MBlktahoe

Hi all - has anyone with the new 2013 diesel experienced turbo lag when starting from a stopped position? I've noticed a 1-2 second lag - just enough to make me concerned about pulling out into a busy street. After the lag there is excellent power. I haven't tried starting out in a lower gear, hoping it won't come to that. This is my first MB diesel, wondering if previous versions have had the same lag. Thanks.

cookstar

I am guessing you are experiencing this when flooring it while in motion, if this is the case the lag is most likely attributed to the vehicle taking time to downshift+ the slight turbo lag which makes it feel like you have to wait allot before it moves, I have not noticed anything yet since I am still in the break in period ( engine RPM does not go over 2200)

MBlktahoe

This seems 100% turbo lag. Watching the RPM's, you see the jump. Plus, wouldn't the car be in low gear due to slowing down and stopping? It's only a concern when you need to jump out into traffic quickly. Let me know what you experience once you get out of your break in period.

Otis123

I've had a couple bmw 5 series gas turbos and just got my gl350. on both cars you don't feel the power for a beat or two. I plan and adapt my driving around the torque /power curve of the engine the first 2 3 seconds pulling out will not feel fast, but then you get into the power band and the car really moves out - it you want it too. So I go lightish on the pedal when initiating acceleration then pour or roll on more power once the rpms are up a little more and the turbos are engaged. I have a fairly heavy foot / I'm a fairly aggressive driver and I am 100% please with the power and acceleration. I think you just need to get used to how to tap the power which is all about knowing where the power band in terms of RPM. Once you know where it is and how to use it - I think you will be pleased. If you are really into popping off the line - I'm not sure how to help you. Good luck

cookstar

The "7G Tronic +" or any other modern transmission made recently will ALWAYS seek the highest gear possible in order to get the highest mpg, in speeds of 50km/h (30 mph/h) I noticed on both my 08 and 13 that it is on the 7th gear, it can shift down multiple gears but there is always some lag even with with the improved 7G tronic, you get the slight turbo lag and the downshift lag which makes it worse.

even when slowing down unless you come to a stop it wont shift into first, in winter I read somewhere that it shifts from second instead of first, the ultimate goal is fuel economy and the goal is mpg first and performance second, this applies to the biturbo v8s.

Otis123

Btw cookstar - I thought for break in you were supposed to keep the rpms below 2/3 of redline. Given redline on the GL350 is 4000 that should be slightly over 2600. Am I wrong? I'm going off page 128 in the manual.

cookstar

I think its supposed to mean that you should not get it past 2600 rpm ( assuming 4000 rpm red line), so that would mean anything up to 2600 is ok. Most I pushed was 2500.

43221B

I own a 09 Bluetec. It does the same thing. I like everything else about the diesel except for the turbo lag from a dead stop. What you need to do is anticipate when you need to accelerate hard. Gently press the accelerator for 1.5-2.5 seconds, it doesn't take much pressure, while letting your vehicle roll forward (without the brake applied) and then press the pedal harder to accelerate. This will allow the turbo to build compression for when it's needed. You don't want to floor the pedal from a dead stop. The engine will over rev and be above its peak power range. It takes some getting used to.

MBlktahoe

I live in Lake Tahoe off of a 2 lane highway where cars travel 55-65+ mph. Pulling out of my driveway onto the highway is when I noticed the lag. My 06 ML350 (gas) and 08 Dodge Cummins 3500 don't have this issue, been used to driving them, and noticed the difference with the new GL350. Once past the lag the power band is excellent, I just need to get to highway speed quickly (or be more patient).

I've read that the older porsche turbo's had this problem (turbo lag and low torque at low RPMs) and it was solved with some type of variable speed turbo technology. Not sure what type of turbo is on the Bluetec engine.

MBlktahoe

I will give this a try. Is there any way to monitor the turbo compression on this engine?

Steve Maislin

The GL450 is no different. I posted on this a few weeks ago. If you don't come to a full stop and I mean full stop, it does not downshift and when you push down on the accelerator it thinks for quite a bit before it kicks in. It is the single thing on the GL that I find to be disappointing. When I bring it to the dealer (when I get some time) I will be asking about this issue as well as how park assist rarely points out parking spots. Now, I can live without the parking assist, but the couple of seconds of delay when accelerating after coming to a rolling or ALMOST stop is kind of dangerous. I mean you can floor it and it waits way to long to react. Yes, I know it is a big SUV, but this behavior seems to be correctable.

blittle

Without getting too much into areas that I know only a very little about......I do know that the throttle on our vehicles ( and many other new vehicles today ) is electronic. That being the case, if there is an issue here, some of it could involve the programming in that area and that is indeed changeable. Not sure , however, that MB is going to see it as such because any change in program will most likely effect fuel consumption. So far for me...... if its there, I have not noticed it.