Turbo lag

ME120 · Feb 13, 2018

I have had my 2017 raptor for 2.5 weeks, and I love it !

One thing I have noticed is when driving in normal mode or comfort that when I take off from a dead stop there is noticeable turbo lag, just for like 100 yards at the most, but it is noticeable especially on a cold start. After the raptor has been running for 20-30 minutes it seems to be not at noticeable, sometimes not at all. I have not driven the raptor in sport mode or Baja mode, only normal and weather modes.

Just curious if it’s me or if anybody else feels it ?

StrangeRaptor · Feb 13, 2018

Depends on where you live. At high altitude, you should notice more turbo lag. I notice it, but I live at 6,300 feet.

ME120 · Feb 13, 2018

I live in maine at sea level.

smurfslayer · Feb 13, 2018

The Rap uses drive by wire so there’s no direct connection between your foot and throttle. Normal mode is something like 1 to .75 from your throttle input to what actually happens. You almost have to floor it to compel a downshift. This is why a lot of users have gone to either the pedal commander or a tune.

Sport mode is closer to a 1-1 relationship of throttle input to throttle actuation.

If you think the take off has lag, the normal mode hinders passing anything at part throttle.

Mcdonaho · Feb 13, 2018

By you a pedal commander and problem solved

Sent from my iPhone using Tapatalk

reaper1441 · Feb 13, 2018

Most people don't understand what turbo lag is. What you're feeling isn't turbo lag its a delay in the throttle plate opening which is programmed in while in the standard terrain mode. The pedal commander simply opens the throttle faster that is all. Similar to how the throttle curve is programmed in baja and sport mode.

Turbo lag is the time it takes to achieve full boost in a situation that allows the turbo to be at full boost. Most people who are not familiar with modern turbo cars call turbo lag anytime the turbo isn't in boost and their foot is to the floor but that is not correct. To simplify this what it means is flooring the truck from a dead stop isn't turbo lag. The turbo isn't in its efficiency range and cant make full boost off idle(in most vehicles). But at 5000rpm(or any rpm the turbo CAN make full boost) and lifting completely off of the throttle(causing the boost to hit zero) and then going back to full throttle turbo lag would be the time it takes to get back to full boost after the BOV vents the turbos (boost) back to zero. This is also known as transient response. It requires large amounts of fuel at initial "tip in". Which is the initial re-opening of the throttle plate rapidly and is an emmissions defying nightmare and usually produces an overly rich condition on purpose. This is why the throttle plate is often slowed down on production turbo vehicles and one of the reasons aftermarket tuners can make a vehicle seem to run so much than the 6 figure a year engineers who built the truck could. Also the shift points change in other modes.

the Too Long Didn't Read version is: that's not turbo lag that's accelerator pedal to throttle plate lag in the regular terrain mode and is how the truck is tuned. Try a different mode.

ME120 · Feb 14, 2018

reaper1441 said:
Most people don't understand what turbo lag is. What you're feeling isn't turbo lag its a delay in the throttle plate opening which is programmed in while in the standard terrain mode. The pedal commander simply opens the throttle faster that is all. Similar to how the throttle curve is programmed in baja and sport mode.

Turbo lag is the time it takes to achieve full boost in a situation that allows the turbo to be at full boost. Most people who are not familiar with modern turbo cars call turbo lag anytime the turbo isn't in boost and their foot is to the floor but that is not correct. To simplify this what it means is flooring the truck from a dead stop isn't turbo lag. The turbo isn't in its efficiency range and cant make full boost off idle(in most vehicles). But at 5000rpm(or any rpm the turbo CAN make full boost) and lifting completely off of the throttle(causing the boost to hit zero) and then going back to full throttle turbo lag would be the time it takes to get back to full boost after the BOV vents the turbos (boost) back to zero. This is also known as transient response. It requires large amounts of fuel at initial "tip in". Which is the initial re-opening of the throttle plate rapidly and is an emmissions defying nightmare and usually produces an overly rich condition on purpose. This is why the throttle plate is often slowed down on production turbo vehicles and one of the reasons aftermarket tuners can make a vehicle seem to run so much than the 6 figure a year engineers who built the truck could. Also the shift points change in other modes.

the Too Long Didn't Read version is: that's not turbo lag that's accelerator pedal to throttle plate lag in the regular terrain mode and is how the truck is tuned. Try a different mode.

Thank you for the explanation.

Very helpful.

BurnOut · Feb 14, 2018

There are possibly a couple of issues at work here... one of which is, as others have mentioned, accelerator position ≠ throttle position. There are a variety of ways to alter this relationship, whether it's a tune or something like a Pedal Commander.

Additionally, regarding turbo lag, note that there is a difference between turbo lag and the engine's boost threshold: https://www.youtube.com/watch?v=cKvOEZ7JCJc

Mitchy · Feb 14, 2018

I also experience a similar situation as to what you’ve explained. Or at least similar enough that i’ll Post here in case someone else is having a similar issue.

Pull out of the driveway on a cold morning. It’s difficult to build any boost. Then several seconds go by and it’s there.
I’ve always put it down to the electric wastegates stay open. Although I’ve been planning on logging their demand signal.

I can’t say it’s a throttle plate issue. Truck seems responsive enough. It just fails to build boost for the first 1-2 minutes of a drive during a cold start. Once the time is up you can feel the difference in boost/spool and hear the turbos spool.

Not much help as to the response. However I doubt the pedal commander will help my particular case. As typically the truck is responsive.

I’ll try to take a log in the next few weeks.

My other car is a relatively modified Porsche 997 Turbo. So I have some experience with turbos, lag and quirks (wastegate/vnt Actuator demand signals)

Cheers!

Digger · Feb 14, 2018

I have a 17 screw and had a 12 screw. The 12 had a CAI (no real noticeable hp gain) exhaust (same on hp gain) and 5 Star tunes and those were worth every penny and it definitely picked up about 35 hp. That being said my 12 V8 had more "turbo lag" when you jumped on it from a dead stop than my 17 does. My 17 has very good response and borderline instant throttle response in comparison to my 12. I understand what turbo lag because I had 2 Buick Grand Nationals that were both modified (turbos, exhaust, tranny's)and if you wanted to feel turbo lag those motors had severe turbo lag. I'm at sea level in Ma and have only run 93 in my 17 and I'm sure that definitely helps a little with the throttle response and this was all before I got my MPT tunes and the throttle response is just frightening now. It will roast the tires right into 3rd. I let my buddy who's thinking about buying a 17 or 18 Raptor drive mine on Saturday and he was shocked and he then spent all weekend driving to dealers in New England looking at Raptors. I've received a few texts from him since Sat still saying that he couldn't believe just fast my truck was. My wife doesn't like driving it anymore because it just jumps with the lightest touch of the peddle. Just my 2 cents

Turbo lag

ME120

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