always thought pre chambers were the way to go for more efficiency
as long as they didnt lower the compression ratio and whattayaknow
Formula 1 has been using them and not filtering this technology
they stole from long time well proven industrial dinosaur usage.

https://www.youtube.com/watch?v=R453ONkb0_A

https://www.youtube.com/watch?v=WzJaWqhvHf8

question now is which industrial passive pre chamber spark plugs
can we use on our daily street driven cars???

The video talks about two kinds of spark plugs:
* Cold Spark Plug for industrial engines with highly corrosive fuels at extreme presssures
* Passive Pre-chamber Spark Plug for extremely lean gasoline mixtures

The first is not applicable to the A-series unless you're running some home-made experimental fuel!

The second looks very similar to the Mitsubishi MCA Jet or to the Nissan NVCC. Very old (and proven) technology for increased fuel economy. Interesting to hear that F1 is using it now, never heard of it in relation to performance before. Look up Chrysler Lean Burn

yep the passive pre chamber design but now to find some to suit jp engines!
Pre chamber tech prob goes back to ww2 and maybe further back.

The thing is F1 has been using it for quite some time running 17:1 and
for quite some time obviously pre chamber style plugs have been kept
away from mass produced cars or the gains from current super thin nasty
piston rings, direct injection and other complex technologies would be
poor selling points when an A series 30 years ago could get the same
economy as a hybrid today yet with swirly port heads.

Today the same A series with passive pre chamber plugs, piston and
engine heat and friction coatings would ruin many newer engine figures.

If an LS can pass emissions then the venerable A series would easily
too if developed further.

TBH for at least 20 years I wondered why manufactures didnt use
pre chamber designs on their gasoline heads like Mercedes Benz
has now on their new engine which supposedly is 50% efficient
followed by Toyota`s 41% which are both great efforts however
if you saw the Benz tech its so complicated its scary when
just some sparkplugs could do the same.

Mazda is doing it a different way. From what I understand they run similar high compression ratios and very lean mixtures but inject a second short rich mixture, shot at the spark plug to initiate the ignition process.

There are some clever engineers out there doing things with the combustion engine that weren't even thought of a couple of decades ago. The days of big cubes for big power are over.

true, true. They thought of all this stuff decades ago but now have the technology to actually make it run good and warranty it. The new Nissan variable-compression engine is for sale now in USA. Nissan KR engine. Mazda SkyActiv-X is still a dream ...

The days of 7- and 8- liter cars is over, the 2019 Chevrolet is downsized to a 6.2-liter engine

Mazdas tech still uses sparkplugs at certain rpm

Nissans engine is a joke in complexity far removed from the A series

personally one of my old time fave engines is the Buick "nailhead" v8
it produced 1lbs of torque per cubic inch at low rpm, no direct injection,
no complicated circuitry or things that will be hard to replace.

Mechanically almost all is possible without Ecus its just it sells better
and the agenda is to make us all just use autonomous vehicles in time and
be surrounded by a smart grid where we cannot decide a thing for ourselves.

I recall old Honda crx s1 getting 45-50mpg with simple efi and the early
1.3 1973/74 civics doing the same with carbs.

Using a big factory heavy flywheel my old 2cv engine could idle around 300-500rpm
and take off well enough not to need stop start technology and gave me 60mpg.

I believe these spark plugs, along with nailhead style chambers, smaller valves,
accompanied cams with more lift and duration and a hefty custom flywheel and some
thermal coatings for more efficiency, teflon coated pistons skirts, su carb and
90mm stroker crank would make an A15 a happy economy grunter engine to challenge
many modern ones in most departments. (Maybe a catalyc converter could also help)