? I thought it was 2" bore ? I'm confused now. Wasn't the 454 the same as the Holley 2" bore units?

------------------
, Jon (91 RS too many mods to list)
Dale Earnhart, you have done so much, you will be missed.

 

Here is the info from holley... its just as Pablo has stated in the past.

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.


At 05:32 AM 02/24/2001 -0700, you wrote:
>Sender : daniel.workman@schriever.af.mil
>Tracking Number : T20010224002SZ104841
>Pool : fuelinjection
>Sent to : "'fuelinjection@support.holley.com'"
<fuelinjection@support.holley.com>
>Date : 2/24/01 6:38 AM
>---
>
>
>I have a couple of technical questions regarding method of rating airflow
>for Holley TBI units and Carbs.
>
>Do you flow all of your Carbs and throttle bodies, 2bbl and 4bbl at the same
>pressure drop? By Pressure drop I mean flow at a given amount of water,
>usually 28" for cylinder heads.
>
>What pressure drop is used to obtain your flow numbers? (for each type if
>applicable)
>
>
>Thanks for your help
>Dan Workman

 

every body BUT the 454's got the 1 11/16 tb.

454 = holley = 2"

ALL ELSE = 1.6875 or 1 11/16

o, and dan if you could get back to me on the email is sent. thanks, whenever you get the chance to reply.

[This message has been edited by snflupigus (edited March 01, 2001).]

 

So those flow rates are for air AND fuel???!!! Very interesting.

 

Yep, I also find his statement interesting because if a pair of their 85# injectors are at max duty cycle... that's 170#/hr at 6 lb /gallon = 28.3 gallons / hr.... or .47 gallons / minute... at .1336806 cubic ft / gallon, that's .06 cfm of fuel. The only way I can explain his comment is that fuel flow is actually blocking airflow, not just occupying space.

 

I would have to assume that fuel would hinder airflow when combined, if that's what you mean. Well maybe "hinder" is not the word, it's just that the air/fuel mixture is a different (heavier) density and has different aerodynamic properties than just air alone.

 

Picture air attempting to pass through a sheet of falling water and recall what the injector spray cone looks like.

I'm betting the fuel is actually blocking / inhibiting air flow.

 

inevitable. you gotta have it there.

 

OK all of you folk,I have at least part of the answer.Go to www.hotrodarchieves.com and download the article called F-NOTES.These guys did all of the work for you 11 1/2 years ago!Traco(if you do not know who they are,log off)built an 89 RS for Hot Rod and the results were staggering.97 horsepower above stock and 14.20's 11 years ago!I have been searching for this article since I bought my 92 RS in 1995.You all will be surprised for most of the parts that we talk about were available back then!Please E-mail with any questions for this is a great sight and I am new.HOPE I HELPED!

 

1992 Camaro "stripper"
Air delete
No power anything
F-41 suspension
16" wheels
Crane compucam 2031(438/452-208/214@.050)
Edelbrock Headers(for 87-89 Iroc 3")
Open Element
2 chamber floemaster
350 pickup injectors
Factory T-5 with ripper shifter YEAH!
MSD coil
Polyurethane lower control arm bushings
Timing at 6 degrees(with connector pulled)
Edelbrock water pump
NAPA fan switch(p/n FS 113 for 1983 celebity with 2.5l,turns on at 187 degrees)
No cat
Dynomax 3" intermadiate pipe

14.5@95 MPH need I say any more?

 

5.97 to download. anybody who has that actually issue? ill buy it, or could you please scan it and email it to me. 6 bucks just for one article. bs.

or maybe somebody who has it could paraphrase the hole thing into a short article and post it here as a tech article.

that would be nice. 6 bucks to download somethin. damn, internet robbery.

 

ive got the articles, email me at tmonee@firstworld.net

if u get a mailbox full reply, try again... ive got the pdf's sitting in my mailbox until i get home from work.. that will be in 1 hours.. so at 10 pm pacfic time you will be able to email me if u cant already


[This message has been edited by TMoNeE (edited March 04, 2001).]

 

I have well over 1000 magazines and share info whenever I can. If you are so cheap that you expect someone to pay you back for what magazine you payed for, then you are a sorry s.o.b. I only wish I had that hot rod issue to share but my subscription started around 1991. I MIGHT have gotten it at the stand and will look for it right now.

------------------
-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....

Super GRK_Taz World
EFI & Intake Options
AOL IM: superGRtaz | ICQ 82881207

 

CHRIST, lets freak out!

Its not that i dont have 6 bucks, its that i dont feel like paying for information that i could get from somebody here. or when i could by the whole damn magizine for 3.50 What the hell is ****ing wrong with trying to save money.

And for anybody else that wants to flame, go to the gay flamers board.

BY THE WAY, my TBI is not made for an lo3 or a stock 350,and Ive stated that before. just thought i would tell that to whoevers post i deleted, find a new board, or flame somewhere else about something that didnt even concern you.

o and like im going to send my drawings to you, nobody else has seen it, and im not about to have somebody copy the idea. People will see it when the patent is pending aproval and when i have a few tested.

[This message has been edited by snflupigus (edited March 05, 2001).]

[This message has been edited by snflupigus (edited March 05, 2001).]

