I looked up the molecular weight of both: R-12=121, R-134a=102. It would seem to me that if you used a pump pulley small enough to increase the pumps output 20%, there should be some improvement. At the same time if you could change the opening pressure of the expansion valve to account for the decreased density of R-134a, that should also improve the efficiency of the system. Does this make any sense? Gerry Archer '83 300D and 240D -------------------------------------------------- ----- Original Message ----- From: "Tom Hargrave" <[EMAIL PROTECTED]> > R134a has about 20% less thermal mass than R12 and R134a moves 20% less > heat. All of the auto manufacturers made up the difference by upsizing the > units. > > R12 sized evaporators are about 20% too small for R134a. The factory R134c > systems have evaporators that are sized correctly for R134a. > > There is no "magic bullet" fix for this issue but you can help some by > under > charging the system & forcing the evaporator to run colder than it > normally > would. But this causes icing. > > Thanks, > Tom Hargrave > www.kegkits.com > 256-656-1924 > > > -----Original Message----- > On Behalf Of Kaleb C. Striplin, > really, I hadnt thought of that actually. In the past, I have used the > kit > and just removed the R12 (well, there was usually nothign in the system) > and > > recharged with the 134 in the conversion kit. Never had a problem and it > usually worked pretty good, but not as good as freeze you out factory 134. > Next time I do a conversion Im thinking I should change out the drier, > maybe > > pull the compressor and drain the oil out of that, switch the expansion > valve then recharge etc. Anything else? > > --- > Kaleb C. Striplin > Cox Auto Trader > 730 PP Supervisor > > ----- Original Message ----- > From: "Jim Cathey" <[EMAIL PROTECTED]> > To: "Mercedes Discussion List" <mercedes@okiebenz.com> > Sent: Saturday, July 14, 2007 9:32 AM > Subject: Re: [MBZ] 124, R12 v R134 > > >>> any idea why the factory got 134 to cool great in a 124 but if you >>> convert it after the fact it does not? >> >> Too much oil? (As in the old R12 oil is not fully removed.) >> Just a guess. >> >> -- Jim >> >> >> _______________________________________ >> http://www.okiebenz.com >> For new parts see official list sponsor: http://www.buymbparts.com/ >> For used parts email [EMAIL PROTECTED] >> >> To Unsubscribe or change delivery options go to: >> http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > > > _______________________________________ > http://www.okiebenz.com > For new parts see official list sponsor: http://www.buymbparts.com/ > For used parts email [EMAIL PROTECTED] > > To Unsubscribe or change delivery options go to: > http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > > > _______________________________________ > http://www.okiebenz.com > For new parts see official list sponsor: http://www.buymbparts.com/ > For used parts email [EMAIL PROTECTED] > > To Unsubscribe or change delivery options go to: > http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.5.476 / Virus Database: 269.10.5/899 - Release Date: 7/13/2007 > 3:41 PM >
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