an old post repeated:
---
The Turbonator and Tornado devices do 'work' in the sense that they partially
block the airflow and result in less engine horsepower
{and therefore less fuel consumption}
during vehicle accelerations.

For this con to work to the 'optimum' extent, the Tornado must be restrictive,
but not so terribly restrictive and blatantly bad that the customer has to
acknowledge that it is hurting acceleration.

But the key to the tornado device is that most customers do not do a
thorough,
careful, and
scientific evaluation of the device's effect on mpg.

Remember that there is a natural 50/50 chance that the mpg you get on one tank
of gasoline will be better or worse than the previous one.

Without a 'good' evaluation on their vehicles, 50% of the customers will find
that their next
tank of gasoline gives them better mpg, and 50% will find worse mpg.

The profits on the Tornado device are such that even if half the customers
returned it, Tornado's makers would still turn a hefty profit.

This effect is made even greater when you realise that most Tornado customers
will drive somewhat more carefully and conservatively while testing the
Tornado during that next tank of gasoline after installation, than they did on
the tank before. Any 'normal' aggressiveness and jackrabbit-like starts from
stoplights will be restrained because they don't want to 'ruin' their test of
their new 'modification.'

But for Psychological reasons, even half of the 'gypted' customers who measure
less mpg will not return it, and part of that half will even 'brag' about the
tornado any friends who knew in advance they were purchasing it - otherwise
those customers would 'lose face' by admitting to their friends that they were
conned out of money.

Can 'swirl' improve mpg?

Yes, Honda and Ford are both using 'turbulence' valves near the end of the
individual runners of the intake manifolds just before the valves.

These butterfly-like valves partially close at low rpms and part throttle
conditions to swirl the slow moving air/fuel mixture and get better
atomization.

This is only needed at low rpms and airflows - at higher flows natural swirl
can be achieved by curves in the runners and at the valve seat.

4 valve cylinder heads do much the same thing by only opening 1 intake valve
and leaving the other valve closed at low flows/rpm/part throttle. The Toyota
Tundra 4.7V8 does this.

The 1992-2001 Magnum 3.9/5.2 and 5.9 'beer barrel' intake manifold runners are
slightly twisted along their lengths to promote swirl, as is the 'heart
shaped' combustion chamber. In addition, the 0.100 step (miss-match) between
the BeerBarrel intake manifold and Magnum cylinder head port is there to
re-entrain fuel droplets back into the air flow, and to block 'reversion' of
exhaust gases.

If you want to read more about real swirl,
study these articles:

http://www.theoldone.com/articles/The_Soft_Head_1999/

http://www.edelbrock.com/automotive/...r99/index.html

http://victorylibrary.com/mopar/intake-tech-c.htm

http://web1.mitsubishi-motors.co.jp/...GDI/page1.html

Want to add more low flow turbulence to your existing Magnum engine and
improve low flow mixing of air and fuel?

There is an aftermarket intake manifold to cylinder head gasket available
{check the Summit or Jegs catalogs}
that has a wire screen across the runner openings. This actually has a much
better chance of working than the Tornado because it is downstream of the fuel
injector spray.

You could also make your own by adding screen mesh between two stock gaskets.
Low speed fuel droplet atomization might be improved at the risk of losing
10-30% of available hp at higher rpms.

HankL

PS, How to do a MPG test that really detects small changes:

Got a buddy with a Dodge Ram with the overhead trip computer?

Since you are making a modification with hopes of getting better MPG
why not do a "before & after" test?

Do a 'before test' with both trucks
* you and your buddy fill up at the same gas station and put the same air
pressure in all tires
* Pick a highway without too much traffic and hopefully where the wind is a
head wind or tailwind (side winds mess things up)
* Your Ram and your buddy's Ram follow one another staying at least 6 vehicle
lengths
apart.
* talk to one another with cell phones or walkie talkies
* drive at the same speed
* reset the overhead computers at the same time
* drive at least long enough to burn up one gallon
* write down average MPG at end of run
* exit highway, turn around, and do same test again in opposite direction
(this is to cancel out wind direction)

After doing your modification redo the test,
hopefully at a time of day where the temperature is about the same as the
'before' test and the wind speed & direction is not a problem - which you
can check here:
http://tribunewx.wunderground.com/US...WindSpeed.html
Note that in the above weblink you can type in your zip code and get exact
wind,
temperature and other weather data.

The value of your buddy's Ram is that on this 'after' test
if his MPG is greatly different you should suspect something has gone wrong
like strong cross winds, a change in temperature, tire air pressure, etc

If you want to test two trucks against one another that are already modified
like comparing 3.21 differential gears to 4.56 gears
or an underdrive pulley, thermostat, SuperChips, etc......
you can modify this test slightly.
Swap two tires from one truck to the other.
Now both trucks have the same 'average' tires.
Weigh the trucks and add weight to the lighter truck to make them even.

If you really want 'gold standard' accuracy that you can trust
(or if you are measuring a small effect like a thermostat)
then swap the mod over to your buddy's truck
and do the tests another time with your truck as the 'control'.

If you are presently thinking

"Wow, who would be that careful for a lousy MPG test?"

then just think about a dragstrip - which will have
carefully measured distances,
accurate timing,
know its altitude,
and have a weather station.
All this type of MPG test is doing is applying the same standards to MPG
that is expected when someone brags about their vehicle's ET.

By doing a test this way you are doing a simplified version of a SAE/TMC Type
IV fuel economy test RP 1109.

Here the SAE stands for Society of Automotive Engineers and
TMC stands for Truck Maintenance Council which is a group
of professional 18 wheel truckers who have banded together to share
information.

Credit for inventing a 'reliable' MPG test like this goes to many, but
especially Claude Travis, known to his peers at TMC as "Mr. MPG,"
who has spent 37 years managing the operation, maintenance and testing
of heavy-duty, on-highway vehicles. Highly regarded for his exhaustive
research in the field of heavy-vehicle fuel-economy, he is principal of
Claude Travis and Associates, Fleet Consultants, Grand Rapids, Mich.