Diamond

why has bmw been stuck on this 3 L I6 engine being the biggest they will go aside from the m cars of old. I have seen a few tuners bore out the n52 engine to make it 3.2 l and get 300 hp from this. Why not make a 3.2-3.4 L engine in their amazing I6 design, and along with their technology they could be pumping out 300 plus hp with NA I6 engines to compete in the horsepower wars. Now I understand they are going to FI but for years and years bmw was way behind in HP (non-m cars) compared to the competition despite having amazing engines, people wanted HP. What is the downside to giving consumers a 3.2 L NA I6 engine with 300 plus hp. I think it would be a hit. Not sure why 3 liters is all they will go. I know it fits since obviously the M54 engine worked size wise and I have seen people bore it out-any thoughts

mfumbesi

I'm not sure I get your question, are you saying BMW does not have I6 engine with >3L displacement.
The S50B32 and S54B32 are 3.2 I6 (found on E36 M3 and E46 M3 and Z4M), and then there was the old 535 from the E28 (M30B34 I6).

BMW also makes V8 engines with > 3L displacement.

luigi524td

I may be mistaken (or my data may be dated) ... don't many countries apply a tax on automobiles based on engine displacement/# of cylinders/or HP?

That may account for the wider availability of small displacement engines in BMWs that are not available in the United States.

eurotunerM3

You're thinking about this in the wrong way.
Yes, BMW can and previously has used larger 3 liter gas engines with different variations of power. But you have to take into consideration a few things.
The average driver isn't looking for a car with 300+ horsepower. The average driver wants a blend of efficiency, style, and power. All of which BMW are able to offer with their 3.0L I6. The engine may not have large amounts of power stock, and yes they are tune-able. However, (and this is just my speculation) I believe that they have found the 3L I6 to be the most gas efficient and most reliable engine to put in their automobiles.
Their larger engines that have much higher rates of compression, and more horsepower are known to be less reliable with higher mileage on the odometer. I know from experience that my 3.2 I6 in my old e36 M3 had more problems at 80,000 miles that either of my other 3.0L I6's in the e46 325i or the e53 X5.
I beg to differ on your argument that people want horsepower.
In today's day and age where gas prices are constantly rising, and insurance rates are getting higher and higher, even in countries that tax you for having larger engines, people want efficiency more than raw power. People want a balanced car that combines luxury style, sporty performance, and reliability/efficiency, something that the 3.0L I6 engines has to offer. There is a growing niche group of people that crave the power that BMW can offer, but to BMW it is not cost efficient to make cars for this small portion of the population.

Its not that BMW is 'stuck' on the 3L, it is that they continue to choose to use the 3L in global production for reasons only known to BMW. But I can almost guarantee that it is because the cars that have that engine continue to sell.

spiros

Road tax and insurance goes through the roof on bigger engine cc on most EU countries. Some countries actually use the displacement of the engine
for IRS to check on you and your stated income. Based on them, you cannot have low income and a 5l engine, something is wrong ...

etchu

also L6 of larger displacement means longer travel of the pistons, not good for high rev engines

swajames

The answer is packaging. The I6 engine is already a long engine - quite a bit longer than a V6 with equivalent displacement. Make the I6 much bigger, and it won't fit... The BMW 3.0 I6 is about the same length as the 4.8 liter V8.

rambaldi

Not only does BMW offer engines > 3.0L (like the 4.8L V8 of the 550i, among others), but also offers a 3.0 L engine in the 300+ HP area you describe (the N54 TT I6). They achieve a 300+ HP output with turbochargers instead of higher displacement mainly because of fuel efficiency (achieved thanks to the couple direct injection + boost) and usability (mid-range torque).

my530i

Per BMW and other auto mfr, optimal engine size is 0.5L/cylinder.

pukka

+1

I remember reading somehwere that this was one of the reasons why BMW put a V-8 in the M3 instead of a biggeer I-6.