[Franzino]

Originally Posted by PackPride85

The only "lag" I get is between shifting w/ the manual. You really have to rev it nearly to red line if you want immediate power on the next shift. A little annoying but not a deal breaker.

+1; you notice it more in the manual then in the DCT M2....but; still prefer the manual M2

[Franzino]

Originally Posted by atomic837

I've experimented in all three modes. Sport+ is much more sensitive, but I don't think it truly changes much in regards to turbo lag.

Granted, I'm still pre break-in, so I haven't exactly hammered the car yet, but I do notice a difference just driving around town when compared to my 135i N54.

Will update once break-in is complete this weekend.

The turbo lag is the same in all 3 modes...

[Tag]

If after your 1200 mile break-in service it's still laggy ask to have your adaptions reset and then drive it like you stole it.

[ddk632]

The car learns throttle response when 6MT also? Bought mine used (6MT) and thinking maybe need to have that reset also. I always thought it was only the DCT that learned/adapted to driving styles, similar to MB autos and PDK.

[doug_999]

Interesting... while I have yet to drive my 1M since picking up my M2 in January, from memory, the 1M "feels" faster. It could just be the throttle response.

Pulling the 1M out this Sunday.. we shall see.

[mlambert890]

Originally Posted by doug_999

Interesting... while I have yet to drive my 1M since picking up my M2 in January, from memory, the 1M "feels" faster. It could just be the throttle response.

Pulling the 1M out this Sunday.. we shall see.

Im not shocked. Ive found this to be a theme with modern perf cars. Google "throttle lag", "trans lag", etc on *any* forum. The combination of DCT and turbo exacerbates drive by wire issues imo.

Every modern dual clutch car Ive owned Ive found particularly horrible in this area with the exception of the GTR which overcomes it with *very* aggressive clutch engagement and throttle response plus massive low end torque. The M4 I tested set on "maximum aggression" (all 500 settings to S whatever) was pretty good also.

Some people apparently dont notice it, but for those who do youre not crazy. There are pro articles written about dual clutch clutch engagement and modern throttle response. Its part of why the ZF auto has been gaining traction.

[stefan]

While throttle response is fine, there is definite turbo lag in ALL new BMWs. Contrary to how most journalists quip "I can barely tell the difference from an N/A motor!", it is absolutely there and is a physical reality of how turbos work. You're just experiencing it as it really is, and not how most reviewers describe it. Of note, these guys are usually complimenting the car at a track where the turbo remains spooled up at high rpms.

[SeanWRT]

A little bit off topic but can someone explain what exactly the DME is learning/adapting to? What exactly will change out of that and how?

[stefan]

Originally Posted by SeanWRT

A little bit off topic but can someone explain what exactly the DME is learning/adapting to? What exactly will change out of that and how?

If I had to guess, and I'm guessing, it's that these cars probably ship from the factory with a relatively rich tune to account for altitude differences, fuel quality in certain regions, and component break in. As you drive the car the ECU might be learning to give less fuel as knock or lack of knock is measured getting you closer to a perfect AFR. Maybe.

[6734202]

I've also noticed that a lot of reviews talk about how early power comes on and how the torque starts at 1500 rpm. For me...there's definite lag until 4k.

[atomic837]

I drove my unmodified N54-based 135i the last few days and hopped into my M2 this morning..... Confirmed the laggy feel of power on the latter.

On the 135i, hitting the gas, even below WOT, provides an immediate kick to the back of the seat, with a more powerful surge about a half second later. Doing the same in the M2 provides a fairly underwhelming initial acceleration, followed by a more gradual surge of power about a half second later. My rookie hunch leads me to believe that I'm feeling the initial, smaller turbo giving immediate punch, followed by the spooling up of the second turbo for the secondary kick of power.

I miss the immediate kick in the pants feel with around the town driving. It gives the impression that the 135i is a monster in power (even though it peeters out a bit in the higher revs). Comparatively, the M2 feels slower in normal driving... Like you have to really flog it to get it to move. Honestly, did not expect my rather mundane 8 year old "secretary's car" to feel faster than a brand new performance-tuned M car.

Hoping this changes after the initial break-in inspection and once the car is worked through its paces a bit. Maybe I'm doing something wrong.

Both cars are 6MT, btw.

[stren]

Originally Posted by 6734202

I've also noticed that a lot of reviews talk about how early power comes on and how the torque starts at 1500 rpm. For me...there's definite lag until 4k.

