I6 or V8

[1stE53]

Originally Posted by JCL

Money not being an object is not the same as saying one doesn't care about money. I do care about money, but it wasn't a hindrance to choosing the vehicle I actually wanted.

One buys an I6 because the BMW inline six (in almost any version) is simply one of the best, classic, modern era engines. You get a chance to own an incredible engine. The V8 is fine, but it simply isn't in the same class as the inline six. An inline six is inherently balanced, giving it a turbine smoothness that you simply can't get with a V8, with its inherent imbalance. Some people like the rumble of the V8, but that is just another way of saying imbalanced power strokes.

Money was no real object for me, and I chose the I6. It wasn't specifically for purchase price, or maintenance price, or fuel economy, although those are all better with the I6. When I got the 535, I was buying the engine, and I just chose which BMW car to get that engine delivered in. I chose it over the V10 in the M5, which had the same body style.

If money were truly no object, one would not buy a V8, but rather a V12, which is an inherently balanced engine. Not necessarily practicaly, but a solid design choice. The V8 is simply 2/3 of a V12, so it can't really be called the ultimate anything.

Absolutely spot on . That imbalance of a V8 is why F1 drivers did not like the moves from a smooth running V10 @ 22K RPM and now a limited vibrate like hell V8. I can't believe how smooth my I6 is. Thank you for making me feel better about purchasing this engine. So far everyone who knows even a small bit about BMW has told me the same thing about he I6.

[ekimv65]

I just found an 05 4.8is for $23800 with 77 rounds on it, any cause for concern? It was a 1 owner and local.

Thanks much for all of your wisdom!!!

[FSETH]

I agree with you JCL regarding the balance of the inline 6 and V-12. I have had a few BMW inline sixes and my parents have had two BMW V-12's for a long time, but seeing as this was posted in the e53 forum, that is what I was trying to focus on. As far as the e53 is concerned, there is a night and day difference in the overall performance and seat of the pants feel between the 6 and the 8. The 6 cylinder available in the e53 was way underpowered for the heft of the X, imo. Not trying to knock it. It is a good vehicle, but not enough oomph for me. Actually, I wish I had either the 4.6is or 4.8is...more power (insert Tim Taylor grunt here). The only plus for the 6 was the availability of the manual trans, but that benefit was outweighed by the horse power and torque of the 8, imo.

[_XS3C_]

Originally Posted by ekimv65

If money was not a hindrance, I6 or V8.

MPG:
'01~'06_ I-6 engine = 16/21 MPG
'04~'06_ V8 engine = 16/22 MPG
--------
power:
I-6 = 3.0L 225HP/ 214 torque
V8 = 4.4L 315HP/ 324 torque
-------
performance0-60MPH:
I-6 = 8.3 sec
V8 = 6.8 sec
-------
higher end or extra equipment for example:
I-6 = 5 speed step. AT
V8 = 6 speed step. AT + self level R. susp .......
-------
so which one is more: economical /powerful/ better equipped ........

The inline 6 engine is well balanced and great engine that is just perfect for compact size car, but when that same engine is swapped in 5.000 LB vehicle almost twice the weight it is way different story !
OVERALL:
I6 engine is PERFECT for car !
V8 engine is PERFECT for SUV/truck !

[JCL]

In the real world, the V8 does not get the same fuel consumption as the I6. The (theoretical) EPA figures are close, but that is a simulated run, and does not account for the greater weight of the V8 model, or the greater power (which drivers tend to use). You are claiming more power, and the same mileage. You can't have both.

[_XS3C_]

Originally Posted by JCL

In the real world, the V8 does not get the same fuel consumption as the I6. The (theoretical) EPA figures are close, but that is a simulated run, and does not account for the greater weight of the V8 model, or the greater power (which drivers tend to use). You are claiming more power, and the same mileage. You can't have both.

