Toyota RAV4 Forums banner

1 - 13 of 13 Posts
S

·
Guest
Joined
·
0 Posts
Discussion Starter #1
Does any one know about the effects of so called Vortex generators on the 3S? This is one (www.turbonator.com) of many types that i have seen floating around. its one of those typical (gain up to 30% hp...*results not typical) kind of things. Normally i wouldn't give this product a second look but since i put a weapon r intake on my '96 I became a little curious when i tried to undertand what happened to my low end torque and general engine flexability. it was my postulation that due to the increased intake volume, intake pressure and velocity where down. this would definitly cause a low band power drop due to a lower fuel/air mix ratio. i got so tired of it i put my stock intake back on and am now enjoying the low end with a slight sacrafice in the mid and high range. i was thinking that maybe because this is a semi-restrictive design and vortex generators are proven to increase mix efficiency (the Chevy vortec engine are based on this principle) it would have the effect of increasing the power into the low band while retianing the mid and high on large volume smooth bore aftermarket intake systems. any thoughts? I would hate to order this thing and find out its just another hokey piece of "as seen on T.V." memorabilia.
 

·
Registered
Joined
·
986 Posts
It looks to be the same thing as the Tornado Fuel Saver, but costs $20 more.

Maybe it was all those physics classes I took in college, or maybe it's just common sense, but I believe you really can't take more power out of the engine without putting more power into the engine, in one form or another. Now don't get me wrong, you can do some things to increase the efficiency of the power conversion (from fuel/air to mechanical force) however they will only make small differences, if any.

Call me stupid but I think the reason why GM Vortec engines work so well is because the vortex is in the combustion chamber as opposed to being in the air intake hose. Ideally the vortex should be created during or after fuel is mixed with the air, not beforehand.
 
S

·
Guest
Joined
·
0 Posts
Discussion Starter #4
Yes i did reset the ECU by unpluging the battery for 5 mintues. it seems that i have heard this type of complaint before from people who have used the Weapon R intake. lots of mid and high gains and low drops. i am sure that it is simply the nature of the way this engine devoples its torque in relation to its either air pressure, volume and or fuel air mixture. At leaast is seams that should be the case concidering what i have read from official posts on this site about the 3s. as far as jeff's comment, i think you are underestimating the amount that a little tunning with the ratio can do. your absolutly right about taking more out that you put in (the cake mix example comes to mind) but i think you are neglecting that you are actually putting in a hulavolot more than you are gettin out anyway. I am sure in your physics classes you leanred that the internal combustion engine uses anywhere from 6-9% of the energy avaliable from gasoline, and so even a tiny fractional of increase in the combustabilityof the fuel is going to be pretty prominent.
 

·
Registered
Joined
·
542 Posts
if there was any unburned fuel or extra oxygen in the exhaust the ecu would increase or decrease the fuel supply to keep emmissions in check! the combustion of fuel/oxygen is most efficient these days, right!! intakes & exhaust systems can be modified to let more air/fuel in and out to increase power output.

the low end loss of power with the weapon r intake may be due to the calibration tables in the ecu not giving enough fuel for the amount of air being let in under low rpm/high load conditions (wide open throttle @ low rpm)!

you are right, compression/ignition engines are somewhat inefficient at converting the available btu's in fuel into mechanical power. but if you can stuff more air/fuel in, you get more power out (ala turbo style).. to increase the conversion efficiency is somewhat more difficult..
 
S

·
Guest
Joined
·
0 Posts
Discussion Starter #7
its the weapon r dragon. also in reagards to the post about ECU maps...if this is the case, would a chip be the answer to remaping the right amounts of fuel or would i need a fuel pressure regualtor and/or new injectors to handle the job.

p.s. it might help to know that my compresion ration is up from stock due to a mill job. [/img]
 
M

·
Guest
Joined
·
0 Posts
Discussion Starter #8
Some fluid dynamics for you...


With a new intake system allowing for more volume passage, your mass flow rate (more importantly velocity) will be lower, significantly low enough to allow for laminar flow in the intake. Laminar flow is not very good at mixing, even though your injectors atomize the fuel, it is still not completly mixed. A vortex generator essentially creates a dynamic 3 dimensional flow allowing the individual velocity vectors of the air particles to increase, but the overall air flow stays the same, this allows for better mixing. Also, a spiraling flow can move through pipes easier for a reason i cant explain here.

