megasquirt and holley 4d: Grassroots Motorsports forum: Grassroots Motorsports Magazine

Subscribe get a full year for only $23.95 Sample Free Test Drive—no strings attached

Oct. 19, 2011 2:35 p.m. Dusterbd13 Reader

so i want to EFI my old mopar. looking on craigslist, i came across an older holly 4d system for a really reasonable price. after a brief google search, i learned just WHY its a really reasonable price. the computers are crap, and unreliable. no trouble with the TBI itself, just the electronics. so im wondering about megasquirt. i diod some tining with the factory TBI computers in the GM trucks, but never got comfortable or confident with them. supposedly there is an autotune feature for MS that makes it a very easy transition. is that true? does it work as good as the two vauge posts i read about it claim? also, does megasquirt control timing? does the autotune do that as well, or is that all me?

my other options would be a factory GM TBI unit controlled by MS, the autonomics 4bbl TBI, or spending a hell of a lot of money on either the EZEFI or the owerjection3.

i think i have a long way to learn....... so, please teach this young guy a little about MS and TBI's.

michael
Oct. 19, 2011 3:20 p.m. MadScientistMatt SuperDork

We ran one on our Nova. The smog 350 didn't make any more power on the Holley 4D throttle body than it did on a GM TBI, which was a bit of a surprise, but we concluded the engine just couldn't move enough air. It's a lot like the first section of our Nova series:

http://www.diyautotune.com/tech_articles/megasquirt-carb-to-efi-part1-nova.htm

MegaSquirt can control timing if you want it to - I'm not sure I would if you had a well tuned distributor and didn't want to dyno tune it.
Oct. 19, 2011 4:58 p.m. donalson SuperDork

I was going to point you to the DIY autotune nova build...

I would make my choice of TBI system (aftermarket or whatever) and run it fuel only... lot less learning curve if you aren't having to deal with the ignition...

for the autotune (from tunerstudio VE analyzer) thing i'm going based on what i've read on tunerstudio's web page and a few others... read up more on http://www.efianalytics.com/TunerStudio/
Oct. 20, 2011 10:00 a.m. Gearheadotaku Dork

unless you're looking to go beyond 300hp, the 2-barrell TBI should work. Check out tbichips.com for some ideas. I like the idea of megasquirt with a properly built TBI engine.
Oct. 20, 2011 11:00 a.m. John Brown SuperDork

I like the idea of adapting a MS to control a VORTEC GM engine.