Who would've thunk it.

Frogman

Frogman

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I promise to nicer if you promise to be smarter.
I'm getting better fuel economy now than I did before the motor was worked over.

Mods to the motor, sans some other stuff ya'll don't need to know about.

298 Stroker
Aeromotive Rails and regulator for the 98 Cobra
Cobra intake
75lbs/hr injectors.
3.73 Gears
Heavy foot.
And a Torque Converter issue where it locks up just fine, until you romp on it. Then, it stops locking up until you re-upload the tune.

Took several pictures over the span of a few minutes, because there will always be the one guy who says "Awww, shucks! You just reset your average!" OK, Skippy. You reset your average economy and be that consistent.

Yes, the speed is incorrect. With another 2000PM before the rev limiter kicks in, the motor was still pulling hard. That speedo was buried, and the car was still pulling.

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If the VSS is off due to the gears... won't the computer think it's going a mile every .88 or .82 miles?
 
MediumD said:
If the VSS is off due to the gears... won't the computer think it's going a mile every .88 or .82 miles?
Click to expand...

I would tend to agree here. If your speedometer is off then so is your MPG reading. Time for some hand calculations I believe.:p
 
I just flat out call... :bsflag: ...... on this one. Screen shots or no screen shots.

No stroked 4.6 I've ever heard of has done a consistent 30 +, much less 33+, although, I am aware that there are alot of looong downhill stretches in Frogman's neck of the woods. :F

And with giant injectors that dribble fuel like the drool coming from Frogman's chew. :eek:
 
I agree wiyh Bryan.

Your larger than stock fuel injectors are throwing your fuel mileage calculations off a bit.:)

But somehow, I think that you knew that.:D
 
I have seen the 30's often..

Not sure about the injector or what they would cause, but Out where Frogman lives there are a lot of long flat roads between those long up hills and long down hills. Many more miles than the straight stretches bewtween the hills around here.

From Boscobel to Madison on normal driving I will average about 28 mpg. I have hit 30 from time to time. All depends on the type of driving.

For those living around the cities you are going to have lower mpg averages just due to the type of driving you have to go through. Out in the wide open spaces what is traffic, and what is stop and go driving stop sign every what 100 miles? Makes a big difference when you can keep a nice even pace for a long stretch.

Granted the computer ave may not be accurate and a actual hand caclulated test would be better. But then again this isn't a 13.6 run at the drag strip on a stock Mark VIII.
 
Frogman said:
You believe what you think. I'll believe what I KNOW.
Click to expand...

I don't think. I know.

If you were running 3.07's or 2.73's, I'd have no problem trying to believe it.

But 75lb/hr. injectors on a stroked 281 weighing in at 3800 lbs. with 3.73's and a power hungry trans (with a Torque Converter issue) and IRS ain't gonna happen (not even taking into account elevation).
 
Not happening.

When I put 24 pound injectors in my '87 (along with a new motor), my message center read 25% higher, making me think I was getting great MPG.

But if you're one for believing what a Ford message center tells you, more power to you.
 
NYC LSC said:
When I put 24 pound injectors in my '87 (along with a new motor), my message center read 25% higher, making me think I was getting great MPG.
Click to expand...

Sh!t. Are you telling me all I have to do is put 160lb injectors in my Mark and I'll get 55 mpg?

Where do I sign up.

This is a way better idea than the tornado!
 
i'm getting 31mpg on the highway with 60# on my 04 cobra motor through a lockup. I'll have to check with my tuner if my number are off in the calculations but I dont think their that far off
 
phreakness said:
I'll have to check with my tuner if my number are off in the calculations butI dont think their that far off
Click to expand...

Check with your tank ... :D

Unfortunately it's a bi-product of high flow MAF and bigger injectors. Three of my blown cars were doing exactly the same thing, and impossible to correct in the tune. Suprisingly, the 98 ECU doesn't have that problem and shows actual MPG.

Sorry to burst your bubble. That's a fact.
 
injector size doesnt mean squat for cruise mpg. its all in the tune and i do believe it. i managed 30+ with my stock pig rich tune from portland to sacramento.


i picked up 5mpg when i went to 450cc injectors (stock is 360) in the VR4 after i tuned it. thats with it still idling rich at 12:1 due to the fuel pump overrunning the stock FPR.
 
I agree it doesn't mean squat, but it messes with that funky lincoln calculator.

