Is there an easy way to convert an '88-'91 vintage 460 EFI speed density engine in an F350 to Mass air flow? Is there an aftermarket kit available, or was it available from the factory in later years?

 

From what I've heard, it's a fairly easy thing to do, by using a MAF brain from a 302 and setting it up with a bigger throttle body. I think Ford Fuel Injection has some info.

 

Ford Fuel Injection is the place to go for good base information. The 96-97 California 460's came with MAF (and a whole lot of other stuff). You didn't indicate which transmission you have. Things can get complicated unless you have a C6 or manual.

Changing the throttle body has nothing to do with the conversion.

Basically you're gonna need to install a MAF Sensor, add some additional wiring, change around some wire locations in your ECM connector (to match whatever ECM you end up with), and of course replace the ECM.

 

The throttle body, when using the conversion using a 5.0/302 MAF computer has a LOT to do with the conversion.

The amount of air passing into the engine is measured at the throttle body. If you use a 302 throttle body, you'll be pulling 150% of the normal amount of air past the throttle plates. The computer will read this, and keep the injectors open half again as long as they should be. If you're using the 460 Ford injectors, this will be WAY too much fuel. If you can hook up a MAF to a 460 throttle body, then yes, you'll be a ways toward the goal, so long as the MAF sensor is tuned to the amount of air that will be passing by.

Note, I said what I said in context of using the 302 computer. Using the MAF computer from a MA or CA 460, and all its attendant gear, obviates that. But, it's a heck of a lot harder and more expensive to track down all that gear than it is to hook the computer and harness out of whatever 302-powered hulk is in the local boneyard.

 

Well, I really do not wish to be picky, but your remark and reply seems to beg for it.

First of all, there are no sensors in the throttle body (other than the throttle position sensor, what do you think the MAF is doing?). Secondly, why would any one suggest installing a 302 throttle body on a 460 (grant you, they are the exact same size, but linkage, and actuators really mess up the install). Thirdly, I would assume (and I am watching out for what that word can do) that you would use 460 injectors (24# stock BTW) in a 460, instead of installing 19# 302 injectors.

Now, you did get something right (although you really missed the reasoning) in that the MAF sensor needs to be tuned for the engine set up. That means tuned for the injector size and the air flowing past it. Its ouput is a simple voltage reading that tells the computer how long to keep the injectors open. The injector size will determine how much fuel is dumped.

A MAF tuned for 24# injectors will provide the correct input to the computer regardless of the throttle body. Since the stock throttle body's are the same diameter on a 302 truck as a 460 truck the only difference in the set up is the injector sizing.

I would suggest using a 75-80 MM diameter MAF tuned for 24# injectors. You should be able to find the MAF you need on eBay off of a 302 Mustang Cobra with 24# injectors.

 

I did a bunch of searching and found a place that offers a kit to put Mass air flow onto any EFI ford truck. www.mass-air.com I talked to them on the phone and it sounds like a good product--everything to convert to mass air flow on myh 460 for $1500. It is more if you have the A4OD trans, but I have the ZF 5-speed in mine, so it is simplier.

 

Where is the MAF located? I had no clue that the 302 and 460 throttle bodies were the same size, but that is immaterial. I assumed that the MAF was located in, or around, or in front of, the throttle body, which would make some sense. My comment about the bigger throttle body was made in ignorance. I will admit that. It seems odd that that would be the case, but truth will out. I know what a TPS does, and the function of a MAF. Thanks.

The actual point, though, as you pointed out, was that the MAF needs to be tuned to the amount of air flowing into the motor, so that it can provide the right signal to the injection computer. Now, whether that is by finding the right MAF sensor to go on the current 460 throttle body, or by finding the right throttle body with the right sensor already in place, or by going with a custom throttle body, or whatever route is taken, is what is left to determine.

Since he has an EFI 460 already, and according to you, 24# injectors, if he can find the right MAF for his throttle body, and set up with the rest of the sensors needed, he can adapt the 302 injection computer to his 460. Probably cheaper and easier than finding the MAF setup for the 460.

Good tip about where to look for these. Points I'll keep in mind, if I ever need to inject a big Ford.

 

SillyFarmer,

The MAF is generally attached to the air cleaner in line with the hose/pipe going to the throttle body. It is not attached or associated with the throttle body, other than being in the air flow to the throttle body.

