nah - it doesn't have to work - just be marketed well... kinda like the electric supercharger

we hope so to see its true colours.

The whole 'turbulence' (at the throttle plate region) thing is mostly nonsense - esp in the era of efi. Injector placement, and injector spray pattern are the big keys, and secondarily (though only just barely in 2nd place) is the port cross-section, shape and valve/seat shapes. You 'want' turbulence (well not really - more accurat to say 'quick but controlled mixture motion' - all the way into the cylinder, and especially as the piston hits top dead centre and the burn cycle starts. If the mixture is moving quick enough, the flame spreads very quick (but still well controlled) and leads to complete combustion, and needs less ignition timing to get the 'push' happening at the right place to extract maximum power from it. And if it can be done with less timing, then it means less 'negative work'. So for the same amount of fuel burned, the latter makes noticeably more power (or on the flipside, at part throttle, it requires less fuel to be burned to achieve the same burn speed.

BUT you don't want turbulence further upstream in the port. Because that will actually lead to inefficiencies and actually reduce cylinderr filling. What you want is decent velocity (for the rpm range required) decent mixture suspension, and decent swirl (or arguably tumble on some multivalve engines). A google search on 'laminar flow' might bring up some interesting reading.

You aren't going to see (imo) Singh grooves in _any_ race engine where they have enough of a budget to actually test it.

There might be 'something' to it, but it is likely for reasons other than why the grooves were tried in the first place. A bit like those 'swirl' things meant to be placed on top of carbies. The only way they could possibly work (and they were made as a scam, so if they worked at all, the sellers would be genuinely shocked (not that con artists like that would ever admit to it) would be if their location somehow caused turbulence near the fuel bowl vent, or the booster venturi/fuel discharge location, and it upset 'proper' fuel metering. If that did result in lower fuel consumption, then the same result (or considerably better) could be had by throwing the 'device' in the bin and re-calibrating the carburettor circuits to lean it out more at part throttle.

I'd also make a comment on the 'testimonials' some people have given about such 'cyclone' type devices. Some of them were being honest when they said fuel economy was improved. What they didn't realise was that the actual gains came because they had subconsciously driven the car more economically (since they were now mad keen on improving economy) but 'thought' they were driving the same, or didn't realise etc.


Believe it or not - they 'knew' 95% of what there was to know about flow and combustion over 50 years ago. Some of the NACA papers (and stuff by Sir Harry Ricardo - spelling??) bear this out. What they lacked at the time was practical means (i.e. engine management computers that would even fit in a car - remember that in the 50s, or thereabouts, a computer that fills an entire house, in terms of speace, had less computing power than any home PC (probably even less than most modern phone/pad things). Swirl, quench, mixture distribution, flame propogation - they knew all that. There are some naca reports on swirl and combustion/flame propogation - even including pictures inside the cylinder (I forget how they did it - I think through a toughened thick wall window (maybe where a spark plug would normally be) or it might have been in a custom piston and crankcase/cylinder barrel and angled mirrors) showing the burn and how it spread. Fascinating stuff given that the info/research was done 60+ years ago.

On the 'heating the fuel' - I think there's some info out there from smokey yunick's 'hot air engine' if you google it. Basically if you heat the fuel enough it ends up breaking down into what was called (iirc) 'producer gas' - which ends up being higher octane than the fuel itself originally was, and it also allows more efficient/complete combustion, and it then lends itself to better fuel economy (and potentially, though not always) reduced emissions. Certainly such technology works, but it's not going to get anyone 200mpg. At least not in any passenger car (of average size, weight and frontal area). It takes a certain amount of power to push a given car along at freeway speeds due to rolling resistance and aerodynamic drag. So even if you hypothetically got 'all' of the fuel burned efficiently, it just won't be enough to push the car along and only use 1 gallon per 200 miles. Some (quite a lot) of the heat ends up going into the cooling system, and out the exhaust. This is (to some degree) inevitable. Yes there are new cylinder wall materials, and combustion chamber and piston crown coatings that improve things, but they aren't cheap, and they certainly aren't in any way related to a carburettor design that will give 200mpg.


