Turbo Lag and Reviewers...

[TahoeM3]

Originally Posted by Accel Junky

Driving this morning...yep the lag is still there. Punch it at 2k, 3k, 4k, 5k, 6k...yep the turbos still have to spool. Upshifting at redline? Of course there is no lag. Even my NSX with big old-school turbo tech, a BOV instead of recirc, and twice-longer charge piping has instant response on full throttle rev limit upshifts. Same displacement.

Again, if the turbos aren't spooled, there is no design in the world that will have zero lag. If you were expecting that, that's unrealistic. If you keep the pumps primed, so to speak, then there is no lag. You don't have to keep the throttle pegged, but if it is really that noticeable to you, you just have to modulate the throttle in such away as to keep the turbos moving.

[Accel Junky]

Originally Posted by TahoeM3

Again, if the turbos aren't spooled, there is no design in the world that will have zero lag. If you were expecting that, that's unrealistic. If you keep the pumps primed, so to speak, then there is no lag. You don't have to keep the throttle pegged, but if it is really that noticeable to you, you just have to modulate the throttle in such away as to keep the turbos moving.

My original post indicates I was not expecting instant response. I was pointing out that reviewers are being a bit disingenuous about the lag. I can't remember owning a turbocharged vehicle with lag on full throttle rev limit upshifts so surely they aren't getting all gee-whizzed about that...

[Algol]

Originally Posted by Accel Junky

My original post indicates I was not expecting instant response. I was pointing out that reviewers are being a bit disingenuous about the lag. I can't remember owning a turbocharged vehicle with lag on full throttle rev limit upshifts so surely they aren't getting all gee-whizzed about that...

I mean there is always going to be some lag in any turbocharged car. I would hardly call the reviews disingenuous about it. Its a night and day difference between N54 and N55 cars which were already extremely good. I was shocked myself how quickly the car revved too when I first picked it up, something I totally didnt expect.

[Dalko43]

Originally Posted by Tonymiabmw

You don't have to spool the turbo if your in the proper gear it's already spooled.

I was referring to when you are accelerating the car from a stop or from a slow roll; there is noticeable turbo lag.

And yes, even driving at a higher gear at higher speeds, you still feel the turbo lag when downshifting to a lower gear and accelerating. The intake air has to circulate through the turbo's, intercooler and into the engine intakes....this whole process is being driven by the exhaust gases spinning the turbo. The throttle response is extremely good for a turbo, but there is still is lag.

Why you are trying to deny that? The car is amazing as is. Modern turbo engines have unique characteristics just like NA engines. Turbo lag is one of those characteristics (though it's not nearly as noticeable as it was on older cars).

[TahoeM3]

I also don't think the reviewers were being disingenuous able the lag...there's no plot afoot to hide the lag in order to trick people into buying this car. Short of an electric turbo, this is about as close to zero lag as you can get from a 3 liter turbo car. There is also some with the GT-R and with the N63/S63. It's not realistic to expect zero lag under any circumstance.

[jewels]

Originally Posted by TahoeM3

Obviously turbos need to be spooled up before they can provide boost, so throttle modulation is key. If you are going at a steady state or stopped and then press the accelerator, there will be a delay...however brief...before the boost kicks in. In this car it is minimal and comparable to the GT-R. If you want to feel turbo lag, drive a 1977 930 turbo...or even a 997 turbo.

If you drive aggressively, keeping the turbos spooled, there will be no lag. That's why the the reviewers haven't had any lag...they are driving the cars harder than most of us do on the street.

For me, I'd take the minimal lag over a NA engine with no torque. The reference to the Ferrari is inaccurate because that car weighs much less than an e92. You really feel the lack of torque when you're trying to move around 3700-4100 lbs.

I am done eating popcorn..

