7MT owners, do you use 5 or 6?

[Neverowneda4x4]

I went on a road trip and I am finding that once I hit top speed (I drive the speed limit except for passing situations), shifting into 5 causes the turbo to run constantly. Staying in 4 keeps it at 0.0, and the rpms at around 3.1-3.7. Is one condition better for the engine and gas mileage than the other?

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[Brian_B]

5 - yup, on highway. Runs great on flat runs down in the valley. Enough power to pass easily without needing to downshift.

6 - nope. It’ll do it on flat highway, but where 5 will only occasionally flicker on boost 6 sits at a steady 2-4 psi and ends up being worse mileage (and suckier passing without downshifting)

Driving locally (mountains) - mostly 3 and 4, not a lot of opportunity for 5. A few spots I could sit in 5, but it sits at 10-15psi boost

I had asked a similar question here a few weeks back, and the consensus was running at higher RPM was better than higher boost. But on flat land, 5 will run with no boost if it’s steady speed, all the way up to 70-75mph

 

[Boreal]

From the prairies where the nearest hill is 3+ hours away. Running 33’s and 4.7 gears.

4, passing or lugging the camper up a hill.

5, when it’s windy. From a cold start. Or around 90-105km/h. Max gear for Hauling the camper at speed

6, no towing, flat, 105km/h+ speeds only. Always downshift to pass or climb a hill - to avoid LSPI, Det/Ping/Knock and high Cyl pressures.

As @Brian_B said, we recently did a dive into rpm vs boost theories a week or two back… shouldn’t be too tough to find

 

[Dusty]

I use it more now, since I re-geared to 5.13 gears (with 37's LOL)

 

[RagnarKon]

Yup.

5th is my most-used gear on the interstate. 6th gear also gets used fairly often, but usually only on flat & expansive stretches of road. Think I-70 or I-40 across Texas/Kansas/etc. And I'll often have to downshift to 5th gear to make passes.

The fuel economy question is complicated because there is a lot of "it depends". BUT, we can cheat and make a pretty good guess by watching the turbo. Whenever the engine spins up the turbo we can also assume more fuel is being added, thereby decreasing fuel economy. I'll admit on long road trips I often make a little game out of keeping that turbo pressure gauge down. 22.7 MPG was my "high score" so far. Far cry from the 44.8 MPG I hit on my Focus, but not too bad all things considered.

I think the "perfect" factory gear ratio for the manual would have been 4.88. But honestly 4.70 on the Badlands non-Sas isn't horrible. If I ever go to 35s/37s I'll probably copy @Dusty and go 5.13.

 

[Brian_B]

Gearing and tires do make a big difference here. I’m running 4.46 on 35s. It’s my daily right now, in a few years when it gets retired to just being the toy then I may go and throw 5.13 or 5.38 in it; then I bet 6th comes in handy.

 

[burgerking]

I'll have to hit the same hill a few times in different gears with the cruise control set while watching the line on the fuel economy screen.

 

[AZ_Liberty]

6th only on the interstate if going on a slight decline.

At freeway speeds, 6 pulls more boost than 5 in order to maintain speed, so 5th is better for MPG.

IMO, FoMoCo picked dumb ratios for the real world. I'm sure it looks good on a EPA spreadsheet.

I have a Base with the garbage stock minivan tires. I'm sure it would be even worse with decent rubber.

 

[Jawaburger]

5 yes on the highway. 6 maybe if I'm doing over 75.

 

[Lujess]

I admit coming from a smaller, lighter manual (11+ years of multiple Golf Rs) when I first got the Bronco (1/31/2024) I was using 6th the way I did in my old car, meaning pretty much anytime > 70 Mph.

That earlier thread made me rethink/watch performance/gauges more closely...now it's mainly 5th in most highway situations.

 

[615_Bronco]

6th on the interstate around 70-75mph. Sas BL tho so I’m not sure if that makes a difference.

 

[Brian_B]

Yeah the big problem with 6th, at least at the higher gearing ratios:

You sit in what would normally be ideal in the RPM range for fuel economy - high 1ks to mid 2ks - that's just about perfect for cruising. But at that gearing at at those RPMs, you are up around 60+MPH, and the Bronco is shaped like a brick. The wind resistance is considerable, and the 2.3 just doesn't have a ton of low end torque to push against the wind resistance at those lower RPMs. So it has to dip into the boost. And boost crushes the mileage.

I agree with @AZ_Liberty - 6th looks great on paper for the EPA. It might work out ok on stock tires for those with 4.7+ / SAS / Badland builds, and maybe I'll love it if/when I go over 5.xx ratio.

 

[indio22]

4.46 diffs and 315/70R17 (35"ish) tires here in flat low altitude Illinois. Around town mostly 1-4 gears. On the highway 5th works well, and 6th at times when not needing to accelerate. But as others have suggested, I think 4.88 to 5.13 diffs would be a better match for the overdrive gears.

The wide range between 1st and 6th gear makes it a bit difficult to get the perfect diff gear for each. I felt 1st gear was too short with the stock 30" tires, I like 1st better with the 35s. On the other hand, the 35's make 6th gear less usable.

 

[GToddC5]

I don't do much highway driving, so I top out in 4th most of the time from 35->50 mph.

So, only above 50 will I use 5th, and up to ~70.

Every time I've tried 6th, it's a joke.

 

[Tricky Mike]

With 33s and 4.70, 6th was usable sometimes. With 35s I stopped using it altogether. With 37s I stopped using 5th very much.

At some point I'll be regearing to 5.29 or 5.38 and I'll get 6th back for 35s but I expect it will still be unusable for 37s.

Boost is the enemy of MPG, let that baby sing.

Ford dropped the ball not gearing the 4 cyls, particularly the manuals, lower than the 6 cyl.

5 yes on the highway. 6 maybe if I'm doing over 75.

I find the wind resistance over 75 negates the RPM increase and I still have to use 5th. I'm sure it works better with less lift.

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