The 'problem' with the iris setup - again this is opinion - is the difference between fully open and closed, and whether there will be a linear relationship (or at least a driver friendly one) between throttle PEDAL movement and iris opening/cross section area. There needs to be some sort of proportionality to it to enable the driver to use the throttle productively both mid corner and corner exit. This is _absolutely_ critical, unless the engine is woefully underpowered, and corner exit is easy. But in any other performance situation, corner exit is the make or break of things - it'll determine how you end up down the straight, and the better it is, you'll be next to impossible to catch/pass.

Actually let's go into more detail. If you consider a throttle open allowing 5% of total flow. well if you open it a fraction, it will be to 10% of total flow - which doesn't sound like much (compared to 100%) but it is effectively 'doubling' the flow, ot a 100% increase. crack it open a little bit more - you get 15% flow - only a 50% increase. SO these early throttle opening positions are 'far' more critical. When we say 'linear' as far as regular throttles go, we don't 'technically' mean 'linear' but more accurately it might be called a 'user friendly' one.

Having said that, you might be interested to know about the HIF su carbs. They are a good performance carb, but ironically were able to improve upon the SUs already well established ability for excellent fuel economy (if driven suitably of course). Well the 'magical' change that was a big factor on this improvement? Actually it's pretty clever - they altered the throttle link arm/cable attachment, so that you have to move the pedal more in the 0-50% throttle range, about 2/3rds of the acc pedal movement gets you 50% throttle, and thelast 50% of throttle opening is covered by only the last 1/3rd of pedal movement, In practice this makes it much easier to finely alter
throttle position at regular driving/cruise conditions. And it works a charm.

IF anything I would be inclined to think that this iris throttle ends up opening quicker at initial pedal movements, and less during the last segment of pedal travel.

The other thing I'd be worried about is the mechanism itself. It might work very well in test situations (and i haven't read the site in full, so if it covers this, I'll happily stand corrected) but I'd be _very_ worried about a complex mechanism with multiple moving parts - that gets moved/shifted probably on the order of 50-100 times (admittedly not all the way open to all the way closed each time, but certainly for many of them) per lap. Then throw in the air flowing through them, thermal cycles as everything gets up to temp, gets hotter toward the end of the straight, cools a little during braking and corner entry etc.

I reckon it could be a real risk of seizing given some amount of time, which could be fatal. It might not jam altogether, but might end up with 'sticking points' - so it'll be say, 10% open, you push the acc pedal a little, and nothing, and then a little more, and it jumps to 20% open (I picked 10 and 20 percent as random figures for sake of example). Then you lift off a little and it stays at 20% open, you lift off a little more and it jumps back down to 10% open.

The loss of fine throttle control.

And if anyone things this isn't important, I'd point out that (if we hypothetically could fit all the manifolds in question, sometimes they just don't exist) a large single carb and large plenum setup (or efi with large single plenum) are known to produce more peak power. But one carb throat per cylinder/intake port - i.e. twin webers on our A-series, or so called "itb" efi intakes- individual throttle bodys one per cylinder are by the most worthwhile for circuit racing. Even though they miss out a touch of peak power, throttle response, fine throttle control and wider overall powerband will 'clean up' a similarly specced engine with single large plenum

If all that is not enough, it also violates the general 'kis' principle - keep it simple. Or alternatively the 'if it ain't broke don't fix it' principle. The money to get or construct an iris style throttle would easily be able to produce more useful gains spent on practically any other upgrades.

If I was going to run anything like it, I'd run a barrel throttle, or flat slides. They are readily available, arguably affordable, and do the job. But frankly, I'd just stick with the good old butterfly style, just not enough gains to warrant anything more.

I know they say the proof in the pudding is in the tasting - i.e. without testing we can't say 100% definitively as to what they will achieve. But they also say that 'you can't make lamingtons out of pig $#|7' - in other words the idea has to at least be fundamentally plausible/workable (and in this case it has to be workable to an EXTREMELY high degree, as we already have throttle butterflys, slide throttles and barrel valves, and all of them work particularly well for each given application). SO basically it would have to be significantly better than the others to really warrant its use. I concede that in highly competitive racing, even a 1% gain is huge, but I don't think these things, even by the tests they show, is close to that. The difference in pressure drop 'looks' big, but in practice that would be lucky to amount to 4-5bhp on a well developed 2 litre engine, if that. And it still doesn't have the edge at various lower throttle openings, so the overall result is not necessarily better at all - it's 'real world' result on a track might actually end up being a worse lap time instead of a better one.

