How much does teh sea level of a flow beches location effect its #'s of measurent..Seems that in my area most flow benches are pretty low..Sometimes 30cfm in extremme cases..

My cyclinder head shop is a very very reputable shop that most of the east coast stock and super stock racers use as well as some east coast magazines...I have used the bench myself and know that its calibration is correct..Reason i ask is that recently I tested some brodix T1s off a friends setup and the #s were down 15CFM on average..Also tested a set of stock LT1 heads and got a peak of 199 with a 5 angle valve job!
With a comming relocation to atlanta i'll have to find a shop that i can trust and use my results as a reference when i search for a new bench..That and i am starting to wonder if my mazdas heads flow more than the 285/198 peak we got when we went through them..

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FLUCK A SPELL CHECK<I CAN SPELL REALLY GOOD< IT'S JUST THE TYPEING THAT STINK AT!

http://phillyfabanddesign.tripod.com/parts4sale/

http://phillyfabanddesign.tripod.com/phillyfabricationanddesign/

http://phillyfabanddesign.tripod.com/PhillyFabsLT1RX7/id1.html

88 RX7 GTU, 97 Lt1/700R4,10" 3K stall, 4.30 gears,285CFM heads,12.4-1 compression, custom cam and 2700lbs...Daily driven!

 

Too bad Chuck isn't around these days to comment on this stuff.

I have seen a set of heads flow the same peak numbers on the intake on two differen benches, but low lift numbers are up slightly and exaust is up about 10%!!! I don't know how much this had to do with setup, possible slop, or what, especially since most of the disparity is intake/exuast differences not peak numbers. Maybe your just finding shops that haven't had thier bench calibrated in awhile?

For this set of heads, they were flowed in North Carolina and then in southern California.

 

I cant find chucks phone # for the life of me so ifigured id ask here..One day i will die and then Jebus will ansewer all my questions..Only he knows i have few and far between questions..Hehehehe Thanks for your reply though

North to south caro isnt that much of a change in ground level..Im going from 23ft above sea level to upwards of 2000 ft..

 

I have a SF300 and a stock LT1 flows 185-190cfm on my bench. A Track 1 usually flows about 248-254 on my bench. I have flowed AFR 210-cnc heads that "ADVERTISE" 310 cfm and they flow 280-285. Dart Irin Eagle and Pro Action 230-235s advertise 308-320 cfm. They only flow 270-280 or so on my bench. A stock LS1 head flows about 227-230 on my bench and other people claim 240. The only cylinder head amnufacturers that flows what they say on my bench is Edelbrock and Trick Flow? I test with a 1/2 inch clay radius on the intake ports. I do not know what everyone else tests with.
I am not sure how much elevation effects the flow #s but I know my "Flow-Pro" set up screen has corrections for temp, humidity, etc. If you have a SuperFlow bench there is a plate that came with mine. The plate flows should flow 220cfm. Superflow could maybe answer your question. The flow bench should have the correct amount of fluid in the depression scale and the % scale. It should also be level as well.
If YOU flowed the head at your shop and You flowed the head at the other shop than that is a large jump in CFM. If someone else flowed the head at the other shop he may not have checked for a leak before flow testing or the test springs may have been too weak and caused the intake valve to open further or the exhaust to open slightly????. Intake rocker stud could have been left out?????. I know temp. has an effect on CFM so if you do not have anything correcting for temp maybe thats is some of the prob?????.
Do both of the benches have the same dia. bore???
The peak #s could vary depending on if a 3inch plastic radius was used on the intake or if a 1/2 inch clay radius or nothing at all?
If the low #s vary it could just be the person opening the valves and opening the valve .095 one time and .105 the next time. At .600 lift an extra .010 will not matter much but at .100 it is a large diff.
Also if the SAME port with the SAME valves and valve job wasn't flowed that may be some of it? Did he do any work to the heads after he got them? Unshroud/Polish the chambers?
If none of this helps maybe you could call Superflow or Audie techn.
Your flow #s seem to be in line with mine......are our benches wrong or is everyone elses? Or are we honest and actually take the time to check for leaks and make sure things are done correct?