Furthermore, Custom intakes have smooth inner walls, this supports laminar flow in the pipes....

If you want to test my theory, instead of opening the throttle completly at low rpms, gradually open the throttle relative to the increasing rpm. The butterfly valve should cause initial turbulence via the stagnation points. If you feel a difference, then most likely you are having a laminar flow problem.

I would guess that a vortex generator / tornado/ whatever cheap metal thing would help you solve this problem....

Sometimes, too big of an intake supresses your engines ability to mix fuel.

Regarding a previous comment regarding an engine can only output as much energy as is put in. Very true, however, you forgot efficiency, the most important aspect of ANY engine. What we are doing here is increasing the efficiency of the combustion process, by allowing the entire combustion of all the fuel to occur in the power stroke of the piston. A fully atomized and mixed mixture of air and feul and the optimum stochiometric ratio will make this as close to an ideal process as possible. To achieve the best mixing, you want turbulent flow (Re > 4000), the higher the better. Increase your velocity and you will increase your turbulence.

Try my idea above, if you get a horse power gain at the low end, you know what you need to do. There is a lot of fluid mechanics involved and not all the chambers in the air intake system are classified as pipes (hence the Re number of 4000 cannot be used as a turbulence reference point), but the theory behind it is sound. Let the engineering work for you, if you have a laminar flow problem causing less combustion in your powerstroke, step up the velocity by putting that thing in...

I highly recommend testing my theory using that throttle rpm matching sequence. Try it a few times.

Cheers all, e-mail me if you have questions.
 
S

·
Guest
Joined
·
0 Posts
Discussion Starter #9
i have indeed tried the low rpm opening sequence theory because what you have said jives perfectly with what i had initially thought. i have to tell you that is DOES make a difference. (the low throttle rpm theory) which leads me to belive this is true. i kind of got tipped off when my uncle (who is a powertrain engineer for toyota) told my when rebuilding my engine that i should NOT do a port and pollish if i ever planned to turbo the 3s. because of the turbulance needed to atomize the fuel at the higher velocities, and this is consitant with what i have read elsewhere. i think i will try it just to see what it does. i have another uncle working on a pattent for a simliar device that is being tested by fed ex right now and i am going to have him make a prototype for me. thanks for the sound engineering to back up my initial presumtion
 

·
Registered
Joined
·
200 Posts
Bulldog, do you have an aftermarket intake? I'm also curious about those generators since I have a Secret Weapon intake. But the SW intake has a smaller pipe inside supposedly giving greater performance gains by increasing air speed or something like that, so a vortex generator won't fit inside. I'm wondering if it would fit inside the silicone coupler that connects the 3" intake to the smaller throttle body.
 

·
Registered
Joined
·
210 Posts
mechaniki said:
Some fluid dynamics for you...
Very elegant and involved " science speak " nicely done.



With a new intake system allowing for more volume passage, your mass flow rate (more importantly velocity) will be lower, significantly low enough to allow for laminar flow in the intake. Laminar flow is not very good at mixing, even though your injectors atomize the fuel, it is still not completly mixed. A vortex generator essentially creates a dynamic 3 dimensional flow allowing the individual velocity vectors of the air particles to increase, but the overall air flow stays the same, this allows for better mixing. Also, a spiraling flow can move through pipes easier for a reason i cant explain here.
Furthermore, Custom intakes have smooth inner walls, this supports laminar flow in the pipes....

I would guess that a vortex generator / tornado/ whatever cheap metal thing would help you solve this problem....
The one thing not mentioned is ... the point of the throttle body. If this has remained the same the CFM at the outboard side of the TB won't change since it's this device that controls the amount of air flow through the intake ports to the combustion chamber.

As for add on " vortex generators " this seems unnecessary since the intakes are designed to create the turbulence at the intake ports to mix air/fuel for the combustion chamber based on the set amount of CFM supplied.
 

·
Registered
Joined
·
2,904 Posts
well done - These things are a WASTE of time and money.... the only thing that they do is put ANOTHER restrriction in the intake path....
 
1 - 13 of 13 Posts
Top