[T3] FI brains reinvented?

Jim Adney jadney at vwtype3.org
Mon Oct 22 09:49:24 PDT 2018

On 21 Oct 2018 at 10:20, Micah Medway wrote:

> I've been musing for a while on the possibility of re-engineering FI brains
> for VWs 

They probably could, but it's probably not worth the effort, because the OG 
brains have been exceptionally reliable. While there's always interest in 
adding adjustability, that can currently be done externally, and most of those 
efforts turn out to be misleading or counterproductive anyway. 

There's a class of computer-like chips called microcontrollers. I'm sure one 
of those could be adapted to replace most of what's in our brains in a 
package about the size of a large postage stamp. Of course a "new" brain 
would also need power filtering and regulation circuitry much like it already 
has, and interface circuitry to drive the injectors, but most everything else 
could be done in the ucontroller, which would be reprogrammable.

It could all be done for a few hundred dollars, plus a few thousand hours of 
development time. Since you can replace everything with a Megasquirt 
system for about $1000, there seems to be very little point in doing this, 
since very few people would ever buy it.

Consider this: I spent hours and $$$ developing a $75 relay kit to take 
almost all the load off the ignition switch in my '71. That kit would be a 
godsend for anyone with a '71, and it's been working well in my '71 for a 
couple years. I wrote up detailed instructions and packaged 5 kits, but so far 
I've sold exactly one, and it's not been installed yet. It's waiting for the car to 
be finished and working in the stock configuration before the kit gets 

I sell lots of the $25-33 gas tank overflow kits, quite a few $11 or $30 fuel 
pump primer kits, but $75 seems to be a bit more than most of our owners 
are willing to pay for something that seems to be optional, at least at the 

Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA

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