Megasquirt?

[802mx3]

So I've been thinking a lot about how much I dont know about engine tuning. In particular, engine management. I realized that I know absolutely nothing about what actually controls all the timing and fuel, air etc.... Sure, I know about some mechanics, and how to bolt on parts and how to use a torque wrench. The basic stuff I get, and pretty well.
I also, understand the basic idea of an ecu and all, but still really dont get it. This has become a huge interest of mine recently. I figured I would ask for some advice here. What I really want to know is about Megasquirt. What does it do? Why do some people drive around with lap tops? How does OBD1 and OBD2 factor into all this? How does a MAF and O2 sensors get involved into stand alone? What is stand alone? How do you really tune? I just need some direction into this.

Thanks,

Eldon

P.S. What the hell is piggy back? Why do you need that for some applications?

[muttpower]

Boy oh boy, where to begin...

Ok, here goes: Megasquirt is a standalone ems. A stand alone completely replaces your stock ecu, taking over functions such as timing advance/retard, air/fuel ratio, etc.
A piggy back system simply works with the existing ecu to either alter or replace it's settings.
The ECU, whether stock or aftermarker, gets it's data from the various engine components...such as:
VAF=ammount of air flow to engine
O2 Sensors=measures your exhaust and tells the ecu what the air/fuel ratio is, allowing it to adjust fuel maps for optimal burn, as too rich will result in power loss and low economy, and too lean will result in severe engine damage.
Coolant temp sensor=tells ecu what your operating temp is for various reasons
MAP=manifold absolute pressure, which tells ecu what the barometric pressure of your intake air charge is, as to allow it to adjust ammount of fuel added, among other things
basically, each sensor tells your ecu information about how your engine is running, to adjust for better performance/economy...regardless if it's stock, piggy back, or stand alone...

O2 sensors play one of the most important roles to giving the tuner feedback, as they give you your A/F ratio. The stock narrow band sensors only allow readings of 0-1 volts, verses wide band's give a broader reading, allowing you/your ecu more room for A/F ratio adjustments...

Tuning is gathering all of this information that your ecu processes, and building your own fuel maps, etc, to allow your engine to run to whatever your desires are.

Oh, and the reason people occasionally have laptops in their vehicles is:
1) The saw The Fast and The furious, and think that's the way to race????
2) They are using their laptop as a data logger, hooked to their aftermarket ecu, to gather data to properly build their own fuel maps, etc...

Keep in mind, this is just a very abbreviated answer...considering that I, as well as many others on this forum, could go on for hours on this topic..
Hope this helps.

[802mx3]

That does help!!!!! Thank you, you seem to know your stuff. I have so many more questions however, so please everyone bear with me.

How does a stand alone tie into the rest of the cars wiring? Do you simply make your own harness? Sorry for being a complete newbie here but I've yet to actually meet someone with the answers to my questions. Anyway, lets use my car as an example. If I happened to have a, say, BP from an obd1 escort GT. short of installing it and doing all the mechanicals. How would this work, and work reliably given the fact I have an obd2 car? In a sense am I by passing the stock wiring and making my own? I'm just really confused as to how you go about a process like this on any car.

[projectB10]

Try this link...it covers off on the basics of Engine Management Systems (EMS)

http://www.emeraldm3d.com/ems.htm" onclick="window.open(this.href);return false;