People who seem to be happy with the new F80 M3 / F82 M4 engine direction

[BMW269]

But the sound of FI!

[NISFAN]

Originally Posted by Levi

But the sound of FI!

Turbo and probably 2 cat's = too quiet for sure.

[CanAutM3]

Originally Posted by NISFAN

Layman's term maybe, but wrong to a drive train engineer.



No, I unapologetically use the engineering definition. If I were to go by 'EVERYONE's beliefs then I would also have to close mindedly accept that 'Torque wins races' or other nonsensical definitions. Just to recap, a turbo engine responds to throttle input EXACTLY the same as an NA engine, afterall it actually is an internal combustion 4 stroke engine.



If you had used torque in your argument you would have been onto something, but totally failed with the horsepower reference. Lag on a modern turbo system at peak horsepower revs would be negligible. I know you probably used it for a more forum friendly reference, but down the wrong track. The higher the revs = the higher the exhaust gas energy = lower compressor spool time.

At least you agree that, say, the S63Tu at 4.4 litres even when in 'lag' state will be at least if not better than an s65. Kind of poo poo's the people who believe the F10 M5 F12/13 M6 suffers from lag. I'm pretty sure I feel strong acceleration when driving the M6



Yep, you are definitely biased towards the s65.....comes across really clearly. It is a great engine by the way, and deserves the credit it has received. Sadly it doesn't fit in with the modern way of doing things. You have to move with the times in this industry.



This new engine direction has stumbled on a V8/I6 thing, but probably a bigger factor is the NA / FI thing.

Obviously current M3 owners would like the engine they know and love to move into the next car in some form or another.....but simple facts are, to extract the increase of power required, BMW would have to go against the global trends for economy and emissions, on an already thirsty engine.

On the plus side, there was equally as much debate about the F10 M5 / M6 dropping the s85 engine. Seems like s63tu has gone down well with new owners, with only 'the sound' being a negative.

As for turbo lag, check out race two in this e60 M5 vs. F10 M5 (race two singled out as it was closest start point for the both in terms of reaction time). Not bad for a over 100kg heavier car with 12% less displacement.

I am not sure anyone is debating the fact that the S63Tu makes more power and has a broader power band than the S85 as is clearly demonstrated in the vid you posted.

My personal understanding of lag, or turbo lag, is the delay between throttle pedal movement and power output change. A high revving NA engine with individual throttle bodies will have a very sharp response to throttle pedal movements. Such a characteristic makes the car very enjoyable and easy to control and balance at the limit.

On the other hand, a turbocharged engine will have inherent delay between the throttle pedal application and the power increase. Some operating conditions will make this lag worse. For example going from a fully closed throttle position to a fully opened position, regardless of RPM. When the throttle is closed, very little gases pass through the engine and the turbo spools down. When the throttle is re-opened, there is a time delay for the lower pressure intake charge to enter the engine, go through the combustion cycle, travel trough the exhaust and spool up the turbine; and then for the compressor to push more air in the intake, for the higher intake charge to reach the cylinder and finally for the engine to make more power. With your background, I am sure you are familiar with the various methods used to minimize or counter this delay, like using smaller turbos or exhaust fuel injection to keep the turbo spooling (those lovely pops that rally cars do on rundown) just to name two. The engineers at ///M seem to have to done a pretty good job to minimize this on the S63Tu, but the lag is still there to some extent according to most reviewers.

I am very curious about what technology the ///M engineers will use to minimize the lag on the S55 (electric turbo ??). I am sure they will be very creative about it

[Ezio]

the F10 M5 should be able to beat a E60.

Even with little turbo Lag. The lag on a 100% stock car is not going to be that bad. I think its a "feel" of the engine that people don't like as much. People coming from a N/A engine might feel it more so, than people driving FI engines.

[NISFAN]

Originally Posted by Ezio

the F10 M5 should be able to beat a E60.

Even with little turbo Lag. The lag on a 100% stock car is not going to be that bad. I think its a "feel" of the engine that people don't like as much. People coming from a N/A engine might feel it more so, than people driving FI engines.

