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M92PV4U

M92PV4U

Falling Down
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Mikel
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I recall my grandad talking to my dad about this back in the 80’s.
Or something very similar.
He was a very smart engineer and was pretty irritated about it all if I recall.
I’m curious what the basic premise of this gadget is and why it hasn’t been recreated, at least in an EFI tune?
 
M92PV4U said:
Cool, I've heard of and have seen predator carburetors before. I just found this article looking through some old books my grandmother bought me. I wad trying to find something about international transmissions.
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IIRC they were made in Tulare. My buddy Mike wanted to put one on his 73 Olds Cutlass, but never pulled the trigger.
 
I knew I guy out of high school that ran one on a 71 Camaro that hauled ass. That was back when a "500hp" street car was insane, (And usually not a real number) But was arguably one of the faster street cars around 1981-82.
 
He passed away ~10 years ago if my memory remembers right.
 
Be interesting to see what today's cars without all the bloated shit like cameras, PMS scanners, 27 airbags, power everything, could do for mpg. Just a plain car, but that isn't a rattling plastic hunk of shit.

I find it hard to believe a 2024 Accord gets only ~5 mpg better than a 1984 Accord.
Forgot what my 84 had for horsepower, but it did 65-70 without any fuss.
 
There is a guy on Youtube who put a lawnmower carb on a 302. Got 40 mpg, wheel dyno made 60 hp.

First video in the series;


Dyno run in this one at 2:40
 
WhiteTrash303 said:
We've all heard the stories of the oil companies offing people that make these miracle carburetors, but if the optimal AFR is 14.7:1 then I fail to see how a carb can magically make an engine 3x more efficient.
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I never gave any credence to the magic carb either. Efficiency gains are going to be in retaining heat in engine and extracting more work.
Some modern engines use the Atkinson cycle, high static compression, late intake valve closing, late exhaust opening so the power stroke is effectively longer than the compression stroke. Variable cam timing allows it to run normally under power, then retard the cam to Atkinson cycle at cruise. Direct injection makes it easier to avoid double fueling the intake reversion.

I remember articles about Smokey Yunick's "hot vapor" engine in the 80's. Tubocharged, carbureted, no computer 4-cylinder Fiero making 250hp, getting as high as 51 mpg. The intake air was heated to 450°F to fully vaporize the fuel as lean as 20:1 ratio. He never divulged the secret of how he avoided detonation at those temps.
 
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Keep in mind that the original was running vs 40s and 50s designs, when they hardly cared about mpg. It took less improvement to be great.

20 years ago I saw a chart in Car&Driver comparing the Vw Golf from each decade. Mileage stayed at about 45mpg throughout, while power went straight up.

Look at modern 800hp trucks. People are so used to 0-60s, even economy cars aren't really economy.
 
my buddy had one on a 350 in a nova, it really jumped out of the hole. but was never the equal down the track compared to a holey.
 
why did the honda crx hf get 50mpg, and theres nothing really other than a prius that will do that now? and yes, I've owned a couple hf's. I have one now I need to get the engine back together on. theres nothing special about the engine, other than I think roller rockers, and they run a wideband 02 sensor. other than that its all in the computer, and higher gearing on the trans.
 
I thought the HX civics went into a really lean fuel map once a certain set of conditions were met (rpm,tps,load). I had one for a while and you could feel it kick into that. You’d have to lean on it real easy to maintain speed but not send it back into 14.7:1 mode

Either way that thing got insane mileage. Would like to have another one
 
V30crewcab said:
why did the honda crx hf get 50mpg, and theres nothing really other than a prius that will do that now? and yes, I've owned a couple hf's. I have one now I need to get the engine back together on. theres nothing special about the engine, other than I think roller rockers, and they run a wideband 02 sensor. other than that its all in the computer, and higher gearing on the trans.
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I bet most 80s compact shitboxes that got 40mpg with a 4cyl and 5spd would crack 55 easy if they had a modern engine with half the displacement (for double the horsepower probably) and all the fancypants variable valve atkinson cycle bullshit and a CVT if the rest of the vehicle and the emissions standards it had to comply with were unchanged.
 
1960 Mercedes-Benz 190 DB held the world record for fuel mileage till the diesel Golf took the crown. My father had one, 55 mpg. 45 hp, 4 cylinder injected diesel. Didn't need a throttle, a switch for go and stop would have been fine.
 
Quick & Dirty said:
He never divulged the secret of how he avoided detonation at those temps.
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[486] said:
straight toluene
piston rings and lands that last 100 miles
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When the vehicle was driven, the magazine writer asked about that “nasty rattle” an ol’ Smokey said it had a loose subframe or sumting :laughing:

If I recall, Stratified charge was the other part of that design and that’s always intrigued me
 
V30crewcab said:
why did the honda crx hf get 50mpg, and theres nothing really other than a prius that will do that now? and yes, I've owned a couple hf's. I have one now I need to get the engine back together on. theres nothing special about the engine, other than I think roller rockers, and they run a wideband 02 sensor. other than that its all in the computer, and higher gearing on the trans.
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It weighs 2/3 what a modern civic does and based on the lack of them I see the road over the last twenty years wasn't that great durability wise.
 
speed bump said:
It weighs 2/3 what a modern civic does and based on the lack of them I see the road over the last twenty years wasn't that great durability wise.
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They also only made 200k of them total over a 4yr run 30yr ago and I assume that the bulk of those were sold in Japan.

200k units sold would be a good year for the Legacy in the early 90s and a slow year for the Legacy in the late 90s and other than my driveway they're not very common these days or anytime in the last decade.
 
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Read an article about a guy burning used motor oil, IIRC he used the exhaust to heat the oil, according to the article the smoke came out white. The state made him disassemble the two he built because he wasn't paying road tax
 
[486] said:
straight toluene
piston rings and lands that last 100 miles
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I did read that the engine had forged pistons with a custom ring package and Carrillo rods. I guess he just built it like a diesel and let it rattle.
He made a deal to produce conversion kits that fell apart in a lawsuit. I guess they figured out the average shitbox engine couldn't cope with it.
 
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