Gen II Mark VIIIs vs Gen Is in gas mileage?!

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maxmk8

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Can someone who had "real world" experience chime in on this one. I am just curious about this… I would think that the main factor would be aerodynamics, and the different intake.

I have had both a gen 1 and a gen 2. I think my stock gen 2 averaged about the same as my stock gen 1. But I am pretty sure it did about 1-1.5mpg worse on the freeway.

There seem to be a lot of people averaging worse in a gen 2 than they do in a gen 1.

Please compare apples to apples. In other words:

Stock Gen 2, with all maintenance performed to Stock Gen 1 with all maintenance done. Or same mods on both cars, but the same roads and driving conditions. You guys get the drift.

I haven't heard to many of you "east coasters" return really good HWY gas mileage on the gen 2s either. No 30mpg threads I can remember.
 
Based on what I have seen in these comparisons

Driving style/Habits would have more of an impact than the two vehicles would.

Look at your experience, you had both.. and got within 1-2 of the other car.

I'd like to see some "real world" info as well, as I'm just speculating here {sorry}
 
"I haven't heard to many of you "east coasters" return really good HWY gas mileage on the gen 2s either. No 30mpg threads I can remember."

Maybe we "east-coasters" don't lie! My Gen II gets highway - 26. Combined about 18-19. Completely stock.
 
Some people "claim" to get 30+mpg on "some" Mark VIIIs. I have personally gotten 27 at 65mph... My best ever average was 25.5 ... all that was in my gen 1. My gen 2 was modified 2 months after I got it.

Oh east coast gas gives better gas mileage... due to the 93 octane.
 
maxmk8 said:
Some people "claim" to get 30+mpg on "some" Mark VIIIs. I have personally gotten 27 at 65mph... My best ever average was 25.5 ... all that was in my gen 1. My gen 2 was modified 2 months after I got it.

Oh east coast gas gives better gas mileage... due to the 93 octane.
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I can do 30 on the highway, with the AC off.. running less than 65 MPH.

But.. at or above 65..."all bets are off" it goes to 24-26

AC kicks about 3-4MPG off my car
 
I use regular....all the time! 87 octane. When I bought the car from my local L/M dealer, they told me they drove it for about a year. Only used regular. I tried Hi-test. Didn't do any better after about 10 tankfulls. Went back to regular.
 
Might be a difference due to EECIV and EECV as well.

I easily get 30 mpg going 70 mph...but I get help with Lonnie's true lockup converter.
 
my 93 gets better mileage then my 98 both around town and highway. my 98 averages about 15.2 around town the 93 is around 17 on the hwy my 98 does around 25 and the 93 is around 27. my 93 has always showed more then my 97 or my 98 maybe its because my wife drives the 93 and im always hot rodding in my 98.
 
I remember Jeremi mentioning that OBD I cars get better gas mileage than the OBD 2 cars because they aren't all detuned for emission reasons, hence the reason Gen1's are usually faster than Gen2's. Bob(previous owner of my Shark) has a 98 and he's reported the same or slightly better mpg in my car vs. his and he's owned both for years.
 
I always got slightly better GPM with my 93 , but as the 98 got miles on it the GPM improved. If I drive in the upper 60s with the AC off the 98 now can get 30mpg. Also my best milage is using 89 octane, and the gas milage is better at higher altitudes; over 30 in the mountains ,NM,CO.

Ron
 
I have had a few of both Gen 1 and Gen 2. Personally I have noticed that Gen 1 cars get better gas mileage. In my 1995 I got 28mpg at 75 on the hwy. In my Gen 2's I average about 3 mpg less in both city and hwy.
 
j22woof said:
... Also my best milage is using 89 octane, and the gas milage is better at higher altitudes; over 30 in the mountains ,NM,CO.

Ron
Click to expand...

Hi Ron! :)

I find it interesting you get better mileage with 89 octane and better mileage in the mountainous terrain. Hmmmmmm....

Anyways, I just finished a trip out to Indy for the WFC X and averaged 24.5 MPG in my modded '93 cruising 75-80 most of the way except probably 65-70 MPH sections due to traffic in the great state of Ohio.
 
driller said:
Hi Ron! :)

and better mileage in the mountainous terrain. Hmmmmmm.
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Gotta love EFI!

02 sensors see the engine running fat because of the thin air.
so the PCM pulls fuel to get the AF correct.

less air means less fuel, which gives "better mileage".
 
XLRVIII said:
Gotta love EFI!

02 sensors see the engine running fat because of the thin air.
so the PCM pulls fuel to get the AF correct.

less air means less fuel, which gives "better mileage".
Click to expand...

Yes...but you have to press the throttle down farther to get the same amount of power as a car closer to sea level - in effect the same amount of air.
 
Look guys...ya gotta check MPG by hand calulation over a lot of miles...don't check your "INSTANT MPG" on the computer!! Start with full tank, drive for a long distance...ie for highway, 300 miles, refill tank, do the math. Hell, my Gen II gets 99 MPG goin' downhill in 2nd gear lookin' at the instant readout!!
 
Usually my "caculated mpg" is within .1mpg of what the message center says the "Average MPG is".

DTE is always, "pretty close".

I use the "instant" mode to keep me from adding "too much pedal" for a minor speed change.

The instant MPG works alot like a vacuum gauge, it might even reference engine vacuum for it's caculations.

in my SVO mustang I put an aftermarket vacuum/boost gauge and I got very "used" to using the vacuum portion to help increase my gas mileage.

I use the "instant mpg" on the mark 8 the same way.
 
XLRVIII said:
Usually my "caculated mpg" is within .1mpg of what the message center says the "Average MPG is".
Click to expand...

Ditto here, checked it many times. Fill it up, reset the average mpg and check the average mpg at the next fillup against the calculated mpg. It's pretty amazingly accurate by the tankful.

Now if you don't reset it each tankful, your averages will become diluted and may not represent your average mpg for the current tank, see what I mean?
 
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