[JonW]

The trip to CF2 was the first road trip of any length that I've taken in my Challenger. My question is what RPM is the lowest to cruise at in 6th gear? It seems like 75 mph is almost lugging it in 6th, at around 1800 RPMs. How low can I cruise at without lugging the engine?

 

[lonestarsrt8]

I drive mine in 6th @ 70 all the time. It's running around 1500 RPM and seems fine. Doesn't lug it down, but to pass others in a hurry I do have to go back to 5th.
If I do the same speed in 5th, the mileage goes down about 3 MPG and RPM's are up around 22-2300 or so.
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2010 H. Orange SRT8/6spd/Mopar CAI/Moroso catch can/BT nose badge

 

[stevenk2]

I run mine at 60-70 mph on the highway all of the time in 6th - helps keep that fuel economy up (which is no small thing nowadays with *#%@!!! gas at flippin' $4+ a gallon - unbelievable.....but that's another very sore subject).

 

[John Matthews]

I think lugging close to the 1100-1200 RPM, enjoy the milage, quite and then down shift for a quick pass. Remember the skip shift drops you into 4rth at about 1100 RPM.

 

[fyrdude]

I like to cruise at 65 at 1650 rpm in 6th gear. Anything lower than 60 feels like its lugging. Cruise control and open road is your best friend when in 6th gear. No hill climbing going on in 6th either for sure.

 

[plumKrazy]

ive gotten her into 6th @ 30 something.. trying to see how fast i can go without touching the gas.... but normally im @ 50 on the way to work in 6th on all the down hills and 5th other wize

 

[camarochevy1970]

anything above 40 I am generally in 6th, however I sometimes have to downshift if trying to pull a hill

 

[aarcuda]

anything above 40 I am generally in 6th, however I sometimes have to downshift if trying to pull a hill

me too. I can cruise on flat land at 40 in 6th at 1000 rpms. if I need to speed up or if i hit a hill, i need to down shift

 

[Jay6spdRT]

Car will be fine, Jon. I drive mine all the time in sixth gear on the two lanes, 50 mph and faster. The six speeds are only turning 1500 rpm at 65 mph - the engine will last forever I think. I'm up to 12,600 miles on my girl now, after a 1500 mile plus long weekend.

When I run my Trinity in gauge mode, and gauge oil pressure, the pressure is excellent even at 50 mph in 6th. Whenever my speed drops below 50 mph, I shift to 5th, mainly because the throttle response is so bad below that speed in 6th, because RPMs are getting close to high idle range.

 

[Hal H]

I would use 1,500 rpm as the cut-off point for the upper gears, Jon.

Otherwise you have to give so much % of throttle that the engine would go into enriched operation due to the load the MAP sensor + throttle position sensor signals would be at that point.

 

[JonW]

Thanks, Hal. What you mentioned was a concern to me as well.

 

[John Matthews]

That is an interesting observation.

 

[Root66]

I wouldn't use any minimum RPM as a general rule, a motor might be lugging at 1500 on a 6% grade while not be lugging at 1100 on a flat with a tailwind.

 

[Hal H]

I wouldn't use any minimum RPM as a general rule, a motor might be lugging at 1500 on a 6% grade while not be lugging at 1100 on a flat with a tailwind.

I believe Jon was probably referring to a steady-state cruise on a (relatively) flat stretch of road.

If you're on a grade, you're not going to be able to do it under 2,000 rpm- the engine isn't producing enough torque for that to be possible...

I would venture a guess that most drivers would catch on that it would be necessary to downshift and maintain the rpm in the range where it would do the best work.

 

[SRTREX]

I love how this car can run around 1600rpm and move along at 70mph. The mpg are excellent. Just remember that it's OK to be shifting down as soon as you need to speed up or pass. This car is just amazing to be able to do this and other things like 100mph + in 4th. I love being able to have no problem starting in 2nd then shifting to 4th and hardly applying any throttle at all. My 2010 SRT8 gets 24 mpg thanks to 6th. :bigthumb:

 

[MizzouRT]

me too. I can cruise on flat land at 40 in 6th at 1000 rpms. if I need to speed up or if i hit a hill, i need to down shift

Same here. There are no hills in Houston so once you hit 40 mph you can just coast along and pull down some great city mpg's, especially on parts where you know how the lights are timed. Of course, the second you want to add throttle then a lower gear will be required. Springfield has a few more hills!

 

[homerzeppelin]

40 mph is my limit with the 20in wheels and 3.92 gears.

 

[noz34me]

Ditto- -40 mph on flat ground. We just don't have a lot of flat ground where I live in VA. For you guys in the midwest, try a long straight stretch at 40 mph in 6th. Once you hit 40 in 6th, re-set your mpg monitor. You will be shocked at the mileage you're getting.

Under these conditions you're not lugging the engine, but if you hit a hill you'll need to downshift or you will be.

 

[Jay6spdRT]

Thanks, Hal. What you mentioned was a concern to me as well.

I can understand the concern, Jon, - in theory - in reality, I don't think it will happen. At least it hasn't to me. I drive in 6th all the time on the highway with the cruise on at 75 mph, and I'm nearing 13,000 miles on my R/T. I have never once had any fouling or driveability issues. And on the drive from Cleveland to BG on Friday (about 500 miles) I was running 55 mph to 65 mph because I was taking the lead, and toofart was trailering. No issues, even with the DS canned 91 octane tune, and I ran a two 13.4s at the track on Saturday.

 

[jcgrady]

I would use 1,500 rpm as the cut-off point for the upper gears, Jon.

I concur, @ 1500 rpm I down shift.