Author Topic: Pump limits and tuning  (Read 2988 times)

Offline aafa760

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Pump limits and tuning
« on: January 24, 2016, 03:06:59 PM »
Hello Everyone,

so say you limited to 7.0 gal pump like Blown A-fuel guys

and you have 450 inch engine
Do you just run a blank for main bypass and then chase/change nozzles around engine?
nozzle area .0331
my Software calculates that system pressure is only like 77 psi. so you better use a manual high speed.
Bruce I was talking to Bobby Cattrell's guys and was amazed how little fuel the Blown guys get to work with.
and they still run like 20-30 %overdrive or more on the blowers. A/F ratio must be close to being to lean. :P







dreracecar

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Re: Pump limits and tuning
« Reply #1 on: January 25, 2016, 08:01:55 AM »
With a limited pump size it more important to have enough fuel at the hit and why they run clutches instead of 'glides, they run the clutches rather loose to keep the pump speed high. The downside is that the clutch gets extreemly hot and that transfers to the rear main.

  If you dont have enough pump pressure/fuel volume at the hit, means that the power is down and you will go into shake
  Never did care for the A/F class. I the begining it was touted as an inexpensive class to run Nitro and restrictions were put in to keep the cars at high 6's low 7's. They did a lot of monkeying around with it over the years but instead of keeping it at those numbers, the ETs have become lower and lower and a lot of racers/cars got parked do to cost. If people enjoy that type of racing---Great for them, but its a long and costly road