in the real world. However, I'm always open to contradictory evidence.