BMW M3 / M4 Engine (S55): Deep Dive and Interview

[Thurman Murch]

I do like the new focus on power on top with the newer N/S55 however the only place I could see actually using that is on the freeway or the track

How well does this engine rev through the range? The N54 seemed to have instantaneous power down low and lost lungs up top

It seems as if this engine was focused more on NA delivery up to 270nm then the turbos add the frosting to the cake

I see that Ferrari copied the S65 and improved upon it in the 458 and that is a compliment

...but once again the explanation only talks around the actual details and they are keeping everything cryptic

[Smiley913]

Correct me if I am wrong, I think we can get a good advantage indication of force induction (s55 engine) vs na (s65 engine) by looking at the 335i/435i engine vs e46 m3 engine. The 335i/435i is like the f80/f82 while the e46 is like the e90/e92 m3.

[aus]

What ASAP said.
And I remember reading something about keeping the exhaust valves open a little in order to send some gas to the turbos during lifting.

[Zayken]

Originally Posted by jaehshim

let's ask the guy again.
so, what is special about this new engine? besides it being basically a 335i engine

You know what? I totally agree with you.

On the other hand did you ever have a car with N54 ? My friend it was not a bad machine at all. You could easily push it to 380 hp and im telling you it was strong! adding 50 ps more will be a huge improvement. fixing some electric and cooling issues will make it very reliable. I had a Z4 DCT at 380 ps for two years and it worked pretty good. Besides why do you think BMW set N54 only at 306 ps while tuners reached 380 ? It was their plan from the beggining. Man they know from now what engine will have the 2020 M4, im telling you trust me.

I think that most people here forgot what a beautiful engine N54 was. Very responsive, very strong, very very very . So its not necessarily bad that the M4 has a variation of N54 . If they have reached that motor in its perfection , then i trust it will be a highlight.

Lets stop seeing them suspiciously at the moment . Untill the first reviews at least.

[jphughan]

Originally Posted by ASAP

I have no idea how you can keep wastegates fully closed all the time lol. He probably means partially closed.

Agreed. Either that, or if you thought the turbo reliability on the N54 wasn't so hot, just wait until this baby hits the streets.

[Black Gold]

Originally Posted by Thurman Murch

I see that Ferrari copied the S65 and improved upon it in the 458 and that is a compliment

cryptic

Hahahahahahaha, seriously?

355, 360, 430, 458, etc hahahaa

[basscadet]

Originally Posted by Thurman Murch

How well does this engine rev through the range? The N54 seemed to have instantaneous power down low and lost lungs up top

It fell flat on its face at top because the car was tuned exceptionally rich from the factory and pulled boost at high RPM.

Let me tell you that once a N54 car is tuned properly it can pull very hard all the way to high RPMs. I am no fan of the comatose ride and driving experience of the 335i but that engine is an absolute gem.

I want to see the technical specifications of the S55 turbo vs the N54 turbo. My guess is that the S55 turbo is smaller, spools faster, is more efficient, but cannot flow as much as the N54 turbo which I believe was good for up to 400 whp if i am not mistaken. I do not think that the S55 turbo will be capable of that much power over stock and I would expect that there is going to be a healthy market for plug-n-play turbo upgrade kits for the F80/F82.

[Black Gold]

Originally Posted by Smiley913

Correct me if I am wrong, I think we can get a good advantage indication of force induction (s55 engine) vs na (s65 engine) by looking at the 335i/435i engine vs e46 m3 engine. The 335i/435i is like the f80/f82 while the e46 is like the e90/e92 m3.

You are wrong.

Check the powerband of the n54/55 to the s55, the s55 is wider and much stronger at the top. It's much more similar to a gtr in that it continues to make power / not drop power to redline.

It is similar to any modern turbo in that it still makes a lot of average power all throughout the rev range, specifically more than higher revving smaller n/a motors.

[basscadet]

Originally Posted by KennyPowers

Hahahahahahaha, seriously?

355, 360, 430, 458, etc hahahaa

lol I'm glad you caught that before I jumped in...

[Black Gold]

Originally Posted by basscadet

It fell flat on its face at top because the car was tuned exceptionally rich from the factory and pulled boost at high RPM.

Let me tell you that once a N54 car is tuned properly it can pull very hard all the way to high RPMs. I am no fan of the comatose ride and driving experience of the 335i but that engine is an absolute gem.

I want to see the technical specifications of the S55 turbo vs the N54 turbo. My guess is that the S55 turbo is smaller, spools faster, is more efficient, but cannot flow as much as the N54 turbo which I believe was good for up to 400 whp if i am not mistaken. I do not think that the S55 turbo will be capable of that much power over stock and I would expect that there is going to be a healthy market for plug-n-play turbo upgrade kits for the F80/F82.

