How come BMW engines sit at an angle?

[Adammcf]

Just wondering that Ive noticed that nearly all BMW engines except the biggest ones tend to sit tilted over at an angle in the engine bay instead of sitting vertical like most other cars.
Only reason I can think of is that the inlet manifolds are alot bigger than the exhausts and by tilting it over towards the exhaust side it makes more room for the inlet and also balances the engine over the crank.

[d6dph]

rb26 skyline engines and sr20 200sx engines sit at a similer angle.

Dont know why, just thought id share that with you!!

[fuzzy]

cosworth engines sit slightly out of line aswell, no idea why though.

[Simon]

Also, if they were upright, it would cause some problems shutting the bonnet! The inlet manifold get's very close to the bonnet on the M20, and on the E30 M3, you leave anything on the plenum, and you'll have nice dent in your bonnet!

[koos]

I'm with Simon on this one, if they were upright the front of the car would be higher, this way you can get the bonnet down lower, the Sprinter vans I work on engines also sit at an angle, same angle as the Bm's.

[Adammcf]

Suppose, never thought of that one.

[swindy]

Check out almost any VW engine, they are the same, the most I have ever seen in fact, and the audi quattro engines are on a major tilt, I gotta back the other two, sat upright deffinately wouldnt fit under the bonnet.

Mark

[kam-325i]

Its to reduce the height of the engine, if you no what i mean...

When a car is designed, they look at the visual aspect first, mechanical later, if a current engine will do the job, but to tall to fit, they will tilt it to fit, or redesign a current engine to fit the car.

Otherwise the E30 would have a nice power bulge in the bonnet......

[wayneE30]

[Demlotcrew]

Its for weight distribution.

Andrew

[Geeman]

weight distribution....?

I don't follow... surely if it was upright, the same amount of weight is spread over the front axle.

Are you on about spreading the weight from one side of the car to the other...? Surely that's not a good thing to do...

[Demlotcrew]

You want as much of the wight as close to the ground as you can get it.

Andrew

[Geeman]

Aaaaaaah, I getcha now.

[Simon]

As for the weight distribution, it goes againts RHD cars, as the engine leans over to the right, in a LHD car, the driver helps balance the weight distribution out, this would also explain why most cars in rallying/touring car are LHD.

[kam-325i]

Most cars are LHD because 95% of the world drives on the wrong side of the road !!!

[Demlotcrew]

As for the weight distribution, it goes againts RHD cars, as the engine leans over to the right, in a LHD car, the driver helps balance the weight distribution out, this would also explain why most cars in rallying/touring car are LHD.

Dude i cant say thats true as the S14 has perfect 50/50 weight distribution at the front when the engine is sitting on the cross member.

Andrew

[Simon]

As for the weight distribution, it goes againts RHD cars, as the engine leans over to the right, in a LHD car, the driver helps balance the weight distribution out, this would also explain why most cars in rallying/touring car are LHD.

Dude i cant say thats true as the S14 has perfect 50/50 weight distribution at the front when the engine is sitting on the cross member.

Andrew

I read this on S14, I'm pretty sure you commented on the thread, it mentioned the fact that with a driver sitting in the seat (LHD) the car was perfectly balanced!

[Simon]

Most cars are LHD because 95% of the world drives on the wrong side of the road !!!

Even cars built for motorsport in RHD countries though...

[Martinaston]

mY first guess was to keep the low profile of the bonnet, but thinking about it the top of the engine is quite low anyway, it's just the manifold that sticks up so surely they could have designed it to sit even lower.
So i'd say it's due to the weight issue, shame it leans the wrong way though

[DieselMeister]

The way I understand it is that it's 99% about weight distribution. Tilted engine = lower centre of gravity, which in turn means better stability and agility. It's the very same reason BMW puts the battery in the boot and especially important with long, tall engines like straight sixes.

To oversimplify, equal (or as close to) weight distribution and the lowest possible low C of G means better handling.