Agreed, most people respond to a swelling torque curve over revs.....FI gives a pretty hard hit and stays level.

The other FI trait, is it is less dependant on inlet restrictions, which means throttle modulation is de-sensitised. However on modern systems this is programmed out to an extent.

[NISFAN]

Good post

Originally Posted by CanAutM3

I am not sure anyone is debating the fact that the S63Tu makes more power and has a broader power band than the S85 as is clearly demonstrated in the vid you posted.

Firstly the video I showed wasn't really to show an f10 M5 being faster than an e60 M5. It just showed in my view a turbo charged engine giving a pretty good account in the first tenths of a second. Of course there are other factors at play here, but a good display to help reduce the big bad lag issue.

Originally Posted by CanAutM3

My personal understanding of lag, or turbo lag, is the delay between throttle pedal movement and power output change. A high revving NA engine with individual throttle bodies will have a very sharp response to throttle pedal movements. Such a characteristic makes the car very enjoyable and easy to control and balance at the limit.

Don't forget, even an NA suffers from lag, two main reasons are:

1. Fuelling lag - the delay for the ECU to adjust engine parameters in vastly different transient states.
2. Pressure drop - don't forget although we humans base our pressure readings from ambient, an engine runs at absolute pressure. On WOT even an NA engine, manifold pressure will drop to around -0.7 bar. So even a 4litre engine will be producing not much torque at that low pressure. This fact alone busts the instantaneous myth.

Originally Posted by CanAutM3

On the other hand, a turbocharged engine will have inherent delay between the throttle pedal application and the power increase. Some operating conditions will make this lag worse. For example going from a fully closed throttle position to a fully opened position, regardless of RPM. When the throttle is closed, very little gases pass through the engine and the turbo spools down. When the throttle is re-opened, there is a time delay for the lower pressure intake charge to enter the engine, go through the combustion cycle, travel trough the exhaust and spool up the turbine; and then for the compressor to push more air in the intake, for the higher intake charge to reach the cylinder and finally for the engine to make more power. With your background, I am sure you are familiar with the various methods used to minimize or counter this delay, like using smaller turbos or exhaust fuel injection to keep the turbo spooling (those lovely pops that rally cars do on rundown) just to name two. The engineers at ///M seem to have to done a pretty good job to minimize this on the S63Tu, but the lag is still there to some extent according to most reviewers.

Yes good summation of sequence of events. It is true that at very low RPM turbo lag is greater. In fact you could theoretically size a turbo so big that it wouldn't produce positive boost all the way through the revs, upto the redline. Clearly turbo sizing is very important. The lower the 'boost threshold' - the revs at which enough energy is supplied to get the turbo onto the flow map. The lower the 'turbo lag' will be.

No I am not going to change the mind of those that religiously believe in the 80's turbo lag phenomenon (carburettor application has a lot to pay for), but I have personally seen turbo's on 2.6 litre straight sixes make too much boost on WOT, so much so that it caused the turbo to go into 'surge', a condition where the engine can't flow the volume of air coming from the turbo.

I am very curious about what technology the ///M engineers will use to minimize the lag on the S55 (electric turbo ??). I am sure they will be very creative about it [/QUOTE]

On a theoretical engine as swamp mentioned, an NA M4 with 3.0l displacement vs. a turbo variant of the same. The FI version doesn't need to be as 'cammy' to produce the power. Therefore the low rev cam can be profiled to suit low engine speeds, increasing like for like un-boosted torque (outside VANOS limits).

I'm not sure the 'anti-lag' you describe would be an adopted solution for road use, but even launch control holding WOT does get turbo's spooled. (clearly demonstrated in the Nissan GTR, the LC mode obliterates the non LC launch, purely because of boost at launch. On a RWD, this would be too much.

One thing for sure, unless BMW have integrated a 'flat shift' facility, a MT is going to be slower than DCT by a bigger margin. Plus side is the DCT will feel manic going from full boost to full boost straight away.

[04cobra]

E90 M was not easy to mod...this car should be VERY modable....I am excited for it.

