Fuel Saving Devices

What do people think of devices as the one below?

And has anyone fitted one to their car?

The claim to increase peformance and educe fuel consumption is impressive - thinking of giving this thing a go in my MK2 Fiat Punto Sporting, but is there anything that I could potentially damage using it?

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Reply to
Dee
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What you have to bear in mind is that engine manufacturers have a vested interest in building engines that are both powerful and economical. If there was a comparatively inexpensive way of improving both on their engines - then they would do it themselves. Fuel economy devices have been on the market for years and I have yet to see any truly independent research that confirms that any of them actually work. Save your money!

Kev

Reply to
Uno Hoo!

impressive -

I tried one and it made my car run like a pig. Good job there is a money-back guarantee...

I read (on here, probably) that this device reduces the engine braking, thereby making the car *feel* faster.

Reply to
Mark W

Just read the ad and 'recommendations'. Usual snake oil, and it weakens the mixture (great for exhaust valves). Modern engines are already computer design tweaked to run weaker than they should, just so we get 'clean' fumes out of the pipe. A service with new plugs and filters will usually improve economy between five and ten percent. The purveyors of snake oil always recommend a service before fitting their device- so that's where the improvement comes from. Spend your money on a proper service instead. DaveK.

Reply to
DaveK

Agreed.

Reply to
Harry

Only to your wallet. How they managed to get a Cavalier to only return

25.527 MPG at 50MPH is a good starting question.
Reply to
Duncan Wood

The fuel saving device i use is called a citroen ax.

Saves loads of fuel ... does 25mpg more than my bmw730i!!!

You do get earache, backache, clutch foot ache, gearchange hand ache and everyone playing chicken though.

-- (Scum Mail Bouncer In use). (Remove "n" from email address to reply directly).

Regards..... Steve.

Reply to
FEo2 Welder

LOL, ROFLMAO, and all the other ROFL ones I can't remember. : )

Reply to
Stuart Gray

good summary of these 'miracle' devices here

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Reply to
airsmoothed

That is bure BS (on their part) a 2.0 Cav I once owned used to return 40mpg at motorway speeds!

Reply to
Me

But was it still attempting to achieve the same effect?

Reply to
Nick Dobb

No but that's where ecotek gets the words from. It actually did make the air in the combustion chamber swirl.

Reply to
Duncan Wood

I accept that - although over a period the 'average' should improve if the device is working.

I've logged my fuel consumption over the

Looking through my log book (I drive a Rover 75 diesel auto) my mpg varies from 28 - 46 mpg according to the type of motoring I am doing (even worse when towing the caravan!) I still reckon that over a period I could detect a real improvement if one existed.

Exactly,. They are just the modern equivalent of snake-oil - but there's a mug waiting to be fleeced around every corner!!

Kev

Reply to
Uno Hoo!

'airsmoothed' has already explained why I have been cautious in stating that the device appears to do the business.

I kept a fuel log for about a dozen fill-ups before fitting the Ecotek and about a dozen fill-ups after. Prior to fitting the Ecotek I got a mean average consumption of 36.4 MPG with a standard deviation of 1.1MPG (my use of the vehicle is very much routine, back and fro to the railway station and very little else, hence the lack of variation in consumption). After fitting the Ecotek I got a mean average of 39.3 MPG with a standard deviation of 1.2MPG. This new mean is about two-and-a- half standard deviations away from the original mean - in statistical terms, the chances of this having happened randomly is essentially negligible.

Nothing else had happened apart from fitting the Ecotek - same/similar weather, no servicing of the vehicle, same fuel supplier, etc. Also the same type of driving - yes, I know the arguments about this not being a 'blind' trial and has my driving changed to cause this change. I drove exactly the same before and after fitting (my route doesn't give me a lot of scope to vary my driving anyway, steady 70mph pretty much all the way there and back).

I'm not about to tell you why I think the device works (my background is elecronic engineering, not mechanical or chemical) - all I know is that it seems to.

Reply to
Nick Dobb

AFAIK, the round-Britain fuel economy record is now held by the VW Lupo TDI (the "3-litre car"). Certainly this has the best "official" fuel consumption figures of any production car ever. It's not very popular, though, since it costs around £1500 more than the petrol model. That's the point - the public would like more economical cars, but the known technology to deliver this costs hundreds of pounds even at cost price. (And here is the reason, I suspect, why the Daihatsu diesel is no longer with us). Hence a "gismo" that delivers it for £50 should have all car makers beating a path to the inventor's door.

Just about every modern engine uses some kind of swirl technology, to a lesser or greater extent. Most modern engines already have close to the optimum swirl level and would only gain 2 or 3% economy by adding more swirl - even assuming that leaking a bit of air into the inlet manifold would deliver this. The new Vauxhall Twinport engine switches swirl level according to load and speed, but even that only claims about a 2% improvement.

