Lag - It's real, but it's not a problem

[JoeFromPA]

Hi all,

I just wanted to share this: I've got about 900 miles on the car now, 6mt.

I've read alot of reviews saying there's no lag. Heck, I drove the car for awhile thinking the lag is pretty much not noticeable.

I'm going to define lag in two ways:

1. When you push the throttle, response is not instantaneous
2. When the engine responds, it swells in response. Power comes on on a curve, rather than immediately at the appropriate power for the throttle input

This car has both of these characteristics. They are readily experienced and it is something I will notice a good amount.

In sport mode, when going from light/no throttle to full throttle at 2500 or even 3000 rpms in 3rd or 4th gear, there is a very slight delay in throttle response.

Then it responds with a nice push. Then a moment later it SURGES forward, while the RPMs have only risen maybe 200-300rpms.

It's not measurable in seconds or anything. But it is defineable and observable, over and over again.

If you go up to 4000 rpms and do the same experiment, it's vastly less. Borderline un-observable.

However at real everyday speeds of 3000 rpms in 3rd 4th or 5th gear, for example, going to WOT will exhibit a turbo engine characteristics.

This is not a problem. I doubt it will impact trackability. But I wanted to share that it's something you will notice in day to day driving a bit. There's an.....unlinearity to the throttle in these uses that is both intensely satisfying to experience viscerally and also slightly not in line with the rest of the character of the car.

[rsr racer]

Originally Posted by JoeFromPA

Hi all,

I just wanted to share this: I've got about 900 miles on the car now, 6mt.

I've read alot of reviews saying there's no lag. Heck, I drove the car for awhile thinking the lag is pretty much not noticeable.

I'm going to define lag in two ways:

1. When you push the throttle, response is not instantaneous
2. When the engine responds, it swells in response. Power comes on on a curve, rather than immediately at the appropriate power for the throttle input

This car has both of these characteristics. They are readily experienced and it is something I will notice a good amount.

In sport mode, when going from light/no throttle to full throttle at 2500 or even 3000 rpms in 3rd or 4th gear, there is a very slight delay in throttle response.

Then it responds with a nice push. Then a moment later it SURGES forward, while the RPMs have only risen maybe 200-300rpms.

It's not measurable in seconds or anything. But it is defineable and observable, over and over again.

If you go up to 4000 rpms and do the same experiment, it's vastly less. Borderline un-observable.

However at real everyday speeds of 3000 rpms in 3rd 4th or 5th gear, for example, going to WOT will exhibit a turbo engine characteristics.

This is not a problem. I doubt it will impact trackability. But I wanted to share that it's something you will notice in day to day driving a bit. There's an.....unlinearity to the throttle in these uses that is both intensely satisfying to experience viscerally and also slightly not in line with the rest of the character of the car.

You actually drive at less than 5000 rpm's??

This car is just opening it's eyes asking if you really want to play at 4500 and up.

Lag??? I think not.

[Thurman Murch]

The S55 needs getting used to w it's linear throttle especially with the 6MT

You need to really mash it up around 4500 rpm in the third or second and when you get the hang of it it will either make you smile or make you quit

These cars are meant to be driven hard it won't play if you tease it or can't get it going

It's not a N54 335 that has super easy power

[Lups]

Originally Posted by JoeFromPA

Hi all,

I just wanted to share this: I've got about 900 miles on the car now, 6mt.

I've read alot of reviews saying there's no lag. Heck, I drove the car for awhile thinking the lag is pretty much not noticeable.

I'm going to define lag in two ways:

1. When you push the throttle, response is not instantaneous
2. When the engine responds, it swells in response. Power comes on on a curve, rather than immediately at the appropriate power for the throttle input

This car has both of these characteristics. They are readily experienced and it is something I will notice a good amount.

In sport mode, when going from light/no throttle to full throttle at 2500 or even 3000 rpms in 3rd or 4th gear, there is a very slight delay in throttle response.

Then it responds with a nice push. Then a moment later it SURGES forward, while the RPMs have only risen maybe 200-300rpms.

It's not measurable in seconds or anything. But it is defineable and observable, over and over again.

If you go up to 4000 rpms and do the same experiment, it's vastly less. Borderline un-observable.

However at real everyday speeds of 3000 rpms in 3rd 4th or 5th gear, for example, going to WOT will exhibit a turbo engine characteristics.