We will find out but no n54 car continues to make powerl to redline on pump without new turbos, and it certainly can't rev as high. These turbos clearly allow more boost to be held to redline in stock form . Considering they have to be able to perform at high altitude , high temperature and poor gas quality environments, I am certain the car can be tuned to push harder at all rpms even without hardware upgrades. With hardware upgrades it should certainly pull harder up top.

Only one way to find out

Edit : that said, I have a lot of love for the n54

[Tonymiabmw]

Omg I need a review before I implode

[basscadet]

Originally Posted by JoeFromPA

The other thing he called out I thought was interesting: DCT gear shift changes result in no interruption in power delivery (i.e. amount of power on tap).

I presume that means the 6MT is going to see a more notable decrease in boost between gear changes. I realize this is normal, but, sigh.

Just like the E9X, a 6 speed manual is going to be a serious crippling of the performance of the car. BMW's DCT transmissions are just sooooo good. I rank them second only to Porsche PDK, you simply can't pass it up on your options tick-box.

The combination of nice torquey power and DCT is an intoxicating experience. Effortless zipping around slow traffic on highways in my GT-R is one of my favorite memories of that car and that never would have been possible with a clutch/stick.

[jphughan]

Originally Posted by basscadet

Just like the E9X, a 6 speed manual is going to be a serious crippling of the performance of the car. BMW's DCT transmissions are just sooooo good. I rank them second only to Porsche PDK, you simply can't pass it up on your options tick-box.

The combination of nice torquey power and DCT is an intoxicating experience. Effortless zipping around slow traffic on highways in my GT-R is one of my favorite memories of that car and that never would have been possible with a clutch/stick.

And the life-affirming sound that the S65 makes when you blip for a downshift is made that much sweeter by the fact that you got to do it with your own foot -- not to mention the thrill of always chasing that perfectly smooth upshift or heel-toe blip downshift and feeling like an absolute hero when you nail it just perfectly, and the innate joy and sense of accomplishment that comes from getting more out of something as a resulting of investing more effort into mastering it rather than letting something else do it perfectly for you all the time. "Effortless zipping" just isn't what's fun for me.

Don't get me wrong, I drove a DCT M3 on twisty back roads, and the immediacy of the brake/downshift/turn-in trifecta compared to 6MT was definitely exhilarating. So was the straight-line acceleration with absolutely no letup. Even the consistent smoothness was nice during regular commuting. But having driven 6MT for a while now, I can't drive an auto or DCT that has paddles without actually using them because otherwise I'm bored out of my mind, and even the paddles aren't a complete substitute for driving MT. I found that for me, DCT might make intense driving slightly more fun than 6MT, but 6MT makes regular driving a LOT more fun than DCT, and since I do a fair amount of typical driving, 6MT comes out ahead overall. Then again, I'm fortunate to have a commute that doesn't involve traffic.

And with that, I think we've just said everything that needs to be said about 6MT vs DCT on the F8x forums. So this means we won't need to see any new threads on the matter, right people?

[pkimM3r]

so is he saying that throttle mapping isn't changed in sport/sport+ and the only thing is that the wastegates change character allowing a sort of "pre-spool" in the turbos?

is this all what the impulse charging technology was?

on the n20 motor, I feel absolutely no lag honestly.....you press the throttle, the car responds instantly...must be those tiny snails.

This car is going to be a beast and I want to track one ASAP.

[Benstuck]

Originally Posted by Thurman Murch

I do like the new focus on power on top with the newer N/S55 however the only place I could see actually using that is on the freeway or the track

How well does this engine rev through the range? The N54 seemed to have instantaneous power down low and lost lungs up top

It seems as if this engine was focused more on NA delivery up to 270nm then the turbos add the frosting to the cake

I see that Ferrari copied the S65 and improved upon it in the 458 and that is a compliment

...but once again the explanation only talks around the actual details and they are keeping everything cryptic

I have gotten mixed messages on this forum, but is the S55 based off the N55? Some say it is, some say it's a whole new block, some say it shares a few parts.

[jphughan]

Originally Posted by Tonymiabmw

Omg I need a review before I implode

Press embargo is lifted sometime in May. Hang in there!

[Powerslide]

Originally Posted by BhamDavid

Yes but they do that with 6.3 liters of displacement.

Not only with 6.3 liters of displacement - but even that engine - being naturally aspirated, only makes peak horsepower at a single, discreet rpm - not over a range of rpm's (like Mercedes' 5.5 liter turbo that replaced it - which is part of the reason the 5.5L biturbo outperforms even the impressive 6.3L...)