Nick, I'd be interested to know what time period your fuel measurements covered. Fuel consumption varies significantly between summer and winter so this could be having an influence (see section 4 of

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I'd also be fascinated to know what happens if you take it off (orat least disable it) for a bit. BTW, according to my calculation you'dsave 8% of fuel by driving just 3 mph slower on the motorway... Of course, it could be that the Ecotek is leaning the mixture off a bit, and perhaps marginally improving atomisation, since this is (with the greatest respect) not the world's most modern or sophisticated engine. 1993 is exactly the point when cats became compulsory so I guess your car should have a lambda sensor, but it may be one of the last that didn't, or indeed the sensor may not be working correctly since on-board diagnostics didn't come in in Europe until 2000. If it is leaning the mixture you may get a small economy improvement, especially if a 70mph cruise is around the point where the engine starts to run slightly rich for power purposes. 8% still seems implausible, though.

The improved torque must be an illusion, since the valve is shut at wide-open throttle and so can't have any influence.

(replace "nospam" with "fuel" to reply)

Reply to
Tony Cains

SNIP

Swirl is what the manufacturers induce in the combustion chamber by design in order to achieve as close to 100% combustion of the fuel as possible.

What this gizmo (allegedly) introduces into the manifold is turbulent air flow. This is an entirely different animal, and one which the manufacturers have gone to great lengths to eliminate, or at least minimise.

Steve

Reply to
shazzbat

Yes and no, Steve. What happens is that "swirl" (bulk motion of the mixture) is generated by the intake port design. As the piston comes up towards top-dead centre and the moving gas is compressed into a smaller space, this bulk motion breaks down into small-scale turbulence. This turbulence then assists with the burn. The process is well understood and I have seen it myself in a glass engine (yes, really!) The point is that small-scale turbulence naturally dies away quite quickly due to the viscosity of the air so that, if you introduce it at the inlet manifold, it will have dissipated by the point of ignition.

Tony

(replace "nospam" with "fuel" to reply)

Reply to
Tony Cains

manufacturers

If it was small enough scale to dissipate in this way, it would not produce the effect the makers claim. They say they're introducing turbulent air, and that there is a benefit to be had by so doing. The manufacturers have, as I previously pointed out, gone to great lengths not to introduce this. Engine tuners go to even greater lengths to achieve even smoother flow.

Steve

Reply to
shazzbat

Sorry Steve, I spent 10 years working on inlet port design for a major manufacturer and that's just not the case.

Firstly, Ecotek _say_ that they're introducing turbulent air, but have no evidence of this (measurements of turbulence with and without the valve fitted, for example). Nor is there any proof that the benefits (if any) are as a result of increased turbulence. The main effect of turbulence on combustion is a faster burn, and if this really were occuring then the ignition ought to need retarding. But as I said, turbulence within the inlet manifold does not survive in the cylinder to the point of ignition.

Secondly, the flow across the throttle blade at part load is extremely turbulent anyway, since the pressure drop is around 0.4 atmospheres and so the air moves at hundreds of metres per second through a relatively narrow gap into a large space. Gas flow from the purge valve and crankcase breather is often introduced here precisely because the turbulence helps it mix with the main air charge. Hard to see how the 5% or so of "turbulent" air coming from the Ecotek valve could be more significant than this. (This doesn't occur at full load, admittedly, but that's not significant when considering "real-world" fuel economy, and the Ecotek valve is shut off at full load anyway.)

Tony

(replace "nospam" with "fuel" to reply)

Reply to
Tony Cains

I wish now I'd kept all the raw data. It would have been over a period of almost a year (as a tank lasts me about a fortnight) and I honestly can't remember what time of year I fitted it. However I was wary of the fact that any apparent long-term improvement might be due to seasonal weather change. I remember noting at the time of fitting the Ecotek that there did *appear* to have been a step change improvement of a few MPG, comparing the last few tanks before the fill-up with the first few after.

I haven't been keeping a careful fuel log for a while, but there'd be no problem starting again.

Doubt it. It's a dual carriageway :-)

Interesting - are you saying then that there are modes in which a device like this could reasonably be expected to improve MPG on older engines without ill effect? (No offence taken about the tough-as-old-boots Skoda engine, BTW - camchains, don't you just love 'em? My Skoda is a political statement on wheels - "THIS IS JUST A FORM OF TRANSPORT"!)

The valve is set to start opening (=farting) just above idle, so I can't rule out some effect. But it's not something I'd swear to. It just seems that bit more willing to take a certain couple of roundabouts in 3rd gear.

Cheers, snipped-for-privacy@SNAKEOILDEVICEiee.org (remove snake oil device to reply ;-).

Reply to
Nick Dobb

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