4 BAR on LR and 2 BAR Spring on top RR

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  • 28m
    Member
    • Dec 2010
    • 49

    #16
    Seven words...Put the spring behind on the RR.

    You will get the roll that you want and more drive coming off. Dont add the LR bite just yet. Spring on back when on the gas adds more LR bite and drvie.

    You will think you have a new car. PROMISE
    Last edited by 28m; 05-25-2011, 11:57 AM.
    http://s200.photobucket.com/albums/a...8m%20and%201m/

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    • xxx8x
      Junior Member
      • Jan 2010
      • 15

      #17
      thanks, 28m.

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      • powerslide
        Senior Member
        • May 2007
        • 2696

        #18
        Originally posted by 28m View Post
        Seven words...Put the spring behind on the RR.

        You will get the roll that you want and more drive coming off. Dont add the LR bite just yet. Spring on back when on the gas adds more LR bite and drvie.

        You will think you have a new car. PROMISE
        you will have a new car alright. it will have your left front so high up the air you wont be able to see and you will be pushing the nose across the track. this will be compounded if your pullbar travels alot.

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        • Mosidebite
          Senior Member
          • May 2007
          • 717

          #19
          Gotta agree with ^. Our Hoffman car was at it's best on the 4-2 with spring on top to keep left front from being up in the clouds. We actually used a little stiffer rr spring, a 250. With a 200 on the left rear. However used a 3 comp and a 5 reb shock to keep it over on the right rear. RR bar angle was critical to our set up, we always had to have 8 degrees in the lower to keep it from leveling out or actually neg degrees and causing a TIGHT on entry thru the center. Also with the stiffer RR spring we used a little lower rear roll center.

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          • 28m
            Member
            • Dec 2010
            • 49

            #20
            Originally posted by romeropolo View Post
            Question- What changes need to be made to have more body roll to load the RR comming off the corner?
            Weird, I thought he was asking how to get more roll?

            So let’s say you put the spring behind and your LF is "in the clouds", I would add pre-load to your pull bar, stiffen the spring or switch to a biscuit bar. Since your spring will drop on the RR, you might stiffen the RR spring a bit. This will keep the front down, add spring pressure to the RR adding side bite. The stiffer RR will add drive to that wheel as well. This is good because you will be adding drive to the LR by that spring dropping on the RR.

            Another question has to be the type of track you run on. Heavy, slick, banked, flat?
            http://s200.photobucket.com/albums/a...8m%20and%201m/

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            • powerslide
              Senior Member
              • May 2007
              • 2696

              #21
              I think your understanding is correct. only thing i will say in addition is that the spring behind on a heavy/rough track is about impossible to drive. JMO

              We learn by trying so give it a try but i wouldnt spend too much time on it.

              Originally posted by 28m View Post
              Weird, I thought he was asking how to get more roll?

              So let’s say you put the spring behind and your LF is "in the clouds", I would add pre-load to your pull bar, stiffen the spring or switch to a biscuit bar. Since your spring will drop on the RR, you might stiffen the RR spring a bit. This will keep the front down, add spring pressure to the RR adding side bite. The stiffer RR will add drive to that wheel as well. This is good because you will be adding drive to the LR by that spring dropping on the RR.

              Another question has to be the type of track you run on. Heavy, slick, banked, flat?

              Comment

              • romeropolo
                Junior Member
                • Feb 2010
                • 24

                #22
                4 bar 2 bar

                This weekend I went with moving the LR shock behind moved the pull bar over (left) 1 inch(it was right of center 1 inch).

                I race on a VERY small bull ring(VENTURA RACEWAY) with very little banking on the bottom. (which is the prefered line) I couldn't keep it down on the bottom and still had the same bite off the corner.

                Next I'm going to go from 30lbs of bite to 70lbs. Any Ideas??????

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                • washeduptoo
                  Senior Member
                  • May 2007
                  • 1353

                  #23
                  Did you move the lr shock behind or the rr shock behind? Have you tried to reduce the rake in the jbar?

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                  • romeropolo
                    Junior Member
                    • Feb 2010
                    • 24

                    #24
                    I moved the RR shock to the rear and moved the pull bar to the left 1 inch for this weekends race and the car was tighter in and had little drive off. I still had 30 lbs of bite in it.......I am going to put 70 lbs of bite in it for the next race.

