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I think what you're describing will work much better with one ECU treating the unit as one engine.

Jack's point is correct. When you're going for milage pumping losses are large. Whenever you run the engine at part throttle you have a lot pumping losses. This is the advantage of diesels, they don't have throttles. Steam engines don't either, but we're getting off topic. Throttles are terrible awefull things, but just very convenient for gasoline engines.

When you are at partial throttle, there is a vacuum in the intake tract. That means when you're intake valve is open and you're trying to bring in a charge there is a negative pressure on the top of the piston. That means you have to subtract that negative pressure from the positive pressure on a cylinder with combustion. The thing is you are running at light throttle for good mileage, so there isn't that much pressure. This situation hurts you the most when you need the efficiency the most. Gasoline engines use much, much more fuel when they idle than diesels do...

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Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
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Pumping losses are a problem. That's why I want to experiment with this. I am thinking primary cylinder being cable operated and the other throttle bodies being servo operated. This will allow the deactivated cylinder's throttle body to be opened, hopefully minimizing pumping loss. (Too bad I can't seem to find an electrically operated compression release.) This will allow the active cylinder(s) to run at a wider throttle as well.

Anyway, I'll know if it works or not after I give it a try.

TALON

Well, being as I ain't gonna get this vehicle on the road this summer, I have been working on the interior a bit. I got the side panels finished and covered, and worked on the dash top as well. The side panels I painted with fiberglass resin to seal them, then used contact cement to glue on some foamboard, which I sanded down to shape I wanted. I them cut a piece of batting from Momma's sewing stash and stretched vinyl over that and glued it on. They came out pretty well I think.



For the dash top I did it a little different. I glued foamboard first and sanded it to shape, then glued pieces of an old t-shirt over the foam with fiberglass resin. I will cover that with batting and vinyl next. The dash face needs some stain (dark walnut) and varnish to complete.



The first night that I was working on this stuff, contact cement, fiberglass resin cleaners etc. I had some really wild dreams and didn't sleep for beans. I guess I shoulda turned on some ventilation. . .

TALON

Back about forty years ago Smokey Yunick came up with a high-mileage setup. He was rather secretive about how it worked, but looking at the patents later, it became apparent that he was reducing pumping losses by adding a lot of heat to the intake charge, using a low-boost turbo to maintain charge density, and adding huge amounts of EGR to keep knock under control. This was quite a trick in the pre-computer days. Most accounts, even in the SAE journal, focused on the turbo and the charge heating, but the real trick was the EGR control system, which Yunick did not patent - presumably the details are in his papers somewhere. Basically, instead of throttling the intake, he was using EGR to displace air, achieving the same basic thing. The high temperatures extended the flammability limit.

Various carmakers sniffed around, but decided not to bite. There were the usual conspiracy theories, plus Yunick got pretty angry about not being able to sell licenses for his invention. But the turbo was expensive, the engine ran very hot (not much in the way of synthetic oils back then), and the extra bits were all expensive, plus whatever Yunick wanted for licensing, plus whatever development costs to keep it compliant with ever-tightening emissions, plus... even with closed loop computer control strategies, driveability is still an issue with lots of EGR, and Yunick's system used MASSIVE amounts of EGR. With only mechanical controls. Carbureted. And only a handful of people ever got to drive any of the prototypes he converted.


Then there was the "Miller Cycle", popularized by Mazda. Bruce Crower invented it independently in the 1970s and sold conversion kits as the "Crower Mileage System." I have a couple of pre-WWII automotive engineering books that describe the same idea. Basically, they use a huge intake lobe, letting the engine bleed a sizeable chunk of the intake charge back out into the plenum before the intake valve closes. So you have, say, a 1-liter engine on the power stroke, but it's only pulling as much air as a 500cc engine on the intake stroke... and since the bled-off air is downstream of the throttle, there's a reduction in pumping loss too.

The Crower conversions worked well, but I guess at the OEM level it was simpler to just use a smaller motor and turbocharge or supercharge it as necessary.


That seems to be basically what Caterham has done with the 160; it uses a Japanese-market triple similar to the G10, except it's only 660cc, and they use a turbo to make more power when needed.

And done six months before Caterham by Dave (LionsPaw) on this very forum. viewtopic.php?f=35&t=14652&hilit=maxine

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Locost builder and adventurer, and founder (but no longer owner) of Kinetic Vehicles

Yeah, like that!

62hp for the turbo 660 vs. 48 to 55 for the NA 1-liter. Not bad.

The front dress on the 660 looks identical to the G10, so I'm going to assume it's a similar motor despite the entirely different cylinder head. The first-gen G10 had intake and exhaust valves on opposite sides of the chamber, with rocker arms. The second gen had all the valves in a row with bucket followers. The 660 is back to rockers again, but it looks like the valves are at a narrower angle.

Think about this a moment. . .

Cam runs at 1/3 engine speed, fuel injected at the beginning of the first power stroke, water injected at the top of the second power stroke. Half gas/half steam power.

intake - compression - (fuel injected here) - power - exhaust - intake - compression - (water injected here) - power - exhaust - begin again

Fuel burns as normal, water hits hot cylinder and makes steam for the second power stroke, cooling and cleaning as it goes.

Just food for thought. . .

CURT

A couple of thoughts....

