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Old 06-05-2025, 09:28 AM   #1 (permalink)
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Want +20% MPG? Bam, Here You Go - Autoline:

Thx to pgfpro for getting me into this with his great 1991 Talon TSi Compound Turbo AWD thread.
Yes he is running a compression ratio AND Air/fuel ratio of around 30 to 1, as is F1.
So this is a thread for links to related info. Plz do post!




Maserati's MC20 Engine is using combustion pre chambers, meaning its moving out of pgfpro's workshop and F1 and into road going cars you can just buy and the only 'spanner' you need swing is a key.
Isn't that a relief!



IAV - Pre-Chamber Ignition: Key Technologies for Highly Efficient SI Engines




This is coming people. (IMHO) And is already doable today.

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Old 06-07-2025, 06:47 AM   #2 (permalink)
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Pre-chambers on a gasoline engine? Honda did that in the 70s and 80s.
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Old 06-07-2025, 09:13 AM   #3 (permalink)
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Quote:
Originally Posted by Gasoline Fumes View Post
Pre-chambers on a gasoline engine? Honda did that in the 70s and 80s.
Thx. Yet more hope for my carbs.

Here's an interesting video about this beating the EPA standards at the time, as well as future standards and embarrassing? GM

NB that the tested car had a diff ratio of 3.08, vs the stock 2.73... and a sticky float valve in the carb/s apparently.

Last edited by Logic; 06-07-2025 at 10:13 AM..
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Old 06-08-2025, 01:21 AM   #4 (permalink)
It's all about Diesel
 
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I had always been more familiar with prechambers in Diesel engines, and those were supposed to be better suited to lower-grade fuels.

Well, maybe the prechambers could be useful with ethanol, in a similar way to how it served the earliest high-speed Diesels.
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Old 06-08-2025, 06:23 PM   #5 (permalink)
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Quote:
Originally Posted by cRiPpLe_rOoStEr View Post
I had always been more familiar with prechambers in Diesel engines, and those were supposed to be better suited to lower-grade fuels.

Well, maybe the prechambers could be useful with ethanol, in a similar way to how it served the earliest high-speed Diesels.
I haven't spent much time at all on Diesel Prechambers cRiPpLe_rOoStEr,
but as the fuel is injected just before/during the power stroke vs just before/during the intake stroke they are COMPLETELY DIFFERENT.

ie: DO NOT confuse what you know about one with the other.
That road is likely to lead to idiots concluding that this is all BS and pgfpro a big BSer and completely ignoring any/all F1 etc evidence out of convenience..!


This will be helpful with ANY spark ignited fuel/engine IMHO.
Think of how small the spark from the std sparkplug is, vs the HUGE! 'spark' one gets from the pre chamber!

ie: You get a much faster, more even burn, more from the top down than from the inside out.

With all else being equal/stock; you will be able to retard the timing of the flame jets. (which NB: come after the spark plug spark)
That basically means less pressure build up before TDC, trying to reverse the crank rotation.

But the real beauty of the big 'spark' pre chambers provide is their ability to effectively set fire to a much leaner mixture...
THAT is basically how pgfpro and F1 are getting the MPG gains! Basically...

NB that they take it a step further by:
1: Pre heating the air and fuel.
2: Then heating it further with high compression, during compression.
3: Fine control of said compression using the turbo's wastegate and/or an adjustable blow off valve.

IMHO there's a/the Smokey Yunick 'trick' here:
At a certain threshold temperature (pre compression stroke);
the added heat provided by the high compression, compression stroke results in either:
The full pyrolysis of the fuel to gas?
Or:
It goes even further than that...
(That I need to discus with pgfpro etc before elaborating)
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Old 06-13-2025, 01:14 AM   #6 (permalink)
It's all about Diesel
 
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Quote:
Originally Posted by Logic View Post
I haven't spent much time at all on Diesel Prechambers cRiPpLe_rOoStEr,
but as the fuel is injected just before/during the power stroke vs just before/during the intake stroke they are COMPLETELY DIFFERENT.
Interesting. So, let's consider its suitability to port-injection engines. A good way to get rid of particulate filters on newer gassers...
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Old 06-13-2025, 09:52 AM   #7 (permalink)
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Quote:
Originally Posted by cRiPpLe_rOoStEr View Post
Interesting. So, let's consider its suitability to port-injection engines. A good way to get rid of particulate filters on newer gassers...
Oh that's what pgfpro and F1 are doing: Passive Pre-Chambers with no injector in sight!

pgfpro has 1 of his intake and exhaust valves open/close slightly before/after the other to create more airspeed over the nozzle hole during the valve overlap at exhaust-intake.

Now the piston is only traveling around 4mm during the 40 degrees around TDC where is does a dead stop.
ie: For the same fuel injector flow there is very little airflow at this TDC exhaust-intake stage of the stroke, so you get a richer mixture.
At a guess the injector is also aimed to spray at the pre-chamber side of the valve, creating an even richer mixture in the vicinity of the nozzle.

The pre chamber empties/fills by... think of blowing over the neck of a smoke filled bottle to make it 'sing' and clear out the smoke.
All very clever indeed! And cheap and DIY-able!

(It's not like you to skip over a thread. So what happened here?)

Last edited by Logic; 06-13-2025 at 12:23 PM..
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Old Today, 01:28 AM   #8 (permalink)
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Pre-chamber on plain old VW Beetle with carbs!

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