Bmw M5: Boxer Vs. Vee

PhatBimmer

PhatBimmer

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Alright I'm new to the boards so take it easy on me :p


Ok, I was wondering if you were to put yourself in the place of a person in charge of either choosing a Inline for the new M5 coming out in the fall or to go with the V-engine in it already what would you choose? And why?

I've always wondered what kind of view all BMW fans have about V-engines vs. Inline(Boxer)engines. I prefer Inline but thats just me [:D]

And if your a real savy engine guy the more technical stuff you can say the better, I'm all ears to learning this stuff [:p] [thumb]
 
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epj3

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M5 is going to have a V10 in a few years... right now it has V8. I highly doubt and hope they never put an I6 in the M5!!

Also a boxer engine and inline engine are completely different, a boxer engine is shaped like this, ---- || ---- and lays horizontal to the ground. where half the cylinders are on one side and the other half is on the opposite side (this allows for awesome compression due to direct force against the opposing clyinders)

An inline engine is straight up, like this | | where all cylinders are parallel and the plugs are all on the same side.


Inline:


Boxer:


V:


All images from howstuffworks.com
 
codex57

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Inline 6s are inherently balanced. That's partially why BMWs sound so smooth. But, an inline 8, 10, and especially the 12 would be REALLY long and I believe really imbalanced as well. The V configuration gives the packaging efficiency needed for the big honking engine the M5 needs to create the power we all expect.
 
Wadula

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erc, that is some nice stuf you found there. good explanation of the different systems.

personally, i believe in inline engines too. as long as we are talking 6 cyl. max. starting with 8 the change must be to V8. it´s just like an unwritten law isn´t it?
 
PhatBimmer

PhatBimmer

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[?|] STUPID ME!

My appologies at me saying "inline(boxer) engine" I'm a noob at car engines. Thanks for showing me the stuff though, those animations really let me see dif. [:D] thanks again. Seeing the good reason I now know why they use V-engines[hihi] . Thanks guys. And again sorry for the lack of knowledge [?|] LMAO!
 
Kirby

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Regarding the inline 6 to V8 unwritten law, I remember reading an article about engine design that discussed this issue. It said that the biggest issue is crankshaft design for longer inline engines. The crankshaft must become disproportionately bigger/stronger, as well as bearings, etc. to prevent the torque from twisting or snapping it. That goes hand in hand with Codex57's comment about balance. If you try to balance the engine (look at the pistons moving side by side in unison in the graphic from EPJ - cool graphics!), you increase the stress because of the mass of 2 pistons topping/bottoming simultaneously. So the bigger engines go to V configuration for easier, cleaner design.
 
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epj3

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I dont like the thought of a supercharged bmw. I like NA!!

An engine is more impressive, imho, if it can pump 333 HP out of a 6 cyl engine than if a 4 cylinder turbo can pump out the same amount.
 
Dinan55

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450hp in a 2205 lb car... watch out Mercedes...

If the Lotus Elise can do a 4.5 0-60 with a 150hp engine weighing 2000 lbs, then the M1 is going to be incredible.
 
Average Jae

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well i6 in the m5 would be step backwards.. it's already got a nice v8 pumping 400 thoroughbreds, and future projections of a v-10w/ 500 - 550..

sure the 3.2 i6 on the m3 is impressive, but hard to make up for lack of cyls..
 
mikev

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epj3 said:
Because the M division is also all about power. Why buy a I6 M5 when you can get a V8 545i with 6spd?
Click to expand...
because the E34 M5 is faster than the 545i.

I'm not saying the I6 is what they should put in i personally love the idea of the 500Hp V-10 just making the point that the E34 M5 has an I6 and it does sound alot better than the V8 power E39. The M division is NOT just about power. Its about Driving Dynamics. The E34 is a Hand built race car!!! the E39 was and the E60 will be about cruising down the autobahn at the highest speed possible but still be able to go around corners just with less driver involvment. (remember the I6 "ONLY" had 340Bhp 60 short but) an E39 driver would really have to be trying HARD to leave the E34 on a straight and the corners are a completely differant matter.
 
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SoonerE39

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Very cool demonstrations of the engine types! IMO, a flat or 'boxer' engine requires a lot of width which means either they would have to push out the front wheels so it could sit between them (but that add size and weight=bad) or they would have to mount it higher up in the engine bay (raising the center of gravity=bad). This is why the only boxer engined cars I know of are mid or rear engine cars.
 
MrElussive

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I don't know if one engine setup is always better than the other. I mean, V-engines are traditional, but BMW has certainly proven itself with their I6 motors. And Porsche with their use of the boxer engine...who's gonna argue with Porsche??? Honestly though, as long as the motor performs well, sounds good, and lasts long, I am a happy driver (who could care less about the way it's setup). [driving]
 
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