Do I need a new converter?

Mopar Racers Forum

  1. CopperheadDart

    CopperheadDart Active Member

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    Yes it does, havent done it yet but that's my weekend plan. Make a couple pulls and see what is really going on. I'll update when I get some numbers.
     
  2. justinp61

    justinp61 Well-Known Member

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    I'm guessing you're logging RPM and AFR, if you have the capability log driveshaft RPM too.
     
  3. Phreakish

    Phreakish Well-Known Member

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    Fitech breaks everything down by idle, 1100, 3000, and 6000 rpm. This means that you're not at your total timing goal until 3k rpm (assuming that's where you have it set to go to 34 degrees, and hold 34 through 6k). I've found these rpm points give some lackluster results. It's possible in the 'breakpoints' settings to change the rpm values but I've also found that can give some unwanted results. But not reaching full timing until 3k might help explain why it footbrakes at 2400 rpm.

    Fitech uses linear interpolation to determine timing for any given RPM. Assuming you're around 14-15 deg at 1100 rpm (since their instructions say to stay close to idle) that means you've got ~19 degrees of advance from 1100 to 3000 rpm, or about 1 degree per 100 rpm. At 2400 rpm you're only at 28 degrees. If I were you, I might try lowering the rpm breakpoint for mid-rpm down to 2k-2200 and see if you find some results. This should up your torque from 3k and below.

    This is why for racing I'd stick with distributor controlled timing - you get far better control over the curve that way, just takes more monkeying rather than button pushing ;)
     
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    • mderoy340

      mderoy340 Well-Known Member

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      Well the initial timing is not helping at all. With a 246@.050 cam and carb I would be at 32 intial idle and 34 up on the converter.
       
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      • CopperheadDart

        CopperheadDart Active Member

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        Update! Since this spring I made some changes to the car, and I'm edging closer to where I think my combo should be. I played around with timing adjustments to advance sooner, which seemed to help. I also had Dynamic Converters build me a 9.5" converter, which only flashes a couple hundred rpm more than my old one (around 4400). The difference is there though, improving my old best ET by .4 seconds to a 7.28, and MPH is +4 to 94.3. The odd thing is my 60' has only improved by .08 at best. I really don't feel any wheel spin, but a poor quality phone video my friend took showed the car "porpoising" through the 60' until it settled out.
        I decided I won't be changing up the cam or doing anything with the heads unless absolutely necessary, as I'm pretty happy with what I have now. It's at the point I think I can be consistent with it, run an ET class, and a 7.5 index class at my local track. I may look into a set of real shocks over the winter though. I appreciate everyone's input, and look forward to hearing from more people running Fitech's on the track.
        I also weighed the car, came in at 3,340 with me in it- full interior, heater box...

        20200812_151711.jpg

        timeslip.jpg
         
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        • mopowers

          mopowers Well-Known Member

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          Thanks for following up! That's a HUGE improvement .4 sec and 4 mph. Well worth the cost.
           
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          • B3422w5

            B3422w5 Well-Known Member

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            Frankly, its still roughly 1/2 a second slow in what it looks like it would run in the quarter( maybe 11.50’s)
            That time slip is almost a tenth off from what my similar compression( mine was a little less) stock stroke 360 ran this past season with eddie heads i just found out were little, if any, better than stock( they went 255 max)
            My car weighs within 20 pounds of yours. Has same intake, smaller headers, same gear. But more cam and convertor.
            If i had to guess, assuming the FI is doing its job, i would still suspect the camshaft is a big power limiter, and correspondingly would want more flash with a bigger cam. Makes me wonder too about the heads
            Stroker should be 3/4 tenths quicker than a stock stroke deal, falling off a log, all things similar.
             
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            • crackedback

              crackedback FABO Gold Member FABO Gold Member

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              Did you get the timing curve sorted out?

              Put a light on it and log where it is every 200 rpm up to 3K. You really want it all in earlier than later.
               
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              • CopperheadDart

                CopperheadDart Active Member

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                I never put a light on it to confirm, but according to my handheld it ramped to 28* just off idle, and 34* by 3000rpm.
                 
              • crackedback

                crackedback FABO Gold Member FABO Gold Member

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                probably should be all in by 2200
                 
              • B3422w5

                B3422w5 Well-Known Member

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                That shouldn't be causing you any issues at all
                 
              • 33IMP

                33IMP Well-Known Member

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                Do i need a new converter?

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