Originally Posted by bobcowan
There are a couple of good books on the subject of performance EFI. So I won't try and provide all the data here. I'v been working with performance EFI for about 12 years now. The learning curve is steep. But once you get the hang of it, EFI is so much better than a carb, I never want to go back.
First, the best way to think of it is two seperate systems, the EFI hardware and the computer and associated software.
The hardware has three basic types:
- 8 stack: Looks the best. But is more difficult to tune because the linkage is more complicated. It is an individual runner intake system, so you have to be very careful about head and cam selection. Power can be limited in big inch motors, simply because throttle body sizes can be limited.
- TBI: the throttle bodies also contain the fuel injectors. Cheapest. Easiest to install on any intake manifold. The downside is that you still have a wet manifold, and are subject to those limitations.
- MPI: best for power production in big motors. Still uses a common plenum. Can (in theory) use any single plane manifold, any heads, and any cam, and yet still get excellent low rpm street performance. Like any engine, all those parts should match (of course).
The computer system is where it can get tricky. Mild to wild, minimal tuning to all out racing including traction control, data logging, GPS, and accelerometers are available. It all depends on what you need and what you can afford.
You can save some money buy building it yourself with a Megasquirt kit. Then you can custom build the system and harness to exactly fit your needs.
You can even have the computer control a distributorless ignition system, with a coil pack and wasted spark, COP, or simply modify the spark signal from your distributor. If your engine is fairly radical, I highly recommend this.
"Self Tuning" is not all it's cracked up to be. The computer uses a wide band sensor and you tell it where you want the mixture to be. Driving it around will get it really close. But you'll still need to do some manual tuning to fill in the gaps. If you'll be racing, then some dyno time will really pay off.
If the engine isn't going to be too radical, I would take a serious look at Mass-Flo EFI. It uses Ford parts, and a Ford computer. Dead nuts reliable, and easy to install and tune. Mike Forte is a dealer for that system.
Don't get too hung up on sequential vs. bank vs. batch fired. Sequential is only good to about 2,500-3,000 rpm's or so. After that, the hardware can't keep up, so it switches to batch fired or bank fired. The goal of sequential was improved emissions and idle quality.
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