Rather perplexing...

[AudioGuy93DelSol]

Spoiler for what is it:

It's like a v8 with the pistons paired. Anyone have any info on wether this is real/what it's used in?

[2.2 Straight six]

it's real. but it's not a V8.

this is honda's new engine design, the oval pistons apparently offer massive power gains over round ones. it was a design created by hoda's racing motorbike department about 30 years ago, but machining then didn't allow it to work very well, but with new technology research into it has continued.

[Moppie]

Looks rather funky, thats a lot of piston surface area.

Got any more details?

[2.2 Straight six]

http://world.honda.com/history/chall...ine/index.html - info about the original version, on the're '79 race bike.



that's the piston and twin rods.

at the time Honda were totally dominating F1 too, and upon seeing this development in race bikes, oval pistons were banned from F1, although they had never even been tested for it, the FIA banned them to prevent Honda from giving themselves a futher lead above the competition.

apparently, the reason this design is so much better than round pistons, and offers better potential power is down to the number of valves and the little wasted space between them, this allows much better intake/exhaust flow, and it also allows more volume to be flowed too.

in tests the oval piston engine was also able to rev up to 22,000prm.

Honda made about 300 road bikes with this engine, it was the 750cc Honda NR.

Hope that was of some help

[AudioGuy93DelSol]

I always wondered why the FIA rules stated pistons could only be round. I'm thinking, as opposed to what? The truth is revealed. Good info.

[beef_bourito]

you said they're putting more research into them, any info on recent developments?

[drunken monkey]

...and people wonder why I would defend the claim that Honda is just as engineering/racing based as Ferrari ever was. They just happen to also make cars for the average/every day man.
Way before Mazda's rotaries were banned from Le Mans, Honda were banned from even thinking about this in an F1 car.

This is in part why I want Honda to do well in F1.

[GreyGoose006]

it looks like it is meant to have 8 valves per cylinder...
thats a lot, and a bit overkill.
even for a honda.


i guess the oval shape distributes force better in a downward motion and wastes less in friction or something like that.

thats odd.

[UncleBob]

honda did produce a bike, the NR500 and later, the NR750. The GP rules back then, didn't allow any cc advantages to 4 strokes, and honda has always been very fond of 4strokes. So they had to make a 4stroke that would compete with the same cc 2 stroke, which is a very difficult challenge.

Eventually rev'ing to 19.5K RPM's, making 135hp, they did get it to compete, power-wise, with the 2 strokes, but it was too heavy and the bulkiness of the engine made it difficult to mount in a bike optimally.

of course, these days, almost all of the bikes are 4 stroke in the GP races, since they started allowing 4strokes a cc advantage. Last couple years it was 990cc's, and honda was dominating with a V5 engine, making 250ish HP. The rules changed for this year though, dropping the cc's down to 800. But from what has been shown so far....the 800's won't be much slower than the 990's were. Honda went with a more traditional V4 for the 800cc engine.

[GreyGoose006]

V5...

how does that work
two on one side three on the other

[Moppie]

Originally Posted by drunken monkey

...

This is in part why I want Honda to do well in F1.

Its the reason Im driving my 2nd Honda, and when it does will most likely replace it with a 3rd.

[2.2 Straight six]

Originally Posted by GreyGoose006

V5...

how does that work
two on one side three on the other

yup.

in the case of my car, which is a narrow-angle V5, there is one cylinder bank, but the pistons are not in line, there are two off to one side and three off to the other.

[UncleBob]

Originally Posted by 2.2 Straight six

yup.

in the case of my car, which is a narrow-angle V5, there is one cylinder bank, but the pistons are not in line, there are two off to one side and three off to the other.

thats not really a V5, more like an offset or staggered I5

The honda is basically a V4 with an extra con rod journal in the center. They haven't released the exact details, but its believed that the 3 cylinders on one side are smaller diameter than the rear two.

They are also fired in a "big bang" patern, clustering all of the power strokes in small amount of crank rotation.

there's pics of the crank floating around on the net

[2.2 Straight six]

Originally Posted by UncleBob

thats not really a V5, more like an offset or staggered I5

according to VW, it's a VR5 (vee straight 5) the cylinders aren't in line, so it's a V, regardless of it being a single-bank engine.

[UncleBob]

its not a very good picture, and it might not work here....but here's the crank

more pics at http://www.gizmag.com/go/6262/gallery/

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