[turbolag]

Originally Posted by 04cobra

E90 M was not easy to mod...this car should be VERY modable....I am excited for it.

How is E90 hard to mod?

ESS Superchargers, multiple NA tunes, etc.

[ixse]

^^ All FI set up are mod "friendly".
because ESS perchargers are aweful expensive. NA tunes only yield minium gains and awefully expensive on E90 M. vs. FI are easy to put small $ and gain lots of hp.
i.e exhaust and tune on evo yields around 50whp gain on a 2liter engine, vs E90 exhaust and tune if you are lucky to get 15~20whp. meaning on a v6 biturbo platform, exhaust and tune with slight increase in boost may yield massive gains. Remeber supra TT (I6 biturbo)?? go look them up see how mod friendly they were.

[CanAutM3]

You bring interesting points

Originally Posted by NISFAN

Don't forget, even an NA suffers from lag, two main reasons are:

1. Fuelling lag - the delay for the ECU to adjust engine parameters in vastly different transient states.
2. Pressure drop - don't forget although we humans base our pressure readings from ambient, an engine runs at absolute pressure. On WOT even an NA engine, manifold pressure will drop to around -0.7 bar. So even a 4litre engine will be producing not much torque at that low pressure. This fact alone busts the instantaneous myth.

My understanding:

Fuelling lag is pretty much a non-issue on the S65 since it relies mostly on RPM and throttle position to establish the required fuel schedule. So as soon as the throttles open, the right amount of fuel is sent to the injectors for that given RPM. BTW, even on older carburetor engines, more sophisticated units had an "acceleration pump" to push an extra burst of fuel when the throttles were abruptly opened.

While I agree that NA engines do have some lag, the configuration of the engine has a big impact on this lag. The S65 with high revving (good breathing) capability and individual throttle bodies positioned very close to the intake valves greatly minimize the lag to almost nothing.

You might be confusing absolute pressure with total pressure. Manifold pressure is a static pressure measurement. While an intake tract has some inherent pressure loss, the main reason the static pressure drops is because of the velocity of the intake charge. The total pressure in the manifold still remains close to 1 bar.

To repeat our previous scenario with the S65, with fully closed throttles, the static pressure in the manifold is at about 1 bar (no flow). When the throttles open, the ECU instantly adjusts the fuel flow and the full (max) intake charge only has a few inches to travel to reach the cylinder to produce power. Clearly much faster than the turbo scenario.

So not sure myth is "busted" here .

Originally Posted by NISFAN

No I am not going to change the mind of those that religiously believe in the 80's turbo lag phenomenon (carburettor application has a lot to pay for), but I have personally seen turbo's on 2.6 litre straight sixes make too much boost on WOT, so much so that it caused the turbo to go into 'surge', a condition where the engine can't flow the volume of air coming from the turbo.

IMO for a turbo to surge, either the turbo is wrongly sized for the engine application and/or the blow off valve is not properly calibrated. I am unsure of the point you are trying to make here.

(I work with aircraft turbine engines, so I very well know what a surge is: )

Originally Posted by NISFAN

I'm not sure the 'anti-lag' you describe would be an adopted solution for road use, but even launch control holding WOT does get turbo's spooled. (clearly demonstrated in the Nissan GTR, the LC mode obliterates the non LC launch, purely because of boost at launch. On a RWD, this would be too much.

I was not suggesting exhaust fuel injection for street application, I simply quoted an example of technology used to minimize turbo lag. I am not sure anyone would tolerate the machine gun staccato on decel

I am not concerned about lag on initial acceleration from a standing start or from a roll. It is more the precise control of the power delivery that I am referring to. I understand that not everyone tracks their M3, but I do. I have always enjoyed the very precise and predictable nature of the power delivery of my M3s. When cornering at the limit, I can precisely and smoothly adjust the cornering attitude of the car by modulating the throttle. It is this behaviour I hope will be preserved in a FI F80/F82 ///M.

Originally Posted by NISFAN

Plus side is the DCT will feel manic going from full boost to full boost straight away.

