Locking out gears

[wrgrimes]

Audi Q7 4 cylinder? We’ve had 3 Q7’s- didn’t know they made a 4 cylinder.

2017 Q7 2.0T- nice car, but sluggish (OK in sport mode)
In 2020, I tried the 3.0T but moved to the RWD X5 (loved) which I traded for the truck- go figure ?

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[LD50]

I believe there are a couple of benefits from locking out gears when towing. My previous truck was a '19 Raptor and I did quite a bit of towing with it. I was either a pulling a wake boat that was probably a little over the tow rating for that truck or pulling a camper that was well under the rating but pulled even harder due to the wind drag. I always thought I got slightly better mileage but it was hard to tell and I never looked that closely. The other thing I started to notice was that it seemed to run noticeably cooler when spinning the engine instead of relying on boost. It was mostly anecdotal because the truck seemed happier with 8,9, and 10 locked out, so I just ran it that way. The Raptor has a pretty robust info screen that shows a lot of these numbers, which was what got me noticing the possible difference.

I was towing with my powerboost today and thought about this thread so I figured I would do a little experimenting to see if my previous observations had any merit or if it was only wishful thinking. I currently use an OBDlink and the associated app which shows many of the same metrics that were native to the dash screen on the Raptor.

Today I was pulling a UTV on a utility trailer for about 120 miles. Roughly half of that trip is on a stretch of flat interstate, all headed in the same direction. The biggest hills are overpasses crossing other roadways. The trailer and UTV weigh about 3500 pounds and probably have a moderate or lower wind drag. Since the entire stretch is all in the same direction and the light wind was constant, it shouldn't be a factor in what I observed.

i decided to reset the trip meter and observe different readings over two stretches of 15 miles with the cruise set on 65. On the first one, I let the truck run in 10th gear. I had to move from tow mode to normal mode because tow mode held the truck in 8th. During this test, I observed the boost to remain constant between about 3 and 8 pounds. On the second 15 mile stretch, I left the truck in normal mode and locked out gears 9 and 10. No boost significant enough to read on the dash gauge except when going up an overpass and then it would only get to about 2 psi. After doing both runs, I switched the truck back to tow mode where it remained in 8th gear. I only had about 10 miles on this run because the road changed directions 90 degrees and the wind would have skewed the results. Over those 10 miles, I got pretty much identical results as in 8th gear in normal mode, as expected. I just wanted to confirm.

Here is what I saw from the metrics I was monitoring.

10th gear (1,600 rpm)
Mileage - 12.7
Engine temp - 204-209
Cylinder head temp - 230-235
EGT - 1500-1550

8th gear (2,200 rpm)
Mileage 14.3
Engine temp - 194-198
Cylinder head temp - 216-221
EGT - 1300-1350

Not exactly scientific but it matches my previous observations.

 

[Pelican]

I lock out 9,10 every day on my commute. (46 mile round trip)

I do it to keep the truck from cruising at low RPM. (pretending what gear I would be in if it was a manual transmission and it was ME shifting)

In Normal mode the factory shift strategy will literally attempt to cruise at an RPM as low as 1200? Like riding a 10-speed bicycle at low speed but a tall gear.

There's a long stretch on my commute where the cruising speed is 55-60. I will unlock 9th if traffic is light. But not letting the truck have it's 3rd overdrive at that pace.

I monitor a lot of what is going on in the combustion chamber. If you have a digital Boost gauge and you change the range from 0-20psi to -5<>20 psi, you now have a vacuum gauge.

So when in cruise control, you can experiment with which gear is getting you the best fuel economy and least strain, so to speak. A vacuum gauge is an old school Normally Aspirated tool for things like that.

Notice below that at only 50mph, I have to lock out 10th. It's crazy. It's already cruising at only 1300 rpms, but it WILL try to use 10th in Normal mode.
And 8th gear IS already Overdrive.

Yesterday's trip from South Houston back to rural home. Summer temps, of course

How did you get the temps to show up in your guage cluster, specifically the transmission?

 

[Snakebitten]

How did you get the temps to show up in your guage cluster, specifically the transmission?

That's a Forscan edit if you have the higher trim IPC.

The Forscan gurus still haven't cracked the same on the XLT instrument cluster. Which is very disappointing. Why Ford would not include the possibility is strange considering they dropped the digital transmission temperature display from the Gen13.

 

[Atlee]

That's a Forscan edit if you have the higher trim IPC.

The Forscan gurus still haven't cracked the same on the XLT instrument cluster. Which is very disappointing. Why Ford would not include the possibility is strange considering they dropped the digital transmission temperature display from the Gen13.

Can it be found on the OBDII + device?

 

[konoplya]

this thread has been a great read. didn't know anything about locking out gears to conserve mpg. will be trying it out this week for sure.

