Right, that's not bad but what's to say you wouldn't get 30 or 3x mpg with a similar V6 and traverse mid-engine layout in a Porsche size car? This probably matters little to Porsche, but might matter to other automakers. i don't believe a boxer is the most efficient design. All that matters really is brake specific fuel comsumption/output and I doubt the boxer is higher than many V6 designs.
Pros and Cons of owning a Boxer engine
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gathermewool
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I wonder if we'd even notice that much of a change in the way the engine sounds. My 97, and to a certain extent my 08 both have a unique sound some mistake for a diesel. Well, most mistake the noise my 97 makes when cold as dying, but she's made that sound since I bought her 40k miles ago. puuuurs when warm ; )
As a note, flat motors are not perfectly balanced. Because the cylinders must be offset slightly to accommodate the con rods on each crank pin, the reciprocating mass from each side does not directly counteract the other. A slight imbalance occurs that causes the engine to rotate back and forth on it's verticle axis. This is inherent to all flat engines.
It may have a very high order of natural balance, but it's not I6 buttery smooth.
Valvetrain clatter... It what makes a Subaru, a Subaru!
It may have a very high order of natural balance, but it's not I6 buttery smooth.
Valvetrain clatter... It what makes a Subaru, a Subaru!
The Inline six is perfectly balanced to all forces primary, secondary and moments first and second order. The Flat 4 boxer has a free moment of the second order: 2*(F2)*B. The latest subaru sound is pistonslap - the piston form factor and Large bore/short stroke almost guarantee slap. Economy? Our Forester averages 30MPG in the summer with a 5M, which was a couple MPG above our 05 Rav 4. The rav 4 was in a higher state of tune giving stronger midrange torque. I felt the 05 rav 4 was one of the best small suv ever made.
Originally Posted By: GoHack
I own a 2006 Porsche Cayman S, and I've gotten as much as 28 mpg doing 70 mph, on flat highway.
The boxer engine design is the most efficient piston engine design, w/no need for counterweights or balance shafts, w/its only main drawback being its width. It's got a low center of gravity, which is exactly what you want for a sportscar.
There are some motorcycles that use this style engine, BMW and Honda, as well as aircraft.
I wouldn't call that any more impressive than if it was powered by an inline or v-engine, though there's no way to give an A to B comparison.
On an unrelated note I 've never once been in a vehicle with a Boxer engine that was notably smooth. I understand that they are fundamentally balanced in the first order but in the real world I haven't found that to be the case. Go sit in an older 911 and tell me otherwise. Or an older Subaru.
I own a 2006 Porsche Cayman S, and I've gotten as much as 28 mpg doing 70 mph, on flat highway.
The boxer engine design is the most efficient piston engine design, w/no need for counterweights or balance shafts, w/its only main drawback being its width. It's got a low center of gravity, which is exactly what you want for a sportscar.
There are some motorcycles that use this style engine, BMW and Honda, as well as aircraft.
I wouldn't call that any more impressive than if it was powered by an inline or v-engine, though there's no way to give an A to B comparison.
On an unrelated note I 've never once been in a vehicle with a Boxer engine that was notably smooth. I understand that they are fundamentally balanced in the first order but in the real world I haven't found that to be the case. Go sit in an older 911 and tell me otherwise. Or an older Subaru.
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The flat six boxer is balanced in all free forces and moments of first and second order - within a specific crankshaft architecture. This engine worked great in the place it lives in Dr. F. Porsche innovative people car. You'll always get some engine noise/vibration transfer with the powertrain bolted to the unitbody in this fashion. On another note, I would love to see Subaru go to a rear-mounted engine in a "Type III-ish" next gen Impreza - makes more sense for the flat design. I'm sure it wouldnt crash too well though w/o adding excess mass to the structure.
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gathermewool
Site Donor 2023
Originally Posted By: ARCOgraphite
The flat six boxer is balanced in all free forces and moments of first and second order - within a specific crankshaft architecture. This engine worked great in the place it lives in Dr. F. Porsche innovative people car. You'll always get some engine noise/vibration transfer with the powertrain bolted to the unitbody in this fashion. On another note, I would love to see Subaru go to a rear-mounted engine in a "Type III-ish" next gen Impreza - makes more sense for the flat design. I'm sure it wouldnt crash too well though w/o adding excess mass to the structure.
I'd think the crash ratings would go up with out too much extra work. Instead of being designed to crumple and essentially rip off, one could design the front trunk as one big crumple zone. The added weight might help balance F/R distribution, too.
The flat six boxer is balanced in all free forces and moments of first and second order - within a specific crankshaft architecture. This engine worked great in the place it lives in Dr. F. Porsche innovative people car. You'll always get some engine noise/vibration transfer with the powertrain bolted to the unitbody in this fashion. On another note, I would love to see Subaru go to a rear-mounted engine in a "Type III-ish" next gen Impreza - makes more sense for the flat design. I'm sure it wouldnt crash too well though w/o adding excess mass to the structure.
