Gas Mileage Can Be Improved - LONG

R

Rocket Scientist

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I want to start this discussion to try to separate fact from fiction. I live in Alabama and everyone I know with a Lightning gets 12 to 14 MPG, in mixed highway and city. City, I have seen 10 MPG... I average 12.7 MPG. I have a friend that installed the Mass Air Flow conversion kit and gained 2 MPG. A story in Fast Ford and Muscle Mustangs, Feb of 97 I believe had a guy in with a 93 Lightning that got 20 MPG with a super charger. He says the secret was in the electronics and he changed the Fuel to Air ratio to 14.6 to 1, I think. He admitted to changing it to 12 to 1 when towing and dropped down to 14 MPG. This was a 10 sec. in the quarter Truck! I have try to contact the writer of the article to obtain the phone number of this guy, but my attempts have been unsuccessful. I am concerned about changing the ratio for fear on running too lean. SVT's help line was not help of course, young kid answers the phone with no answer... only more phone numbers with same results. Does any out their have any experience with this?? I know we all could use the gas mileage, its the only reason we occasionally consider selling.
 
dear rocketscience, I've had my 94 lightning for almost 2 years and really never had got better than 13mpg mixed city and highway and of course thats sensible driving. I would be very skeptical of claims of 20mpg. If this was obtainable with the 351 it would spell Lean,Lean and LEAN! And of course anyone that has been around superchargers knows LEAN means disaster,and expensive rebuilds. Now I've heard of chip companies tweaking air fuel ratios for optimum performance but not to gain 8 mpg. I say smoke and mirrors, or snake oil. If that kind of mileage was obtainable, I think we would of seen it on the second generation lightning, but no, their gas mileage sucks too. Steve NLOC #343
 
That would be Mike Wesley of C&M fame. If I had a wide band O2 sensor and a laptop running my truck real-time, I could probably get 20 mpg too. It's not reasonable for the rest of us, though. My truck has seen a best of 17 mpg with the Pro-M mass air and it gets pretty consisten high 15/low 16 mpg with the PSP mass air. I think that's reasonable for a 351 in a full-size truck with 4.10 gears.

BTW, there are a lot of claims of what that truck could do, but no one seems to have ever seen it back up any of them. I'm not saying it hasn't or can't, just that no one that I know has ever been able to independently confirm what was claimed.

Later!
Jeff S.
 
Thanks Steve and Jeff,
I had the same opinion as Steve, but Jeff has given me alittle hope... 16 sounds good when your use to 12.7.
 
Rick Anderson of Anderson Motorsports, here in Illinois claims the conversion to Mass Air will pick up 4 MPG. Of course the other end of the spectrum is Chris Johnson, who states it is hard (pain in a**) to tune an Mass Air Lighting. So who knows, but 4 MPG sure does sound good. I would be interested in hearing from anyone who has done the switch as to how it affected driveabilty and gas mileage.

John Wilde
 
i have a 95 and i get close to 15 most of the time but this winter it has dropped especially on shorter trips.... i wanted to get mass air but jeff s has changed my mind i have gotten close to 20 on my 99 at 70 on trips..
 
I consistently get 13-14mpg with mine in metro Detroit traffic. Metro Detroit traffic is a combination of stop-and-go, then 75-80mph runs on the expressway. Mind you, the expressway is by no means steady-state cruising, either. On a loooong trip, 65-67mph low-load cruising, the thing has been right at 17, with an occasional 18 every now and then, but that's really featherfooting the thing.

Mind you, this is with a 100% stock truck with only a diesel intake tube and K&N. Mass air's in the works for my truck, and man would a Calibrator and wide band setup be nice...