 

[Pelican]

That's a Forscan edit if you have the higher trim IPC.

The Forscan gurus still haven't cracked the same on the XLT instrument cluster. Which is very disappointing. Why Ford would not include the possibility is strange considering they dropped the digital transmission temperature display from the Gen13.

Thank you for the reply Snakebitten. I have a Lariat with the 501A package. Is it considered a higher trim? Thank you again

 

[Snakebitten]

I think Lariat is "all glass", isn't it?
(no physical gauges visible when truck is off)

If so, you can indeed turn the digital temps on permanently. Ford only turns them on when the temps reach an UHOH value.

 

[dogboye]

Ahhhhh
Now I understand what is messing with your head.

Similar to yesterdecade engine management being analog, thus the throttle was a direct request for more fuel, the yesterdecade Turbo was being spooled up by exhaust and boost was determined by RPM increasing that velocity of exhaust.
.....

Sorry if I'm going in circles. Lol

Those turbos aren't being spooled (relatively) unless the pcm calls on them to participate. If they aren't being called on, the exhaust isn't being used to compress/spool. And they are so small and efficient that if/when the pcm decides to include them in the torque request recipe, they spool QUICK!

I think going in circles is what I needed.

Boost is really a function of 'struggle' as indicated by manifold pressure (or lackthereof). You can have an engine rev'n at 5k RPM still drawing vacuum. ...

...

... At sea level it'd be ~14.7 PSI, which is the pressure of the atmosphere. Thus to maintain engine performance at altitude, you're not concerned with pressure v. ambient, you want absolute pressure so the turbos can produce their typical pressure plus the additional pressure required to make up for the higher altitude has less total pressure.

Thank you both for going into these more detailed explanations, and for your patience with my density. I understand much better now. Well, better.

Here is what I saw from the metrics I was monitoring.

10th gear (1,600 rpm)
Mileage - 12.7
Engine temp - 204-209
Cylinder head temp - 230-235
EGT - 1500-1550

8th gear (2,200 rpm)
Mileage 14.3
Engine temp - 194-198
Cylinder head temp - 216-221
EGT - 1300-1350

Not exactly scientific but it matches my previous observations.

This data alone seems to strongly support locking out gears, particularly for towing. Those lower temps are significant. Well, mileage, too. But the lower temps seem to be a good result.

 

[Ziggy73]

I did not realize the + / - button can lock out gears, thanks to the responders and thread starter!

98% about keeping down boost, but I don't like towing in 9 or 10th, can't think that's good for the tranny's overdrive gears. But it only runs around 2-2300k RPMs even with those locked out. I'll go as low as 7th depending on the hill or wind.

 

[Pelican]

I think Lariat is "all glass", isn't it?
(no physical gauges visible when truck is off)

If so, you can indeed turn the digital temps on permanently. Ford only turns them on when the temps reach an UHOH value.

I dont know if they're glass, but they are digital and when the truck is off, you cannot see anything. I'll do a little digging into how to turn them on. Thank you again.

 

[mxwrk]

Anyone in SoCal with forscan to help me add the temp reading on my Lariat? I don't even have a windows based PC

 

[Snakebitten]

"glass" might be an Aviation term. Sorry. I've worked for an Aviation company for 25 years. It rubs off. ?

Yes, I meant all digital.

Forscan edit to enable digital temps:

 

[pjc123]

Does locking out the gears also apply to a stock 2.7 Ecoboost (2024). I am picking up a new empty aluminum enclosed trailer this weekend 1000 miles back home (1700 lbs curb weight) on some Northern East Coast hilly terrain. Eventually it will be loaded with no more than 2000 lbs and hopefully heading out West on vacation. Do people even do it without a trailer crossing high mountain ranges?

 

[{tpc}]

Does locking out the gears also apply to a stock 2.7 Ecoboost (2024). I am picking up a new empty aluminum enclosed trailer this weekend 1000 miles back home (1700 lbs curb weight) on some Northern East Coast hilly terrain. Eventually it will be loaded with no more than 2000 lbs and hopefully heading out West on vacation. Do people even do it without a trailer crossing high mountain ranges?

Can't speak for mountain ranges, but yes when towing. I mean you can try it, and see how much fuel it drinks while towing without locking out the upper gears, then try again with them locked out.

I can't imagine even with the 2.7 that your going to be running high rpms in 7th gear while towing. But its an easy visual thing to monitor because you will see as you get to the higher gears even with the rpm dropping you will be producing boost.

I think my 3.5 runs at around 2k rpm in 7th, towing at 68 mph, showing no boost (or at least not enough to trigger the gauge).

The only issue with tow/haul vs normal modes is if you get into slow stop and go style traffic, it might start engine braking when hit the brakes. At that point I'll occasionally switch back to normal mode to reduce that.

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