fbekholden.com

(was meant to be posted last night but had the issue)

I have been reading harvs notes on strombergs and I think ive had a information overload for the night can anyone help with a few venturi sizes and most importantly and the bit I'm having trouble actually finding a answer to match to venturis for the single barrel stromies is a cfm rating I keep get mixed answers that a 5/32 ventri can be 155cfm 170cfm and some say around 200cfm which when calculating a total cfm for my motor gives three totally different results

The flowrates below are at 3"Hg, and have been scaled from the 1 3/32" value (which I found published somewhere believable). The scaling process is not simple pro-rata - I had to drag out Benoulli's theory again .

The numbers are rough - it will vary depending on the throttle body/internals/filter etc used on the specific carb.

1 3/32” = 162cfm.
1 5/32” = 210cfm.
1 9/32” = 287cfm.

Cheers,
Harv

Harv wrote:The flowrates below are at 3"Hg, and have been scaled from the 1 3/32" value (which I found published somewhere believable). The scaling process is not simple pro-rata - I had to drag out Benoulli's theory again .

The numbers are rough - it will vary depending on the throttle body/internals/filter etc used on the specific carb.

1 3/32” = 162cfm.
1 5/32” = 210cfm.
1 9/32” = 287cfm.

Cheers,
Harv

They flow higher numbers than i thought I'm wanting to run triples but have only ever came across the 1 5/32 carbs but that's 630 cfm what size carbs do people run on there grey motor triples 630 cfm seems a lot of fuel to be throwing at a 6 i will be running a 202 12 port head cam at a guess rev range will be hopefully from around 2400 to 6800 only as i had a cam years ago that ran around those figures and it had a sweet note and went well but that was on a 9 port head running doubles

Dammit, I misread my notes. Should be:
1 1/32" = 162cfm
1 3/32” = 201cfm.
1 5/32” = 210cfm.
1 9/32” = 287cfm.

I got the 1 5/32" right though .

Remember that these are at 3"Hg pressure drop. You are probably used to seeing numbers for 4-barrel carbs, which are measured at 1.5"Hg. To convert the numbers above to the 4-barrel scale:
1 1/32" = 114cfm
1 3/32” = 142cfm.
1 5/32” = 148cfm.
1 9/32” = 202cfm.

Grey triples normally run the BXOV-1 carbs (1 1/32"), factory red twins (HD/HR 186ci engines) ran twin 1 3/32" carbs. 1 5/32" triples would likely be overcarbed and boggy, even on a 202. If all you can find is this size, they can be venturi restricted back.

Cheers,
Harv

Thanks harv need this info archived.. greatly appreciated

wot das the 1 7/32" flow ?

fb delivery wrote:wot das the 1 7/32" flow ?

i'd be choosing a number in between these two

1 5/32” = 148cfm.
1 9/32” = 202cfm.

Id be guess at about 175cfm with how my brain works but i needed help to start with