Engine swap, new engine has larger compressor, charge weight more/less?

[Z2TT]

Hello,

I have a Toyota Soarer from 1987, I'm doing an engine swap in it, putting a larger motor in it from a 1990+ Soarer. The original engine for my car had a Denso 10PA15, the new engine that's going in has a Denso 10PA17 attached to it, a higher displacement compressor

So basically I'll have the same A/C System in the car but a larger compressor, what affect will this have on things?
Will I need to increase or decrease the recommended charge weight or leave it alone and the new compressor will just deal with whatever load it's put under?

Any ideas?

Thanks.

[cadwaladr]

the same i would guess,check they both will run on the same gas?

[Z2TT]

Yep both compressors are compatible with the same gas, was just curious of the affect putting a larger displacement compressor on the existing system, whether you can't mismatch compressor displacement if the system is too small.

My thinking is it just deals with whatever duty it's placed under

[mikeref]

Yep both compressors are compatible with the same gas, was just curious of the affect putting a larger displacement compressor on the existing system, whether you can't mismatch compressor displacement if the system is too small.

My thinking is it just deals with whatever duty it's placed under
Nope, No can do. The a/c system is designed for the 10PA15c compressor, not 17. Running the 17 will cause a/c to run too high discharge pressure and gas flow, which the condenser will not handle in moderate to high temp conditions.. further problems is expansion valve will loose its auto function to regulate gas flow and evaporator will run too low pressure and iceup. Then, there is the high temperature of the compressor generated from pumping high pressure.. mike.

[Z2TT]

Oh ok, guess it wont cool well then.

I'll try see if the 10pa15c fits on the new engine and re-use that.

Thanks.

Edit :

Just like to mention, the car I have came with 2 different engines, 2.0L and 3.0L Engine. The 3.0L Engine came with the 10pa17c.
I looked at the parts diagram and it turns out between the car that has the 10pa15 and 10pa17

The expansion valves the the evaporatos is the same part number, and also piping is the same between 10pa15c and 10pa17c equipped models.

Only the condenser looks a tad larger on the 10pa17 model.

[paul_h]

Well first point: your old compressor is clean, so I'd prefer to use that. The larger one may be full of contaniments possibly.

But other than that, (edit: car) a/c compressors are usually variable, designed to work at ever changing engine RPMs anyway and they wouldn't be that different capacity wise if made for the same evaporator and car.
So if the old one fits, use it, as the 2nd hand one may not be good without a clean out and rebuild.

[Z2TT]

Hi,

Actually the current one has a leak, so the one that comes with the engine I'm putting in might likely be better.

[mikeref]

Hi,

Actually the current one has a leak, so the one that comes with the engine I'm putting in might likely be better.
The 10PA15 and 10PA17 have thoes numbers for a reason. Years ago i fitted a 10 cubic inch displacement compressor in place of an 8 cu/in in my vehicle, the 20% difference gave me no end of trouble with head pressures. However, there is only one way to learn from your situation i guess. Basically make sure the refrigerant return temp to compressor is cold when cabin is down to temperature at approx 1300 rpm.Compressor body temperature must always remain warm and discharge temperature should not exceed.. say, 90c at same revs. Change out oil before fitting compressor and drier prior to vacuum. Good luck.. Mike. P.S. Hope you get some rain soon to fill thoes dams over there, water restrictions are such a drag.:)