Me and my buddy were talking about this, and I couldn't quite figure this out. What is the purpose of running a standalone ECM? The one advantage to it that he pointed out is that you are no longer limited to using a MAF, but on say a 93 camaro it doesn't use a MAF anyway. I know another advatage to a standalone is that you can rev to whatever, as with a stock ECM in camaro's you can't go over 7200 (but what if you weren't planning on revving out that high anyway). He mentioned that it is better due to the fact that you are no longer using a piggyback system, where you are just tricking your car into giving it more or less fuel by faking a false lean/rich condition to the ECM, but if you just reflash/chip your stock ECM you dont even have to do that. I know standalone's are big thing with turbo setups. What else can you do with a standalone that you can't with stock ECM exactly, What are some limitations that you have with a stock ECM, that you no longer have with a standalone?... Bare with me, i'm kinda new to the whole tuning thing, but i'm learning as I read a bit.

 

Aftermarket ECU's are generally better equipped to accomodate power adder applications. While you can program the stock PCM for high boost applications, and for some nitrous applications, it usually involves some sort of "work-around"..... example - programming a system that was designed strictly for a 1bar MAP sensor to accept the input from a 2bar or 3bar sensor in a boost application.

An aftermarket ECU has open architecture.... you know exactly what each function is and how its programmed. The factory PCM has some features hard coded, like the closed loop A/F ratio. With an aftermarket system, you can program it for anything you want.

Running nitrous, my MoTeC is capable of running an optimized "NA" program, then switching to a whole new level of programming and offsets for a 300-shot of dry nitrous.... simply because it knows the master N2O arming switch has been moved to the "on" position. No need for external devices to retard timing, alter fuel pressure or adjust A/F ratio. The unit incorporates features that eliminate the need for things like a window switch, WOT switch, etc. Its all internal to the ECU and asy to program. Fully selectable rev limiting, using random or fixed fuel or spark cuts or a combination of both. Internal data logging. Ability to run closed loop with either narrow-band or wide-band inputs. Data channels for things like EGT sensors. Programmable on the fly, using a laptop. High speed processor with high definition injector pulse width drivers. Ability to run either high or low impedance injectors, or even multiple injectors per cylinder. Selectable for bank-to-bank, semi-sequential or full sequential injection. Programmable injection timing. Individual fuel and timing trims for each cylinder. User definable offset tables. Larger fields for tables, allowing more precise control of timing and fuel. Adaptable to virtually any ignition timing input, including the infamous Opti optical sensor. Add-on drivers for 8 direct fire ignition channels.

You can do an amazing amount with the stock PCM, and many people have. They are suprisingly flexible. An aftermarket ECU simply makes it a bit less esoteric.

The MoTeC system can also handle things like full traction control, drive-by-wire systems, fully variable camshaft timing, etc. - if you need it

Interesting reading:

http://www.motec.com/products/ecu/tutorial.htm

 

damn, thats some pretty sweet that you can do that much with that ECU. How much does something like a motec standalone cost?

 

I bought mine used for $1,500.... about 1/2 of the price for a new one. Wideband control is an extra cost option, as are many other things. Full data logging, full access to the code, lifetime software updates and the interface cable add another $500. The IEX 8-channel ignition driver is $450 extra.

 

I'm running a standalone FAST in the turbo car (no factory PCM anymore). The FAST ECM samples quicker, can go higher in RPM and the C-Com software is a lot more flexible than the reverse-engineered/hacked programs for the LTx computers. Plus, I don't know of a way to make the GM PCM work w/ an MSD Pro Billet or a crank trigger.

 

I think most aftermarket units are far easier to tune as well. I know with tunercat or LT1 edit there are no instruction manuals... no booklet. You are basically on your own without a place like this of course where people pass along some of their trial and error learning.

And to be honest I believe the aftermarket units are infinitely more controlable but they are just so expensive that they arent an option for most people. If I can get away with using the stock computer then Ill save my $3 grand for something else.

 

yeah, I had no idea that standalones costed that much cash, I knew they were expensive, but 3 grand is a LOT of car parts that could've been bought. Seems like running a standalone, judging by the price, its seems to be something you get after you drop 15 grand into parts and have a potential 8-9 second car.

 

I went for the cheaper route for when I spray. I have the LTCC ignition, which has an input to change timing when spraying.

I also have a standalone fuel system incorporated to the wet system, so I adjust that relative to the jetting I'm using... and therefore do not need to make A/F adjustments to the N/A program.

 

When you first got it, how did you get the car up and running? Was there a baseline v8 350 tune or did you have to create everything from scratch? Will the mail-order guys program these things?

 

I like the factory pCM as well but I will be gettign the BS# stand alone system. ITs pretty badass and is gaining popularity every year.
www.bigstuff3.com

 

The shop thaat built my engine is an authorized MoTeC installer/tuner. They loaded an initial tune based on their experience, that was probably a 95% quality tune from the first time the engine turned over. After that, it was a very long series of engine dyno sessions to dial in the timing and A/F for three different cases..... NA, NA + single stage 125-shot for the street, and NA + two stage 275-shot for the track. We actually started the engine running alpha-N, and got amazingly good results considering it was a daily driver. Later, when we ran the nitrous up to a 300-shot, we went full speed-density.

I let the pros set it up, and limit my tweeking to trying to adapt to track conditions, or improve driveability.