Breakign down EFI options

[Tom Wells]

Ace23,

Lots of good opinions and some experience above; I'll add mine.

I have two large engines (521 in the Cobra, 557 in an 81 Zephyr wagon). Each has a Holley HP system which is throttle body and multi port.

Each engine started life with a carb and each migrated to EFI because of problems - one Demon carb that couldn't be tuned and one Holley carb that kept boiling the substance we laughingly call gasoline due to underhood heat.

The EFI has given each car a new personality that makes them easy to drive on the street and very nice when running track days at Sebring, Daytona etc etc.

Both have been what I call "learning experiences."

Here are a few examples.

1) Fuel pressure: The Cobra ended up with a sumped, baffled tank after a highway cruise showed fuel starvation due to gasoline running away from the fuel pump pickup on a normal interstate highway curve at 75mph. With a carb you wouldn't notice because the float bowl buffers the momentary lack of fuel pressure. With EFI, the engine stops when its fuel pressure drops to zero. The wagon has an in-tank setup I really like: Aeromotive Phantom. Fairly easy to install and has its own way of resisting fuel starvation that really seems to work.

2) Tuning: The self learning can get you 70-80% of the way there. It still needs work to tune it.

3) Bung(s): All these systems as far as I know need O2 sensors installed in the exhaust system. Mine are one per car, and are located at the beginning of the collector just after the four individual tubes join together. That location seems to work OK.

I'm sure I have forgotten several things - the mind tends to eliminate bad experiences.

The good includes easy starts, decent mileage, good throttle response. The lumpy idle can be programmed in ;-)

I have no regrets about switching. If I were building another engine I'd go EFI from the beginning.

As to different brands, most of the majors are fine. If you have someone conveniently nearby that would seem to be an advantage as long as their hardware is good and their tuning skills are up to snuff - don't ask me how to evaluate that! I like the Holleys because I've been using them for more than ten years and know a little about them.

Have fun with the decision,

Tom