Quote:
Originally Posted by PAUL K
I can believe a 1.39 venturi could flow a true 850 CFM.
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the true cfm would be on a wet flow bench to simulate the fuel being in suspension. and that is very hard to find today, cuz it costs millions to build a bench like that. sure it may flow 850, at an unrealistic pressure drop an engine never sees, and dry.
an 850 Holley is rated at 1.5" Hg (Mercury) by Holley, that would be 20.4" of water on a Superflow 1000. Buy a new Edelbrock 1308 for $957, drop it on an SF1000, open all 4 barrels, see what it flows dry. Cuz then someone is lying.
Is it Holley who's been building 850's since 1960's, or Edelbrock who just started making them last year, changed owners, and choked down the venturis from 1.56" to 1.39", then added 4 annular discharge boosters, which block even more flow. That VRS carb probably doesn't even flow 700 cfm, let alone 850.
When BG would put straight annular boosters on their 1.56" throat 1025cfm carbs, the carb would drop to 820cfm rating compared to the original downleg boosters.
When they did the same to their 1050cfm 1.59" throat carb, it would drop to a 950cfm rating. This was wet flowed on a very, very expensive flow bench. $250,000 back in the 1990's.
That was with the correct 1.56" throat, and an even bigger 1.59" throat, and standard 1.75" butterflies.
Now imagine what it would flow with a 1.39" throat. No way in hell will it be the same. BG never put annular nozzles on a 750 or lower carb for this reason, it chokes the flow. All the BG Demon 1.40" throat carbs with downleg boosters flow 750-775cfm.
That's about what that Edelbrock 850 would flow, IF it had downleg boosters.
It may only flow 650cfm with the straight annulars, and 1.39" throat.