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63 vs. 64 supercharger pulleys

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  • 63 vs. 64 supercharger pulleys

    The 1964 R2 engines had a larger crank pulley and a smaller supercharger pulley than the 1963 models. I guess the faster spinning blower was to increase performance, yet the HP rating was the same for both years. I know a different carburetor was used in 1964(I assume different jetting). So what effect did the different size pulleys and carb. have? Was it performance, fuel economy or some other reason. Would the peak HP be at a lower RPM on a 1964 setup?

  • #2
    If the blower had a smaller diameter pulley, then the boost would be higher for any given rpm. If they installed a larger diameter crank pulley along with the smaller blower pulley, it could well balance out and make for the same boost as the previous year. Engineers make such changes for many reasons...production costs, parts durability, etc. Carburetor's change with different jetting to meet particular requirements, to overcome service problems, emissions...you name it.

    If they increased crank pulley diameter and reduced supercharger pulley diameter it's probably a wash in power production. There must have been an engineering/cost reason to do so.




    Poet...Mystic...Soldier of Fortune. As always...self-absorbed, adversarial, cocky and in general a malcontent.
    Poet...Mystic...Soldier of Fortune. As always...self-absorbed, adversarial, cocky and in general a malcontent.

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    • #3
      I thought increasing the size of the drive pulley(crank) and decreasing the size of the driven pulley(blower) at the same time would increase the boost more than just decreasing the blower pulley only. I still ride a bicycle occasionally and with the pedal(crank) in the biggest sprocket and the wheel in the smallest gives the highest gear, at least my connecting rods think so.

      regards,
      Jay

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      • #4
        I don't think the standard pulleys are different between 63 and 64. The R3 had HO pulleys and the HO pulleys may have been an option on R2's.

        I don't have my parts book handy to check.

        ErnieR

        quote:Originally posted by IMJ

        The 1964 R2 engines had a larger crank pulley and a smaller supercharger pulley than the 1963 models. I guess the faster spinning blower was to increase performance, yet the HP rating was the same for both years. I know a different carburetor was used in 1964(I assume different jetting). So what effect did the different size pulleys and carb. have? Was it performance, fuel economy or some other reason. Would the peak HP be at a lower RPM on a 1964 setup?


        1988 "Beater" Avanti---R5388 @ Macungie 2006

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        • #5
          There was a high output pulley option in '64...may have been for R3's only. That could be the source of the question.

          Changing pulley sizes is very complicated beyond the mere change of sizes. When boost increases, it goes up faster than the mere proportion of the change as rpm's increase. It's a delicate balancing act, If the boost goes up too high, too quickly, many bad things can happen...overboost, heat, wear of parts, etc. I'm not sure comparing it to gearing on a bicycle is accurate...on a bike that may mean mechanical advantage...like the rear axle ratio of a car and the transmission. Boost pressure goes up far more than proportionately as rpm's increase.




          Poet...Mystic...Soldier of Fortune. As always...self-absorbed, adversarial, cocky and in general a malcontent.
          Poet...Mystic...Soldier of Fortune. As always...self-absorbed, adversarial, cocky and in general a malcontent.

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          • #6
            In a centrifugal type blower that is. In a Roots type positive displacement blower, the boost pretty much corresponds to the pulley ratio (because it's stuffing the same amount of air into the engine for each revolution, no matter what the RPM)

            nate

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            55 Commander Starlight
            http://members.cox.net/njnagel
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            • #7
              The bicycle analogy was merely a comparison on larger pulley on drive and smaller pulley on driven would increase rpm on blower more than just smaller pulley on blower would alone. I assumed, probably incorrectly, that an increase in blower rpm would also increase boost. My parts book lists different numbers for the pulleys used in 63 and those used in 64. I was told that the 64 had a larger crank and a smaller blower pulley than 63. I assumed it was to spin the blower faster. I was also told it was to increase performance. But if the HP is rated the same I don't understand where the enhancement would be.

              regards,

              Jay

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              • #8
                I wish I had access to my parts book. Most listings that I recall are before or after a certain VIN or production date not year specific. Maybe someone else can verify but you are the first person that has mentioned that there is a difference between 63-64 non-HO pulleys.

