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83 SD

84 CD

To give you some idea on the AC drag... you only have about 67 hp to start with...and the AC can take typically 5-7 hp from you....
When I took apart several aftermarket hangon type AC's and put them into my Karman Ghia I put a switch on the shifter which my thumb could hit... and when I was getting up to speed while shifting I just depressed it... it just took the compressor out of the system while it was depressed... that can not be done on all systems as some are not cycling clutched compressors.... but it worked great on my VW.
Some cars had switches which took out the compressor when you really stepped on the gas...

My 300D was slow when I first got it due to extremely sloppy linkage between the pedal and the IP throttle arm.

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84 300D, 82 Volvo 244Gl Diesel