New at the track question about launching with red line tires

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  1. MrBubbles211

    MrBubbles211 Active Member

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    Hi all

    First I would like to thank everyone at FABO for the excellent advise that they have been passing along.

    I'm kind of new to this.. I mean I used to street drag back I the days

    Now to get up to date... I currently own a 1969 Dart GTS with a pretty much stock 340 recently rebuilt zero deck, Quick Fuel 750 carb and 3.91 rear end.

    Im thinking of taking it to the track here to sort of get an idea of how it does.

    The main questions that I have is that I'm using red line diamond back tires 24 inches tall with my 3.91 rear end... lots of torque... but probably also lots of smoking them down the whole length which is no good for et.

    Should I even do a burn out or would I better with just a could of dry hops and what kind of tire pressure should I be run?


    I'm thinking conservatively that this car should be I in the 14s... would love to get a little lower but that would definelty require slicks


    Anyways thanks for your time


    And is 14s about what I should be expecting
     
  2. KosmicKuda

    KosmicKuda FABO Gold Member FABO Gold Member

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    4 Speed or auto?

    Diamondback applies red lines to newer radials. Not necessarily hi-po tires either.

    Generally most people on street tires drive around the water box to keep the tires dry. You don't want water in the tire grooves when you stage.

    Having said that I'd say youll have to experiment. Burn out to heat the tires or not? Tire pressure? Is there a test and tune night at your local track? That should give you more opportunities to make lots of runs to make adjustments, fast lap it so the car is the same temp every run. Only make one change at a time and take notes.

    Take a look at the F.A.S.T cars and see what they're doing though they usually have their cars optimized to the nth degree.

    I'd expect you'll have to baby it off the line and get on the throttle after the launch.

    I have a "retirement project" 69 'cuda340 with factory 3.91, 4 speed, bench seat and manual brakes and steering. I'd guess about 14.3 on E70 belted redlines with good technique.
     
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    • 318willrun

      318willrun Utube channel 318willrun

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      I think the F.A.S.T. class uses worn corkers and heat them to no end. they also have extreme-tuned suspension. Some are in the 9's with those tires. Amazing
       
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      • furrystump

        furrystump Well-Known Member

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        I run f70-14 redline bias plys. I drive around the water and back the rear tires in. Roll out of the water and do a VERY short burnout. The first hint of smoke and thats it. Pay attention when you stage. I just barely turn on the stage lights that way I know that I'm in the same spot each time. For me I load the converter to 3000 rpm. Launch the car holding the throttle steady until the nose just hints at dropping, then roll into it. Average 1.76 60' best of 1.71'
         
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        • MrBubbles211

          MrBubbles211 Active Member

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          It's a 4 speed
           
        • MrBubbles211

          MrBubbles211 Active Member

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          Oh sorry I forgot it is a 4 speed car
           
        • MrBubbles211

          MrBubbles211 Active Member

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          Well I made it to the track for the first time this is my car

          1969 340 Dart bone stock 340 with 4500 miles on it. With a 4 speed, 3.91 gears, 24 inch Redline tires, and no tach so not sure Rpm for shift points.

          First of all it was brutal to get off the line. Smoking the tires was no good so.... I pretty much had to leave at idle

          I was leaving on the 3rd yellow.


          Reaction 0.475, 0.506, 0.314
          60ft 2.2157, 2.423, 2.2639
          1/8 mph 76, 75.5, 76.35
          1/4 et 14.7, 15.09, 14.78

          I did have some issues it seemed with my clutch not coming up very quick... seemed to take a while for it to engage.. would this be part of the reason for the slow reaction and 60 ft times.

          ALSO I did have some bogging

          I would have liked to do better is this about as good as I can expect for my combo

          I know slicks would improve my times


          Any advice would be appreciated
           
        • furrystump

          furrystump Well-Known Member

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          Four speeds and very small tires are a PITA! It is probably the hardest combo to launch well and consistently. To much rpm and you blow the tires off. To little and it will bog. Think of it this way, a torque converter can be tailored to flash or "slip" to a consistent rpm to where you can use the most power without blowing the tires off. 4 speed YOU are the converter. You need to slip the clutch coming out just enough that the tire holds. Which as you have probably guessed is hard on the clutch. That being said I have seen that tire with a four speed turn consistent 1.70's 60' times. So your power level may actually be your limiting factor at this time not the tire. Best advice is SMOOTH. You can't shock the tire. I run 26 lbs in them.
           
