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Old 05-19-2002, 08:24 PM   #1
MattDell
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Default The Benefits of a Boxer Engine?

I couldn't think of a better place to put this, so mods move it to a better place if you think so.






Anyways, I'm just wondering what the benefits are of having a boxer engine are and why.
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Old 05-19-2002, 08:37 PM   #2
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Compared to what?

According to subaru, its got lower center of gravity, a whole hell alot of torque for a 4banger (at very low rpms)... Im sure there are more things that are good about it...Why else do porches come with flat 6 engines?? .

-justin
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Old 05-19-2002, 09:38 PM   #3
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The lower center of gravity helps with handling, and a boxer engine is inherently balanced because the pistons act as counterweights for one another so it is a very smooth running engine.

Eric
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Old 05-20-2002, 12:10 AM   #4
MattDell
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Quote:
Originally posted by Blindeye_03
Compared to what?
I guess compared to a "regular" engine. I'm not very knowledgable about engines.
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Old 05-20-2002, 01:28 AM   #5
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The boxer engine is also shorter and much much lighter than any other 4-banger out there of equal displacement because is doesn't need to be balanced.

Because the engine is a boxer type isn't the reason why they have low-end torque, that's because of the displacement and tuning.
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Old 05-20-2002, 02:47 AM   #6
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Sounds alooooooot better
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Old 05-20-2002, 07:58 AM   #7
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It makes it sound bigger than it is. So you won't get any tin, coffee can sounds. Joe
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Old 05-20-2002, 10:53 AM   #8
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The flat configuration means it's not very "deep" into the engine bay, so it can be mounted more forward to aid traction.. I much enjoyed the benefits of this in my old FWD '87 GL wagon.. Nearly the entire engine was in front of the front axle. That thing was a tank in the snow.

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Old 05-20-2002, 11:54 AM   #9
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I thought the boxer was mounted lower and further back to provide a lower center of gravity and better weight dispursement. Not further forward over the front axle.

Is that what I get for thinking?
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Old 05-20-2002, 12:16 PM   #10
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I am pretty sure Subaru's display at the Baltimore Auto Show this year had stressed that the engine was further back into the car.

The Boxer 4 has one, big disadvantage though. The exhaust pulses cannot be properly scavenged out of the cylinders. A 4-to-1 header would be the only solution, but there is no room for one. The exhaust pulses on one side of the motor are not equally spaced time-wise. This could be one reason why you don't see any N/A RS Imprezas doing low 13s. We have a local N/A Neon that does 10s!
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Old 05-20-2002, 02:20 PM   #11
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Here is my take on it...
The term "boxer" is used to decribe the engine in that the pistons are located directly across from each other, and they move in and out in unisen (which apparently looked like the fists of a boxer to the designer). The major advantage is that boxer is going to be incredibly stabilized as it winds up. In the case of a V or Inline configuration, there the net inertia is not always stabilized by the moving engine parts alone, and corrections need to be made. The result is incredible low engine torque. (please correct me if im wrong, its has ben awhile since i took physics )

the limitations are that the size of the engine is larger than most 4-cyl engines, hence great efforts are made to mount it in the engine compartment. For this reason, along with cost, the only companys that use boxer engines are subaru and porche. Ever wonder why your NA impreza costs only about $2000 less than a Z-28?

Another advantage is the center of mass issue. the engine sits low, which lowers the center of mass close to directly between the front wheels, inhancing handling. Furthermore, the engine design allows the transmition to be located directly behind, which moves the center of mass of the entire vehicle to almost below the stick shift! Ever wonder why subarus handle so much better than most vehicles in their class?

Hope im not toooo wrong on this stuff, and hope it sheds some light
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Old 05-20-2002, 02:53 PM   #12
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Default boxer engine advantage - cylinder oil on startup?

I was once told that Subaru engines can last a long time, because when you shutdown the engine, the oil in the cylinders don't drain down into the oil pan, like they would in other engine designs, where the cylinders are more or less vertical.

Since a coating of oil remains in the cylinders after it's been shut off, it helps reduce wear when you start the engine next.

Was I told a pack of lies, has anyone else heard this, or is there truth to this idea?

Paulo
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Old 05-20-2002, 06:12 PM   #13
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Hi, everybody!
I remember reading a while ago that the manufacturing processes for boxer engines are also less prone to casting errors than those of other engines. Bang, ergo, zoom Subaru engines (and Porsche engines) tend to have somewhat stronger weakest links. Hope that made sense.
Jon
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Old 05-21-2002, 02:11 AM   #14
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Quote:
Originally posted by BugBomb
The exhaust pulses on one side of the motor are not equally spaced time-wise. This could be one reason why you don't see any N/A RS Imprezas doing low 13s. We have a local N/A Neon that does 10s!
I think the biggest reasons are
a) the AWD
b) the lack of RS N/A tuners, most go turbo

If you were to say, use the Cobb tuning N/A block/head/cams on a FWD Impreza with racing tires and gutted to save weight along with engine management systems, I wouldnt be surprized to see low 13's, high 12's
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Old 05-21-2002, 02:15 AM   #15
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Quote:
Originally posted by Kostamojen

I think the biggest reasons are
a) the AWD
b) the lack of RS N/A tuners, most go turbo

If you were to say, use the Cobb tuning N/A block/head/cams on a FWD Impreza with racing tires and gutted to save weight along with engine management systems, I wouldnt be surprized to see low 13's, high 12's
I agree. Our cars can weigh over 500 lbs. more than a Neon slimmed down for drag racing. Add that to the drivetrain loss that AWD has and bingo, you're talking a huge difference in e.t. with the amounts of power we are talking about.