...cylinder deactivation has been real in production cars for a number of years now. Case in point, all Honda V6s. They used to run 6/4/3 cylinders, but I think all have now been converted to 6/3. Drive one and you can't tell its happening. In fact, Honda added an idiot light to so you know when less than 6 cylinders are active. The system not only shuts off the spark and fuel, it holds the intake open via VTEC (not sure which version without looking, probably i-VTEC). I also think it may recirculate some exhaust through the cylinder to keep it up to temp. I believe some (all?) Dodge V8s now have a similar system. And suspect that if we dug deep enough, we'd find more engines using cylinder deactivation. In part, because a 6 or 8 will be smoother than a turbo 4, and can achieve = or better performance (including MPG).
...Miller cycle engines (or close variants) are still in production for a number of cars, particularly hybrids. Honda uses them on their hybrids, I'm pretty sure that Toyota uses them at least for the Prius, I believe the Hyundai hybrids use them, and so on. BTW, how do you figure compression ratio on the Miller cycle engine?

If it was possible to add electronic valve actuation of the deactivated cylinder, it might be possible to easily avoid the vacuum problem.

Generally they wing it and consider "trapped" compression from whenever the intake valve closes. Works well enough for judging octane requirements.

There's a lot of... enthusiasm about fuel economy tech. Some of it is more PR than tech. The good stuff is in the old engineering books dealing with large Diesel engines. Car engineers care about volumetric effiency. Diesel engineers care about Brake Specific Fuel Consumption. When you're powering the electric grid or a ship, every drop of fuel comes out of your profit margin.

The other resource you want is Glassman's "Combustion." Mine is the third edition, but any will do. Glassman is a combustion chemist; his book is about making things burn. It's chemistry, but quite readable; his targer readership isn't chemists, but engineers and plant managers who want to burn stuff. Most of it is directly useful to automotive engineers.

There's also a bunch of useful stuff in the old NACA papers. NACA was the predecessor to NASA; they did basic research on engines and fuels. NASA has made most of the papers available at nasa.gov, but they have changed to a new interface that's hard to navigate. There's a British mirror at cranfield..ac.uk, which also includes some of the British Admiralty and air service papers, but mostly aerodynamics last time I checked.

<Complete_Off_Topic>

As I am getting towards the later part of this build, I have most of the components sorted out in my head, so there is little to do between my ears beside actually doing the work. So I have been thinking about the "next one". (I know, bad idea.)

Anyway, I ran across a Cadiliac Mountain motor in a running, very rusty '70 Fleetwood. Would a book-ish type frame around a 472 be any fun to drive? Weight isn't too much more than a SB (80 pounds or so), and it looks like a couple people are even putting BB in more traditional frames. . .

Just thinking. . .

</Complete_Off_Topic>

For the love of all that is holy, PLEASE DO!

It'll need a throttle stop to keep your tires on the rims, but it'll be awesome.

I'm thinking 8 straight (ok, ok, maybe some mufflers hidden...) pipes out the bonnet or along the sideboards,, and a Cruella De Vil styling, because why not?

Dang it. Now I'm thinking of shoving a Lincoln Continental 462+C6 combo in a frame...

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Walt
06 RX-8 Shinka
04 RX-8 GT
06 325xi
Some people never have anything except ideas. Go do it.
Emissions & fuel economy haven't exactly been areas of strength for past rotary power plants, but absolutely no one with a soul has ever cared.

The Call of the Weird can't be denied...

I've seen pictures of several Jaguar V12 builds, and the Jag is *much* larger and heavier than the Caddy...

If you decide to go with a manual transmission you need to make sure the back of the crank has provision for a pilot bearing. Some were cast solid back there. All it requires is pulling the crank out and taking it to an adequately-equipped shop.

OK, enough flights of fantasy, back to work. Working on body work. I need scoops on the sides to get airflow through the radiator, so here's what I came up with. Foam sheets glued together and shaped like I want them. I have fiberglass cloth ordered and some resin. This is stuff I need to get done before it turns cold. I can warm up the garage enough to work in it in the winter, but not do fiberglass.






I also finished up the shifter boot and most of the upholstery, except the seat. There will be some more small panels, but most of the rest will be done in black carpet.



I was also trying to figure out how to do door handles inside and out and coming up dry, then I spotted this on the shelf. I'll need to get another one for the other side, but it solves the door handle question pretty handily. I just need to put some push button switches in where I can hide them on the outside and on the inside somewhere.



TALON

Yo Talon! Stop me if you already know this... Did ya order poly resin or epoxy resin? Is that plain ol' styrofoam or some of that fancier stuff that I don't remember the name of? (Polyisocyanurate... I looked it up... ) My point is, poly resin melts most foam insulation materials... You know that, right?

Other than that, I like the swoopy scoopies you made, they're gonna look cool!

Is that shifter boot purple or burgundy? On one of my screens, it's purple. TWWTFM would like that!!!


JDK

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JD, father of Quinn, Son of a... Build Log
Quinn the Slotus:Ford 302 Powered, Mallock-Inspired, Tube Frame, Hillclimb Special
"Gonzo and friends: Last night must have been quite a night. Camelot moments, mechanical marvels, Rustoleum launches, flying squirrels, fru-fru tea cuppers, V8 envy, Ensure catch cans -- and it wasn't even a full moon." -- SeattleTom

The foam is insulation board with the tin foil on it that needs peeled off. Cheap stuff, but not as cheap as styrofoam board. You can use styrofoam if you use the epoxy resin, and Tuff-R board if you use the polyester resin. I like the Tuff-R board because if sands so much better that the little beads in styrofoam. Tuff-R needs the resin that uses the little tube of MEK for hardener. This resin stinks more, and is less safe to use, but the resin is cheaper, ya just gotta keep the garage door open when it cures. By the way, GreatStuff works with the polyester resin as well.

I was thinking burgundy when I sent my dear sweet bride to get me some vinyl for the upholstery, but it looks more purple. She likes purple. And the suspension parts are yellow. She is a high school teacher in a neighboring town, rivals with our school. Our town's school colors are orange and black, her school colors are purple and yellow. And my youngest just graduated from high school last year. Do you think there might be a bit of rivalry involved?

TALON