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How low can You go?

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  • Iron Duke NCRS #22045

    #31
    You can't have your cake an eat it too!

    Let's compart two engines - the 327/300 and 327/340 in '63. The 300 made more peak torque (360 lb-ft @ 3200) than the 340 (344 @ 4000). If fact the 300 made more torque, which means it made more power (HP=TxN/5252) than the 340 up to about 3500 RPM. At that point the 300's torque begins to drop faster while the 340's torque continues to climb a bit, then level off and not drop much until about 5500 RPM. This is because the Duntov cam shifted the entire torque curve about a thousand revs up the scale, but the increase in top end power came at the expense of low end torque, and therefore, low end power. It's power that accelerates a car and that's why a torque shy engine with lot's of top end power need a "shorter" gear. When we say an engine has lots of torque, we are saying that it has lots of low end power. Modern engines use all kinds of tricks such as variable valve timing and variable inlet tract lengths to try to flatten the torque curve as much as possible, but an absolutely flat torque curve has yet to be achieve, although the "torque bandwidwith" of modern engines is much better than our vintage engines.

    BTW, we refer to the top gear in the transmission as "high" eventhough it's lower numerically than the other gears. This is because it provides a higher speed at the same revs. Rather than talk about "high" or "low numerical", how about if we standardize on "short" for a high numerical ratio and "tall" for a low numerical ratio.

    Duke

    Comment

    • Dave #24235

      #32
      ok,ok, if ya wanna talk torque curves......

      ...a wide ratio (WR) box strings them together for optimum quarter mile times. We are trying to arrive at a gearbox that gives quiet, low rev high speed results and still has enough ass to flatten 5 liter Mustangs at stoplights. A close ratio (CR) will do that with a 3.08 - not as well as a Doug Nash 5 speed, but the four speed is cheaper and easier to install. For the best performance in both worlds (street & strip) the DN is tops. - Dave

      Comment

      • Iron Duke NCRS #22045

        #33
        No way!

        A Special High Performance engine with a CR and a 3.08 will not flatten anything across an intersection including ricers in ten year old slammed four door Accords with slushboxes. It's like starting out in second gear. The intergear ratio of a WR and CR is the same for 1/2 and 2/3, but the WR has a big gap to fourth. If off the line performance is important, the wide ratio is the way to go, but the shift to fourth makes the car fall on it's face. Or in my case, the car is flat on it's back until about 40 MPH, but the payback is when I shift to fourth at 6500 and 130 and the revs only drop to about 5000 instead of 4400, so the engine remains in the sweet spot of the power curve and keeps pulling until the front end lifts off and you can't steer anymore.

        Comment

        • Iron Duke NCRS #22045

          #34
          Re: Free At Last, Free At Last

          Well said, Chuck. After spending seven years rearranging deck chairs on the Titanic (IBM) I bailed out in 1991 whle I still had my self respect and before they made 200,000 people walk the plank. Then I caught caught up in California's worst economic conditions since the thirties and it was tight for a while, but I finally figured out how to make ends meet and pursue what I enjoy without being someone else's galley slave. I did have to eliminate the cruise around the world and the trip to LeMans this year. Life's a beach!

          Duke

          Comment

          • Iron Duke NCRS #22045

            #35
            It's the other way around!

            2.20x3.36=7.39. 2.54x3.08= 7.82, so a WR with a 3.08 provides better starting torque multiplication than a CR with a 3.36. The price you pay is the big gap to fourth. It would take a 3.55 with the CR to equal the starting torque multiplication of a WR and a 3.36. For midyears the standard axle with the torque shy mechancial lifter SHP and FI engines was a 3.70, and you could only get the four speed in a CR version from the factory. You had your choice of WR or CR with the '66 and '67 hydraulic lifter SHP engine, and the available axles were 3.36 and 3.55 with the WR and 3.70 and 4.11 with the CR.

            Duke

            Comment

            • Chuck S.
              Expired
              • April 1, 1992
              • 4668

              #36
              Re: Free At Last, Free At Last

              Duke,

              Let's see; You worked in automotive, you worked in aerospace, and you worked computing? Now that's flexibility. You must have nailed the interviews. Only person I've met who changed careers as much I did.

              For me, it was aerospace, petroleum/petrochemicals, and plastics (an abortive mini-career).

              Hey, you're not one of them there day traders, are you?

              Chuck Sangerhausen

              Comment

              • Don O'Connell #33101

                #37
                Ya gotta love FORTRAN 77..

                they added long variable names! I'm sitting here starring at a circa 1973 17 column, mark with a #2 pencil, marked FORTRAN card. I keep it on my monitor right next to the convert-the-45-to-a-33 LP spindle "spider". I use them for quizzing my engineering new hires....

                Don

                Comment

                • Wayne M.
                  Expired
                  • March 1, 1980
                  • 6414

                  #38
                  Re: Ya gotta love FORTRAN 77..

                  Don --- When you're interviewing those new hires, slip the phrase "nested DO-loop" into the conversation, and watch them blink.

                  Comment

                  • Iron Duke NCRS #22045

                    #39
                    Day trader?...

                    Nope. By the time I was 45 about the only thing left was to become the plumbing department specialist at Home Depot. I started working when I was eleven. I've done some trading in the past, but now I'm locking myself into some good yields with intermediate maturity bonds. I like to sleep at night! Careers and women are temporary. Corvettes are forever.

                    Comment

                    • Iron Duke NCRS #22045

                      #40
                      ...77? Never got that far!

                      I think it was called FORTRAN IV when I used it from '64 to '70, but I sold some FORTRAN 77 compilers on VAXes when I was with DEC in sales.

                      Duke

                      Comment

                      • Iron Duke NCRS #22045

                        #41
                        You've got it backwards, Dave......ntx

                        ntx

                        Comment

                        • Dale Pearman

                          #42
                          YA GOT IT TOGETHER DUKE!

                          I hope everyone in NCRS reads your post. These relationships are widely misunderstood. Most of my buddies don't even understaned that torque is a twisting force, let alone the mathematical relationship to horsepower! Also they have no concept of "real life results" of variations in these relationships! Thanks for an exceptional post!

                          Dale Pearman

                          Comment

                          • Iron Duke NCRS #22045

                            #43
                            MIT, eh?...

                            I figured there was something behind that "aw shucks, I'm just white trash" schtick. I know - you got it from Smokey Yunick. He's probably read more text books and technical papers than you and I put together. I didn't go to MIT. I DID get accepted to their graduate progam in internal combustion engine research, but decided to go with the University of Wisconsin IC engine program, instead.

                            I understand your frustration with the torque and horsepower issue. Most car enthusiasts just don't understand what they're about and the relationship between them.

                            If anyone wants to pursue this - ask questions, tell me I'm all wet, burn me with a flamethrower, whatever - let the discussion begin!

                            Duke

                            Comment

                            • Don O'Connell #33101

                              #44

                              Comment

                              • Dale Pearman

                                #45
                                Re: MIT, eh?...

                                Duke, Ya didn't miss a damn thing by turning MIT down! Based on my opinion of your thinking in jest about everything ya post I'd say ya learned your trade a lot better where ua went! Took me nine years to learn my trade at MIT and then decided, "It's Booring!". Got my EDUCATION under a shade tree here in Tennessee with a bunch of "good-ole-boy" dirt track racers. "PURA VIDA", PURE LIFE!

                                Smokey Yunick & me is chums! Here's a dude as major as Norbert Weiner! A real gunius, but, does he know how to read? He sure knows how to act like me!

                                The Rev.

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