This is not a problem. I doubt it will impact trackability. But I wanted to share that it's something you will notice in day to day driving a bit. There's an.....unlinearity to the throttle in these uses that is both intensely satisfying to experience viscerally and also slightly not in line with the rest of the character of the car.

Hey Joe!

I think out of two of us, you will be for sure more qualified and better with words for this stuff, but I still will try to come up with an answer. I think you are going through the same phase as I was, you were trying to find it, and then pinpointing it. Now, after 10k I'm at the place I want to be with Peter and I indeed can avoid the little things that could eat me alive.

Turbo lag of course is there, it is a turbo toy. Drivers adjust to it, and make the most of it. NA guys can go and tell us all about perfection after the revs are in the moon.

It's there as you said, life sucks. We have manuals because we love going around these small issues.

[aperng]

Totally agree, there is turbo lag, though its relatively small. When getting on it under 2k RPM, the engine hesitates before spooling up. There definitely is a power curve. Small price to pay for all that massive torque.. and the 6MT is pure joy.

[shortseller]

Originally Posted by Thurman Murch

It's not a N54 335 that has super easy power

Can you expand a bit on this comment? As I wait for my new S55 I'm curious how it will compare to my old N54.

Thanks.

[ASAP]

Originally Posted by shortseller

Can you expand a bit on this comment? As I wait for my new S55 I'm curious how it will compare to my old N54.

Thanks.

An n54 especially when tuned is a torquier motor down low... it has a nonlinear tq curve that is much more peaky than the S55 down low... the smaller turbos generally have that advantage... but they also have a power disadvanage.

To expand on the OP's comments... lag is lag, it will always exist to a degree on a turbo motor. The larger the displacement of the motor the better... for example the M5 V8. FWIW, I will take the tiny bit of lag any day of a very responsive albeit torqueless S65.

[JRV]

Originally Posted by ASAP

An n54 especially when tuned is a torquier motor down low... it has a nonlinear tq curve that is much more peaky than the S55 down low... the smaller turbos generally have that advantage... but they also have a power disadvanage.

To expand on the OP's comments... lag is lag, it will always exist to a degree on a turbo motor. The larger the displacement of the motor the better... for example the M5 V8. FWIW, I will take the tiny bit of lag any day of a very response albeit torqueless S65.

Oh c'mon your better than that torqueless S65 comment. The delivery is different...300ft/lbs of torque is not torqueless. It's the same as the 335i lol

[Racer20]

Joe

I agree with your assessment. The main thing that I experience is:

"1. When you push the throttle, response is not instantaneous"

This happens when going from light throttle openings/loads to high throttle openings/loads, like when flooring it from a cruise. Under sustained "spirited" driving in sport+, the pretensioning technology appears to do its job, as even on my 6MT, upshifts show no perceptible lag. I think under trackday conditions, the car will truly perform like a naturally aspirated engine.

Have you tried sport+? I think one of the big differences besides is that the boost holding feature is more aggressive.

[ASAP]

Originally Posted by JRV

Oh c'mon your better than that torqueless S65 comment. The delivery is different...300ft/lbs of torque is not torqueless. It's the same as the 335i lol

Do you know what kind of a difference peak tq at 1300-1500 rpm is vs 3900? Then the there is the fact that the M3 was a bit heavier. lol

[JRV]

Originally Posted by ASAP

Do you know what kind of a difference peak tq at 1300-1500 rpm is vs 3900? Then the there is the fact that the M3 was a bit heavier. lol

Yea I used to have an n54 very usable in DD. Wish I had kept it.

[shortseller]

I hope I will not miss my old 408bhp 440tq N54.

[ASAP]

Originally Posted by shortseller

I hope I will not miss my old 408bhp 440tq N54.

It depends on what you're looking for... as an all out DD with the TQ the N54 makes especially when tuned, it's hard to beat. That was my number one complaint about the S55... I am sure it would change once tuned. The S55 is much more linear in the power curve regard. This is of course purely engine speaking... the car as a whole is on another level.

[Andrew115]

Originally Posted by shortseller

I hope I will not miss my old 408bhp 440tq N54.

sounds like you my friend will need a jb4 to be impressed.

[MaynardZed]

When I was tracking the M4 the engine was very responsive at high rpm while remaining in the same gear. There was a little twisty part of the track where you're in 3rd gear at about 5K rpm where you have to give a quick burst of throttle input to flatten the car out before breaking or otherwise you may eat the wall in front of the paddocks. The S55 did just fine here.