[WAGGIN]

I love articles and tech info like this. Although I am an NA fan now, I cut my teeth on import turbos (4G63, EJ20, and MZR DISI)

The S55 is shaping up to be a good all-purpose engine and I look forward to trying out both transmissions :P

I also wonder how the engine response is in the upper RPM range and how it feels in the 6000-7600 rpm range. I had a Mazdaspeed3 once and didn't bother revving past 5500 and just upshifted...

I'm interested in seeing the engine bay/packaging in person. The engine bay is a little bigger in the F3x/F8x but that looks quite complex.

[Kash]

Originally Posted by Powerslide

Exactly - I absolute love my S65 to death - best engine I've ever personally owned. But don't get me wrong - but you're making 414 hp only at a single, discreet "point in time" - i.e., at 8300 rpm. With the S55 - you may only be 11 hp peak hp better - but you're there for a heck of a lot longer period of time - 5500 to 7300 rpm over and over again (1st through whatever gear you're at when you decide that you don't want to risk going to jail). I agree that this engine will be much faster - given that you can be at a virtually constant 425 hp as you accelerate (assuming you shift at 7300 rpm) - whereas the S65 you have to wait until 8300 rpm just to get to 414 hp, then when you shift at 8300-8400, your rpms drop what - 1800-2000 rpm (so now your hp just instantly dropped from 414 to 325-350, or whatever it is, gradually building back up to 414 by the time you again reach 8300)...

With naturally aspirated engines, peak horsepower used to be the most important single factor for acceleration (relative to the car's weight and other factors too, of course). Now, with turbos making very wide, flat power plateaus over a wide rpm range - it seems the most important single factor for acceleration is for how wide of an rpm range (or for how long of a period of time) can the peak power be maintained?

I couldn't agree more with Powerslide. Being able to tap the full potential at low RPMs is awesome and I love the new M4 spec. for this aspect. How many of us are driving In tracks 2 times a day and 5 days a week crossing 8000 rpm?

For the 75% of the crowd/use case with numb DCT for DD the M4 engine is a heavenly gift.

Well said Powerslide. Well said.

[pkimM3r]

Originally Posted by Kash

I couldn't agree more with Powerslide. Being able to tap the full potential at low RPMs is awesome and I love the new M4 spec. for this aspect. How many of us are driving In tracks 2 times a day and 5 days a week crossing 8000 rpm?

For the 75% of the crowd/use case with numb DCT for DD the M4 engine is a heavenly gift.

Well said Powerslide. Well said.

how do you "tap the full potential at low RPM's" exactly? Not really an electric motor is it?

[Kash]

No offense. You may be a more advanced roller than I am. I agree.

But, What I meant was that the clunky feeling with E9x until you cross 5K RPM and then a sudden surge to a heavenly feeling when the car comes alive at higher RP is not very suitable for DD.

With the new engine; you get the intoxicating feel well in advance starting at lower RPMs in normal driving conditions . This doesn't mean you reach the full potential at low RPMs. I owned E90 M3 and I enjoyed it but Extracting joy in DD conditions that involves Downtown commute and local traffic was a challenge with that platform.

[bradleyland]

Originally Posted by Powerslide

Exactly - I absolute love my S65 to death - best engine I've ever personally owned. But don't get me wrong - but you're making 414 hp only at a single, discreet "point in time" - i.e., at 8300 rpm. With the S55 - you may only be 11 hp peak hp better - but you're there for a heck of a lot longer period of time - 5500 to 7300 rpm over and over again (1st through whatever gear you're at when you decide that you don't want to risk going to jail). I agree that this engine will be much faster - given that you can be at a virtually constant 425 hp as you accelerate (assuming you shift at 7300 rpm) - whereas the S65 you have to wait until 8300 rpm just to get to 414 hp, then when you shift at 8300-8400, your rpms drop what - 1800-2000 rpm (so now your hp just instantly dropped from 414 to 325-350, or whatever it is, gradually building back up to 414 by the time you again reach 8300)...

With naturally aspirated engines, peak horsepower used to be the most important single factor for acceleration (relative to the car's weight and other factors too, of course). Now, with turbos making very wide, flat power plateaus over a wide rpm range - it seems the most important single factor for acceleration is for how wide of an rpm range (or for how long of a period of time) can the peak power be maintained?

I get so sick of explaining to people how two cars with identical "peak" horsepower can perform so differently. I remember when VW introduced the 1.8T with 180 HP (peak), but it out performed the 200 HP 24v VR6 engine available at the time. The 1.8T was underrated, but the biggest advantage was the earlier swell in power.