I was as stumped as you Brian when the 98 would show actual MPG (and it wasn't pretty ;)). I know of tens of other cars that do exactly as the one pictured. I talked at length with Lidio about this problem (for some) and we didn't get anywhere. Even mighty Jerry wasn't able to get this sorted out on several blown cars down in FL. Maybe some computer codes are prone to this, and some are not ?

LIke I said before, it's best to check it at the pump when you fill up. Built and supercharged motors are more efficient (to a point of course), but believing the 33mpg avg solely on this funky display is :rolleyes:

Charlie's car does exactly the same thing, but he's sane enough to know that 30 avg MPG @ constant WOT on a 550 rwhp is not possible in this chasis.
 
It's comfirmed. But there has been a considerable amount of private discussions about the incorrect MPG readings we get on our message centers once we do alot of changes to our fuel delivery systems. It is burried in the way the calcs are done from the fuel tables, and their aint no one yet who has gotten it straight. You are going to have to do the old gal/mile to get accurate to a general degree. I really depended in the past on my mpg so I did everything i could to trace the deal down, but alas I have quit and went back to how we did it in the "old days". The M Maker has it right.
 
Roadboss said:
It's comfirmed.
Click to expand...

What's confirmed?

I'll stand by my statement. A stroked 4.6 with big injectors and 3.73's can't do 33.1 mpg unless it is rolling downhill.:burnout:

And I'm not picking on Frogman. I just want accurate info posted on this site.
 
just having the speedo off messes the whole calculation up,
when i swapped to a 2002 tranny the internal gear went from 7 teeth to 8 teeth,now my speedo is off 10%,when i am doing 60mph it shows 66mph....70mph is ~77mph...

guess what,my MPG is now up 10% on the display,but of course in real life it hasnt changed,

The fuel calculator uses fuel used/ to distance traveled/,so the car now sees me traveling 10% farther on the same fuel as before,tada 10% increase in mpg.
Frogman told us the speedo is incorrect,so not even worrying about all the other mods on the car,we already know the speedo is going to mess with the fuel calculation.
 
Even a stock mark VIII doesn't get 33 MPG! I don't care what anyone claims. Sure your mileage calculator may tell you so but it's not correct. Yes mine tells me that I'm getting 30+ on the highway, but when you actually do the math and figure it out (miles vs. gallons used) It's more like 16-17 MPG Average (city and highway combined) A lot of stop & go traffic. This is true on my 95 Mark VIII & my friends 94 Mark VIII. BTW both cars are in top notch condition without any issues. Ford rated an EPA esimated 17 city 24 highway, well we all know that this is BS because the Goverment is mandating that the EPA calculations be changed to more real life numbers.

You cannot go by your fuel mileage calculator!!!

:bsflag:
 
turborich said:
Even a stock mark VIII doesn't get 33 MPG! I don't care what anyone claims. Sure your mileage calculator may tell you so but it's not correct. Yes mine tells me that I'm getting 30+ on the highway, but when you actually do the math and figure it out (miles vs. gallons used) It's more like 16-17 MPG Average (city and highway combined) A lot of stop & go traffic. This is true on my 95 Mark VIII & my friends 94 Mark VIII. BTW both cars are in top notch condition without any issues. Ford rated an EPA esimated 17 city 24 highway, well we all know that this is BS because the Goverment is mandating that the EPA calculations be changed to more real life numbers.

You cannot go by your fuel mileage calculator!!!

:bsflag:
Click to expand...

When I drove back and forth from Florida and Minnesota mine was dead on balls accurate. I got over 500 miles to a tank. But your right for every day driveing, its about 85 to 90% Right.
 
turborich said:
Even a stock mark VIII doesn't get 33 MPG! I don't care what anyone claims. Sure your mileage calculator may tell you so but it's not correct. Yes mine tells me that I'm getting 30+ on the highway, but when you actually do the math and figure it out (miles vs. gallons used) It's more like 16-17 MPG Average (city and highway combined) A lot of stop & go traffic. This is true on my 95 Mark VIII & my friends 94 Mark VIII. BTW both cars are in top notch condition without any issues. Ford rated an EPA esimated 17 city 24 highway, well we all know that this is BS because the Goverment is mandating that the EPA calculations be changed to more real life numbers.

You cannot go by your fuel mileage calculator!!!

:bsflag:
Click to expand...




ive got 3.55 gears. ill be happy to go do some highway driving for you and get better than fords ratings.

i DID do the math when i went to cali and the calculator was on withen 1mpg
 
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