What's the most efficient cruising speed? [Archive]

baltimoremm

03-19-2006, 07:11 PM

My wife and I are moving next month from Baltimore Co. to Harford Co. MD, and my new commute to work is going to be about 70mi round trip, mostly highway. I'm planning on using my work truck a few days a week to save on gas. Here's my question...
What have you found is the most efficient highway crusing speed to maximize MPG? (stock, no mods)
Thanks for the input!

Warbuff

03-19-2006, 07:20 PM

I live in Baltimore and have about a 74 mile round trip to work each day... all highway driving. I have found that somewhere around 75mph is the best for me........... that is no lie. Bone stock except for a cold air intake.

Welcome to BALMORE!

TripleTransAm

03-19-2006, 07:41 PM

My 2 stock Marauders seem to prefer something between 66 and 68 mph, with the cruise control on. I see a noticeable difference in consumption above 70mph.

mpearce

03-19-2006, 08:08 PM

something between 66 and 68 mph

Same for me. When I drive up to Detroit from Cleveland I set the cruise at 68. I have 4.10's, and usually drive up there on my 100 octane tune (because of dyno reasons). I can go forever at that speed with that gas. I also have the pro guard...Mike Poore said that helps fuel economy also.

-Mat

BAD MERC

03-19-2006, 09:21 PM

I made a trip from Orlando to Ft. Myers last night (202 miles) with 5 passengers and averaged about 90 MPH in NO traffic. I used less than a half tank which equates to about 20 or so MPG.

O's Fan Rich

03-20-2006, 04:13 AM

You guys can actually drive 65-70mph around the Beltway and the like down there?
Everytime I go thru there, and traffic is flowing good, 80mph seems to be, well, sorta slow for traffic!

Btw: Pa to Miami 2 years ago I-95 70-85mph 27.7 mpg... she was stock then.

cyclone03

03-20-2006, 09:50 AM

Just go with the flow...
You'll drive yourself nuts trying to maintain a speed less than the flow of traffic just to save $4-$10 a week.At 140miles a day you'll get 21/2-3 trips per tank.

A standard DR tune will get you very close to 3 trips,25-27mpg.

merc6

03-20-2006, 09:58 AM

A tune, and throttle control gets me 310 on the trip meter and usualy means I can pump 16 gallons into the car exactly when or shortly after the light comes on. Also what shift points are you guys using? I'm gonna dyno to see if the A/F is good where it is or if it needs to change.

SID210SA

03-20-2006, 10:08 AM

On my trip to Dallas for the Le Peep Breakfast I went 380 miles on one tank of gas doing any where from 80-85 mph. The only two mods that I have that helped were the JLT and the Proguard. On the way back I hit a lot of head wind and got about 340 miles on that tank of gas.

Lou

03-20-2006, 12:02 PM

Mine is bone stock and I get at least 300 miles on a tank areound town, stop and go traffic. This is around 18 MPG

The best I've done on the road is 400 miles which is better than 26 MPG.
That's 80+ with the A/C on.

duhtroll

03-20-2006, 12:31 PM

There is no best cruising SPEED for a MM.

There should be, however, a best cruising *RPM* setting for the MM. I have found 2150-2250 seems to be the "sweet spot" for good mileage. That can slightly different speeds for different Marauders, especially given gears, etc..

-A

Badger

03-20-2006, 12:38 PM

I just cruised down to SC from Washington DC.
Set cruise at 79 mph. I averaged 24.09 mpg.

TripleTransAm

03-20-2006, 12:38 PM

Actually, I believe speed does have an influence on the results. It's the aerodynamic portion of the equation. Otherwise, you could put 2.73:1 gears in the thing and get the same mileage at much higher road speeds, which doesn't happen.

hdirish50

03-20-2006, 12:50 PM

I drive about 30 miles to and from work each day. I either take I-95 or SR476 into Philadelphia. I’ve tried many things to improve my gas mileage. However, it always remain the same.

duhtroll

03-20-2006, 01:14 PM

Yeah, but with a tail wind . . . or a head wind for that matter. . . Can't compute wind resistance unless yer gonna cause yerself a headache planning your vacation. :)

Actually, I believe speed does have an influence on the results. It's the aerodynamic portion of the equation. Otherwise, you could put 2.73:1 gears in the thing and get the same mileage at much higher road speeds, which doesn't happen.

TripleTransAm

03-20-2006, 04:59 PM

Okay, I didn't mean you actually had to sit there and compute the damn thing. :) Just that it isn't totally correct to look at the RPM to get the optimum mileage speed.

Let me throw in a totally unscientific example: last summer I discovered that my mileage was practically unaffected if I spent a little more time in 5th gear instead of 6th gear at my usual highway cruising speed, with my WS6. That meant a cruising RPM of 2200 RPM or close to it. So to summarize, maybe I was spending 50% of the time in 5th instead of 100% in 6th.

2200 RPM in 6th would put me up beyond 85 mph, which has been proven to use much greater quantities of fuel per mile.

Smokie

03-20-2006, 05:04 PM

duhtroll

03-20-2006, 05:30 PM

I like to lock it in 1st and do 2200. :)

jgc61sr2002

03-20-2006, 07:50 PM

2200 RPM's is approximately 75 MPH. I got 24 MPG on an extended highway trip.

LVMarauder

03-20-2006, 08:05 PM

a buck forty

CBT

03-20-2006, 09:41 PM

Warp speed, baby.

TripleTransAm

03-21-2006, 12:19 PM

I like to lock it in 1st and do 2200. :)

Why? Just keep it in reverse and watch the gas tank needle creep up.

duhtroll

03-21-2006, 01:00 PM

Every other day I drive to work backwards to keep the miles down on my MM.

You thought you had seen people slowing down thinking I was a cop before!! Now they all turn off the road for fear I might give them a ticket for going the wrong way.

Why? Just keep it in reverse and watch the gas tank needle creep up.

hbarrett

03-21-2006, 06:05 PM

Hi,
I live in Havre de Grace, and drive I-95 each day to Abingdon (35 miles round trip). I have found that 65 - 75 mph on cruise control seems to give me good mileage, and that's with 4.10 gears. My combined city and highway is about 18 -20 mpg.
Howard

My wife and I are moving next month from Baltimore Co. to Harford Co. MD, and my new commute to work is going to be about 70mi round trip, mostly highway. I'm planning on using my work truck a few days a week to save on gas. Here's my question...
What have you found is the most efficient highway crusing speed to maximize MPG? (stock, no mods)
Thanks for the input!

MENINBLK

03-21-2006, 10:11 PM

I just completed a 1400 mile trek to North Carolina and back on stock programming.
I don't have the EXACT MPG, but I was able to get way over 400 miles
on a full tank while crusing up and down 95 at speeds over 75+ MPH.

I've now got over 50k on my Marauder.

I only use 93 Octane fuel derived from US CRUDE.