Tractorsport Flowbench Forum Archive

Posted: **Sun Nov 28, 2004 11:30 am**

MAJOR BRAINSTORMING TO FOLLOW:

I setup a swirl sensor that sits in the bore of my flathead blocks, it shows rotational speed and direction. What I'd like to ask is what exatly do I want to see with it? How is it really used or should I say how do you use the info it supplies? I know the theory behind high swirl ports and heads, is it just trial and error to findout what works?

I've found it interesting already testing my billet head design to a stock head. I am able to make swirl with my head as opposed to the stock head that does not swirl. Anyone care to shed some light on how they use a swirl sensor on their bench?

Posted: **Sun Nov 28, 2004 7:02 pm**

I have no practical experience of this myself, but from what I have read between the lines, there is no particular universal best figure to aim for.

It is all about setting up the most favorable conditions for optimum combustion. Swirl is just one factor along with chamber shape, cylinder bore, valve layout, squish, plug placement, compression ratio, fuel burn characteristics, rod ratio, ignition timing, and probably your astrological sign.

The trick seems to be to get it to burn in the shortest time while still maintaining reliable combustion stability. If you can achieve that, you may be able to safely run a slightly higher compression ratio, and it will probably require less ignition advance. This is not easy. The larger the cylinder bore, and the higher the Rpm, the more critical it becomes.

I believe you are supposed to do extensive dynamometer testing to decide what combination works best in your particular engine family, and then measure swirl to give some sort of reference number that you can return to. It is just an attempt to isolate one factor from all the rest. The swirl number by itself in isolation probably does not mean much.

The people that really know are not likely to tell you either.

And I certainly do NOT know. I wish I did !

Posted: **Mon Nov 29, 2004 3:16 pm**

I've found it interesting already testing my billet head design to a stock head. I am able to make swirl with my head as opposed to the stock head that does not swirl. Anyone care to shed some light on how they use a swirl sensor on their bench?
====================================

there was an article titled;
"Swirl and Tumble , may make you Stumble"

i have a digital Strain-Gauge type Swirl Meter that reads in Inch/Ounces of Swirl Torque,..the Strain-Gauge is hooked to a limited-rotation C or CC direction Honeycomb.

i painted a thin bright yellow "radius" line facing me ontop of the Honeycomb to see "action" of Honeycomb movement or "jitter" thru Plexiglass Bore Fixture , as a means for more info along with the digital readings.

There are also commercially available Tumble-Meters and Paddle or Fan Type Swirl Meters...maybe someone has a Hot-wire Grid setup hooked to a Computer ??

Swirl should help you more with a Carburetor, at low RPMs , and with Cylinder Head Chamber design that have combustion problems or Race Engines with too much Dome in the way, bad spark plug placement, not enough Squish/Quench, etc.

Its possible to have too much Swirl and "centrifuge" Fuel out of mixture and deposit on Cylinder walls at higher RPMs

Back in 1975-1976 running NHRA C/SM & B/SM class Camaro with SBC...it was 1st time i had Gas-ports in Pistons...when you would take off Cylinder Heads, you would notice Clockwise swirl pattern of oil/gas scum trails left from gas port holes in the direction of Swirl...and CounterClockwise pattern on the other "mirrored-image" sister adjacent Cylinder
..that was the 1st Time i noticed or was made aware of "Swirl" in either Clockwise or CounterClockwise motion
...later on, when i purchased a Swirl-Meter i found out why .

There's
Cylinder Swirl in Clockwise or CounterClockwise motion direction

Tumble in both directions

Bowl Swirl/ Valve area Flow Conical Swirl in either direction

GM made a very High Bowl-Swirl cast-iron head a few years back.....it had high bowl swirl and it killed Flow numbers,
just helped lower RPM combustion efficiency, made terrible HP numbers at higher RPM range
....there is a way to create the same Bowl-Swirl GM did but not loose any Flow...but Dyno and DragStrip tests show no real benefits from all that hard work.

The NHRA SuperStock SBC heads i port have tremendous Swirl
with no Dome in the way....the Swirls just a side-effect of the way you have to port heads to make Power.
The Chrysler SBC heads i port have less swirl numbers than Chevy SBC heads, but make the same HP/Torque percentages from the Flow numbers..the higher Swirl numbers in the Chevy SBC heads seem of no advantage in HP/Torque

..so this leads into why someone wrote an article
"Swirl and Tumble , may make you Stumble"
....if you have exhausted all means to making more HP/Torque in a Cylinder Head..then i would look at maybe Swirl and Tumble.
looks around 20 or less HP gains on a 600 HP SBC
theres so much more HP to be gained from correct Porting.

Posted: **Wed Oct 12, 2005 8:57 pm**

I am interested to buy a swirl meter.
A guy at Superflow europe told me that it is better to buy (Back at 1998) a swirl Torque meter from Quadrant Scientific that the one they sold at that time from performance trends, which have have readinds about rpm as i know.
I searched for the swirl torque meter but as i know quadrant scientific was closed. The AUDIE swirl meter have a honeycomb but is measure torque.
i realy do not know which to buy...
you , maxracesoftware, where did you bought yours?

Tractorsport Flowbench Forum Archive

Swirl sensor ?'s