"The theoretical EPA figures" - [from page 79 in the OFFICIAL '06 BMW X5 brochure] will be then close for the I-6 engine as well .......
Only 231lb is the difference between N62 V8 engine X5 and I-6 - where the V8 have the as called "CLOSE" economical MPG to the I-6 with the extra on top 90HP power [when compared to the I-6], and I'm not talking about the perfect weight distr. on N62 V8 X5's ~ almost 50/50 vs also almost 48/52 for I-6 E53's.
IMO and the FACTS are that N62 V8 engine [when compared with the I-6 engine], instaled in E53 shell - DOES HAVE BOTH: mileage and power [HINT- 6SP AT does make some difference at the MPG to ] !
[IMO N62 V8 E53 - PWR/MPG is as CLOSE to perfect as 98.9% ....... ]


heck, we should compare I-6 SUPERCHARGED engine with V8 engine to see the PWR/MPG difference, otherwise it is apples vs oranges

[JCL]

Originally Posted by _XS3C_

"The theoretical EPA figures" - [from page 79 in the OFFICIAL '06 BMW X5 brochure] will be then close for the I-6 engine as well .......

The EPA figures for the two vehicles, and which are the basis for the brochure, are very theoretical. They are measured on a test cycle, and then adjusted by a correction factor. No vehicle actually achieved the published number. Check out the test methodology. The numbers are based on a test cycle which:

• is on a dynamometer, which does not account for the vehicle weight difference
• is at a pre-programmed acceleration rate (which is the same for both vehicles) that is very slow, thus not using any of the V8's hp advantage
• is so slow that the additional top gear doesn't come into play

That is why the theoretical figures are the same, and why I call them theoretical. It is easy to check, look and see how many members in the real world are getting the same mileage on the two vehicles. Sure the V8 has more hp. But if you take advantage of it (which burns more fuel, that being how power is created....) you won't get the same mileage as the I6.

So, your FACTS are theoretical, and not available in the real world. But they did help BMW sell more vehicles.

No argument that the V8 is faster.

[Fraser]

Give me a break! Writing off the V8 because it isn't perfectly balanced is like saying that Kim Kardashian is unbalanced because her left nipple is two microns bigger than her right nipple.
The fact is that both the IL6 and the V8 (being a 90-degree) have perfect balance of the primary and secondary inertial forces, the big factors in determining if an engine is smooth or not. And while the IL6 also ticks both boxes in terms of perfect balance of primary and secondary free moments of inertia whereas the V8 scores a '10 out of 10' for secondary free moments but only an 'eight of ten' for primary free moments, is no big deal either way.
On the consumption issue there's so little in it that it's irrelevant. Much more significant is the fact that the V8 is more immediate in its response and a much better 'drive'. I could live with a 6 but only with a manual, preferably the post-'04 six-speeder. For me my '05 3.0d beats the pants off the petrol six or either 4.4 but that's another story and irrelevant here...

[JCL]

Originally Posted by Fraser

Give me a break! Writing off the V8 because it isn't perfectly balanced...

You can't tell the difference in smoothness between an I6 or V12, and a V8, when driving them?

[Fraser]

Originally Posted by JCL

You can't tell the difference in smoothness between an I6 or V12, and a V8, when driving them?

Let's forget V12s for the minute. Theoretical argument only. As E53 V8s, either the pre or post update 4.4, or the 4.6is, or the 4.8is, I have never stepped out of one of them (I've driven them all) and thought I wouldn't buy them as the engine is too rough. However, after driving the six, especially with the auto box, I've always felt let down. Pushing something as big and as heavy as the X5, the six lacks urgency at low and middle revs. As I said, it's better with a manual, especially the six-speeder...
Don't get we wrong, the six is a sublime engine. Brilliant in a 3 Series and great in a 5 Series, but underdone in the X5 especially for give and take highway driving where you need good passing power. Now, if you add a couple of small turbos, that's a very different story.
And to answer your original question, yes the IL6 feels a tad smoother than the V8 but what tiny difference there is fades into insignificant when looking at the big picture.