I think they mean how much torque there is once lag is over. I agree though the engine did feel a bit more laggy in some circumstances than the N54 to me. However in others (particularly low revs) it felt a bit better. Bear in mind lag has two dimensions - how long does it last and how much torque/power are you making during the lag period. I would say from my memory that the response of N54 below 2K felt laggier in the time domain but faster between 2K and 5k rpm. When the N55 was lagging though the torque felt higher. This shouldn't be a surprise though given the differing turbo setup and lower boost on the stock N54. I haven't revved out the M2 so can't comment on the high end, but the N54 did always run out of steam at higher RPM - maybe the N55TO wins there? It's a good enough engine for me though not particularly special. Luckily the whole car is a well balanced package with a great character so it doesn't matter to me and overall I love it. The B58 by contrast felt more plush and smooth than the N55 even though there was still similar lag. In fact I'd say I was able to shift far more smoothly with the B58 regardless of sport setting - I'm not sure why. While the B58 was still fast, it didn't feel passionate either. At least The N55 should be pretty reliable though.

I also noticed some weird throttle things going on - seemingly cutting power after up shifting (6mt) when pulling reasonably hard on a corner (possibly lag or dsc - didnt' have enough time to investigate) and occasional random throttle blips when in sport+ with the clutch in when coasting to a light.

[Bluenose-2er]

Going from a N54 135i to a N55 M2 - I really did not see any more lag. Also, the N55 gives a much smoother delivery of power. To each their own I guess.

[mmmpassion]

Originally Posted by stren

I think they mean how much torque there is once lag is over. I agree though the engine did feel a bit more laggy in some circumstances than the N54 to me. However in others (particularly low revs) it felt a bit better. Bear in mind lag has two dimensions - how long does it last and how much torque/power are you making during the lag period. I would say from my memory that the response of N54 below 2K felt laggier in the time domain but faster between 2K and 5k rpm. When the N55 was lagging though the torque felt higher. This shouldn't be a surprise though given the differing turbo setup and lower boost on the stock N54. I haven't revved out the M2 so can't comment on the high end, but the N54 did always run out of steam at higher RPM - maybe the N55TO wins there? It's a good enough engine for me though not particularly special. Luckily the whole car is a well balanced package with a great character so it doesn't matter to me and overall I love it. The B58 by contrast felt more plush and smooth than the N55 even though there was still similar lag. In fact I'd say I was able to shift far more smoothly with the B58 regardless of sport setting - I'm not sure why. While the B58 was still fast, it didn't feel passionate either. At least The N55 should be pretty reliable though.

I also noticed some weird throttle things going on - seemingly cutting power after up shifting (6mt) when pulling reasonably hard on a corner (possibly lag or dsc - didnt' have enough time to investigate) and occasional random throttle blips when in sport+ with the clutch in when coasting to a light.

Are you referring to a B58 in a m240i 6mt / m140i 6mt? Comparing with 1m and/or M2 it has to be considered that the overall ratio of the 6MT in m240i / m140i is much longer and the engine/car is not adjusted/tuned by M GmbH.

[stren]

Originally Posted by mmmpassion

Are you referring to a B58 in a m240i 6mt / m140i 6mt? Comparing with 1m and/or M2 it has to be considered that the overall ratio of the 6MT in m240i / m140i is much longer and the engine/car is not adjusted/tuned by M GmbH.

correct 6mt m2 vs 6mt m240i.

[6734202]

Originally Posted by stren

I think they mean how much torque there is once lag is over. I agree though the engine did feel a bit more laggy in some circumstances than the N54 to me. However in others (particularly low revs) it felt a bit better. Bear in mind lag has two dimensions - how long does it last and how much torque/power are you making during the lag period. I would say from my memory that the response of N54 below 2K felt laggier in the time domain but faster between 2K and 5k rpm. When the N55 was lagging though the torque felt higher. This shouldn't be a surprise though given the differing turbo setup and lower boost on the stock N54. I haven't revved out the M2 so can't comment on the high end, but the N54 did always run out of steam at higher RPM - maybe the N55TO wins there? It's a good enough engine for me though not particularly special. Luckily the whole car is a well balanced package with a great character so it doesn't matter to me and overall I love it. The B58 by contrast felt more plush and smooth than the N55 even though there was still similar lag. In fact I'd say I was able to shift far more smoothly with the B58 regardless of sport setting - I'm not sure why. While the B58 was still fast, it didn't feel passionate either. At least The N55 should be pretty reliable though.

I also noticed some weird throttle things going on - seemingly cutting power after up shifting (6mt) when pulling reasonably hard on a corner (possibly lag or dsc - didnt' have enough time to investigate) and occasional random throttle blips when in sport+ with the clutch in when coasting to a light.

WOT after 4k rpm solves all problems! Car just PULLS.

[DTNJNQ]

Originally Posted by Bluenose-2er

Going from a N54 135i to a N55 M2 - I really did not see any more lag. Also, the N55 gives a much smoother delivery of power. To each their own I guess.

I've got both a N54 135i with JB4 and the N55 M2. I agree that there isn't any more lag in the M2.