I'd think the crash ratings would go up with out too much extra work. Instead of being designed to crumple and essentially rip off, one could design the front trunk as one big crumple zone. The added weight might help balance F/R distribution, too.
Originally Posted By: GoHack
I own a 2006 Porsche Cayman S, and I've gotten as much as 28 mpg doing 70 mph, on flat highway.
The boxer engine design is the most efficient piston engine design, w/no need for counterweights or balance shafts, w/its only main drawback being its width. It's got a low center of gravity, which is exactly what you want for a sportscar.
There are some motorcycles that use this style engine, BMW and Honda, as well as aircraft.
I went to look at Cayman with one of my friends who is interested in one and it is the nicest car I have seen in many years.
I own a 2006 Porsche Cayman S, and I've gotten as much as 28 mpg doing 70 mph, on flat highway.
The boxer engine design is the most efficient piston engine design, w/no need for counterweights or balance shafts, w/its only main drawback being its width. It's got a low center of gravity, which is exactly what you want for a sportscar.
There are some motorcycles that use this style engine, BMW and Honda, as well as aircraft.
I went to look at Cayman with one of my friends who is interested in one and it is the nicest car I have seen in many years.
Originally Posted By: JHZR2
I had heard of older subarus being long-life cars, but never saw proof myself.
My sister and brother in law have 3 Subaru's with three quarters of a million miles collectively.
Subaru #1 - Pea Green GL10 wagon. 290,000 miles.
Subaru #2 - Red Loyale Wagon. 250,000 miles.
Subaru #3 - Red Outback Wagon. 200,000 miles.
And I have a H6 in my 2002 Honda Goldwing as well.
I had heard of older subarus being long-life cars, but never saw proof myself.
My sister and brother in law have 3 Subaru's with three quarters of a million miles collectively.
Subaru #1 - Pea Green GL10 wagon. 290,000 miles.
Subaru #2 - Red Loyale Wagon. 250,000 miles.
Subaru #3 - Red Outback Wagon. 200,000 miles.
And I have a H6 in my 2002 Honda Goldwing as well.
Could this be called a Double Boxer?
http://engineeringtv.com/blogs/etv/archive/2008/07/01/opposed-piston-opposed-cylinder-engine.aspx
Interesting concept!
http://engineeringtv.com/blogs/etv/archive/2008/07/01/opposed-piston-opposed-cylinder-engine.aspx
Interesting concept!
Originally Posted By: expat
Could this be called a Double Boxer?
+1 Great link. Awesome. Clearly ideal for aircraft. Probably will be used in all those spy drones too; the guy said one side can totally shut off while the other half is running, for a big improvment in partial load conditions.
Could this be called a Double Boxer?
+1 Great link. Awesome. Clearly ideal for aircraft. Probably will be used in all those spy drones too; the guy said one side can totally shut off while the other half is running, for a big improvment in partial load conditions.
Originally Posted By: gathermewool
Originally Posted By: ARCOgraphite
On another note, I would love to see Subaru go to a rear-mounted engine in a "Type III-ish" next gen Impreza - makes more sense for the flat design. I'm sure it wouldnt crash too well though w/o adding excess mass to the structure.
I'd think the crash ratings would go up with out too much extra work. Instead of being designed to crumple and essentially rip off, one could design the front trunk as one big crumple zone. The added weight might help balance F/R distribution, too.
I agree, arco, wool. Myself, I like the slim small spritieness of the type 3 vw (it's narrower than a normal car). Perfect 4 seater with lots of cargo.
So, in my perfect world, mr subaru would make this beauty with a rear mounted turbo 1.3 liter two cylinder H2, and a hybrid lite package up front along with crumple zones and smart car type armor. Four SLA batteries driving two small motors integrated in the front wheel hubs, that can do a little charging at idle, and a little regenerative braking. It'd be less than a foot shorter than the type 3 and be offered as a 5 door wagon, and a 3 door sports hatchback / aero wagon (mini saab 900 style) and handle almost as good as a 911.
Originally Posted By: ARCOgraphite
On another note, I would love to see Subaru go to a rear-mounted engine in a "Type III-ish" next gen Impreza - makes more sense for the flat design. I'm sure it wouldnt crash too well though w/o adding excess mass to the structure.
I'd think the crash ratings would go up with out too much extra work. Instead of being designed to crumple and essentially rip off, one could design the front trunk as one big crumple zone. The added weight might help balance F/R distribution, too.
I agree, arco, wool. Myself, I like the slim small spritieness of the type 3 vw (it's narrower than a normal car). Perfect 4 seater with lots of cargo.
So, in my perfect world, mr subaru would make this beauty with a rear mounted turbo 1.3 liter two cylinder H2, and a hybrid lite package up front along with crumple zones and smart car type armor. Four SLA batteries driving two small motors integrated in the front wheel hubs, that can do a little charging at idle, and a little regenerative braking. It'd be less than a foot shorter than the type 3 and be offered as a 5 door wagon, and a 3 door sports hatchback / aero wagon (mini saab 900 style) and handle almost as good as a 911.
