What speed is best for MPG on highway?

[seeforyourself]

Hello all


What is the best speed, for best mpg? Obviously the stock GS 2001 MGM doesn't have a tachometer. Does anybody know what speeds are the best? I heard 70MPH and 44MPH is the best, but is that true? I need to drive 100 miles round trip from longisland to NYC... Thanks

[tjc78]

LI to NYC it's not like you'll be moving very fast anyway!

Keep it under 70 and you'll pull 24 pretty easily.

[IPreferDIY]

For my 2000 MGM with its shitty stock tune, I do best in the 55-60mph range, and that gives me at least 23.5mpg. My owner's manual actually says "traveling at 88 km/h [55 mph] uses 15% less fuel than traveling at 105 km/h [65 mph]".

[jaywish]

Generally a minimum of 40mph will provide the best mileage. Maybe cruise @ 45 for hyper mileage.

[Brown_Muscle]

For what it's worth, ive also had vehicles get worse mileage at 55 than at 75 (our van, which is a brick, comes to mind)

[sly]

the 93 with the stock engine and 2.73 open rear would get 28 mpg at 65... same car with the pi engine and 3.55L gears gets about 22 at 70 and because Texas and it's high speed limits, I haven't gotten better than 19 in a long time because you gotta drive 80-90 to not get run over. This is the main reason I don't highway the beater much at all. I don't like having people blow by me doing 20+ mph more than me. The beater will get 21.5 with the 3.55L rear if I keep it below 60. The whale with the npi engine and highway open rear will do 24 every day of the year at 65-70.

[Kodachrome Wolf]

The best I've seen in the '97 was 28-29 MPG while keeping cruise at 72 MPH in 70 zones and 68 MPH in 65 zones. That was done on a trip between GA and PA. I got around 420 miles out of a tank of gas, which was great in my opinion. It has 2.73s, so it's easy on the highway. Mixed driving I usually see 18-20 MPG.

The '87 prefers to be kept under 65 MPH for any reasonable economy. I haven't logged any real steady interstate driving with it yet to get a proper judgement. Last highway run I did I was pushing it along at less than ideal speeds (75-85) and netted a garbage 13 MPG. In reasonable mixed driving I'm used to netting 16-17 MPG. It has 3.27s, so it's decent around town, but I do have to limit it on the interstate, considering aerodynamics are not on its side. Over the weekend, I should be able to get a more accurate reading since I'm taking a trip to NC.

[GM_Guy]

At least the speed limit. ;-)

I can't say I've yet noticed any significant difference if I'm doing 55 or 70 in the vomit comet. My box didn't make much difference between about 55 and 80--the only catch with that was it had to be steady state driving. If traffic got a bit thick and speed wavered, the mileage would drop due to always having to slow and accelerate.

Alex.

[gadget73]

Never seems to matter to me. If I hit 19, its a good day. I just keep up with traffic and fill the tank as needed. It would probably do OK in the 55-60 range but I'd get run over. The car feels happy at 70-75 anyway.

[Brown_Muscle]

Never seems to matter to me. If I hit 19, its a good day. I just keep up with traffic and fill the tank as needed. It would probably do OK in the 55-60 range but I'd get run over. The car feels happy at 70-75 anyway.

Even with the new tune John gave it?

[gadget73]

Haven't spent much time on the highway. One tank seemed higher than typical then its back to pretty much the same mileage its given me for a decade.

[slack]

Never seems to matter to me. If I hit 19, its a good day. I just keep up with traffic and fill the tank as needed. It would probably do OK in the 55-60 range but I'd get run over. The car feels happy at 70-75 anyway.

Same exact results here with my 89. It's been a while since I checked but I think my rear gears are 3.08.

Edit: just saw this was on the 4.6l forum. With my 94 and 97 Town Cars I believe I got low to mid 20s on the highway.

Sent from my Nexus 5 using Tapatalk

[Salty Dog]

55-65 for la pantera. I got about 20 MPG on the highway.

[DerekTheGreat]

My '88 Townie with it's LoPo and 3.27's would get 19-21mpg at 79mph on the expressway and recently netted 24.5mpg @ 65mph. Pretty impressive I think. I'm with gadget though, I just put gas in it when it needs it but not having to stop for 400+ miles is awesome. Even with 18mpg or less I'd say I spend less money on gas than most do on just their car payment per month.

[DrHax]

My Lopo Vic averaged 22-23.

It liked only speeds ending in 5's

35 55 and 65.

Runs best at 65.

Was an amazing road trip car from isanti mm to alma Wisconsin only took 1 fill up for each trip. I always fill at half a tank.

Usually costs 16 bucks to fill her up on average. Loved e15.


I am curious to see how the HO truck motor does with MPG.