In the new hot rod, page 122. it says stock TBI is 520 cfm, bored out stocker flows 585, 454 TBI flows 620cfm.


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-Tas
'89 Formula WS-6
[soon to be Torch Red with black hood and headlights =) ]

305, TBI, auto, 14x3 chrome flat based open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips....

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at what " ?

I am interested.

 

just an addition bit of info. Turbo city says the "bored out" 454 TBI flows 670cfm.

 

So the holley unit is a bored out 454!
Either way I ordered the 670 holley unit.

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, Jon (91 RS too many mods to list)

 

E-mail from Holley:

We flow the 4 barrel units at 1 1/2 inches of vacuum. 2 barrels at 3
inches of vacuum. We flow everything with air and fuel. Not just air.
There is a difference.

E-mail from Turbo City:

(TC) Stock 350 TB = 520 CFM
Hi Flow = 590 CFM

(ME)Thank you for the information. It would be very helpful if you could tell me the pressure these measurements were taken at. IE 28" or 3", etc.

(TC) Sorry to say, but that information wasn't provided to us.


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1988 T/A,
9" Ford, 3.50 gears, Auburn posi, 700r4 -w- 2100 converter
350 .060 over with forged 1 pc rms crank, and forged TRW pistons, 9.5:1 cr
Factory GM heads Pocket ported, 2.02/1.60 valves, back cut
Lunati roller 219/227, .479/.480, 112 LSA
Holley 700cfm 4bbl on TBI truck 7747 computer and chip by Howell-EFI
Edelbrock Performer EGR intake, Edelbrock TES and 3" cat

[This message has been edited by Dan W (edited March 06, 2001).]

 

The standard test for flow is at 1.5" mercury pressure drop.

Holley was B.S.ing you. The A/F ratio for max power is 13:1 . That ratio is by weight. By weight that is only 7.6% fuel to make any difference. But airflow is measured as a volume. Fuel takes up over 100 times the volume in vapor form as it does as a liquid... and just how much volume depends on its temperature. The evaporation process itsself only drops the air temperature about 12F degrees. Not all the fuel will evaporate given room temperature and 1.5" pressure drop, and it is doubtful if Holley knows exactly how much does evaporate before it exits the throttle bore. They are just adding complexity to something that should be simple.
As you should be able to tell by now, the only true way to get a standard measurement is to use just air @ the normal 1.5" of mercury.

 

I've also worked out the conversions as far as raw volume of fuel goes compared to TB cfm. Turns out that its only like .06 cfm of fuel with a larger injector. I think there is something else going on here. I believe the fuel is actually obstructing airflow as air has to move through the fuel cone to make it into the motor.

If this holds true, it would explain why Holley flows the TB units with fuel as it would give a more accurate measurement of flow as installed. I don't know though... just taking guesses.

Also, Turbo city doesn't have data as to what their units were flowed at.

 

The fuel is not going to make any significant differences, that would take a LOT of fuel. look at those sprays, do you think the air cant get thru there or something. its not like its an aluminum cone, its a liquid cone that is vaporizing!!

I agree with ODB, just use the standard. Besides, why wouldnt holley want their numbers to be as high as they could get them, ie, without fuel. I mean, MARKETING!

I think I will bring along my 454rochester, and my little tbi, when i take my design to the flowbench. Then, we will all know the truth.

 

Yeah, baby! Flow them all, Snuffy! That would be good info...