Quote:
Originally Posted by NeighborsComplaint
I could see that possibility. My mechanical pump draws through my Holley vane pump without issue though. I don't drag race the car but on short bursts of WOT, it doesn't run out of fuel with the mechanical pump alone. I do have a dual bowl Holley carb which could possibly compensate with its larger bowl capacity.
Before I installed the Holley pump, I put a reducer on the inlet side and ran some low pressure compressed air through simulating a stream and really didn't note any difference in flow out of the pump vs the supply. Not entirely scientific but a test at least. I just decided to plumb without the bypass and see. It has worked just fine without the bypass.
Perhaps if I were a drag race and running at sustained WOT on a Qjet with limited inlet needle and bowl capacity, I might notice a difference but the current setup has worked just fine since installed. The recent onset of a vapor lock condition was the first time the car ever stumbled. Todays fuel of course continues to evolve.
|
Thirty years ago, we installed a Carter high-performance mechanical pump and a Holley blue pump on a 1973 Formula 455. With the qjet, it would sometimes stumble under acceleration if the electric pump was off AND on a long drive on the highway. We would eventually have to turn the electric pump on.
With the Holley 800 spread bore DP, the stumble under acceleration was lessened but, eventually, we had to turn the electric pump on if driving down the highway.
With the Holley the problem was less noticeable under short bursts of acceleration than it was with the qjet, probably, as you noted, due to the larger fuel bowls.