[augerpro]

So the current N55 intercooler is air-to-air? At what HP is the current intercooler limited? Anyone foresee improvement or limits with the new air-to-coolant intercooler? I'm almost sure I'm buying a M240xi (and mod it) when the lease is over on my M235xi and this looks like the only point of concern I have.

[clemsonkev]

Originally Posted by augerpro

So the current N55 intercooler is air-to-air? At what HP is the current intercooler limited? Anyone foresee improvement or limits with the new air-to-coolant intercooler? I'm almost sure I'm buying a M240xi (and mod it) when the lease is over on my M235xi and this looks like the only point of concern I have.

How's the M235i? (ever had a 3 series to compare it to?)

and why the x-drive in Denver? snow?

[augerpro]

Originally Posted by clemsonkev

How's the M235i? (ever had a 3 series to compare it to?)

and why the x-drive in Denver? snow?

LOVE this car. That's why I'm pretty sure I'll buy one when the lease is up. First BMW.

Not gonna blow up this thread on why I bought an xdrive

[Manbnda]

Maybe off topic, but why is BMW reporting the exact same figure of 0-100 km/h in 5.1 Sec for this new engine (340i) as it is for the 435i with the N55?

[E90Fleet]

Originally Posted by Manbnda

Maybe off topic, but why is BMW reporting the exact same figure of 0-100 km/h in 5.1 Sec for this new engine (340i) as it is for the 435i with the N55?

The official numbers are foir marketing. You can see test reports always find the cars quicker.

335i was 5.5, 340i now 5.1
435i is 5.1, upcoming 440i will probably be listed at around 4.7

4 Series is shown as quicker as it is marketed as being slightly better than the 3 Series. Just like the 6 Series against the 5 Series.

Marketing

[Manbnda]

Originally Posted by E90Fleet

The official numbers are foir marketing. You can see test reports always find the cars quicker.

335i was 5.5, 340i now 5.1
435i is 5.1, upcoming 440i will probably be listed at around 4.7

4 Series is shown as quicker as it is marketed as being slightly better than the 3 Series. Just like the 6 Series against the 5 Series.

Marketing

I find that weird. Could it be that maybe they program them slightly different to make 4s, a couple of tenths faster?

[E90Fleet]

Originally Posted by Manbnda

I find that weird. Could it be that maybe they program them slightly different to make 4s, a couple of tenths faster?

Just marketing.

4 is marketed as slightly faster and has better standard trim and commands a higher price.
Engine, software and ECU exactly the same

Done in all industries.

[Iron Man]

Originally Posted by 135Pats

Yes, though i'd be very interested to understand the reasoning behind it. For a stock/OE build, a fully closed deck shouldn't be required. Adds weight and heat. The 54/55 were partially closed decks and are some of the strongest blocks BMW has made in years. It's not like we're seeing a lot of cylinder walk on those motors. It could be the shared architecture with the S55 just necessitated a shared closed deck block due for economics, i'm not sure.

But yea, absolutely a departure from previous boosted BMW motors. I'm worried this motor may be a bit too complicated to really see what it can do with a proper turbo, but that's all speculative. I have no doubt this will be a great factory motor.

Would this be due to their switch to a modular design across the 3, 4 and 6 cylinder engines? (all made on the same line) They might be looking at some very high boost designs on the 3 and 4 cylinder engines, which necessitated a closed block, therefore all three designs would have it.

[135Pats]

Originally Posted by Iron Man

Would this be due to their switch to a modular design across the 3, 4 and 6 cylinder engines? (all made on the same line) They might be looking at some very high boost designs on the 3 and 4 cylinder engines, which necessitated a closed block, therefore all three designs would have it.

Yea that seems logical to me. With the increased focus on cross-platform part sharing, would make sense.

And especially agree with your note RE: cylinder pressure. With the move towards smaller displacement, small turbo (twin or TS singles) it necessitates a lot of boost pressure to move a modest amount of air. The N20 is at what, 19 pounds or so from the factory? Takes high compression, high boost to make decent power with such little displacement and such a small turbo.

I'm guessing the same will be the case with this motor.

[Iron Man]

Originally Posted by 135Pats

Yea that seems logical to me. With the increased focus on cross-platform part sharing, would make sense.

And especially agree with your note RE: cylinder pressure. With the move towards smaller displacement, small turbo (twin or TS singles) it necessitates a lot of boost pressure to move a modest amount of air. The N20 is at what, 19 pounds or so from the factory? Takes high compression, high boost to make decent power with such little displacement and such a small turbo.

I'm guessing the same will be the case with this motor.

Correct, I believe the N20 maxes around 19 psi or so. They want the small turbos for better throttle response, so yeah, you have to get the HP somehow.

A lot of the turbo OEM's are looking at lighter weight/higher temperature materials for their spools, so this might change the dynamic some eventually.

[augerpro]

Originally Posted by augerpro

So the current N55 intercooler is air-to-air? At what HP is the current intercooler limited? Anyone foresee improvement or limits with the new air-to-coolant intercooler? I'm almost sure I'm buying a M240xi (and mod it) when the lease is over on my M235xi and this looks like the only point of concern I have.