- Kevin
 
Well I have also researched this I dont know if you guys know but I ripped out my PIGGYBACK MASS AIR CONVERSION because when you use an A9L computer it needs two O2 sensor readings for left and right side of the engine.The reason for this is the diffrent amount of fuel flow in the stock fuel rails one side gets more flow than the other.To prove this if any of you guys have a 5.0 MUSTANG you can switch the leads from left to right and your car will run like crap.In your mass air conversion the two are spliced together so your A9L has know way to know wich side of the motor needs more fuel.Some conversion put a resistor in one side to try compensate for the diffrence it works but not very well.The computer needs real time readings to make adjustments during normal cruising to each fuel injector bank.To fix this problem on my truck since I have a c-6 I just put in an A9L computer and put in two o2 sensors.I think it is possible to fix this on a mass air conversion kits if you put in two sensors one on each side about 6" from the collector and then wire them to pins 43for the left and 29 for the right to the A9L computer and cut and tape the two that are going to these existing pins. To see if your PIGGYBACK mass air does splice the two wires together test the two pins mentioned above while the truck is running with your DVOM if the voltage is the exactly the same on both you know your computer does not know the diffrence between the right and left side of the motor one side is probably running lean.I dont know if this info is applicable to the motorsport lightning mass air becuase the engineers at ford figured out the diffrence in the fuel map in the right and left fuel injector banks to compensate for any problems.I had a piggyback mass air conversion in and I got about 12-14mph when I had an E4OD now I get the same with a three speed c-6 no overdrive and no lock up converter ,after wiring an A9L straight to the truck and getting rid of the piggyback sys.
Hope this info is helpfull and not discouraging.

RICHARD
 
Thanks Richard... being new to the Lightning world, also owner of a 89 Mustang coupe (modified 5.0 with 5sp conversion--never again), I had to read your message twice. I have a few questions, stupid as they may sound... what is an A9L computer? Is this aftermarket? How is the PIGGY BACK SYSTEM different from the FMS system? Is the piggy a home made system? Lord, what was ever wrong with carburetors... feeling my age. I build Delta IV rockets for a living and I am having trouble keeping up with FORD. Spent two weeks trying to get the 5 speed to live in the automatic computer.
Thanks for the help.
 
Hey guys, Sal here. I suppose I should chime in on this topic. Gas milage has always been a popular topic with Lightnings. Improved MPG has been a common request by customers who buy chips and mass air conversions from Power Surge. All of the things discussed so far are true, but there is something that many do not understand. It is true that you can program the PCM to have leaner values to improve MPG. You can also do this without damage to the motor, since you can set the A/F at any rpm and load. But simple as this may seem, many do not realize that once the vehicle reaches 130 degrees, it goes into closed loop. During closed loop operation, the PCM will monitor the oxygen sensors, and adjust the A/F ratio for 14.7:1 (stoich). No matter what you set the A/F for, it will run at 14.7:1 unless at WOT. Also, it doesn't matter whether you have one or two oxygen sensors. On vehicles that only have one oxygen sensor, there is a table in the PCM called Exhaust Pulse Delay. This table allows the PCM to know which "side" of the motor the oxygen sensor is reading. The only real option for better MPG is to run a full time open loop program, which will allow the truck to run off what is programmed. I do have open loop versions for our Lightning chips and custom mass air kits. And since we are comparing MPG, I was getting about 17mpg on my 95 with 17psi of ATI Dominator D1-B.

SAL- Power Surge Performance
http://members.aol.com/NLOCsvt/svt.html
 
The A9L is the 5 speed OBD-I MA Mustang computer. It's what Pro-M uses in their mass air conversion (actually mine had a C3W1, but it's the same thing). Later versions of the Pro-M conversion did come with the arrangement for dual O2 sensors.

It's termed a "piggy back" conversion because it uses the new (Mustang) computer to run the engine and the stock truck computer to run the transmission with a "Y" between the two computers routing sensor signals to each one.

Guys, don't get clouded in boost and supercharger installs and mileage. If you don't stick your foot in it then that supercharger is just along for the ride. You can get the same mileage with or without a supercharger if you have your cruise control set at 70 mph and are riding down the highway. Have a twitchy right foot and mileage will go down the tubes pretty quickly, though... boost requires fuel. Period.

I sometimes cruise without the belt on the supercharger, but that's simply so I can run 87 octane and save a few dollars on the drive. I don't do that much - would rather have those ponies on tap.

BTW, I have gone over 500 miles between fill-ups on highway trips. My truck can do that much easier than my bladder and kidneys can.

Later!
Jeff S.
 
As for the info I posted above it is for a mustang 89-93 A9L stickshift computer in a piggyback set up mass-air conversion such as pro-m's or downs ford, that does use such a computer and it does need 2 02 sensor readings weather from one spliced 2 both leads or 2 seperate sensors.It would be fair to say I have never played with the stock speed density system so I dont know what it is capable of,sal is right you can change parameters for better gas milage but I did my whole conversion for $350.00 the computer was $100.00 the mustang wire harness was $50 and I got used c-l 80mm mas air meter for $200.I think a good chip cost this much.
 
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