        • furrystump

          furrystump Well-Known Member

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          Clutch not engaging quickly could be many things. Its old and slips, the linkage is binding, motor mounts could be old and make the linkage bind more under power. The air space between the pressure plate and clutch disc could be on the bigger size.
           
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          • MrBubbles211

            MrBubbles211 Active Member

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            Well I had it at the track the best I could go was 14.7@96 mph
             
          • jimjimjimmy

            jimjimjimmy lobsterman FABO Gold Member

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            Your mph is not bad I would say low 14's high 13's with traction . no doubt there is more in it when you get tuning the car and yourself .
             
          • mderoy340

            mderoy340 Well-Known Member

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            My 73 340 Dart Sport ran 14.5 @ 99mph. 727 Auto, 3.91 8 3/4, Summit cheapo headers, 235/60/15 PEP boy's Super Sport cheap radial 26" tire. Everthing else on the car is stock, A/C/PS/PB console, big bumpers with extra interior plates still installed. Car is heavy.
            I drove around the water, no burnout, and feathered off the line a few feet and rolled into the throttle. I have found that driving technique is more important than raw HP. Fix the clutch issue and go experiment with the car. Can you borrow some better tires? MT Sportsman are DOT bias and are period correct.
             
          • ocdart

            ocdart Inland Mopars Car Club FABO Gold Member

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            Just for comparison, back in the early '70s my old 340 Swinger ran 14.28 @98+mph at OCIR here in SoCal.
            Stock 340, 3.23 non-Sure Grip rear end, 727, Goodyear Polyglas G70-14 tires...
             
          • moparmat2000

            moparmat2000 FABO Gold Member FABO Gold Member

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            Read an article about a high 9 second 68 hemi super bee that Dave Dudek built for the fast series. He said other than tire pressure changes and cokers that are burned out till they are almost slicks. His chassis mods consisted of no front sway bar, worn out rear shocks, and worn out 318 station wagon rear leaf springs to get it to squat on launch. Not sure if he used slant 6 or 318 torsion bars in the front. Very simple setup.
             
            Last edited: Oct 2, 2017
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            • furrystump

              furrystump Well-Known Member

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              It's been my experience that Dave has always been a pleasure to talk to and if you ever have an opportunity to meet him. Take advantage of it. He never ducks my stupid questions!
               
            • Vitamin c

              Vitamin c Vitamin c FABO Gold Member

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              You want to see something impressive, hit the pure stock drags in Michigan, this was my third year and I'm hooked. I've also done the last two years at the fast/ factory stock races. Id say a four speed on bias plies is a killer against most of these cars, you just cant get out of the hole with any consistency. With temperature changes as the day goes you'll gain or lose ET on top of all the other variables. One of the biggest problems coming out of the hole light, is trying to gauge where to have you clutch pedal when the lights come down. You need to remove all the free play you can without rolling through the lights, and when the last yellow hits you want to bog the car to keep from spinning. All of this going through your head at the tree creates horrible reaction times, or at least just inconsistent times. To compare, If you run slicks you can just bury the throttle and dump the clutch. This year another problem that was thrown into the mix was the track guy spraying the sticky stuff, every couple runs he would re spray and mop the starting line. If you were the next cars in line the track would actually get slick before the rosin would tack up. Most of the quicker pure stock guys have some tricks going on, I watched a 455 Buick GS lifting the drivers front on bias plies, now that's impressive.
               
            • Cudafever

              Cudafever Well-Known Member

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              I think the first two questions is, are the 3.91 an open or locking differential? 2nt do you have a pinion snubber and how much travel is there between the snubber and the floor pan.
               
            • furrystump

              furrystump Well-Known Member

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              Pinion snubbers really don't work with the small tires. They tend to bounce the tire and unload the suspension.
               
            • Cudafever

              Cudafever Well-Known Member

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              Hmmmm i have no experience with a stick shift.

              but i bet with a stick, you could control the bounce and make it plant harder with some spring clamps to keep the from segment of the spring from wadding up under launch......
               
            • furrystump

              furrystump Well-Known Member

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              The bounce is really in the tire not the spring. The snubber hits the floor and loads the tire quickly, but because of the tire pressure we run, the tire bounces. Also because the a body front spring section is so short I have never clamped the front of the spring. It's practically a ladder bar as is. I do remove the rear clamps to let the spring fan out.
               
            • Cudafever

              Cudafever Well-Known Member

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              After years and years of abuse i had to clamp my SS Spring because it was bending in that so short section. I have no experience with stick shift and skinny tires...so i will just leave it at that.
               
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