Any one have input on this? I'm afraid an air-to-coolant intercooler might be a bottleneck for modders, or even track use. I know when I drag race my times go down (the engine pulls power) when intake temps get up into the 130's, and spraying a water hose on the coolers in between runs brought some consistency by keeping those temps below 120F.

[Daftasabrush]

I would imagine the limitation will be the gearbox rather than the charge cooler. The gearbox is still only rated for 500NM and a stock 340 is already doing 450 on paper and BMW do tend to underestimate. I wouldn't want to be putting any unwarranted power through the transmission without an upgrade. The MPPK is likely to be right on the limits of the 'box.

[S4NoMore]

Originally Posted by augerpro

Any one have input on this? I'm afraid an air-to-coolant intercooler might be a bottleneck for modders, or even track use. I know when I drag race my times go down (the engine pulls power) when intake temps get up into the 130's, and spraying a water hose on the coolers in between runs brought some consistency by keeping those temps below 120F.

Since liquid water has a higher specific heat (2nd highest of any chemical compound) and higher thermal conductivity compared with air, I would suggest that the charge air cooler will no longer be an issue as it has in the past with air-to-air setups.

If you check out the S55, anecdotally it sounds as though the liquid-to-air coolers work like a charm.

[WilliCO]

Originally Posted by augerpro

LOVE this car. That's why I'm pretty sure I'll buy one when the lease is up. First BMW.

Not gonna blow up this thread on why I bought an xdrive

If you are willing sometime, I'd love to talk with you about that car. My F10 lease is up next summer, and it would be a lot more useful to spend an hour with a guy who has owned the car than 15 minutes on a test drive with a CA. Beer's on me.

[augerpro]

Originally Posted by WilliCO

If you are willing sometime, I'd love to talk with you about that car. My F10 lease is up next summer, and it would be a lot more useful to spend an hour with a guy who has owned the car than 15 minutes on a test drive with a CA. Beer's on me.

PM me, I'm on vacation July 20-Aug 3.

[augerpro]

Originally Posted by S4NoMore

Since liquid water has a higher specific heat (2nd highest of any chemical compound) and higher thermal conductivity compared with air, I would suggest that the charge air cooler will no longer be an issue as it has in the past with air-to-air setups.

If you check out the S55, anecdotally it sounds as though the liquid-to-air coolers work like a charm.

AS I understand it though you now have two stages of heat exchange, neither of which is 100% efficient, being multiplied together. You end up with a lower overall efficiency. You'll need more cooling capacity to make up for the lost efficiency. Plus even more capacity on top of that since you are adding a new load to the coolant system.

Plus there will be a "harder" lower limit on the intake temp since the coolant will always be warmer than the surrounding air. I suspect intake temps have caused me issue drag racing before.

I don't know that the S55 is relevant since it is designed to handle track abuse, while the N55/B58 is optimized more for typical passenger car usage.

[S4NoMore]

Originally Posted by augerpro

AS I understand it though you now have two stages of heat exchange, neither of which is 100% efficient, being multiplied together. You end up with a lower overall efficiency. You'll need more cooling capacity to make up for the lost efficiency. Plus even more capacity on top of that since you are adding a new load to the coolant system.

Plus there will be a "harder" lower limit on the intake temp since the coolant will always be warmer than the surrounding air. I suspect intake temps have caused me issue drag racing before.

I don't know that the S55 is relevant since it is designed to handle track abuse, while the N55/B58 is optimized more for typical passenger car usage.

What I'm saying is that the engine has greater charge air cooling capacity by use of water/coolant. The lost efficiency due to multiplication of losses is overcome by the advantages of water as the working fluid, it's that much more efficient compared with air.

The coolant will be warmer than the ambient air, yes, but without knowing how much warmer I think it's just speculation to say that there will be a harder limit on minimum IAT.

Part of the case for going liquid-to-air is that a liquid can do a better job of pulling heat from air in comparison, so even if the air is cooler (which is sometimes barely true during hot weather) the warmer liquid is still advantageous.

The S55 is relevant because anecdotally M3/4 owners are turning up the boost and not feeling like they are limited by IAT and/or heatsoak. Yes, the 340 will be scaled down in all things, but I think it's fair to say that turning up the boost on it may likewise produce more power without a huge deficit due to the charge air cooling.

My 2 cents anyway.

[bimmercar]

here is B58 graph

[clemsonkev]

Originally Posted by bimmercar

here is B58 graph

My math isn't great. How much BHP and WHP does this equate to?

[zenmaster]

240 kilowatts = 321.845302 BHP, WHP is somewhere around 12%-15% less.

[clemsonkev]

Originally Posted by zenmaster

240 kilowatts = 321.845302 BHP, WHP is somewhere around 12%-15% less.

thanks.... but crap!

I was hoping BMW, in typical fashion, was UNDER-rating this new engine's output. 320bhp is what it's listed at. Many of were expecting dyno results to be closer to 340bhp.

(I know HP numbers aren't everything, but gotta keep it close to the C450 AMG)

[NightWriter]

Originally Posted by clemsonkev

thanks.... but crap!

I was hoping BMW, in typical fashion, was UNDER-rating this new engine's output. 320bhp is what it's listed at. Many of were expecting dyno results to be closer to 340bhp.

(I know HP numbers aren't everything, but gotta keep it close to the C450 AMG)

This is marketing data (ie conservative), not a consumer dyno test.