Years ago, there was a thing called 'negative supercharging' it took an existing idea - tuned length headers - and then totally over-stated the potential gains. They used pseudo science. I think I know where they got it too. David Vizard did an article on 'exhaust scavenging' years back, And he (quite rightly) pointed out that the 'suction' (I'm grossly dumbing down the language there to save a little time) from the outgoing exhaust gases, on valve overlap when the piston is at the top, the end of the exhaust stroke, an the intake valve is just starting to open - well that outgoing exhaust pulse can pull on the intake charge at something like 300% as 'hard' as the piston will as it moves down the bore on rthe intake stroke. Now this is absolutely true (I'm not sure the exact figure, but 300% is close enough, it's not a big deal) No question about it. But the next logical 'step' the budding reader has to put together (I'm not sure if VIzard mentioned it, but that isn't an 'oversight' on his part, imho he always wrote in a way to inspire people to take things on board, and use it as a basis for their own experiments, a helping hand, rather than spoon-feeding) - anyway - the important thing here is yes, it pulls at 300% as hard, but it's also happening at a time when the exhaust and intake valves are open only around 50thou or so. And as we know, they don't flow that well at such low lift. So 300% of the pull, but only (perhaps) 10% of the flow available compared to at full valve lift. Which is why the tuned length headers and exhaust scavenging only tend to add 5-10% power for most apps (versus a non tuned length exhaust, but one that isn't restrictive. Of course tuned length versus stock cast iron exhaust and small diameter main pipe will show a much bigger improvement, but we have to separate gains from reducing or eliminating back pressure, and those from actual exhaust scavenging).

the topic used to come up on the moparmarket forums every 6-12 months, and people (myself included) got sick of having to write 10 page essays cutting the thing to shreds and explaining the real deal.

What I'm getting at is that as car enthusiasts, by definition we have enthusiasm. That's a good thing. The trouble is that sometimes we 'want to believe' and sometimes the item in question just doesn't pass the smell test. Sometimes it is down to genuinely hard working people trying something and getting a result and thinking 'X must have caused it' when actually it was something else. That's no big deal. The man who never made a mistake, never made anything. And even the best inventors/scientists in the world would experience numerous failures and so forth. It's just the way it goes. Then there is the 'other' type of person (and I am not talking about any of the items discussed here but there is no shortage of this sort of person in the car vendor community) - where they have a very dodgy item indeed, and don't give a darn about the fact it is rubbish, and market it anyway, using pseudo science. And even if you had all the proof in the world, it would be irrelevant to them, they are in it for the money (mind you they'll happily go on and on about how great they are - intelligent and generous and passionate), but in the end it's just greed.

There's some articles on 'theoldone.com'

http://theoldone.com/articles/Hot_Rod-Talking_Heads.zip

http://theoldone.com/articles/CircleTrackSwirlPowernComm.zip

http://theoldone.com/articles/Hot_Rod-The_Soft_Head.zip

Larry Widmer isn't perfect by any means, but the above articles are good reading. What I find perhaps most informative of all is how a number of engine builders commented against him and his work (and theory about swirl etc) saying it was not possible. Since that time, try and find a nascar engine that didn't employ those very principles in the years afterward.

yeah, that's what i said.... lol

Thats quite a post there, It would take me a week to type that!

Thought thats what you said ;P
The modulation can be changed but definitely agreed the longer the manifold and complexity its a gimmick but how about short sidedraft quads with or without boost?

Blah Blah Blah...

Overlooking the fact that they are trying to overcome a restriction at full throttle on an engine that exceeds 18,000RPM at average speeds exceeding 280KPH.

It all sounds like a bunch of high horses having a joust...

Doesnt sound like high horses but a bunch of uni students having a go which is worrying
http://www34.homepage.villanova.edu/s ... hrottle/meet_the_team.htm

and reading this its even more worrying
Quote:

then looking at again the iris deserves a black eye!

Attach file:

---

  cossy barrel section.jpg (49.29 KB)