                The pulley change on my car was only good for 1 maybe 2 lbs difference in boost. The real plus for performance was that boost came in a little quicker.

                ErnieR







                1988 "Beater" Avanti---R5388 @ Macungie 2006

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                • #9
                  The Paxton blower isn't all that efficient on some engines due to the cubic inches. Put the same blower on a 185 cubic inch six with the same rpm's and pulley speed and the boost increases greatly due to smaller total combustion chamber volume and can add proportionately far more horsepower...at the cost of potential engine destruction. That's why balancing pulley sizes is so important. Heat buildup, combustion chamber pressures are a real danger, especially with no waste gates to bleed off excess boost.

                  Studebaker used the Paxton for a couple of reasons...it was pretty much the only game in town to quickly add power without going to the time and cost of designing a bigger engine, plus they bought Paxton just for that reason. It was more expedient, plus added a bit of the exotic for the Avanti.




                  Poet...Mystic...Soldier of Fortune. As always...self-absorbed, adversarial, cocky and in general a malcontent.
                  Poet...Mystic...Soldier of Fortune. As always...self-absorbed, adversarial, cocky and in general a malcontent.

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                  • #10
                    if anyone thoroughly researches this, I wouldn't mind a x-ref between Stude part nos. and pulley diameters. I started to do something like this for water pump, crank, etc. pulleys a while back and gave up because of the sheer impossibility of finding known parts to measure. The problem that I had was trying to piece together pulleys for an A/C setup that wouldn't eat up the belts (anyone who's seen a Lark or Hawk with factory air knows what I'm talking about) but I gave up when I realized that the hood wouldn't clear the compressor using the factory bracket, and the aftermarket bracket I ended up using did not use a water pump pulley because the idler was on the driver's side, so I didn't have to worry about it anymore.

                    nate

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                    55 Commander Starlight
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                    • #11
                      1557958-Pulley, supercharger drive Note 1 63V
                      1560406-Pulley, supercharger drive Note 2 63V,64V


                      1557956-Pulley, supercharger driven 63V
                      1560405-Pulley, supercharger driven 64V

                      Note 1-used on model 63V
                      before car serials K V-24,729
                      exc.K V-24,811

                      before engine No. JTS-1,546


                      Note 2- used on and after car serials and engine number in Note 1

                      from 59-64 chassis parts catalog Sept. 1963

                      regards,
                      Jay

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                      • #12
                        The parts book shows that '63 &'64 pulleys, drive & driven, are the same. The larger drive pulley is listed as R3 only. The R3 used the same driven pulley as the '63-64 R2's. I don't think you would put a smaller driven pulley on the blower, and putting a larger driven pulley would increase the maximum permissible engine rpm before damaging the blower. With a larger crank pulley and larger blower pulley, the drive ratio would stay close to the same, but an improvement in belt retention might be had. I'm only guessing at that. (Sorry, my comments apply to the Avanti. I didn't realize you were talking about JTS setups.)

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                        • #13
                          I am using an original 59-64 chassis parts catalog dated Sept. 1963 and getting the info from the green Jet Thrust Engine Equipment section. My book does not have any R3 or R4 info. in it. I apologize, maybe the confusion is between the Avanti double belt pulley and the Lark single belt pulleys. The info. that I posted earlier shows a different driven pulley between 63 and 64 model years and a different drive pulley specific to before and after engine number.

                          regards,
                          Jay

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                          • #14
                            Thanks to all for your input. I am sorry I should have specified Lark R2 from the start. I assumed if Studebaker made a change to the supercharger drive of a Lark R2 they would also make that change to an Avanti R2. At my age I should know better than to [u]ass</u>u[u]me</u> to much.

                            regards,
                            Jay

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                            • #15
                              it looks like I assumed also in thinking Avanti even though you didn't mention it.



                              1988 "Beater" Avanti---R5388 @ Macungie 2006

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