I did perceive turbo lag on upshifts though (6MT), but I wonder if some of this perceived lag was actually the nannies kicking in a bit? It was my first time with the M4 on the track and was too chicken to turn them all off.

[shortseller]

Originally Posted by Andrew115

sounds like you my friend will need a jb4 to be impressed.

Have already taken a ride with a fellow Bimmerpost member in his beta test jb4 M4 two weeks ago.

[JoeFromPA]

Gents,

Let me be clear: I'm not talking about driving it on a track and experiencing lag. That is a distractionary direction alot of people are taking the discussion around lag in - i.e. "No i don't feel lag when driving it hard/tracking it."

That's totally fine and for me I also agree - when I'm driving it hard, there's no lag.

I'm talking about day to day driving. I'm not complaining about it at all. I love this motor. My point is simply that it exists and not in a "i'm sure it's there but I can't feel it" kinda way - i can feel it, distinctly, and in a number of situations I find myself every day.

[m3less]

If you aren't complaining then why start this thread? Not sure of (nor do I care) your previous automotive background and the vehicles u have driven but, a stock block(2.0 liter) FP red evo is a good description of lag...

[JoeFromPA]

Originally Posted by m3less

If you aren't complaining then why start this thread? Not sure of (nor do I care) your previous automotive background and the vehicles u have driven but, a stock block(2.0 liter) FP red evo is a good description of lag...

Subaru 2.0 and 2.5 turbo engines, ford 2.3 liter turbo, e39 m5, porsche 2.5 flat six, n54 in a 535xit, and some others...

My point behind this thread was there's been alot of.....misinformation...about whether this engine has lag or not.

I wanted to share my impressions about it.

[shortseller]

Originally Posted by JoeFromPA

Subaru 2.0 and 2.5 turbo engines, ford 2.3 liter turbo, e39 m5, porsche 2.5 flat six, n54 in a 535xit, and some others...

My point behind this thread was there's been alot of.....misinformation...about whether this engine has lag or not.

I wanted to share my impressions about it.

I do believe you, not just because you say so...but because I've have 4Ts and 6Ts in my life, ie all turbos have spool up, can't get by it - it's the way it's designed, some less than others but you will feel something. The funny thing is, so many "reviewers" have gone out of their way to convince us otherwise, I've read or heard many say "no lag", and that's just BS or just a concerted effort from BMW to convince them to convince us.

Marketing has gone a long way here, you were merely trying to help most believe what we already know before getting mind fk'd.

[JoeFromPA]

That's an accurate summation of it

And listen, with a DCT it's less noticeable for various reasons. And almost every reviewer under the sun drives a DCT nowadays. I get that.

I read alot about the S55 prior to picking it up and I'd say 95% of what you read indicates no lag. I think that's the clear impression you get when tracking/beating on the car at higher RPMs and/or in sport plus mode and/or with DCT transmission.

The point of this thread is simply to put out there that if you have a combination of the following, you'll notice this engine has lag:

1. Low rpm driving
2. Quick transitions in-gear from low/no throttle to high throttle input
3. Manual transmission
4. Long pause between gear changes before you input throttle

[CanAutM3]

Originally Posted by Racer20

Joe

I agree with your assessment. The main thing that I experience is:

"1. When you push the throttle, response is not instantaneous"

This happens when going from light throttle openings/loads to high throttle openings/loads, like when flooring it from a cruise. Under sustained "spirited" driving in sport+, the pretensioning technology appears to do its job, as even on my 6MT, upshifts show no perceptible lag. I think under trackday conditions, the car will truly perform like a naturally aspirated engine.

Have you tried sport+? I think one of the big differences besides is that the boost holding feature is more aggressive.

That is also my perception.

When running at constant speed with part throttle and then suddenly flooring the accelerator, there is a clear lag before full power is delivered. I tried it at different RPM (2000-6000RPM) in Sport+ and this lag is present at all engine speeds, there is no denying it.

That being said, during my ED, I was lucky enough to be able to drive a relatively long mountain pass with zero traffic very aggressively. Hard braking into a turn, down shift, turn-in, quick lifts to tighten the line, squeeze the throttle to track out, full throttle upshifts then brake again. Over and over again. With the engine is Sport+ and DSC off, I was astonished with the engine response . Never did I feel any lag in this driving context .

Can't wait to try this car at the track at the end of the month .