Agreed. The DCT will definitely contribute to make this new power plant shine. The quick shifts will keep the engine on boost and if the gear ratios are well chosen, the acceleration curve will be very linear going from gear to gear.

[swamp2]

Originally Posted by NISFAN

Layman's term maybe, but wrong to a drive train engineer.

Neither of us is a drivetrain nor automotive engineer and again our education nor titles don't really matter either. Everyone on the planet including automotive engineers agree on what turbo lag is.

Originally Posted by NISFAN

No, I unapologetically use the engineering definition. If I were to go by 'EVERYONE's beliefs then I would also have to close mindedly accept that 'Torque wins races' or other nonsensical definitions. Just to recap, a turbo engine responds to throttle input EXACTLY the same as an NA engine, afterall it actually is an internal combustion 4 stroke engine.

Well you couldn't be more wrong about that. If your definition of turbo lag is what you provided earlier - that all NA engines are on "lag" across their entire rpm range. Again, nonsense.

Of course I agree about the importance of hp over torque.

Originally Posted by NISFAN

If you had used torque in your argument you would have been onto something, but totally failed with the horsepower reference. Lag on a modern turbo system at peak horsepower revs would be negligible. I know you probably used it for a more forum friendly reference, but down the wrong track. The higher the revs = the higher the exhaust gas energy = lower compressor spool time.

I said there are operating regimes and the lag regime is as previously noted always greater at lower rpm.

Originally Posted by NISFAN

At least you agree that, say, the S63Tu at 4.4 litres even when in 'lag' state will be at least if not better than an s65. Kind of poo poo's the people who believe the F10 M5 F12/13 M6 suffers from lag. I'm pretty sure I feel strong acceleration when driving the M6

Sure, but that isn't an apples to apples comparison. The new M3 will be getting 3.0-3.3 liters and will not produce anywhere near the power the current S65 does when under miniumum boost.

Originally Posted by NISFAN

Yep, you are definitely biased towards the s65.....comes across really clearly. It is a great engine by the way, and deserves the credit it has received. Sadly it doesn't fit in with the modern way of doing things. You have to move with the times in this industry.

Modern or cost savings? Turbos are not modern, I think you know better. Yes they are getting more popular and are being modernized but are not modern per se.

Originally Posted by NISFAN

Obviously current M3 owners would like the engine they know and love to move into the next car in some form or another.....but simple facts are, to extract the increase of power required, BMW would have to go against the global trends for economy and emissions, on an already thirsty engine.

Yes, again it is about cost and fuel efficiency which BMW M have put aside in the past. Did you happen to note that the Ferrari 458 get bets fuel economy and revs higher than the prior 430 model. It is possible, just not cheap.

Originally Posted by NISFAN

On the plus side, there was equally as much debate about the F10 M5 / M6 dropping the s85 engine. Seems like s63tu has gone down well with new owners, with only 'the sound' being a negative.

Just like all of the 335i fanboys saying that car has "no" lag. No lag my ass. The new F10 has been equally or more so complained about. Let's use this quote from Automobile magazine,

The biggest disappointment with the M5 is turbo lag. Yeah, yeah, how typical that I'm complaining about a turbocharged M5. Actually, I'm not complaining about the fact that the M5 wears turbos: I'm complaining that the S63TU engine has so much more lag than the non-Valvetronic S63 did. In that silly X6M (and the slightly less silly X5M), the turbos were among the most responsive I've ever experienced. Not so in the M5 - the lag is significant enough that you have to drive around it.

Uhhhh, yeah, no lag

Originally Posted by NISFAN

As for turbo lag, check out race two in this e60 M5 vs. F10 M5 (race two singled out as it was closest start point for the both in terms of reaction time). Not bad for a over 100kg heavier car with 12% less displacement.

Hmmm, peak hp wins races, what a huge surprise. Let me also "surprise" everyone here with some other items from my crystal ball

-The new M3/4 will be lighter than the existing model.
-The new M3/4 will have more power than the existing model.
-The new M3/4 will be faster than the existing model.

