Question about timing retard

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by Senior moments, Dec 26, 2012.

  1. Senior moments

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    I run a dragster with a 511 BBC, alky stack injection, MSD ProMag12. The car runs 7.70's running 38 deg advance. I'm old skool, so I don't know much about top-end retard
    boxes - like the MSD 8168. I know there's the MSD Grid 7730, but I will set that aside for now.
    I have not dyno'd the engine but figure it's putting out about a true 800 hp. The question is....would using the 8168 MSD box to pull some degrees out at the top end using an MSD RPM activated switch - result in any visible difference in ET on my relatively low hp package? The engine clears the traps at about 7900 rpm. I have heard that pulling degrees out is only beneficial for high HP cars - but I don't know. Any advice would be appreciated. Thanks ITA
     
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  2. Mike Canter

    Mike Canter Top Dragster

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    I believe that most all ET is made by the 330' mark and very little after that. You can lose ET if something goes wrong after the 330 but most everything after the 330 results in MPH. The only reason I would ever pull out timing at the end is for safety because I had it too far advanced the timing at the start. I think this is a real good topic for discussion.
     
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  3. Bottlefed

    Bottlefed New to Blowers

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    Retard on top

    Whats up Mike been ages.

    Anyhow on the retard deal, its been my understanding that in NA applications its more effective with Gasoline than Alky. Also that it depends a lot on gear ratio, that is if the motor is running out of gear it may allow the engine to spin easier, but if its still under good load then you are not likely to see much change.

    Is this close or do I have the whole deal backwards?
     
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  4. rb0804

    rb0804 Member

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    Mike, I used to agree with you until I came across this run by Mike Austin testing earlier this year in Jim Whiteleys car from last year with the B&J quick drive two speed. Mike Austin is slower on all incrementals, but carries more mph out the back as well as a quicker 1/4 mile elapsed time. I now know that you can make up some 'time' in the second half of the track. I pulled these numbers from drag race central and included the link below. If I have offended anyone by posting them here I apolagize in advance. To go along with the converter weight break rule in the other section of this forum, Whiteleys cars was a solid .20 car and the converter car only ran mid to high .40's before they quit running it for whatever reason.


    Left Lane: Mike Austin Runs 5.512/260.26, Now #5; Best prior run: 5.484/261.07, Was #5
    Right Lane: Garrett Bateman Runs 5.557/243.24, Now #7; Best prior run: 5.548/245.94, Was #7

    Eugene Tumbarello is on the bump spot at 5.549 and is a No Show for this session.

    Bateman's fueler is strong on the bottom end, but starts to drop cylinder on the top end. He slows just a tad to stay #7.

    No issues for Austin, but he slows a little too. He will not get into the top half of the field.

    Mike Austin's incremental times: 60ft-0.949 sec., 330ft-2.447, 660ft-3.633/209.04 mph, 1,000ft-4.650.
    Garrett Bateman's incremental times: 60ft-0.932 sec., 330ft-2.436, 660ft-3.618/208.26 mph, 1,000ft-4.649.

    http://www.dragracecentral.com/DRCStory.asp?ID=246563&Filter=Year2012#indextop
     
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  5. Mike Canter

    Mike Canter Top Dragster

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    I am only talking blown alcohol here. It maybe so but I have never seen a change but I guess that depends on if the base ting was good or not or advanced purposefully to give more power in first part then retarded to save the motor in the second half. That may appear to be a benefit that way. A motor can get away with more ignition advance when it is pulling quickly through the lower gears but that long pull in high gear will blow the motor unless timing is pulled out or fuel is added.

    It is hard to base an improvement on a single run one needs more data points to fully evaluate a change like that.
     
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  6. underby6

    underby6 Active Member

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    In regards to converters: Taking timing out doesn't help, you will lose et and mph if you take it out for too long. When you take it out for maybe the last 320' it only seems to hurt mph. A car leaving at WOT like Austin usually has about 20 degrees knocked out by .2 and it stays out until 1.5 or so, maybe longer. After that point the only reason to remove timing would be activating an input at the shift to minimize tire slippage.

    Brandon Booher
    NHRA TAD #34
     
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  7. rb0804

    rb0804 Member

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    The example of Austin's car was in response to mike canter saying he believed that the ET is made in the first 330 ft. If you look at the numbers Mike Austin is behind in every incremental except 1/4mile et and mph. It appears the A/F car that he was running dropped a cylinder late in the run, but again, if you look at the numbers, Mike was slowly gaining on him the entire run. I was also making the point that the car he was driving was a soils high 20 to low 30 car before they put the two speed converter in it for the converter haters.
     
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  8. Greg Kelley

    Greg Kelley Member

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    My thinking is the same a Mike's - with the minor modification of retarding to get the timing in the correct spot for best power as opposed to hurting something.

    Example:
    BBC bracket car alky injection:

    Timing static 32* 1/8 mile ET 5.04 1/4 mile 7.90 167mph
    Timing static 36* 1/8 mile ET 4.99 1/4 Mile 7.89 166mph

    Timing 38 at launch and retarded to 31 at 5 seconds out= 4.97 1/8 7.84 169mph

    There is probably a significant AF ratio factor in this as well. I did not have an O2 when me and a bunch of my friends used to do this.


    gk www.motorsportsinnovations.com
     
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  9. underby6

    underby6 Active Member

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    Gaining on him but likely a wounded a-fueler as you mentioned. I'll look at his splits vs. other splits and put something up later. With a converter the et is absolutely by the 330...I even believe the 60'.

    Brandon Booher
    NHRA TAD #34
     
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  10. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    trouble

    If you are heads up racing, there may be a hun or two if you hit it dead right. It's not going to be an automatic gain, which I think is the answer you are looking for.

    I would recommend just run static timing and not worry about it.

    Outside of et gains, retarding the timing late in the run can be a bit easier on parts if you are pushing it early like Mike said, but I doubt you are pushing it that hard.
     
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  11. Senior moments

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    Thanks for everybody's input. I'm TD bracket racing so the engine isn't on "kill". For the minimal possible ET increment that is to be realized with a retard set-up, it doesn't pencil.
    I'm gonna pass on it, but again thank everybody for the input. This is why I come to ITA. Straight no BS answers.
     
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  12. Mike Canter

    Mike Canter Top Dragster

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    Brandon, I agree that one's fate is decided somewhere before the 330 and somewhere after to 60 and probably closer to the 60. The problem is those are our two standards that we have to measure by. For a clutch car most of it is decided from launch until the clutch lockup time which for a NHRA legal PM is close to the same time as the 60 ft time. After the shift into second gear the car's performance is pretty well set. One can do things that will change the MPH but MPH is not what wins races.
     
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