RPM's at 65 mph.

[JimmyTwoTimes]

1715 RPM is cake for the engine. They are designed to be safely operated up until redline.

I understand that the engine will run all day at 1715 rpm, it's just that that's a high engine speed for it to be running at highway cruise for engine noise / fuel economy purposes. I only let my current car's engine get that high during acceleration to highway speed or out of red lights, certainly not for any extended length of time. In around-town driving I usually like to keep the tach pegged at 1,000, and on the highway at 1,300; it'll just be a change for me to let the engine rev that much on a regular basis. I'm sure the gas mileage will be atrocious.

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[geokots]

Right now I'm averaging 8.7L/100klm.
I drive a similar distance at 130klm round-trip but most of my drive is heavy traffic.

the 8.7L/100klm is based on roughly
30% city - stop and go
40% highway - stop and go traffic
30% highway - open road 120-140klm/hr

 

[Colleton]

I understand that the engine will run all day at 1715 rpm, it's just that that's a high engine speed for it to be running at highway cruise for engine noise / fuel economy purposes. I only let my current car's engine get that high during acceleration to highway speed or out of red lights, certainly not for any extended length of time. In around-town driving I usually like to keep the tach pegged at 1,000, and on the highway at 1,300; it'll just be a change for me to let the engine rev that much on a regular basis. I'm sure the gas mileage will be atrocious.

 

[geokots]

LOL
I'm just assuming that he's joking.

 

[Colleton]

Well I hit a Roo on the way home from work tonight. Fortunately I was in the Land Rover Defender, and not the MINI.

No damage to the car. (Bull Bar) Roo was dead before it hit the road.

As interesting as they are, they are really stupid. This one was the size of a large Labrador. Jumped right in front of me, with about a second to spare.
Fortunately no one in the oncoming lane, when it bounced off my car, as it would have gone through the windscreen.

Cheers,

Ken

So they're like deer here in the southeastern US. I didn't realize the population was that large.

 

[Patrick S]

I understand that the engine will run all day at 1715 rpm, it's just that that's a high engine speed for it to be running at highway cruise for engine noise / fuel economy purposes. I only let my current car's engine get that high during acceleration to highway speed or out of red lights, certainly not for any extended length of time. In around-town driving I usually like to keep the tach pegged at 1,000, and on the highway at 1,300; it'll just be a change for me to let the engine rev that much on a regular basis. I'm sure the gas mileage will be atrocious.

atrocious? i am sitting at 22 MPG on my current tank of gas, 21.1 overall average... not atrocious for a GT, really.

 

[JimmyTwoTimes]

atrocious? i am sitting at 22 MPG on my current tank of gas, 21.1 overall average... not atrocious for a GT, really.

I only get 21-22 in my V6. If I really lace into it and let the engine run to 3,000 rpm, I get 14 or 15.

It all depends on your driving habits. I mean, if I'm doing straight highway driving, just fill up the tank and get on an interstate and drive until the tank runs out, I get 33 or 34 mpg. But in normal driving, with a lot of traffic, you're never going to get anywhere near that. I was in traffic on the highway this morning and it took me two hours to go three miles... I'm in traffic like that three or four times a week; it really kills your mileage.

 

[Patrick S]

I only get 21-22 in my V6. If I really lace into it and let the engine run to 3,000 rpm, I get 14 or 15.

It all depends on your driving habits. I mean, if I'm doing straight highway driving, just fill up the tank and get on an interstate and drive until the tank runs out, I get 33 or 34 mpg. But in normal driving, with a lot of traffic, you're never going to get anywhere near that. I was in traffic on the highway this morning and it took me two hours to go three miles... I'm in traffic like that three or four times a week; it really kills your mileage.

OMG. that is why i moves away from the big city. No way would i ever ever ever want to sit in that sort of traffic, ever, ever, ever again. :thumbdown:

I moved here from San Diego and all of the freeways suck, all day, all night, bumper to bumper. I hated it........

to your point, at least you were not maintaining 1750 RPM.. out here, i am not in traffic, maintain freeway speeds throughout the trip to work and home unless i need to pass someone... in which i will drop into 5th and romp from 65 to 90, pretty rapidly, Just to remind the slow driver who really is the king of the street...

my response was to maintaining 65 MPH at 1750 RPMs, which is most of my drive to/from work, which is 44 miles round trip.

 

[Mudnut]

I think he's talking about mileage, and possibly about exhaust drone at higher RPM's if he goes aftermarket. I'm sure if you take the same Mustang and applied 3.73 gears vs 3.15 gears and tested them at 75 mph, the .15 would come out far ahead in mileage due to the lower RPM's.

As a general question, can anyone chime in on RPM's contribution to gas mileage on these 5.0 V8's? Big difference between the 3.31 and 3.73, given identical external circumstances?

Yes, this was the general idea I was thinking about. Mainly fuel consumption over cruising distance at 65 mph (100k speed limit here) I was not considering drone, of aftermarket exhaust, but now that you got me thinking.......

The original was idea was to compare, fuel consumption between the GT, and Eco Boost, so that I could justify a GT to my wife.

Thanks for all the replies, and keep them coming.

Cheers,

Ken

 

[Old 5 Oh]

I understand that the engine will run all day at 1715 rpm, it's just that that's a high engine speed for it to be running at highway cruise for engine noise / fuel economy purposes. I only let my current car's engine get that high during acceleration to highway speed or out of red lights, certainly not for any extended length of time. In around-town driving I usually like to keep the tach pegged at 1,000, and on the highway at 1,300; it'll just be a change for me to let the engine rev that much on a regular basis. I'm sure the gas mileage will be atrocious.

Not sure what to tell you. The AT/3.15 combo runs over 1,700 RPM by about 60 MPH, so there's not really a lower-rpm combo this year.

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