Megasquirt in a 72 1.7L 914 ???, Need advice Options

[rotary914]

I'm new to this list........ So Hello

Well - the title says it all.
I will probably keep my 1.7L for at least another year and I want to replace the 33 year old F.I. with something new.
I'll probably get new injectors too.

Has anyone converted to a Megasquirt on a 1.7L??
Any significant improvements over a properly running stock F.I. system??
Any negatives??
Easy to tune (I have a LM-1 Wideband meter)??
Any particular megasquirt model??

Any recommendations??

thanks

Steve C
72 914
81 RX-7
99 Volvo S-80

[lapuwali]

QUOTE (Mueller @ Apr 6 2005, 02:07 PM)

QUOTE I noticed he was able to do this without a TPS. This is part of new code in the megasquirt, right? Can we do that for the 914 and not need a TPS? I believe for most applications the TPS is really only needed for fuel enrichment during acceleration (it should be a little quicker than MAP based) and for decel, so the motor will get less fuel on coasting...the MAP will do the rest...

I believe the very latest code (the "extras" code) has a mode that allows you to only use the MAP sensor, even for accel enrichment and fuel cutoff. Decel generally results in a MAP value below idle MAP, so you just set a threshold below the idle value for fuel cutoff. Accel enrichment can be done using a MAP rate of change as easily as a TPS rate of change. There probably is a better response rate with a throttle sensor, but ditching the TPS seems to be a win to me. Using a TPS makes things a touch more reliable, as the MAP thresholds are going to change from car to car (even engine to engine). Set the fuel cutoff too close to idle and you'll find the car stalling at lights regularly. Set it too low and you'll get popping on the overrun because the cutoff never happens.

The set price is pretty good compared swapping to a complete aftermarket system. It's admittedly not a big market, either. If he maps the ECU to work with your CIS engine (2.4, 2.7, 3.0, and mods), then it's a much fairer price.