Turbo Lag?

[ExpeditionAndy]

Back in 1994 I bought a 1987 Mercedes 300 SDL Turbo Diesel. That had turbo lag. From a dead stop you had to floor it to get the RPMs up over 2000. Once you passed the 2000 RPM mark it took off like a rocket, the problem was it took about 5 seconds to get to 2000 RPM. It was a fun car to drive.

 

[jeff kushner]

Come on guys, I resisted the urge to write in this thread and the OP was probably better off for it....he's now educated and I didn't need to repeat anything<LOL>....

Andy is correct about the turbo's in our trucks are always "on". Ford used very small exh manifold passages to increase and maintain high enough exhaust velocities to keep the twin turbos spinning and producing positive pressure(boost) even at near-idle speeds, quite an accomplishment in the turbo world.

Your '16 should not be experiencing any turbo lag and I would suggest disconnecting the battery for an hour and let it default to it's "as new" ECM program then driving it normally.

Also, are you experiencing this when you floor it from a stop or when you gently step on the gas while already on the highway?

jeff

 

[Idaho Beachbum]

Thanks to everyone who has posted a reply.. I am... getting educated and understanding this more .

I usually experience this when coming from a dead stop or when I am making a right turn at a four way with a green light. I slow down and when I come around the corner I push it and sometimes I can get that I just left my gut behind me a few feet feeling. I have never felt this going down the freeway/highway and going to pass someone or getting up to speed on the on ramp...

 

[powerboatr]

Thanks to everyone who has posted a reply.. I am... getting educated and understanding this more .

I usually experience this when coming from a dead stop or when I am making a right turn at a four way with a green light. I slow down and when I come around the corner I push it and sometimes I can get that I just left my gut behind me a few feet feeling. I have never felt this going down the freeway/highway and going to pass someone or getting up to speed on the on ramp...

the round the corner off the throttle then back on, i bet is two things
the transmission is uncoupled as in coast and it has to find a gear and the engine rpm are low.
rolling stops are hard on the ecm. it thinks your coasting and of course stopping so it is relaxing and not ready to GO, sometimes the trans will not be in 1st, and it has to reshift.
this was brief, arms are tired

 

[bobmbx]

The air conditioner can play a role here also. Engaging the compressor right when you need the throttle can feel like lag, but is really a siphoning of horsepower at lower rpms.

 

[TravisDBQ]

I was just wondering this the other day with my Expedition. Great explanations!

 

[jeff kushner]

Those two responses by Powerboatr & Bobmbx are on the money....a power-off, coast, power-on condition involves several systems including the fueling, turbo blowoff valve, turbo boost controller, transmission, torque converter, braking systems, ignition systems, etc and some of those while being "electronic" are still just controlling manual valves with electricity. It still takes some period of time for each of these systems to perform it's job, then communicate this to the central controller to expedite the next requirement...so yes, in that type of situation, you can adjust by coming back on the gas a bit slower and more relaxed or anticipate the slight delay and slam into it earlier....not recommended<LOL>. You may also find that the off throttle to on-throttle transitions are just bit more twitchy in a "boosted engine" when it's on boost which your is from just over idle.

So all this probably paints a clearer picture of why it's doing what it's doing. A smoother foot with reward you with smoother operation.

jeff

 

[J Ski]

@jeff kushner should jump in here, but I'll try. The turbo is always on and it is always producing boost. (here is the part where I may be shaky) when the engine doesn't need boost it opens the waste gate and lowers the pressure by dumping the excess air. I have noticed, going around a corner from stopped and stepping on it hard, some lag from what I think should happen and what does happen. When I do the same thing but press the gas just a little slower, I have tons of acceleration, Jeff has a better way of explaining it but that is what I understand. That is the only time I notice any lag.

I have read that certain tuners can fine tune the gas pedal response which will make it more reactive.

Do you know how much boost our 2016 ecoboost engines produce by chance?

 

[jeff kushner]

No J, I have not checked. I've read things like 19PSI & 26PSI but I honestly don't know. Considering that most mass-produced Turbo'ed engines produce in the 8-12PSI range, the "26PSI" just sounds bit high to me but it could be right....I do not know.

jeff

 

[powerboatr]

i can tell you a had zero lag this morning, i rolled through a stop sign and wet road from water spray and got on the go stick pretty abruptly.
lost traction, promptly began a rear drift out to the right and turned to stop the swerve, traction light flicked and i let off gas.
then hit it again and took off. it was fun... had to digress to to a teenager for a second on a slightly slick patch