hi i need help on fuel injection setups..im putting a 428 clone fe into my 69 mustang fastback. i was thinking of an edelbrock efi manifold and fuel rails and just use an elbow with air meter nd throttle body. instead of a speed density garbage they sell. my problem is i need a distributor for this setup? my custom ground cam will be a 114lsa .485/470 @.50 i will also use a AoD trans. just for street use. any help would be greatfull......

 

Why not carb? A lot cheaper and will work just as well once set up right(though they can be a real pia to set up right sometimes). Do you already have parts? I ask just to make sure you're not going EFI because you think it's necessary in order to get mileage, throttle response etc. There are tons of carb myths floating around out there.

As far as an EFI system, you might want to check out FAST's EZ-EFI. It's a speed density system, but so is nearly every aftermarket race system(including their XFI systems, which are on some of the fastest EFI race cars in the country). The unit bolts onto a carb intake like a carb does(sensors and injectors etc are contained in the unit), and it's self tuning as you drive it(similar to how new cars work). It's already proven to perform exceptionally well across a wide array of engines. Distributor with that setup works just like on a carb setup. It's cheaper and easier than most systems, still provides the wet flow intake advantages of a carb, and FAST offers tons of really good support and is extremely high quality.

Otherwise, if you piece a set together, you may have issues finding a computer that will work with it that was set up for MAF on an engine that size etc etc. Have you thought about what to use for a harness and computer? And what MAF? MAF has to be calibrated for the particular engine and injectors etc. You can't just throw a MAF and TB on and plug a computer in and expect it to run right(or even run at all in some cases). Then you get into whether it controls ignition timing or not, can you get a compatible dizzy etc.

And just FYI, SD and MAF function almost exactly the same in terms of how the computer operates. The only difference is in MAF the input voltage comes from a MAF sensor as a primary input instead of a MAP like in SD. But all the ECM sees is voltage across a range. The only thing a MAF does better is pass emissions, on account of the MAF sensor being precise over a wider range of conditions. In terms of power and reliability SD is just as good or slightly better, so don't be afraid to use it. Like I said, nearly all the aftermarket high end race systems use speed density and not MAF.

Since speed density is good enough for Formula 1 engines, 2.4L V8's turning 18,000rpm, and making 750hp naturally aspirated(before recent rules changes, turning 20,000rpm and making over 800hp), I don't understand why so many people think it's not good enough for their street or performance car. There's a lot of SD myths out there.

 

the only difference between SD and MAF that I can see is that MAF is a hell of a lot better idea if you drive from the coast into a mountain and then back down. The MAF with a heated wire will measure actual air no matter if it's thick or thin air. the SD will only pick up on air volume. yes, MAF it an advantage. Especially when car companies produce cars of the line and ship to every country in the world. However my Mustang in Ireland will never see more than 300m altitude difference and I guess the same counts for Delaware. Once tuned your fine. And I'm sure that if you'd ever go up a mountain the EZ-EFI would adjust for it.
The very same problem you'll have with a carb. However as 67m302 pointed out is if you have your carb set up correctly then there should be not much difference in power or gas/mileage. there's better ways to get more gas mileage like a 5spd box.

Long story short I was once looking at EFI but can't afford it and if I ever will I'd simply go for the EZ-EFI as well. Every article I read about it simply praised it.

as for the distributor. I don't know the system you want to run, but yes you'd need a spark at the cylinder and only a distributor with coil can provide that. The EFI will need it to get the rpm signal.

 

take a look at my website, it has some pretty good info on what all it takes to make an early model efi. It's not difficult, but it is somewhat extensive. electrical, fuel system, etc...

I've had mine fuel injected for about 6 years now and LOVE IT. we did my son's 72 F100 also.

 

The way most factory SD systems worked for altitude, is they used adjustment tables based on barometric pressure. When you first started the car and powered the MAP sensor it would check the baro and adjust accordingly. As you drove up in altitude or weather changed, it would lose tuning accuracy...unless you went to WOT which would bring the manifold pressure to about the same as atmospheric, giving the MAP an accurate reading and it would recalibrate. BUT, it would use different lookup tables for fueling, because the baro pressure was lower than 1 ATM. So it would fuel like it was at 96% load for instance, when it was actually at 100%.

Newer systems use an actual baro sensor in the inlet tract somewhere. The EZ-EFI(and other SD systems) went a step further, and rather that adjusting for altitude based solely on baro pressure(MAP reading at WOT) and using a different lookup, it checks for pressure differences between the MAP and baro to determine load, then uses the proper lookup table for that load. So that way at high altitude etc, the ECM still sees 100% load(difference between MAP and baro, which is pretty constant based on an engines induction system) and uses the proper part of the lookup table, then simply tweaks fueling based on baro and O2 readings.

Like I said, the main reason for MAF(the only reason really) is emissions. Because it responds instantly to any changes in either the engine or ambient conditions, it's extremely precise across a very wide range of conditions. Most engines can be +/- 3 to 5% fuel and it doesn't effect power or the way they run, but it will change emissions. And it's not uncommon at all for SD on the same engine(with a good system) to slightly outpower MAF, if for no other reason than you don't have a MAF filament and mount blocking the inlet tract and heating the incoming air.

MAFs work by using a platinum filament that is constantly heated to about 400* F above ambient, a given mass of air at a given temp removes a given amount of heat, and extra voltage is added to keep the filament temp at that constant "ambient +400* F", the voltage increase corresponds directly to temperature drop, which corresponds directly to a given mass of air. Since the ECM also knows the temp of incoming air, it can calculate the actual mass of air....hence the term, mass air flow meter.

 

yep the more power i need to keep up the temperature of that wire, the more air mass is passing. thats how I understood it as well. Never knew that the SD systems could adjust to altitude. some good idea with the barometer. Well of course the throttle position sensor could take care of that as well ... at least help. but then again as you said if WOT is not used how would you find out.

 

That's why the new SD systems don't require going to WOT to check the baro again. But manufacturers switched to MAF a long time ago for the precision is gives in controlling emissions. MAF can also adjust for engine changes too, SD tables are based on a known and specific engine configuration. So you start changing crap on SD systems, heads, cam, exhaust etc, and it throws the tune out of whack.

 

My son is doing this to his Falcon right now. He simply wants the advantages that EFI offers over carbs.

And yea, we started the process with a visit to your site....

 

For a 289/302 that's not heavily modded(even one with a decent h/c/i) the stock MAF setup is quite capable of dealing with it, and runs well when properly tuned.

 

He picked up a S/D setup from a Crown Vic, it should work fine for his mildly built engine in his cruiser Falcon.

I will post it up in a week or two when we get it running.