Well now that the sarcasm is done here is the last point

-The new engine in the M3/4 will be substantially less appealing in character and also likely in throttle response (as compared to the S65).

Wasting a lot of breath here...

[Rob///M5]

Hey Swampy, stop reading BS journalists and come for a ride in my F10. You need to experience the lack of lag personally.

The new M4 could be very special indeed. Drop 300lbs and add real torque from 1500 to 8 grand. Honestly, my biggest concerns are steering (which they appear to be working out with F10/12 LCI) and turbos overheating (limp mode be gone!)

I will miss the NA noise, but the S65 just isn't torquey enough.

[The Automotive Enthusiast]

The M3/M4 won't be able to do this:

Or this:

Or this:

or This:

[mkoesel]

swamp, I don't recall seeing that comment about the S63Tu vs the S63 before. I have to wonder about how the addition of Valvetronic would effect turbo lag itself. I'm sure turbo lag is present in some form or another in any current turbocharged engine, so I won't argue that point. But the attribution of the increase in lag to the Valvrtronic throttle control seems like it could be debated. It seems to me that this would more likely point toward throttle lag. Perhaps the software in this case was not fully baked yet and needed tweaking. You and I know this type of situation well, what with the early DCT software woes. Speaking of which - there's one more place in the system that lag can rear its ugly head - gear ratio changes. Of course, we'd like to think BMW has that all handled by now. Still, it is curious that the X5 M also uses a different transmission from the M5, which somewhat interferes with the idea of comparing their ability to respond to driver inputs.

I believe that some day we'll be driving turbocharged cars with lag-less character. But I don't necessarily think BMW is going to usher us into that era with the S55. However, they may be prepared to make a significant breakthrough at least. I for one am excited to see what, if anything truly revolutionary, they've come up with. I think that is one thing we all anticipate here, and can all get behind. It could be the single most exciting trait about this engine if even some of the current rumors pan out.

[hector]

Originally Posted by mkoesel

s...
I believe that some day we'll be driving turbocharged cars with lag-less character. But I don't necessarily think BMW is going to usher us into that era with the S55. However, they may be prepared to make a significant breakthrough at least. I for one am excited to see what, if anything truly revolutionary, they've come up with. I think that is one thing we all anticipate here, and can all get behind. It could be the single most exciting trait about this engine if even some of the current rumors pan out.

wasn't an electric turbo (as part of a tri-turbo system) supposed to be a possible solution to the lag problem, or tangentially related, an electric motor complementing a FI engine?

[mkoesel]

Originally Posted by hector

wasn't an electric turbo (as part of a tri-turbo system) supposed to be a possible solution to the lag problem, or tangentially related, an electric motor complementing a FI engine?

Theoretically.

In practice it hasn't been done yet to my knowledge, at least not in a production car. The problem is, it takes a significant amount of energy to keep turbos spinning at high RPM and boost pressure up. A KERS type system could work, but adds weight and cost. There's no free lunch.

In any case a separate electric turbo (so-called tri-turbo) seems like an inefficient solution. Instead, you can add electric assist to the existing turbos, eliminating some hardware and complicated manifold routing.

[swamp2]

Originally Posted by Rob///M5

Hey Swampy, stop reading BS journalists and come for a ride in my F10. You need to experience the lack of lag personally.

The new M4 could be very special indeed. Drop 300lbs and add real torque from 1500 to 8 grand. Honestly, my biggest concerns are steering (which they appear to be working out with F10/12 LCI) and turbos overheating (limp mode be gone!)

I will miss the NA noise, but the S65 just isn't torquey enough.

Thanks for the offer, I PMd you. I have not driven the new M5 (nor ridden in it).

I mostly agree with all of your other comments. However, I don't think the M3 (with it very large torque multiplication through gearing) needs much more low end torque.

