Snake Oil ?

[Suffolk944]

Having (like many here) been suitably unimpressed by various incredibly cheap and dubious "performance" add ons being touted on fleabay etc I was intrigued to see this item for sale at a rather more mainstream outlet (at a rather more mainsteam price too !)

Am no mechanic/engineer but my initial reaction was not one of unmitigated enthusiasm for it. Would be grateful for those who know far more about such things than I to shed some light on whether this thing is in any way credible or just the automative equivalent of snake oil ? [&:]

http://www.design911.co.uk/fu/pt697_703_-cma81-cmo123-ct309/Porsche/944-1982-91/Porsche-944-Turbo-25L-8V-1989-91/Performance---Tuning-Parts/Air-Induction-Kits/

Thanks !

 

[tref]

Wot, no dyno figures????[]

 

[graham.webb]

Need proof, surely? I've got a distant recollection (anybody read David Vizard's books) that cylinder head ports (especially when polished etc) are designed to promote laminar flow (ie no vortices/turbulence) so that the careful design of the combustion chamber can then "swirl" the charge to mix the fuel and air thoroughly as it reaches the spark?

Another thought...it's widely advised that some Porsche models (forget which??) do not benefit from having their intake tract fiddled with!

 

[JamesO]

For half that sixty quid I would be prepared to rip up a beer can for somebody to stick in their intake. I suspect it would help performance just as much. I would even drink the beer for an extra charge.

 

[zcacogp]

I'm with JamesO. Utter snake oil, and someone is making profit out of people's niaeveity (spa?)

If this sort of thing did anything at all, manufacturers would build them into engines in the factory.

On the other hand, I have some very nice magic beans I can sell you ... very good price - £1000 each, but think about what they will do ... []


Oli.

 

[edh]

Has to be pointless

In any case, If you fit post filter & pre-turbo, any effect that it may introduce would surely be lost anyway?

I've got some nice shiny resistors here - £10 each....cheaper than magic beans and just as effective...[]

 

[zcacogp]

Oh Ed, resistors never work. Everyone knows that.

That's why anyone reading this should buy my magic beans ... tell you what, special price for club members. Normal price £1000, club members price £1200. Can't say fairer than that! []


Oli.

 

[dann944]

I have a glass hammer and some tartan paint if anyone is interested

 

[Flick]

A vortex generator before a turbocharger?

You could argue the case on a N/A car if it was on the intake runners (and probably be labled a crank) but on a turbocharged car it's snake oil.

 

[Mike_Pollock]

I ve a special left handed stubby for undoing the dizzy - not goos doin it up thou'

 

[Indi9xx]

Probably loose you some power.

If Someone wants to buy one and send it to me, I will be happy to be a mythbuster by doing a back to back dyno run... But its not going to work.

Although, there is an outside possibility that if you were racing in a series where you were restricted by intake or exhaust use, and that exhaust or intake had a nasty tight bend.. one of these could possibly be used to close down the airspeed difference between the short side and long side of the turn and cause some increase in flow potential,

However any increase in airflow may be reduced to marginal increases or even a decrease depending on the loss of flow due to inserting a obstruction like this into the airflow...

 

[Diver944]

ORIGINAL: Indi9xx

If Someone wants to buy one and send it to me, I will be happy to be a mythbuster by doing a back to back dyno run...

Please don't test it on LIL []

....... but if you do, please use an Irn Bru can. It's brewed from Girrrrrrders and is her tipple of choice

 

[Suffolk944]

Well am glad my initial non-techie gut reaction was right - Can laugh such stuff off on fleabay but bit disappointing when its peddled elsewhere. [&:] And for the record no I wasn't tempted to get one ! []

Just need to PM Oli about his magic beans now...

 

[sawood12]

I'm inclined to think it would be a waste of time.

For a start to produce a vortex will sap energy from the intake. It takes energy to move things, sothis will create a load onto your engine during the induction strokes. Any benefit would depend if the energy sapped from the intake to create the vortex is beneficial compared with the energy sapped due to turbulent air (similar effect).

Also if it were to generate a vortex then that vortex would be disrupted as soon as the air passed through the AFM/throttle body, around a tube bend or as soon as it hit a non-smooth surface inside the intake hose.

Also the vanes bending into the airflow actually creates a restriction, so you are in reality restricting your intake.

Also if a true vortex was generated then you are reducing the pressure in your intake (bad) as the airflow in vorteces are faster moving air and faster moving air has a lower pressure.

On balance this thing is a waste of time. If getting significant improvements with such a small and simple device was really that simple then all cars would have them. Vortices are not new discoveries in engineering. Concorde relied on vortices to keep it in the air at sub sonic speeds as its wings don't work below the speed of sound.

I think it would be quite beneficial to have a vortex generator just before entry into the cylinder as this would promote better mixing of the fuel into the incoming airflow. A tube of laminar flowing air is difficult to penetrate with atomised fuel so you don't get great mixing, however with a vortex since more air is moving past a given point at any time you get more fuel mixing. You certainly get vortex generators built into injectors in gas turbine engines. However in 4 stroke engines you probably just want to get as much air into the cylinder as possible so therefore want to suppress any turbulence or vortices.

I actually think the best use of vortices in a car is in a Dyson vacuum cleaner type of device that can replace the air filter and seperate particles from the airflow using a vortex and remove the much greater restriction of a traditional air filter.