Fine Tuning a 360 Magnum with a Brawler "Double Pumper"
So it’s a lot of back and forth stuff? I’ve heard the annulars are better for daily/low end fueling and suffer in the top end, which doesn’t really matter to me.
I’m just hoping I can run a really lean transition and still keep it safe once I crack open the throttle, that’s my goal. This truck with this cam barely does anything to stay moving down the highway, so I can really get some good mpg if I can run it lean
You do NOT have to sacrifice top end power for driveability. Nor should you.
That was what I was saying above. I have 850 CFM carbs out there with the booster I use that run on primary jets between 66 and 69, PVCR’s in the mid to high 60’s (and thats a touch far but I err on the side of caution there) T slot restricters no bigger than .070 and secondary jets in the high 70’s.
That absolutely drives some guys wild because rather than giving the engine what it wants, they tune to what is considered “orthodox” jetting for any given Venturi and throttle blade size.
They think that if your jetting doesn’t fall into what has been used for decades without regard to booster design then they go off the cliff and run them fat and they didn’t fix anything.
I promise you that you’ll end up with a main air bleed no bigger than .028 and if the booster works very well you may go as small as .024.
The smaller the main air bleed, the later the booster starts so you are leaner at low throttle opening.
And at WOT that small air bleed doesn’t bleed off as much signal so the fuel curve goes pig rich up there. That’s where the much smaller main jet comes in.
All the emulsion bleeds and air bleeds and booster design all affect each other. The trick is figuring out how the trim the fuel curve when it goes fat or lean.