[pkimM3r]

i guess we could still slap on an ESS / VF supercharger to the new M4. Combo charged just like that old crazy lotus:

[pkimM3r]

Originally Posted by CanAutM3

I am not concerned about lag on initial acceleration from a standing start or from a roll. It is more the precise control of the power delivery that I am referring to. I understand that not everyone tracks their M3, but I do. I have always enjoyed the very precise and predictable nature of the power delivery of my M3s. When cornering at the limit, I can precisely and smoothly adjust the cornering attitude of the car by modulating the throttle. It is this behaviour I hope will be preserved in a FI F80/F82 ///M.

This is exactly what most people do not understand. They just go WOT in a straight line and say, "And you said this shit had turbo lag. I just smoked you!"

But I'm sure (or hope) that ///M works its magic - all the cars are pretty special.

I hope the torque just doesn't drop like a cliff at high revs.

[Eau Rouge]

Originally Posted by ixse

^ obvoius answer coming from current e92 m3 owner. wonder how effective that "instant" response is.. as far as i remember, torque wins races.
and mpg pwns you =)

Originally Posted by Ezio

Toqure doesn't always means win. BMW made the e92 m3 with gear ratios and launch control to keep revs high when racing at the drag. and at the track you are keeping the car in the power zone. Its not a hugh problem. But for the most part torque is more important for drag racing, and Horse power is more important for the race track. Ask any F1 driver....

The only thing i can see someone like you complaining is when daily driving, where you are keeping revs low. not in the power zone, where the next M3 will shine.

With that said. I love the sound of a V8, and the high revs. I could carless about MPG also. i am a rare breed, or maybe just have a lot of cash... either way.

I think this is something you might not understand. honestly i do see where people like you are coming from. a engine thats makes more power, better on gas, more torque. i get it.

but to me. i have never really liked practical cars. but this new one is better for BMW, and for many people

Originally Posted by pkim1079

Mustangs dont win races LOL.

Ferrari 458 has a pretty damn close hp to tq ratio as the e9x m3. No one is complaining there.

But yes you obviously need instant torque to make lane changes in a 35mph zone.

Originally Posted by mkoesel

Drivers win races. And power-to-weight determines a car's ability to accelerate. Torque wins on the spec sheet.

Ezio, Pkim and MKoesel on target. Nuff said.

Originally Posted by NISFAN

You prefer NA? An engine that suffers from lag from idle to the redline.................hmmm I see where you are coming from

Swamp/Koesel seemed to already dismissed class. Damn!

Originally Posted by Needsdecaf

Don't let the door hit you in the ass on the way out.

Post #5 was your best in this thread. Cheers.

[Ezio]

Originally Posted by pkim1079

i guess we could still slap on an ESS / VF supercharger to the new M4. Combo charged just like that old crazy lotus:

sounds sick

[font9a]

Originally Posted by imserious

Wow. I'm pretty sure that's the first time I've heard anyone say that.

For 335 owners or e46 m3 owners it's all upside. More hp/torque. Same 6.

For e9x m3 owners it's a bit of a let down. But the v8 was really an anomaly. Very surprising choice for the m3 and it will forever be that anomaly.

Even though it will lose that exotic v8, the next m3/4 is going to be a beast. Most people will forgive BMW for going turbo when the new m3 rips it up. And the e9x m3 will become a classic for that special engine...

Exactly why I moved up from my N54 335i (tuned+) to a new S65 M3 ZCP DCT. I am completely in agreement with OPs thesis. I asked myself, "I love my 335i with close to 400HP and 400TQ, why would I want an M3?" Until I drove one, and it is undeniable how much better the M3's steering, transmission, and suspension are. Worlds apart. Leagues apart. "But what about this new engine, this high-revving, linear, low torque, high horsepower, lionized plant that everyone raves about? It's not that quick. It certainly doesn't *feel* as quick as my N54 did..."

But it is quick. Quicker. And with more finesse, excitement, and sheer speed that the 335i could ever muster, no matter how good a car she was. And now that the V8 growl sings to me every day, it's beautiful music. More violin-like, than drums 'n bass thuggery of the N54. Not as eager to kick my coccyx into the seatback and spin the rears at 1500rpm, but a scalpel around the bends, and surging crisp upshifts all the way up the speedo; never wheezy above 6000.