 

Thanks..Now i know im not the only one that thinks company's inflate #'s...Most of the #s that you have posted are quite close to what ive tested..Ive been using a 1/2" clay setup when i dont have the intake.Most of the time i setup a 4" bore unless its going on a 400 block...
Hopefully i will find a shop down south that will have an accurate bench..

 

I am in Red Oak Tx. Thats 15 mins south of Dallas.
(is that south enough for ya)
call or e-mail me if ya need me.
Elliotts Portworks
Red Oak Tx 75154
972-617-5671
NightTrain66@msn.com

 

North Carolina vs South California

 

Brodix i think doesn't inflate their numbers too much....

BUT

sometimes you can wait and wait on the superflow to allow the number to happen. Instead of just taking the quick/fast reading which is what the motor would get anyhow

My stage II ported track 1s flow 298/208 (no pipe on the exhaust)

 

It could just be advertising claims, but according to Superflow:

For an air flow motor of this type, the efficiency is only 50% to 60%. The rest of the energy becomes heat transferred to the air. As a result, the air gets warmer in the exhaust direction as it goes through the bench. The temperature does not affect the flow reading because the flowbench measures the ratio of the pressure difference across the orifice, to the pressure across the valve. Both the orifice and the head see air at the same temperature, density, and humidity. A flowbench of this design provides results, which are independent of the atmospheric conditions. In fact, if you put a cylinder head on the flowbench, and run it at a barometric pressure of 24" of mercury, and run it later at 29" mercury, with the same cylinder head, you will get exactly the same flow numbers. You don’t have to correct for temperature or correct for pressure.

http://www.superflow.com/support/sup...works-how.html



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Hear LT1 cam WAVs, DIY head porting: members.***.net/gmarengo

'95, !CAGS, CAI, ForceII, Hooker Shorties, 14.2@103

 

I know when testing an exhaust port in 90 degree weather the temp will creep up to 130 degrees or so in the flowbench. When you look at the Actual CFM and compare it to the Corrected CFM there is sometimes 20 cfm diff. between the 2.
I was guessing the heat caused this. If you let the flowbench cool down or if you switch the bench to "intake" and let the bench suck in cooler air and then retest the exhaust at .700 lift while the bench is cool the ACFM and CCFM #s are 2-3 cfm off.
??????????
I just assumed it was the heat. Maybe the heat is affecting the Flow-Pro and not the Bench?????????????
I have never done the math off of the flow bench scales and compared to what the Flow-Pro is saying.
??????????
NightTrain66

 

While the SF site did say that you don't have to correct for temperature or pressure, it went on to say that the SF-60 and the SF-110/120 flowbenches were an exception:

"The exception to this is on the SF-60 and the SF-110/120 flowbenches. They both have the blower actually located in-between the inlet orifice and the outlet orifice, because that makes for a less expensive design. A temperature correction, which ranges from 0 to 4%, is necessary. There are thermometers built into these flowbenches for this correction."

The SF300 wasn't even listed as a product. Maybe it's an older SF bench similar to the newer 110/120?

The bottom line according to SF, is that flow numbers from an SF600 that is correctly calibrated can be compared to any other correctly calibrated SF600, independent of atmospheric conditions. They also said that operator setup has a large bearing on the flow numbers; i.e., whether a pipe was used, the diameter of the inlet, clay setup, etc.


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Hear LT1 cam WAVs, DIY head porting: members.***.net/gmarengo

'95, !CAGS, CAI, ForceII, Hooker Shorties, 14.2@103

 

This really goes to show that there really isnt a solid standardized testing procedure..I spent yesterday running up to NY to try another bench that i myself was allowed to use..Useing the same setup as i always do my #s were right on the money up till the .550 area as they seemed higher..

From now on i may do my testing with a pipe and intake..If at all possible..Now i do beleave that most #s running around the net are truely inflated because ever since i insisted on flowing heads in my pressnse or myself ive found #s to be lower..

Another thing ive recently learned is that the slightest fluctuation in the shape of the clay will effect #s..It was reccomended that i use a wet finger to do my final shaping of the clay..Supposedly fingerprints wont effect #s but the unevenness of the clay may have an effect..
Later this week i will be returning to the head shop and talking this over with my friend..