Again, the throttle body does not enter into the equation. The MAF must be tuned to the injectors. It puts out a voltage level to the computer based upon how much air is being sucked thorugh it (now that is determined by the cubic inches, rpm, and the throttle body (only if it is restricting air flow)).

Given the same amount of air flow (302@WOT/460@65%WOT) the voltage output depends on the injector size.....smaller injector higher voltage/larger injector lower voltage). In this example MAF output voltage would be 5.0v for the 19# injectors and 3.3v for the 24# injectors. Still got 35% more WOT on the 460....need more fuel...gotta have more voltage from the MAF...it maxes out at 5.0v.

You can change the throttle body to whatever you want, the MAF does not care. Change the injector size without reprogramming the MAF and you got trouble.

 

BuckBrian,

It all depends on your mechanical...No, your electrical abilities. You can do the conversion from the junk yard for around $250 if you are so inclined.

AL9 ECM---$100
MAF #24 Injectors--$100
Intake Duct Work---$75
Reading schematics, wiring, splicing, soldering, hair pulling--Priceless!!

It really comes down to your pain threshold. I can assure you it will be a bit painful whicever way you go, but money does ease some of the pain!

 

If you want to see a factory MASS AIR 1997 460 from Cali. check out my gallery.
Leadmic

 

What exactly do you gain going from speed density to maf sensor? i have a 97 / 460 and E4OD thats speed density.

 

OK.. let me see if I can offer some input and clarify some things. On paper sefi mass air has the potential to deliver better milage because it fires the injectors sequentially instead of in batches of 4, and performance because it actually measures the amount of air the engine is using and doesn't totally depend on manifold vacuum and preset tables like SD does. The reason it's not a foregone conclusion that you'll get better milage with mass air is because a lot depends upon how well the system is matched to the engine, and it won't really be matched that well unless it's an all stock motor, the computer and MAF meter are a matched pair, and both of these are matched to the engine. It's a common misconception that MAF meters are matched to the injectors, but really the MAF meter is matched to the computer because it holds the meter's transfer function which is the voltage generated versus the amount of air passing through it. Any other claim of "calibration" by MAF manufacturers is really just a trick to make a larger MAF/injector pair appear to operate like the stock parts. And this technique works up to a point but the further away you get from what the computer is programmed for the worse the results. So an 80mm meter and 24lb injector pair would work reasonably well on a computer setup for a 70mm/19lb pair, but a 110mm/48lb pair would run terribly without tuning. And that leads to the last point I wanted to make, a 302 computer could be used to run a 460 but it wouldn't work that great without tuning.. no matter what injector and maf meter were used.

 

Thanx Conanski, You seem to be pretty knowledgable so I have another question. Just to refresh i have a 1997 F350/w a 460 non maf. I have installed a set of timing gears for a 1968-1973 (I believe those are the years) 429 interceptor which really "woke up" my 460. I wanted input or advice on going to maybe a 30# injector and a larger throttle body. How will this affect motor performance without having a maf sensor (remember mine is speed density). I also want to replace my cylinder heads with a set that breath better, but the only ones Ive found so far are a napa brand and Im still researching them. Thanx again.

 

Check out RJM Injection. For $200 thier harness will make the factory Speed Density harness MAF. It adds individual injector control, (2) 02 sensors. Looks pretty good, compared to the $500 and up harnesses out there.

 

Ya can't put larger injectors on an EFI motor without telling the computer somehow, it controls the duty cycle of the injectors based on how it was programmed for that engine and larger injectors would supply more fuel all the time, and that's not what's needed. Additionally... the only feedback the computer has on the job it is doing of maintaining the right A/F ratio is from the O2 sensor, and the system doesn't have an infinite range of adjustment. Besides all that larger injectors are probably not necessary until the motor is upgraded quite a bit more, 24's will support 350hp as long as the fuel pump can support them, which is likely to be the first threshold you reach. A dash mounted fuel pressure gauge would allow you to monitor this. A larger TB is no issue at all but dont expect major gains from it alone. Heads will be a problem because it seems the EFI versions are somewhat unique and earlier and afteramrket heads for carbed motors don't match up with the stock EFI intake.