Shame they gave the E30 steering from a cruise liner....

[kam-325i]

Shame they gave the E30 steering from a cruise liner....

You've got that mod aswell then !!!

[Demlotcrew]

I read this on S14, I'm pretty sure you commented on the thread, it mentioned the fact that with a driver sitting in the seat (LHD) the car was perfectly balanced!

Thing is SI, most race cars use coilovers which can adjust corner weights and ARB preloads, so even if this was true and the engine was making the car heavy to one side it would be corrected when they adjust the suspension on the scales. When I was messing about with my engine I found it to have really good balance from left to right with all the associated parts attached and lifted up by the two jacking points on the block and on the front timing covers.

Andrew

[Simon]

I read this on S14, I'm pretty sure you commented on the thread, it mentioned the fact that with a driver sitting in the seat (LHD) the car was perfectly balanced!

Thing is SI, most race cars use coilovers which can adjust corner weights and ARB preloads, so even if this was true and the engine was making the car heavy to one side it would be corrected when they adjust the suspension on the scales. When I was messing about with my engine I found it to have really good balance from left to right with all the associated parts attached and lifted up by the two jacking points on the block and on the front timing covers.

Andrew

OK then, I think it was a good theory!

[kam-325i]

Two reasons:

1, lower centre of gravity for engine.

2, To make the engine fit under the bonnet.

Thats it...........

[Simon]

Two reasons:

1, lower centre of gravity for engine.

2, To make the engine fit under the bonnet.

Thats it...........

And to make access to the dipstick easier..

[TheDutch]

It seems to me that this statement:

even if...the engine was making the car heavy to one side it would be corrected when they adjust the suspension on the scales

equates to:

with good suspension the weight distribution of a car is irrelevant

[Demlotcrew]

^ Not quite, as we are talking about very small amount of weight. As there are other counter balance parts on the car (Exhaust, petrol tank, battery, electrics)

Andrew

[Adammcf]

So I was pretty much right then.
Its just that when you compare the engine on a 325 for example the angle at which it is tilted at is alot more than most other rwd cars.

[kam-325i]

Have you seen the tilt on some of the older peugot diesel engine ?
Looks like 45Ԛ°.

[TheDutch]

OK Andy that's true, just wanted to make sure you weren't enjoying a day out at the Fantasy Dreamworld theme park!

[Turbo-Brown]

Just to throw this into the mix, My E36 M3 Evo engine when sitting on the ground and at the correct angle only has ever such a slight tendancy to fall over, i.e. you can hold it up with one finger kind of thing.

I'd say that it is just to keep the weight and bonnet line low.

Surely they wouldn't have designed it to counter balance the weight of the driver as the mass of the average bratwurst eating Geman could vary hugely!

[MrDazzle]

You think that's bad...look at the angle at which they mount the engines in their bikes



As others have said...it's too lower the CoG and improve packaging. I cannot recall ever seeing a car (or indeed, vehicle of any kind!) with a perfectly upright engine. Upright inline anyway...v's are usually upright, but that's like two inlines cranked

[Fushion_Julz]

The Nissan 200sx S13 has a perfectly upright engine....inline 4

The old mini also had a perfectly upright engine...transverse 4

Mk2 Jags...inline 6

probably plenty of others, too...either where the motor is not too tall or where the bonnet line is high...

[Andy335Touring]

For our RHD cars the battery should be on the passenger side really, lazy Germans !

Impractical for a road car but i'd guess the best place for it would be in a battery box mounted to the rear passenger foot well ?

I'd love to get my car corner weighed, not that i could make much improvements/adjustments as my car stands but still interesting.

[Barx325i]

Most cars are LHD because 95% of the world drives on the wrong side of the road !!!

Even cars built for motorsport in RHD countries though...

aye, in addition to the direction in which the motor leans, that choice (e30's anyway) is due to manifold routing & servo linkage..

On the engine lean, in addition to the above points, the mount arms offer greater torsional resistance. win win really..