I must say if you look at the latest motorbike
carb and efi setups there is some emphasis on the
area that this old bloke focuses on. The base of
the throttle or slide are biased in a way to increase
the flow of air at a point on the base.

Like all things we wont know till someone or
others have tried it with conclusive evidence.
Mercedes have their own vortex generator manifold
device patented but never looked at it myself.

The Iris throttle body is interesting if used for
Formula 1 but would it suit lower road engine speeds
is the real issue.

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i know. didn't say they work, didn't say they didn't work either. just sharing. no offense taken :)

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the answer to that is no, the iris and roller style have a very large opening very quickly and therefor would not offer the fine control at low throttle

if your butterfly style throttle is too small for the application and therefore you are getting pressure drop... then do what everyone else is doing... put a bigger throttle body... or muck around knife edging it

1200rallycar wrote
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have you tried it? a large throttle body will offer better control at low throttle compared to the mentioned at the proportinate size for your engine if your foot does the same with both? I dont think your statement is correct.

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Actually lack of air with a too small TB (reduces the volume of air) the idea Bakat put up focuses on air fuel in a vortex and centrally focused highly mixed/atomised fuel air path similar to what latest bike carbs and TBs seem to be designed to do.

i dont mean to be rude but i've read both your comments multiple times and have no idea what your trying to say

If the iris tb works as it says it does and the right size is matched to your engine its doesnt make it a F1 or comp use only so your statement of no is open to criticism.

They would open as quickly as your foot allows, im my understanding they cause no obstruction to airflow.
The iris design centrally focuses the flow away from the walls of manifold so perhaps a quad iris setup will be directing the charge in a more biased method.

watch the videos on Bakats links it shows the modification supposedly improves atomisation, and some kind of turbulent vortex at low pressure intervals. Im not convinced it works either but until someone tries is or proves it wrong Im open to the idea(s) as you never know.

well this takes us back to the days of products like the "turbozet" or whatever it was where they installed a pc fan in your inlet to increase pressure and turbulence.... turbulence is probably good in the combustion chamber but i don't think it is in the manifold and ports, why would so many people match port and polish etc if turbulence was a good thing, in fact i think some things are starting to contradict here.... if the iris throttle is good for laminar flow no pressure drop and reduced turbulence... then why do you want to induce these things by adding groves in the throttle body

my point with iris and roller throttle is that the initial opening happens in an undesirable way...

i.e. by pressing the throttle 5% you may open the throttle area 20% of full
whereby pressing the throttle from 50% to 100% may only open the throttle another 20% in area
therefore the effect of the throttle pedal is reducing exponentially

i would think a butter fly throttle would be quite linear compared

it's hard to explain as i dont know the facts on this, but i suspect something like the above which would seriously hamper your ability to modulate the throttle at the lower end (and therefore make it not good for road driving)

Thats a bit extreme to consider this mod as an electric supercharger, actually match porting doesnt always show improvements and neither do incorrect porting and polishing but thats another area that is hard to parallel or compare with this modification. Ive learnt that flow and combustion are most efficient when these events are centralised yet highly atomised away from port and bore walls much like modern direct injected diesel chambers for one.

I wouldnt never suggest using the Iris with the Gadgetman mod. You have to choose one or the other but so far would prefer an Iris that works like a camera shutter instead.

I dont agree with butterfly throttle been linear due to the rounded passage (square throttle body would be linear but not suitable for sealing unless using rounded ends).

A butterfly throttle body opens up from the bottom and top the same but initial opening focuses the air at the base of the passage into the manifold so its not ideal for laminar flow while creating turbulence also at the top as air hits the top edge of butterfly and most likely deflects up causing a pressure drop up the top and tumble turbulence instead of swirl or centralised flow. A shutter or Iris TB just makes logical sense to me so far.

but consider the exit of the Iris, you have an opening of say 1 inch in a 3 inch pipe, yes it's in the centre but its like falling off a cliff when you exit it

the air passes through a 1 inch hole into an immediate area of 3in, the turbulence at an exit of an iris would be about as bad as you could get

i think you have grasped onto a small portion of good air flow principle and are not considering the factors which come in to play

yes the air flow is faster in the centre of a pipe and yes there is friction on the side walls, but you need to consider how much air your flowing and how you are regulating it, the side wall friction is only going to come in to play if you are flowing a high amount in a small pipe... the thing is this is taken into account by throttle position, if you are on part throttle and your not getting enough air flow due to losses in your throttle body the simple solution is to open throttle body a little bit more my pressing your foot down a little more on the accelerator..

(btw - i agree butterfly is not linear, just saying it is more linear)

the proof is in the pudding and no pudding yet so the jury is still out. If its better then we should see aftermarket iris throttles out soon enough flood the market