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]

Do a search here on Megasquirt. Yes, it's been done, more than once. The most significant improvement is you get to remove the mechanical MPS, and thus remove a part that's pretty hard to replace anymore. The biggest problem in the installation appears to be fabricating a TPS mount, as the stock throttle body spins the wrong way to use the commonly available units. Some of done this, and you can also use relatively recent MS code to simply skip using a TPS altogether (so-called MAPdot code). Some people have also had some trouble getting the stock distributor points to reliably trigger the MS w/o causing resets. Using one of the Hall Effect or optical ignitions will cure this.

Other than relatively small revisions, there's really only one "model" of MS readily available. There are several different software packages you can install, but these have mostly been distilled into one package now (the "extras" package, I believe). The MS forums are a better place to get info on software. The newest MSII stuff that's only just come out (like in the last few days) isn't required, and isn't yet available in quantity. The stock v2.2 kit in use now should be plenty adequate.

On installation, everyone seems to be going their own way. One person has installed everything in the rear trunk, but is having heat-related problems (the rear trunk gets pretty hot). Others have run the wiring harness through the firewall and installed it up under the dash. Me, I'm going to make a complete waterproof housing and mount it where the relay board goes (this area doesn't seem to get as hot), but I may have to fall back to installing it in the cabin if this doesn't work out.

The stock injectors are large for the application. They're also low-impedence, so you'll either need to use a resistor pack or the "flyback" board or the external relay board. You should only need to get new injectors if yours are broken, which is unusual. The stock plumbing should be just fine, as is.