                    ****Question is will the change give it more drive off or just make it even tighter?

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                    • charcoal01
                      Senior Member
                      • Jul 2008
                      • 545

                      #25
                      Originally posted by romeropolo View Post
                      I moved the RR shock to the rear and moved the pull bar to the left 1 inch for this weekends race and the car was tighter in and had little drive off. I still had 30 lbs of bite in it.......I am going to put 70 lbs of bite in it for the next race.

                      ****Question is will the change give it more drive off or just make it even tighter?
                      is the spring on the shock or is the shock separate from the spring, and the spring is on top of the axle housing?

                      how much lead do you have on the car and where?

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                      • oldtrackchamp4x
                        Senior Member
                        • Nov 2009
                        • 270

                        #26
                        On my car when i up the bite it is looser in and more drive off.

                        Comment

                        • washeduptoo
                          Senior Member
                          • May 2007
                          • 1353

                          #27
                          Both changes you made would make the car tighter, one on entry, other one on the gas. Increasing lr bite should loosen entry some and tighten the car off. How close are you to bottom out rf shock? Are you trying to loosen the car up some? IMO, look at the jbar rake, I recommended 5in of rake and the dw8 guy recommended 4.5in of rake. Good luck.

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                          • charcoal01
                            Senior Member
                            • Jul 2008
                            • 545

                            #28
                            Originally posted by xxx8x View Post
                            On a 2 link lr spring in front rr on top. whats the best shock in front or behind on rr.OR IS IT DRIVER PREF.
                            depends on if you have a split valve shock or not. if its a straight 5-5 or 4-4, it wont matter as much because the axle sees the same resistance in and out. on a split valve its going to make a difference.

                            i ran a 4-3 on my rr, spring on top with lr spring in front, shock behind. car was a little tight in. i took the rr and moved it to the front, freed me up just enough and felt much more comfortable to me so i left it there.

                            theory is as the axle wraps forward on decel, it momentarily sees an increase in weight on that wheel as the shock is on the compression side, thus planting the rr a little more than the left (if shock is behind). does the reverse if you put it in front. its not a huge swing one way or the other, just a fine tuning tool.

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                            • romeropolo
                              Junior Member
                              • Feb 2010
                              • 24

                              #29
                              Originally posted by charcoal01 View Post
                              is the spring on the shock or is the shock separate from the spring, and the spring is on top of the axle housing?

                              how much lead do you have on the car and where?
                              On the RR....225 spring on top, 95 pro shock behind axle, 1/4 inch lead in RR. 7 inches of Rake in the J bar.

                              Two things I want to change is the bite and the rake. But I will make the bite change first from 30lbs to 70 lbs on the LR....if that dont give me the forward bite I want I will make the J bar change.

                              Comment

                              • 28m
                                Member
                                • Dec 2010
                                • 49

                                #30
                                Originally posted by charcoal01 View Post
                                theory is as the axle wraps forward on decel, it momentarily sees an increase in weight on that wheel as the shock is on the compression side, thus planting the rr a little more than the left (if shock is behind). does the reverse if you put it in front. its not a huge swing one way or the other, just a fine tuning tool.
                                I agree with the last statement here..."Its not a huge swing" If you’re so tight getting in that you can’t keep the car on the bottom and your lacking forward drive...the shock placement isn’t your answer. JMO of course

                                J-bar won’t help drive off necessarily. It will help your entry which will let you keep momentum and ultimately make you faster... that is a lot of rake to me and is probably why the tight entry.

                                Too both loosen the car getting in and tighten coming off, increase your LR spring rate and decrees your RR spring rate. This will be a much more effective adjustment than shock placement but not as drastic as moving your RR spring to the back of the housing like I suggested earlier. I guess it depends on how close you are. .1 second off…move the shock .5 second off…change springs 1 second off…move the spring.

                                I agree with you adding more LR bite. Pretty sure your headed the right direction with that.
                                Last edited by 28m; 06-01-2011, 07:00 PM.
                                http://s200.photobucket.com/albums/a...8m%20and%201m/

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