A tech question

[gardener]

Adding an Air conditioning system to my spit 69, this will weakens the engine, what I can do to counteract this without altering the engine, what can I use to give a little extra power. Also if some one have the harness to atatch the hard top to the sides of the body.

 

[TR3driver]

My suggestion would be to add a microswitch to the throttle linkage, so it disables the AC compressor when you get on the loud pedal.

 

[gardener]

I am truly amazed with your answer and the fact that no ones have a better answer :banana:

 

[poolboy]

There's nothing wrong with Randall's answer. In fact the TR6's that had dealer installed AC used a switch, vacuum activated, I believe, to disable the compressor during acceleration.

 

[martx-5]

My Miata has a throttle switch to shut off the A/C at WOT...although they put in about a one second delay. I guess Mazda wanted to make sure you were serious about accelerating. :laugh: Of course, since I put the blower on, it's a moot point.

 

[DrEntropy]

mehheh.

Some time back, TR6Bill had an issue with A/C and there ensued a lengthy thread on the matter. It may have been a year or so ago, not certain. His was an idle cut-out but a WOT arrangement could be fabbed up in similar fashion, certainly.

Scrolling thru his posts would find it.

 

[gardener]

If I install an air conditioning system, how can I'll disable the compressor, this answer is like a antagonism, but ok, what kind of microswitch, Like this

 

[DrEntropy]

Likely you'll need something a bit more stout than those.

 

[TR3driver]

Vacuum operated would work too, if you can find a suitable switch.

The concept is that the A/C only sucks power from the engine while the compressor is running, and the compressor only runs while it's clutch is supplied with 12v. So if you insert a switch into the wire to the clutch, such that it opens when you want full power to the wheels, it will shut the compressor off and stop it from robbing power. Of course it will also stop cooling the interior of the car, but it will take some time to warm up and hopefully by then you'll be off the throttle.

I'm not familiar with the throttle linkage on your Spit, so I can't give any specifics. But the idea is to build a bracket that holds the switch, so the switch operates when the throttle is nearly open. Letting the lever for the pedal hit the lever for the switch might be the easiest way, but you'll need to use a little imagination. Hanging it on the side of the carb could be easier to get at (but also more cluttered looking with wires & whatnot).

Lots of switches would do, but be sure the one you choose is rated to carry the current of the A/C clutch, and there is a suppressor diode on the clutch to reduce kickback. The optimum solution might be to use a relay (if you don't have one already), but a bare switch will do. If you switch the clutch directly, the wires to/from the switch also have to carry the clutch current.

 

[poolboy]

mehheh.

Some time back, TR6Bill had an issue with A/C and there ensued a lengthy thread on the matter. It may have been a year or so ago, not certain. His was an idle cut-out but a WOT arrangement could be fabbed up in similar fashion, certainly.

Scrolling thru his posts would find it.

What that was, was the electric cooling fan drew so much current that the idle speed dropped when the fan kicked on; so he came up with "plunger" that pushed down on the carb linkage when the fan came on.
I took it off and just raised the idle speed so that when the fan did come on, the idle remains smooth...it's an S2 cam in there.

 

[DrEntropy]

Ooops! Just the opposite of what gardener is lookin' for!

...well, the idea's th' same... :blush:


kinda.

 

[gardener]

My car has overdrive, and is stock, nothing added! I don't want to shut the compressor I want to add some horsepower just a little, to compensate the loss -+, and please don't tell me to put a Clydesdale under the hood!!

 

[martx-5]

Well, somehow you're going to need about another 5-8 HP. On that engine, that's about a 10%-15% increase. Not too easily done without altering the engine. You can get more HP without altering the engine by going with forced induction.

 

[poolboy]

Adding an Air conditioning system to my spit 69, this will weakens the engine, what I can do to counteract this without altering the engine, what can I use to give a little extra power. Also if some one have the harness to atatch the hard top to the sides of the body.

Lets see, you want extra power but you don't want to alter the engine and you don't want to turn off the A/c compressor.
That could present a problem.