paint.roper
New Member
- Joined
- May 17, 2011
- Messages
- 31
What's everyones opinion on the two, which is the better conversion? I've talked to a few offroad shops and they recommended TBI.
I never seen a TBI out perform an EEC-IV SEFI injection.
TBI is generally a GM throttle body EFI off a late 80's or early 90's truck. GMs bargin aproach to making EFI, make something that will drop on top of a conventional carbed intake. Properly tuned they run like a properly tuned carb. There are a handful of companys that make kits based on this sytem with a semi-custom chip to try and match your engine. For the most part they start, idle and drive around very well. Seen a few on the dyno, under load both were so far out of tune it pegged the dynos wide band oxygen sensor. Biggest design flaw is they are guessing at airflow. Look at RPM, manifold pressure, spit out some fuel. Closed loop driving it will tend to compensate for having the volumetric effiency of the engine not programmed right. Under load it goes open loop and all bets are off on how well it will run.
The mustang based EEC-IV computer ('89 to '93 has the MAF) is more able to adapt to an engine. It looks at the airflow, knows how much air is entering the engine, figures how much fuel it needs, knows how big the injector is and squirts the right amount of fuel. You can play around with volumetric effiencys of an engine (cam and heads) and it will change the airflow through the engne. But the MAF will give readings and for the most part the computer will still get it right or at least very close. Much better choice to put on a non-matched engine.
If it doesn't have a MAF, it is speed density based. Which is a perfectly good way to manage fuel injection. Trouble is the computer must be matched to the engine just right for it to stay tuned and working right.
Shops are in business to make money. TBI systems are a better business deal for them. More profit for less work. Buy a kit, bolt it on, cash your check. The mustang based EFI is a better system, but not as fast or easy to install. No quick mail order "kit" with everything in it. They actually have to think and work. Often using used parts which are not as pretty and profitable as shiney new parts.
I am looking for more reliabilty...
...and performance.
Now MAF vs. Speed Density, that would be a good debate.
Now MAF vs. Speed Density, that would be a good debate.