Hi,
ueberoo - The Type 3 VW was a great car. I collected a new Fastback from Wolfsburg in mid December 1966 - 43 years ago! My first new car!!!
The Type 3 engine had a horizontal fan (and much better cooling) so the whole engine package was great. Dr Porsche would have been very pleased I think!
Double boxer?
The Commer TS3 was a horizontally opposed piston, two stroke, diesel engine. Called the "Commer Knocker" it was quite popular in English trucking circles. It was popular here in NZ and Australia too with many still on the roads into the 1980s. The noise was very satisfying to many!
ueberoo - The Type 3 VW was a great car. I collected a new Fastback from Wolfsburg in mid December 1966 - 43 years ago! My first new car!!!
The Type 3 engine had a horizontal fan (and much better cooling) so the whole engine package was great. Dr Porsche would have been very pleased I think!
Double boxer?
The Commer TS3 was a horizontally opposed piston, two stroke, diesel engine. Called the "Commer Knocker" it was quite popular in English trucking circles. It was popular here in NZ and Australia too with many still on the roads into the 1980s. The noise was very satisfying to many!
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Hi Doug! those Fastbacks are very elegant looking little things. I have a '72 Squareback that's not yet functional that I'm trying to bring back to life; when running it should be a very quirky practical minimalist type of car. 1st time I've heard of a Commer; they do sound pretty interesting http://www.youtube.com/watch?v=L40_PsyaVp8
I almost forgot the above video for the "double boxer" is a 2 stroke 2 cylinder but 4 piston engine.... so it really is like an 8 cylinder almost in power; amazing for such a small thing. A very neat idea, though it probably wouldn't be allowed on roads anymore unless there'd be some new method of cleaning up that exhaust.
Do you think a 4 stroke 2 cylinder H2 would be too rough to power an econobox? Would there be a way to make that pulsating acceleration feel more normal using some sort of electric motor assist?
I almost forgot the above video for the "double boxer" is a 2 stroke 2 cylinder but 4 piston engine.... so it really is like an 8 cylinder almost in power; amazing for such a small thing. A very neat idea, though it probably wouldn't be allowed on roads anymore unless there'd be some new method of cleaning up that exhaust.
Do you think a 4 stroke 2 cylinder H2 would be too rough to power an econobox? Would there be a way to make that pulsating acceleration feel more normal using some sort of electric motor assist?
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Hi,
ueberooo - I think the 4stroke 2cyl econobox boxer engine is very sound (especially aircooled and for use in poor developing Countries) and has been previously used as such.
This configuration was also used in may auxilliary engines driving compressors, generators and the like. Again especially as an air-cooled unit
The Commer TS3 engine was three cylinder supercharged of course - with six pistons! The Sulzer design has been used in numerous marine applications
ueberooo - I think the 4stroke 2cyl econobox boxer engine is very sound (especially aircooled and for use in poor developing Countries) and has been previously used as such.
This configuration was also used in may auxilliary engines driving compressors, generators and the like. Again especially as an air-cooled unit
The Commer TS3 engine was three cylinder supercharged of course - with six pistons! The Sulzer design has been used in numerous marine applications
Originally Posted By: Doug Hillary
I think the 4stroke 2cyl econobox boxer engine is very sound (especially aircooled and for use in poor developing Countries) and has been previously used as such.
Nice to hear. Also, on 2nd thought, I think the viscous coupling in an automatic transmission would also do away with the pulsing in city driving, while locked into gear on the highway, the higher revolutions (2500 to 4500) would take care of the rest; so the pulsing would maybe really be quite okay.
I think the 4stroke 2cyl econobox boxer engine is very sound (especially aircooled and for use in poor developing Countries) and has been previously used as such.
Nice to hear. Also, on 2nd thought, I think the viscous coupling in an automatic transmission would also do away with the pulsing in city driving, while locked into gear on the highway, the higher revolutions (2500 to 4500) would take care of the rest; so the pulsing would maybe really be quite okay.
Hi,
ueberooo - It is also amazing what modern electronics (some quite simple), metallurgy, drive chains and etc will allow today
A modern version of the Type 3 engine would also be interesting. This engine (and the Type 1) were used with the first "usable" EFI. We had a couple of these (Typ 3) based with me in Copenhagen in 1996-7 for winter testing in Sweden
ueberooo - It is also amazing what modern electronics (some quite simple), metallurgy, drive chains and etc will allow today
A modern version of the Type 3 engine would also be interesting. This engine (and the Type 1) were used with the first "usable" EFI. We had a couple of these (Typ 3) based with me in Copenhagen in 1996-7 for winter testing in Sweden
Porsche stole the boxer engine from Tatra's head engineer. He was kept under house arrest so he wouldnt complain. I drove VW bugs for 20 yrs. The engines lasted about 100k before # 3 exhaust valve broke and took out the cylinder and usually the case. A crude little engine by modern standards. A slow car that was a blast to drive fast.
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