jet size program

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by jrracing, Mar 19, 2017.

  1. Mike Canter

    Mike Canter Top Dragster

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    It doesn’t error either way. It does what you tell it to do. My recommendation is to find your best run in the past that you have weather and fuel notes on and put that run into AP then take it to Bradenton Nd put that weather in and go from there. Another recommendation is to pick an RPM and gear such as 9000 in second gear or if you don’t go that high then 8000 in second gear and look at the data logger and get boost, fuel pressure and fuel flow if you have it and also put in what leanouts were on at that time of the run. You always want to use the same point in the run for fuel data. You can calibrate AP to show exactly the same fuel data as shown on the logger. If you have a flow meter then every run is a flow bench run. Make sure you download the instructions from the www.alky-Pro.com website and read it. You can also download a trial copy of the software and can use it for a short period of time to decide if you want to buy the license for it.
     
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  2. td3829mk

    td3829mk Member

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    Thanks mike. I'll use data points at 8000. I don't have a flow meter on the car (yet). But I do have everything else. (Fuel pressure, boost, ect) And we put a new blower on the car that is showing 5 more lbs of boost on the blower dyno than the last blower did on the car which is adding another variable to the mix.

    As far as calculated AFRs go...I've been told 3.5:1 is a good number. Would you agree?
     
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  3. Mike Canter

    Mike Canter Top Dragster

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    I would never call dividing boost by fuel AFR. It just happens that the answer falls within the range of real AFR. I would say that in your calculations 3.5:1 would be a very lean start off. Your numbers are reverse of what would be real AFR. With real AFR the smaller the number the richer it is not so with your computations. A good safe way would be to multiply .34 times the pounds of boost. That should put you close. So if you had a good GPM on your old blower then put all that data into Alky Pro and increase the amount of fuel by 5 X .34 and that would be real close to right on.
     
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