Automotive Air Conditioning Information Forum (Archives)

94RX-7 on Mon November 14, 2011 1:02 PM

Year: 1977
Make: Mazda
Model: REPU
Refrigerant Type: R-134a

I'm in the planning stages of putting together a complete A/C system for my Mazda Rotary Engine Pick-Up. I'm planning on using a compressor bracket from an '86-91 RX-7 The two compressors that this bracket will accept are an SD708 or a Nippondenso 10P15 both in a direct mount (where the bolts go through the compressor body) configuration. I would like to use a compressor designed from the ground up for R-134a such as a Denso 10PA series, or whatever the modern Sanden equivalent is.

The question is, did Sanden/Denso keep the mounting bolt locations the same, or alter them dramatically? From what I've read, the 10PA is just a revision of the 10P. I have no idea what the modern equivalent of an SD708 is.

Is there a big listing of compressors and their mounting dimensions anywhere? I can't seem to find anything like that from either Denso or Sanden...

ice-n-tropics on Fri November 18, 2011 9:39 PM

The 134a version of the SD708 is the SD7H13 (same 129cc swept volume). 4 direct mounting bosses are the same.
You may want to swap heads to use your RX7 pad type type hose fittings. Be careful that the pad bolt does not bottom out and cause a leak crack in the bottom of the threaded hole. RX7 had a problem with this type of leak.
Wankels require a monster battery when compression is low, therefore A/C clutch should be off when starting.
Cordially,
hotrodac

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Isentropic Efficiency=Ratio of Theoretical Compression Energy/Actual Energy.
AMAZON.com: How To Air Condition Your Hot Rod

94RX-7 on Thu December 15, 2011 4:34 AM

Great info...thank you!

Regarding swapping heads...I'm building this system basically from scratch, so I can put any fittings on the ends of the hoses I want to. Is there something inherently superior about those pad mount type fittings? I was planning on just using the "default" screw on (MIO?) fittings.