Throttle response is less responsive in the M2 unless it's in Sports+ mode. I've got a sprint booster installed on the 135i so the throttle response is always good.

I also agree the power delivery is smoother in the M2.

[ashburyn54]

The M2's power curve actually comes in earlier than any OEM n54 car. Earlier torque with the single twin scroll. Feel is one thing, I get it but the facts don't support it. I came from an n54 car as well. That's awesome you still have both!

[SeanWRT]

Technically, what we felt is the time it takes for push to come, a result from the combination of throttle response time (the programmed time to react pedal input) and turbo lag (the time turbo takes to build boost).

With partial throttle, boost is very low and NA part makes most of torque, so the responsiveness is less relevant to to turbo. Throttle programming is what matters here. I admit my friend's Z4 35i feels noticeably more punchy in city than my m2 in C&S, but pulls way weaker as I floor it. Though M2 in S+ turns table around in responsiveness, which I even think is overly aggressive and is difficult to fine control. Probably that's because I'm not a pro racer.

It goes without saying one single small n55 twin scroll turbo driven by 6 cylinders, spools faster than 2 smaller n54 mono scroll turbos each of which is managed by 3 cylinders. It was all well documented by BMW as an advantage of n55 being the n54 replacement. It is also the pure physics that you can't have both quicker spool and better flow capacity, unless turbo material is different or something is very wrong with turbo engineering, which is very unlikely.

[atomic837]

Interesting... I always thought that two smaller turbos will spool more quickly than a single, larger turbo (twin scroll or not). Less lag at least. Why have a twin turbo setup at all? Seems far more complicated than a single variant.

I'm having the break-in service done this weekend, and I'll be putting the car through its paces in Sport+... above 5000 rpm. Will report back with my impressions.

[SeanWRT]

Originally Posted by atomic837

Interesting... I always thought that two smaller turbos will spool more quickly than a single, larger turbo (twin scroll or not). Less lag at least. Why have a twin turbo setup at all? Seems far more complicated than a single variant.

I'm having the break-in service done this weekend, and I'll be putting the car through its paces in Sport+... above 5000 rpm. Will report back with my impressions.

In ideal world, you will always want single turbo for any boost target. Because bigger turbo is always more efficient than smaller ones.

In addition, the reason 2 small turbo isn't necessarily spooling quicker is because there is less cylinders to support each of them.

Packaging is the only reason to go twin. You just can't have single turbo for V6 without compromising exhaust manifold design, but it'd be fine doing it with L6. Though as power target goes higher, you have to also go twin because single big one is too big for compact engine compartment.

Google what the pros from Garratt have to say on it.

[ZPrime]

Originally Posted by atomic837

I drove my unmodified N54-based 135i the last few days and hopped into my M2 this morning..... Confirmed the laggy feel of power on the latter.

On the 135i, hitting the gas, even below WOT, provides an immediate kick to the back of the seat, with a more powerful surge about a half second later. Doing the same in the M2 provides a fairly underwhelming initial acceleration, followed by a more gradual surge of power about a half second later. My rookie hunch leads me to believe that I'm feeling the initial, smaller turbo giving immediate punch, followed by the spooling up of the second turbo for the secondary kick of power.

I miss the immediate kick in the pants feel with around the town driving. It gives the impression that the 135i is a monster in power (even though it peeters out a bit in the higher revs). Comparatively, the M2 feels slower in normal driving... Like you have to really flog it to get it to move. Honestly, did not expect my rather mundane 8 year old "secretary's car" to feel faster than a brand new performance-tuned M car.

Hoping this changes after the initial break-in inspection and once the car is worked through its paces a bit. Maybe I'm doing something wrong.

Both cars are 6MT, btw.

Note that to most people who actually want to drive the car for performance, progressive build of power is more desirable than "boom instant torque." It's hard to control a car that has near-instant high torque, like trying to balance on a razor blade. Racecar drivers want a linear powerband, not one with big fat lumps of pull that are hard to predict.

If you want insta-torque, go look at N/A American V8 stuff...

This all comes through in the better reviews of the M2 as well - they tend to mention that the car seems to want to be wrung out and shifted more - to keep it up higher in the rev range. This is atypical compared to the small single turbo 4cyl ~2L mills so common on most of the cheaper small hot cars today - WRX/STI, Focus RS, GoRf, etc. Those cars tend to hit peak torque pretty early and plateau there, but then begin to gasp and wheeze at the top of the powerband. I can state from experience that the Mk2 TTRS is the same way - the torque comes in very early, but it's out of steam by 5800 or so. Redline is at 6800 but there's not much reason to spin it all the way out there, which makes the car a bit less exciting. (Supposedly the motor/valvetrain is actually OK to rev to more like 7200, but there's zero reason to take it that high since it's way outside compressor efficiency.)