 

okay sorry for the delay, my mailbox is empty now and i have the articles so just mail me guys... dont worry about the other dude he is just freakin out hah

 

Jeeeze!Did'nt know Ihad created such a stir.Someone IM'ed me two nights ago to have me download it to them.It is a very useful TBI TOOL espically with the type of user that asks for info on this site.
RENEGADES OF FUNK!
Drove my car,it thawed out enough.
One day
That's it
MAR/2/2001
Could not help it!
Only time car has been driven diuring winter.

 

i think the article is over rated and they spent too much $$. 5k could have been a supercharger, with rear, etc.. and been well below 14. am i wrong?

 

plus u have like no selection.. u have to use exactly what they used.. and **** for 5 grand.. not only supercharged with rear end.. but a damn 350 worked out pulling mid to low 13's... no way id spend 5 grand to do mid 14's

 

t r u

 

I wanted to clairify some things about airflow for some of you that are debating about the throttle body size.
The standard for measuring dry airflow is 1.5"Hg (mercury not water). There is little reason to use any other method for comparison purposes with carbs or TB's.
It is true that two larger bores twice the diameter will flow much more air than four smaller bores of half the diameter. Also the shape of the bore and total surface areas will affect the airflow rate.
Airflow is primarily dependant on pressure drop across the throttle bore. That means that vacuum in the intake manifold determines how many CFM the bore will be flowing. This changes dynamically as the engine goes through it's RPM range. For most street engines the max Volumetric Efficiency will be reached around 3000 rpm where some engines approach or even eclipse 100%. The VE is much less at 6000 RPM's. The total airflow required per minute is higher at 6000rpm but the airflow per engine revolution is much lower.

Fastbroker: in your example of the 390cfm fourbarrel and the 500cfm two barrel making those high power numbers, you are correct. The small orafice does not literally choke the engine of power directly.
If you do the math, in theory if the engine produced 3"Hg pressure drop with a 390cfm carb, that means the carb would actually be flowing some 550cfm's of air into the engine. The 500cfm two barrel would be flowing 707cfm @ 3"Hg.
By the same token, a 700cfm carb @ 0.5"Hg would only flow 404cfm's of air.

So how can an engine make more power with less cfm's of air? Well as I've stated several times on thirdgen,
an engine is NOT an airpump, and airflow is NOT directly related to power output of an engine.
The secret to making power with an engine is air density. Denser air contains more oxygen and if it is trapped in the cylinder with the right amount of fuel on the compression stroke, then it makes more power.
1.5"Hg of pressure drop is equal to about 0.7psi. Atmospheric pressure is about 14.7psi and is the force that feeds air into your engine to make power. Atmospheric pressure also determines the beginning air density that we have to work with on a naturally aspirated engine.
The cylinders are not fed by the 1.5"Hg or .7psi pressure drop at the intake manifold, but more correctly by the pressure drop between the cylinder and the other side of the intake valve. Since the pressure is already dropped from 14.7psi down to 14.0psi in the intake manifold then we have lost almost 5% of our air pressure to feed the cylinder. This 5% air pressure drop equates to a drop in air density (less oxygen) and about a 5% drop in potential power.
So you do not choke your engine of airflow with a smaller TB. You are only decreasing density in the intake manifold which reduces potential power gradually based on RPM.
When you put on a bigger TB and reduce the pressure drop in the intake, then you are adding air density in the intake and actually lowering CFM through your TB. As long as the proper fuel delivery is supplied with good atomization then the result is more power at higher RPM's.

The secret to making the most power is manipulating air density at the intake valve.

ODB



------------------
*I do custom performance mods on Edlebrock Performer carburetors (dualplane intake mods in the works),
White 1986 Irocz, 305 with iron #416 heads,
383 with aluminum TFS heads,
Edlebrock Performer-RPM intake and Performer #1407 carburetor, +110hp shot of crack, 700R-4 tranny, Vigilante 2400 lockup converter, 3.25:1 Ford 9" rear, Mcreary Road-Stars, SLP-stainless 1.75" shortie headers & Y-pipe, single 3" Borla exhaust, Linginfelter-TPI camshaft part number 74216 pulls 17" vacuum solid. Cam specs 213/219 @.050 114-LSA, sometimes advertised at 216/219 @.050 112-LSA .462/.470 lift @1.5:1 ratio. Using Harland Sharp 1.65:1 roller rockers. MSD-6AL, billet distributor, multi-retard, blaster-3 coil, and RPM switch. SouthSide machine subframe connectors, SSM lift-bars, Moroso 4" underdrive crank pulley.

N/A runs 10.9 @124,
Crack-runs 10.3 @135
haven't run at track since Oct-99
* vizit miy homepayge * http://www.geocities.com/trailerparkpage/

 

Nic,
Your new TB design sounds great in that it can bolt up to about any intake/spacer out there.
Be sure to keep us posted on what kind of test results you get from flowing it.
Which ECM is it going to work with?

I will be looking for the 1000+cfm model ! anybody else with me on this?
ODB

 

Hey i am in your boat buddy. Thank god for NJ SPEEDER he sent me on the right path. I was gonna kill the TBI this summer. But hey look at his car! Oh for the heck of it. I go threw Elmira to get to Rochester for school.....use to date a girl from there. Well horseheads :0)

 

I just saw in the new HotRod in the PitStop section that the stock small block throttle body flows 520 CFM. And going by the old formula (engine size x RPM divided by 3456) for finding out the correct carburetor for your engine. The stock throttle body on a 305 is good for 5900 RPM.

------------------
92 Camaro RS 5.0 5-Speed
14" Open Air Cleaner
HyperTech Chip
UltraFlo cat-back exhaust