First Turbo car Saab 900..LOTS of lag, many since that one, ALL turbo's,
Audi S4 had some lag but not a lot of punch, 993TT NO LAG to speak of, GTR NO LAG period. what was similar about the previous 2 is that they had smaller turbo's that took less time to spool and only needed to work 3 cylinders each...M4 very little Turbo lag ..but in my opinion it is extremely reasonable considering what the turbo's are doing and the profile of engineering for this engine. It is not that people "don't know how to drive"
it more like they are trying to compare it to a naturally aspirated or supercharged engine...not the same animal.
If I were to date myself I would elaborate on how long it used to take the second 4 barrel to come in on a dual quad set up with vacuum secondary's... but I degress

[Mik3ymomo]

Could have possibly lessened the lag with a complicated sequential twin turbo system but the power would have been lower and had even less of a linear power delivery when the turbos transitioned.

Honestly back in the 90's even seeing full boost by 2-3k rpm was acceptable in most performance cars.

This car makes a lot of torque under 2k rpm. It's a huge improvement in boost/power delivery.
If you want to see Lag have a look at those big HP Supra dyno sheets online. Compare the power this car makes and how early it's making it in the RPM range.

Nothing to complain about from anyone who has driven high power turbo cars.

Of course there is detectable lag. Anyone who knows how turbochargers work know they are driven off the engines exhaust and if you want the car to make good broad power it won't spool immediately.

BMW did a nice job on turbo sizing to balance out spool characteristics and outright power through the entire RPM range.

Welcome to turbocharging OP.

[ES_TRADER]

Originally Posted by Accel Junky

Driving this morning...yep the lag is still there. Punch it at 2k, 3k, 4k, 5k, 6k...yep the turbos still have to spool. Upshifting at redline? Of course there is no lag. Even my NSX with big old-school turbo tech, a BOV instead of recirc, and twice-longer charge piping has instant response on full throttle rev limit upshifts. Same displacement.

so if u punch the throttle like that, what is the lag? like are you counting "one, two, three, four..." and then BOOOOOM!

i dont drive my car that way so i guess ill never feel the lag...i like to give it gradual throttle, even when driving competitively on the streets...i feel bad for the car punching it out of no where all of a sudden.

[CanAutM3]

Originally Posted by Mik3ymomo

Could have possibly lessened the lag with a complicated sequential twin turbo system but the power would have been lower and had even less of a linear power delivery when the turbos transitioned.

Honestly back in the 90's even seeing full boost by 2-3k rpm was acceptable in most performance cars.

This car makes a lot of torque under 2k rpm. It's a huge improvement in boost/power delivery.
If you want to see Lag have a look at those big HP Supra dyno sheets online. Compare the power this car makes and how early it's making it in the RPM range.

Nothing to complain about from anyone who has driven high power turbo cars.

Of course there is detectable lag. Anyone who knows how turbochargers work know they are driven off the engines exhaust and if you want the car to make good broad power it won't spool immediately.

BMW did a nice job on turbo sizing to balance out spool characteristics and outright power through the entire RPM range.

Welcome to turbocharging OP.

I think you might be confusing boost threshold and turbo lag here

[AMPowerJ]

I get what the OP is saying ... there is some sort of 'lag' whether it be turbo lag, etc. I just expect a 1/2 second delay when I punch it say in 6th gear driving on the Interstate. Then I'm like holy #$^# and slamming on the brakes to keep from hitting the guy in front of me at 100+ mph. No complaints.

[Mik3ymomo]

Originally Posted by CanAutM3

I think you might be confusing boost threshold and turbo lag here

I am making an assumption that the OP is complaining about what is commonly referred to as Lag.

It's what most people complain about on turbocharged vehicles.

I can't even imagine someone complaining about a reaction from throttle response already at speed/RPM.

It's even less waiting.

[///M///]

The OP was merely pointing out that the car does have lag. And it isn't to say that he is surprised by it. He pointed it out because the hype surrounding this car has been that it has "NO Lag". I think the point is simple enough to understand. Not sure where the confusion is

[Accel Junky]

Originally Posted by Mik3ymomo

Could have possibly lessened the lag with a complicated sequential twin turbo system but the power would have been lower and had even less of a linear power delivery when the turbos transitioned.

