Does anyone have experience with after market Fuel injection systems, " Megasquirt " in particular. There is a huge presence on the web about the system, but is seems very disorganized. Having 'inherited' a system, ( basically a box of components ) when I purchased a rebuild project, I'm wondering if I should not acquire the oem harness & ecu, rather then reinvent the wheel. The engine is a 4AG 20 valve Toyota "silvertop". I am not as interested in wringing the last bit of power out of the engine, as I am in driveability.
Thanks in advance for any insight.

If components for the silvertop are a problem we have them in abundance down here in New Zealand. Very reliable engine, not bad on fuel but do tend to use a bit of oil.

They were sold new in only japan and south africa I believe, but due to the sale of used japanese imports are very common in NZ.

If you need some info on the silvertop or a source of parts google toyspeed. Its a NZ toyota club and has a couple of toyota parts guys that are quite helpful. Only problem with getting parts from here is going to be the cost of the freight.

The blacktop is a nicer engine, they just tend to throw rods out the side of the block if abused. Easiest fix is silvertop rods.

I suppose I did glance over the issue of "driveability"...but I dont see it as an issue if MS was tunned properly. I've used three of their ecu's and once everything is adjusted properly there were no issues. Its not a very complicated process at all other than following instructions and changing the fuel table by reading an air/fuel ratio gauage. As far as saying the system is less capable than stock, that really depends on your perspective. Both accomplish the same goal of operating the same systems. If it really effected the driveability then no one would use them. Some of us just prefer the ability to adjust their engines as required without spending 1000 dollars on a standalone system with tech support.Instrument Manifolds

It seems that much of the discussion has focused on how much difference there is between an OEM system and an aftermarket system.  I would like to pose this:

ALL of the current OEM's now use fuel injection rather than carburetion for two reasons:  1)  They just simply perform better, and in a competitive world, a substandard performance automobile will not sell, and 2)  A carbureted engine cannot meet any emission requirements, period.  One can toss any add on components you wish and a carbureted engine will not compare with the emissions controls of an EFI engine.

Now, will the driver feel the difference between a carb engine and an EFI engine?  Usually not, no matter how well calibrated ones butts is, the proof of the pudding is in the lab.  There have been numerous hot rod tests comparing a carb engine against an EFI engine and the end results have been a very close call, barely measurable, but in the long term, the EFI engine will ALWAYS perform better since it is constantly calibrating itself (at the OEM level).

Back to the discussion.  A tuner with a laptop sitting in the front seat tweaking the engine while driving is a poor comparison to the lab and tuning resources of a major OEM.  When the end result is taken in, the driver may never FEEL the difference, but the actual "out the tailpipe" can be evaluated.

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