Fuel economy question.

Bullymong88

Bullymong88

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What is the average mpg supposed to be on premium because we get about 16.3 mpg, which is some city 30-35 but mostly 50-65 mph some 70-75 on straightish back highway, I just feel like it should be getting higher mpg maybe I'm crazy lol.
 
The best I ever got with a stock 97 was 25mpg running 70-75. Since I opened up the air box, its dropped to 22 on the interstate with premium but up to 23 on extra or regular. And that's pushing 90-95 at times. Around town its more like 18-20 just going easy. With my car buying premium is a waste of money. I may run some once in a while just to clean out the injectors with a WOT here and there.

Here is what you can expect when averaging these cars.
Lincoln Mark VIII MPG - Actual MPG from 33 Lincoln Mark VIII owners
 
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Thanks for the reply, I'd be afraid to run into knock issues running anything other than premium though, have you had knock issues running regular? And was the 25mpg instant or average because I've seen it hit 50 on instant flip flopping between all the numbers lol. But if you're getting numbers that high with virtually the same car something isn't up to snuff on mine, and I'm curious as to what it can be.
 
I have read that the PCM will automatically adjust the ignition timing if pre ignition knock is sensed. I have never heard the 4.6 knock.... ever. And I run 87 virtually all the time. As a mater of fact the 25 mpg I got driving it back from FL where I bought it was on 87 octane. I never bother with the actual MPG reader. Its all ways on average setting. On that FL trip to home TN, I also hand calculated the mileage on my cell phone calculator only to find the 3 full tanks of interstate running matched the cars 25mpg average read out. I was surprised to see it match up since this is the first car I'v owned that had an accurate mileage reader. when it was reading 25 average, a full tank fill up would say it has 428 miles until empty. The other difference is I live up at 2000 feet above sea level so my millage will be less than the lower elevation run up from FL. I did have my fuel pump replaced and that may be something to it of the 2-3 mpg lose I'm seeing on the interstate runs. The car has 74K miles on it with stock plugs in it. I'm curious to see what happens to the millage once I get the Base exhaust swapped out for the 2.5 Stainless duals I have. Slightly less back pressure at the crusin rpm might kill a bit off the millage..... I hope not but I'll find out once winter hits and I get more shop time under the car. Not looking forward to that job!
 
I've never owned a car with an mpg readout before and I wonder if living in the east TN valley has anything to do with it, as far as knock adjusting I suppose I could give it a shot using 87 but I feel like the car having 139k has a LOT to do with it. And to be honest I haven't changed the wires but I put NGK laser iridium's in it about 2000 miles ago, i was wondering what exhaust your going with I haven't found much support in the aftermarket world other than a nice set of kooks long tube headers which I'm saving up for after I get the front end repaired.
 
With 3.73 gears

B9719991-D587-46D1-8FE0-9955B72743A1.jpeg
 
Bullymong88 said:
I've never owned a car with an mpg readout before and I wonder if living in the east TN valley has anything to do with it, as far as knock adjusting I suppose I could give it a shot using 87 but I feel like the car having 139k has a LOT to do with it. And to be honest I haven't changed the wires but I put NGK laser iridium's in it about 2000 miles ago, i was wondering what exhaust your going with I haven't found much support in the aftermarket world other than a nice set of kooks long tube headers which I'm saving up for after I get the front end repaired.
Click to expand...

As far as the pipes, I'm basing it on the True Benz 2.5 SS pipes with a variety of straight threw mufflers and cross over that I will cut open and glass pack them. Its a cat back set up. Since you mentioned this, I pulled up Super Coupe Performance and see he's dropped True Benz and now has complete systems! Not stainless but finally some one came up with a complete system. I like the ball/socket connector hes now selling. If I can't find that in SS I'll have to order a pair of those. I'm only chasing down a tad over 300 hp so headers is pretty much not in my future vision for this car. 30 years ago, it may have went with your thoughts but not these days! LOL
 
xtriggerman said:
As far as the pipes, I'm basing it on the True Benz 2.5 SS pipes with a variety of straight threw mufflers and cross over that I will cut open and glass pack them. Its a cat back set up. Since you mentioned this, I pulled up Super Coupe Performance and see he's dropped True Benz and now has complete systems! Not stainless but finally some one came up with a complete system. I like the ball/socket connector hes now selling. If I can't find that in SS I'll have to order a pair of those. I'm only chasing down a tad over 300 hp so headers is pretty much not in my future vision for this car. 30 years ago, it may have went with your thoughts but not these days! LOL
Click to expand...
I was wondering if those would work with the kooks or not and to be honest I've never upgraded an exhaust before I've never had a car worth upgrading lol, tbh my back is killing me thinking about it but I'm probably gonna save up for one of those quickjack setups before I snag the headers and exhaust to make the job easier.
 
xtriggerman said:
That's an interesting shot. That's more difference than I would have thought comparing the speed/revs to the stock 3.02 gears of my base. The 3.02's run 92mph @ 2500 revs. Question is, whats your average mpg?
Click to expand...
21mpg +/-1 depending speed/how/where I’m driving.
 
Very nice! man you'v got those head lights polished up like new. I have to live with spider cracking on the inside. :(
 
I love the chrome delete of the LSC, and I swear the red looks clearer on yours then mine, and what would the under drive pulleys do on a na engine I know they increase boost on forced induction, and I'd bet the farm that tune has a fair bit to do with the mpg.
 
Under drive pulleys spin the AC, Alternator, and power steering pump at slower rpms, that in turn reduces stolen power from the drive shaft. With his 3.73 gears giving him higher revs at cruising speed, "he" can get away with that sort of upgrade without a 12v charging issue. Smartly done.
 
Wait I just got to thinking won't that also spin the water pump slower, I live in Loudon tn and my wife who drives it works in Maryville which is about a 50 minute drive, and its been very hot the last few years wouldn't it run a high risk of overheating?
 
No risk of overheating at all. I run a 170* thermostat with the fan commanded to come on earlier through the tune. It will idle all day in 95* without breaking a sweat let alone going down the highway. Look at the temp gauge in the pic.
My son and were Longhaulers in PowerTour this year with this car. Piece of cake!
 
I recommend the Steeda 701-0002. They are the best quality. You have to be careful what balancer you run on these engines so you don’t wipe out the oil pump gears. The Steeda balancer is SFI approved.
 
Is the steeds the kit you're running? Also what else do I need to do with it or is it a bolt on and done?
 
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