Timing new motor

Discussion in 'PSI Superchargers Tech Questions' started by dragster156, Apr 12, 2019.

  1. dragster156

    dragster156 Member

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    Hey guys , I know its gonna be run it and see to get it where it wants, but looking for a nice starting point.

    Last year it was a 526 (4.375x4.375) brad 5 head motor. Compression was around 11 / 11.5 to 1. Not sure exactly though. It was driven 32 over and made 40 lbs of boost once in the best air of the year. it was usually 38 lbs.

    This year the combo is mostly new (it's the same blower, hat, fuel system etc. But now it's 532 (4.4675x 4.25) with brad 8x heads. Compression is close to 12.1 and it will be spun at the same 32 over.

    The guy I bought the 5 headed motor had the timing at 24-25 and I ran it like that all year. Just wondering does this diff head require a much diff timing set up? Not brand new to the hemi stuff but new enough not to know the ins and outs yet but trying to get there lol. If more motor is needed just let me know what you would like to know.

    What is max timing guys run is stuff like this when they "go fast". Also looking for something a step or so safe from that. But it would be nice to know the people who know opinions.
     
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  2. Mike Canter

    Mike Canter Top Dragster
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    24-25 degrees is still good. You can go to 26 if you put in more fuel and are willing to be on the edge.
     
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  3. Randy G.

    Randy G. Top Alcohol

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    If you have enough fuel in it 26* would be considered very safe. Not "on the edge".
     
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  4. tad1011

    tad1011 Member

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    Are you controlling timing or is it at a fixed number.
     
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  5. dragster156

    dragster156 Member

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    Fixed throughout run. Just started car today, its at 23.5. I will begin running with that and go from there I guess.
    guys running a few more degrees early and pulling it back out going down track?
     
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  6. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    Now that you are 4.467 bore you should be able to run more timing than the 4.375. Also the 8x heads will most likely want some more fuel since they flow more than the 5's.
     
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  7. Randy G.

    Randy G. Top Alcohol

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    I did a lot with timing and the response was quicker than adding or subtracting fuel. I have back to back to back runs 7 years ago that prove moving timing vs leaving it alone was worth a solid tenth of a second, and the least I ran was 27* unless I was pulling it back in low from 10' to 60' to keep it from blowing the tires off. After that it was ramped back in. Just to be safe I pulled it back to 27* in high gear unless we were in Las Vegas where the corrected altitude was higher. And by most standards I ran high compression. But you better have enough fuel in it or you'll knock the crank out of it. BTW, I ran 4.375 bore and ran a lot of fuel and did crazy things with the timing...and got away with it. Brad 6 heads was the newest I ever ran, and I ran a .900 Waterman Red pump with a pump loop jet.

    While the times and speeds are quicker today with the newer heads and Camaro bodies, I'll give you an example. At the 2012 Winternationals, which was the last time I raced my car with Daniel driving, we ran a 5.529 against Lombardo in the second round. Prior to that the quickest run of the event for everyone was a 5.51. In the semi final we had to race Bartone/Boggs. Daniel wacked the throttle hard enough when he rev'd it up to stage that he hit the full throttle switch under the gas pedal and set off my timers. By the time he launched the car everything was done (timing/fuel curve, etc.) so no timing. Loosing my combination it fell off a tenth of a second and ran a shake free full blast of 5.62, beating a tire smoking Bartone. For the final we changed a cylinder head because it dropped a valve after the finish line against Tony, but I left the car alone. This time Daniel did not hit the full throttle switch revving it up to go in in the final, and we ran a 5.531 slowing as he rolled off the throttle just before the finish line, winning the event against Jay's 5.54.
     
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