Eric
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Old 05-21-2002, 08:13 AM   #16
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On thing I didn't see mentioned is the ability to make the front of the car very slim, due the flat engine, which helps in air drag dynamics.

I have now knowledge of the exhaust header design, but what about making a dual exhaust from the both headers individually - I mean like 2-1 twice. Is it worth it?
That would be nice setup I think...



tony
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Old 05-21-2002, 09:19 AM   #17
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Imprezas are not for drag racing. Drag racing is onle a few seconds of "boy, I can go in a straight line!" Get a g-tech if you just HAVE to know your 1/4 time.

Imprezas are for the twisties, and the boxer engine is perfectly suited for this. Great torque and low center of gravity. Also, with some work she'll ake more boost than most IIRC. Having only 2 cylinders per bank makes the block that much stronger.

-IggDawg
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Old 05-21-2002, 09:39 AM   #18
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Quote:
Originally posted by IggDawg
Imprezas are not for drag racing. Drag racing is onle a few seconds of "boy, I can go in a straight line!" Get a g-tech if you just HAVE to know your 1/4 time.
Indeed. Drag racing is for Trans Ams with huge, butt-ugly, overstyled nostrils and 21452176 cubic inches of V98 "engineering". Subarus are for rally-x and hillclimbs, and are well-suited to such.

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Old 05-21-2002, 03:21 PM   #19
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Quote:
Originally posted by tonytiger
On thing I didn't see mentioned is the ability to make the front of the car very slim, due the flat engine, which helps in air drag dynamics.
one such occurrance: the Subaru XT/XT6 body had the lowest drag coefficient of any mass-produced passenger car up until one of the recent Porches was released, IIRC.
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Old 05-21-2002, 04:39 PM   #20
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So, there's a bunch of good technical reasons. What do I notice every day? It's the smoothest car I've ever been in at idle. Get in my wife's Honda and it feels like I'm in an earthquake.

It seems that Subaru ignored a lot of the wind resistance pluses of the boxer, though, with the body of the car undoing anything the boxer might have done by its positioning.

And I think a lot of the reason our cars aren't much less than Camaros is the supply/demand factor, and the fact that our transmission is more advanced than anything a muscle car could hope to have.
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Old 05-21-2002, 04:54 PM   #21
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Also,
because of the set up of the boxer (lower, and "flat") the entire drivetrain can be done in a straight line. Other AWD systems have to go back to the rear wheels and have a complex configuration of gears and shafts that have to run back along the side of the original shaft.... causing weight distribution to be uneven from one side to the other of the car, not just front and back. Our far advanced Subaru's look more like this. Front ->H---- <-Back compared to a straight six Front -> --==-- <-Back, or a V6 Front-> >==-- <-Back
as you can see by my tacky diagram. the straight six and V6 have more weight on the left side.
Okay Kids. Done with my bad lesson of the day.
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Old 05-22-2002, 04:40 PM   #22
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with the better balance and lower center of gravity the boxer engine helps you jump your car with a greater deal of control and confidence, if you are into that kind of thing. Bo and Luke watch out for the subies!!
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Old 05-22-2002, 11:36 PM   #23
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although the low drag is a plus too, another good thing about the low hood is the visability of the road directly in front of you (especially visable on the new wrx, where the center of the hood is much lower than the edges where the headlights are)

i know this sounds kinda lame but compare it too sitting in a camaro, you feel like your driving a cruise ship

in defense of drag racing and the argument that subies wernt made for it, well, neons wern't exactly made for it either but they seem to do pretty well.
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Old 05-23-2002, 03:36 AM   #24
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someone mentioned that space requirements was a disadvantage to a boxer motor. i'm wondering how that would be? the only dimension a boxer engine would be large is is width. that only forces the car to be wider; while that does increase frontal area (and drag) it also makes the car wider for a larger, more stable platform. subaru was able to add an extra piston to the H6 and it only increased in length by 33%. sounds pretty space efficent to me.

andy
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Old 05-24-2002, 12:59 AM   #25
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well, the EJ25 also has a large bore for its stroke. That probably has something to do w/ the engine couldn't be any wider and fit in the car. a longer stroked engine wouldn't fit into the bay.
I also wanted to say that my car seems to run smoother than most of the honda's I've been in. Hondas seem to vibrate which sounds and feels weird to me. Surprisingly, the Si's seem smoother(even at high RPM) than the base models.
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