Finally had it dyno'd

Discussion in 'High Performance Modifications' started by chieft82, Dec 16, 2015.

  1. chieft82

    chieft82 Veteran Member

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    no popping or missing over 5000 but it definitely sounds flatter, it screams up to about 4800 then sounds like it levels out
     
  2. 76z28

    76z28 Veteran Member

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    performer rpm air gap
    get rid of that and put a victor jr and that sound will go away :)
    I had this problem on my 489.. It lost NO, NONE, NADA for bottom end and only gained everywhere.
    Don't let people sway you to believe that the RPM airgap is the end all intake. It restricted my big block, it could restrict a small block.
     
  3. Z73

    Z73 Veteran Member

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    I have a very similar set up to what your running ,385 ci, Ik180 stock springs,blue racer cam 232/234@50 494 lift with 1.52 rockers kb flat tops should be about 9.8.1 with my 70cc chambers, performer rpm,670 holley .It made 415 at 5400rpm and 437 torque at 4400 and 400 torque at 2900rpm.we ran the engine to 6000 rpm and the power only dropped to 400 horse.I'm useing the springs that came with the heads which are basically Z/28 spec.I'm not sure how you came up with your crank horse power figure but I was told add 20% for an auto trans and 15% if you have a manual which comes up to 384 horse at the crank which with fan,alternator,power steering pump, (A/C compresser) which would put you a little over 400 horse which i believe is still a little light which I think you should be in the 430-450 range. The one thing that caught my attention is you said your running 1.6 rockers! Assuming your cam specs are with a 1.5 rocker your bottoming out the springs which are only rated at 525 lift you would be at 537intake and 560 exhaust with the 1.6 ratio.Not sure if thats your problem but if it is a good set of 1.5 roller tipped rockers will probably get you pulling above the 5000rpm mark?
     
    Last edited: Jan 8, 2016
  4. Z73

    Z73 Veteran Member

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    Also not sure what you ran for total timing but mine liked 36 degrees
     
  5. chieft82

    chieft82 Veteran Member

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    well I did some digging and found out that the motor is running less compression than I thought only 9.5.1 this being the case I was thinking of shaving the heads down to a 58cc chamber to boost the compression up or sticking a small blower on it with 7 or 8 lbs of boost (my 03 cobra got me thinking about adding a roots blower) but is 9.5.1 too much compression to run a blower?
     
  6. DB Z28

    DB Z28 Veteran Member

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    not at all but thats about the max in compression for a turbo or blower
     
  7. Z73

    Z73 Veteran Member

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    How do you only have 9.5.1? Do you have dished pistons?
     
  8. Goodwrench1965

    Goodwrench1965 Veteran Member

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    I've got a 383 with hyd. Roller cam 236 242 @ 50, 195cc Canfield heads, long tube hookers, 3.73 gear ratio, Tremec 5 speed in #3825 track weight on slicks launch with front tires off the ground. Speed sifting without lifting off the throttle except slightly 1st to 2nd gear. I've still never broke et into the 7 second eighth or 12 second quarter range. I'm sure more suspension and engine tuning would make difference but point is 11 second quarter mile with cars #3800 plus and 3.73 would take some magic. I'm sure Warren Johnson could tune his nephews camaro that quick bet as for us mortals I'd but Cheif82 car runs 13s in quarter and 8s in the eighth.
     
    Last edited: Jan 22, 2016
  9. chieft82

    chieft82 Veteran Member

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  10. hutchenc

    hutchenc Veteran Member

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    Why don't you put on a set of better valvesprings and see what happens? Would be a lot cheaper than any kind of power added or pulling and decking those heads.

    If you wind up pulling the heads and decking them, you might think about a different set of heads instead. I wouldn't put anything smaller than a 195cc head on a 383.

    Also...you should post your dyno graph. If it's really a problem with the valvesprings floating it'll show up in the graph when the power line goes from smooth to bouncing around.
     

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