A/C efficiency and serpentine conversion
 

Hi,

I have a 3.0 Targa S, and converted the A/C to a parallel-flow, front mount evaporator and a SANDEN 708 compressor. I replaced it all - including the lines, drier and expansion vale and even the front evaporator.

It works OK, but a few things are still annoying as they prevent me from making this my daily driver:
1. The coolling starts after a while, it can take 10 minutes for cold air to start coming out
2. In idle, it does not cool. Probably as a result of low RPM and no efficiency

I have been advised to install a larger crank pulley: looking for one I came across the serpentine conversion by Clewett.

Questions to you guys:
Does anybody know of a larger crank-pulley setup? And who makes it?
Does anybody have experience with the Clewett serpentine upgrade inclusive AC and can point to the parts required?

I wrote to Clewett and await their response, and yet your impartial opinion is highly appreciated!

Thanks,

I think the compressor is not the right size, most use the 507, but it sounds like you have other problems. What gas are you using r12 0r 134? You might have the wrong amount. Is the proper expansion valve in? Is your thermostat calibrated. Is the clutch engaging the compressor?

Just trying to put together the puzzle you have here:
Assuming you have:
*a 1975, cabriolet
*2 condensers, maybe a PF over the engine and something upfront,
*you replaced the evaporator in the smuggler's box
*a sanden 508
*barrier hoses
*new drier

1) First off, if you have PF deck lid or front condenser I'm amazed your car is not making ice cubes for all of Florida.... according to the PF experts.... OMG ! However, we won't fault the PF problem design just yet.
2) If the car is a 2 condenser car in FL, and its cabriolet, you may need more condenser area, but we'll hold off on that for the moment.
3) If this car was a factory stock 2 condenser car, you should have enough cooling
coming out of the vents even at an idle, and after leaving the car in the sun all day,
to notice "some cooling.
4) A smaller 507 will cool just as well as the 508, that is not your problem.
5) What you could gain if you could either use a smaller compressor pulley or a larger
crank pulley is not going to benefit you with respect to the cost in time and materials to try to get it to work. Clewett has some nice stuff, but don't think you need to convert your crank and compressor pulleys to serpentine; no benefit.
6) A serpentine evaporator and condenser is more efficient than the stock Tube & Fin designs, And some serpentine designs are better than others, and some serpentine designs can be nearly equal to PF.


Before you spend another dime on parts:
I would suggest to simply think back on your AC evacuation and charge, chances are something is no right. PM if you need further help.

Its a cruel world, Griff...

Right on on all components not being equal... OP -- Call Griffiths, fill out their assessment and then go from there.

Thanks!
 

I have run some tests, looks like the front evaporator is not enough tomlower the pressure, hence I am adding a high velocity double-fan. If this does not help then I will add another evaporator inline, am considering a few options but my inclination is to go with the tail-mounted one, because I am lazy and from. Piping perspective it willl be the easiest place for it. I am also considering adding a high velocity single fan back there, which should also reduce air temp for the intake.

The serpentine conversiosn looks like a nice update. They replied almost imediately and it does not look like the right solution for this specific issue. Also, they do not offer a double-channel pulley as it will not fit in there.

If all fails, it will be ice cubes in my groin. Works like a charm:-)

Stop, stop trying to invent the wheel !. It really sounds like you are throwing money down a hole when the solution is right above. Just call Griffiths.

I assume you meant condenser (not evaporator) - the evaporator is the heat exchanger component inside the car . . .

Plus 4 - Call Griff...

Ouch. And LOL.