hey guys, ive been on this forum for quite a while researching and learning anything and everything i could about the rx7. im pretty sure i have all the basics down but i just cant seem to find anything that could help me understand ecu and ems(?) and what the difference is. and also all the different types of ecu like piggyback or standalone.

thanks for any help guys!

 

ECU generally refers to the stock Engine Control Unit.

EMS refers to standalone Engine Management Systems, which replace the stock ECU. (Haltech, Microtech, PowerFC, Megasquirt, etc...)

Piggybacks are just devices that hijack signals to the computer to trick it into doing things like increasing or decreasing fuel. (SAFC, Greddy E-manage, etc...)

 

The engine management forum has some interesting info.

 

okay so essentially the ems and ecu are the same? what are the benefits of having a standalone compared to a ,uhhm, normal one? sorry if these questions are annoying!

*off to the engine management forum, funny how i never noticed it

 

A standalone EMS system allows you to fully tune every parameter of the engine.

The stock ECU allows you to tune nothing.

That is the primary advantage of a standalone.

 

okay sorry to bump this up again, but with a standalone you wouldnt need to have a fcd or a safc? ive been trying to do research but its hard to understand!! thanks guys

 

I just took 37 min and wrote alot of stuff but this damn stupid forum logged me off while i was writing of course like it always does, and now i lost it all when i tryed to post it. boy that pissess me off. wtf

 

soulrider,

As far as my newbiness understanding goes, you are correct. A standalone will operate perfectly fine and better without a safc or piggyback system.

If you want to put it in tiers, I kind of understand it this way (best down)
1. Standalone system
2. safc/piggyback/fcd
3. stock ECU

 

Correct. The FCD is there to eliminate boost cut with the stock ECU, which would not be an issue with a standalone. The S-AFC alters AFM signals to trick the stock ECU into supplying a different amount of fuel. Because you can fully tune the fuel tables in a standalone to your heart's desire, an S-AFC isn't needed.

Write long posts in a word processor, save the file, run spell check, then copy and paste into a forum post. It makes sense to do this for any forum when making a long post...

 

thanks again for all the help! im sorry to bump this up again but i have another question...
okay so ive been looking into the power fc and learning about how it works. i keep coming across the terms lc-1 and lm-1, what exactly does it refer to? something to do with the o2 sensor?

 

what kind of car do you have?

 

The LC-1 and LM-1s are wideband O2 sensors made by Innovate.

Personally I don't recommend them. I find them kind of finicky to use.

 

okay sorry but what exactly does wideband mean? thanks

oh and i drive a saturn sc2, dont own a 7 yet. im learning everything i can before i actually get one

 

dont feel bad bro, im a noob at the rx7s to, my mistake was buying one before i learn enough to take are of it, thats why im really glad we have these forums to help us out!

 

A wideband O2 sensor is an oxygen sensor designed to give an accurate A/F ratio reading across a wide range of ratios. Up until a few years ago, most cars came with narrowband O2 sensors which were really only accurate around 14.7:1 AFRs. This made them quite unsuitable for tuning. Most widebands are accurate from 10:1 to 18:1.

 

As Aaron mentioned, there are what are called narrow-band and wide-band 02 sensors, narrowband outputs a signal 0-1 vDC and wide-band outputs 0-5 vDC. Obviously with a "wider" band of output there are more values more "spaced out" for the computer and user/tuner to be able to see engine conditions as oppossed to only being able to see between 0-1 vDC. In a narrow-band sensor there just isn't "enough room" voltage-wise to display all the AFR's (Air/Fuel Ratios) correctly so the cars ECU only "looks"at it when it is close to 14.7 AFR (stoichometric), and then pretty much ignores it the rest of the time and uses it's other sensors and correction factors/maps to run the engine, hope this helps out a lil bit. On another note...the best way to learn about rotaries is by owning one and seeing the issues we talk about here first-hand because some things are easier to comprehend by seeing....you can read the forum all day but you won't remember everything....now I'm not saying go out and get a POS car and restore it, but buy yourself a cheap, recently rebuilt, normally aspirated FC (sorry FC guys but FD's are too nice to be used as a training platform, and FB's are too precious and cool to be cut up for training) and drive it around for a while so you can learn about the pains and tribulations of being a rotary-owner from a 1st person perspective and then when you're ready (you'll know when) get an FD...but please no neon lights or fast and the furious tail lights ok? Laters!