Honestly back in the 90's even seeing full boost by 2-3k rpm was acceptable in most performance cars.

This car makes a lot of torque under 2k rpm. It's a huge improvement in boost/power delivery.
If you want to see Lag have a look at those big HP Supra dyno sheets online. Compare the power this car makes and how early it's making it in the RPM range.

Nothing to complain about from anyone who has driven high power turbo cars.

Of course there is detectable lag. Anyone who knows how turbochargers work know they are driven off the engines exhaust and if you want the car to make good broad power it won't spool immediately.

BMW did a nice job on turbo sizing to balance out spool characteristics and outright power through the entire RPM range.

Welcome to turbocharging OP.

Been there, done that. Including the single turbo Supras.

[solstice]

I'm not sure I would say that "No lag" is a hype. The engine is responsive enough that I'll give anyone who can't feel lag a pass especially people who just drive the car normally and aren't looking for lag. And again, since it's not an issue in power modulation it's more a scientific discussion than a driving one

[onatuesday]

OP is simply pointing out that there is lag. He's not saying he didn't expect it. He's not saying it's a bad thing. He's not even saying it's a big deal. And he's certainly not saying he doesn't like the F8X (heck he has two and has been very helpful in providing tips for other community members such as the exhaust mod video).

OP your opinion right or wrong is not only valid but it's highly encouraged. And for what's it worth I agree with your original post.

[khanyam4]

There's turbo lag on the new m4 or m3 and it's fine automobile.

[imserious]

Originally Posted by khanyam4

There's turbo lag on the new m4 or m3 and it's fine automobile.

The op's point exactly.

Regardless of your position on turbo vs NA, you have to admit that turbo cars have come along way since the 90s.

It's amazing to see the hp numbers coming out of 4 and 6 cylinder engines. Add to that the torque at low RPMs. Add to that the relative minimal lag. These are really amazing engines. The only problem is that amazing engines are more common now and people are taking them for granted.

In the 90s you wanted the turbo version lag or not because that was the only way to make big power.

[Tonymiabmw]

Maybe you feel more lag with the manual? Gear ratios different. I feel next to 0 with DCT

[Kurt_OH]

Originally Posted by Tonymiabmw

Maybe you feel more lag with the manual? Gear ratios different. I feel next to 0 with DCT

Lag is ALL about RPM, the amount the throttle was open before and after you applied the additional throttle, and velocity of throttle application. If you're just off idle and stomp or briskly roll on the gas, it's gonna be a second before it gets exciting. If you're at 4k RPM at half throttle and slam it full open, it's just gonna jump forward.

[Tonymiabmw]

Originally Posted by Kurt_OH

Lag is ALL about RPM, the amount the throttle was open before and after you applied the additional throttle, and velocity of throttle application. If you're just off idle and stomp or briskly roll on the gas, it's gonna be a second before it gets exciting. If you're at 4k RPM at half throttle and slam it full open, it's just gonna jump forward.

And what determines RPM on shifts....................Transmission

[TahoeM3]

Originally Posted by Kurt_OH

Lag is ALL about RPM, the amount the throttle was open before and after you applied the additional throttle, and velocity of throttle application. If you're just off idle and stomp or briskly roll on the gas, it's gonna be a second before it gets exciting. If you're at 4k RPM at half throttle and slam it full open, it's just gonna jump forward.

Lag has nothing to do with RPM. You can have lag at 2000 rpm or 7000 rpm if you are driving at a steady state and the turbos aren't spooled.

[PackPride85]

Originally Posted by TahoeM3

Lag has nothing to do with RPM. You can have lag at 2000 rpm or 7000 rpm if you are driving at a steady state and the turbos aren't spooled.

Correct. I believe it's a factor of engine load.