Aftermark engine management system – nice to have or need to have?

syclone98

New Member
Joined
Oct 24, 2003
After a long hiatus from the GN community, I’m just starting to build two project cars (86 & 87) that I purchased recently. The primary reason for this thread is to determine whether purchasing an aftermarket system like DFI, XFI or BS3 falls into the category of nice to have or need to have.

Since I also have an 07 Corvette which I tweak with an HP Tuner (someone else did the primary tune for me), it’s easy to get a little spoiled with the number of different values you can control when compared to a stock GN ECM. At the same time however, having that kind of control over an engine can get pretty overwhelming at times as the learning curve is pretty steep. While I know from tuning the Corvette that it’s nice to have control over so many different aspects of the car, I also know that at the same time my motor *should* have the capability to go almost (if not just) as fast with just a decent carburetor. I also know this is true with the GN as many people have cars that are insanely fast while still running only the stock ECM and a custom chip.

I have different goals for each of the two GNs as one will be a daily driver and the other will be used primarily at the track. The common goal between the two cars however is that regardless of the type of turbo I run or injector size or any other performance upgrade that I have, I’d like to know that I’m always getting as much performance out of the car as is possible.

In case anyone has noticed that this thread is also in the Engine Tech section, that was actually done on purpose. What I was hoping for was to hear from people who are very familiar with these systems as well as people who had considered one but decided against it, or even had one but later decided it wasn’t worth the extra money (and that they should have invested in something else like a bigger turbo as an example) and subsequently would have little to no reason to frequent the ECM forum.

So what’s the verdict? Nice to have? Need to have? Or somewhere in the middle?

Thanks for reading,
Christopher
 
Lots of guys (and gals) run very fast using the stock ECM either with a MAF or MAFless. So, I guess that means it is not essential to have an aftermarket ECU to go fast.

You could use the stock ECM with a powerlogger and a stand alone WBO2 and get close, but the stock ECM isn't operating in closed loop at WOT. It basically ignores the O2 sensor.

Some people don't feel comfortable doing their own tuning, don't want to mess with a laptop, or want to "Do it " their way.

I personally wouldn't build a serious engine without one of the latest aftermarket ECUs. The latest generation ECU's offer huge flexibility with built in datalogging and closed loop AF correction at WOT using wideband O2 sensors (and many other features). These two things are absolutely essential in my estimation.

With an aftermarket ECU, you can make a run, record the info, analyze the data and make informed tuning corrections. AND the ECU learns and adjusts the Fuel tables based on the WB O2 sensor. Something the stock ECM doesn't have. On the other hand, It also gives you many more opportunities to screw up and BLOW up your engine if you don't understand what you're doing!!

Both systems have their place. If I were building a street car, I'd use the stock ECM, If I were more serious, I'd strongly consider an aftermarket unit.

Does that help??

Dave
 
Yes that does help, thanks.

That's probably what I'll end up doing - leaving the stock ECM in the street car and use an aftermarket one for the track car.
 
.....

The latest generation ECU's ......

..... the ECU learns and adjusts the Fuel tables based on the WB O2 sensor.


Which ECM learns WOT from the wideband? As far as I knew, in all of the aftermarket ECM's, the corrections were only real-time, and not 'learned'.

Bob
 
Wasn't that what the "L" key was for J/K Bob and Dave. Dave pry meant that It made corrections to a point.

Steve
 
I can't speak for all Aftermarket ECU's, but when enabled, the BS3 learns and adjusts the fuel table based on WBO2 input. Learning isn't enabled at idle or WOT......but I didn't say that!!
 
I would say nice to have for a street car. For a car just for the track have to have!
 
I run a classic fast system on my Hybrid Camaro. I like the WBO2 feedback I get for adjusabilty on the fly while driving it's hard to beat how easy it is to tune.
I have HP Tuners for the newer vehicles I tune that I turbo charge. All factory systems have far more setting and values than a aftermarket.
It takes alot more knowledge and time to properly tune a factory ECU than a Aftermarket. Having experience in both takes time. I'm learning HPT as I go along..... It's not easy!
I can have a FAST system car dialed in very quickly.
If you get all the proper stuff you'd need to tune a stock buick ECM these day's it's almost the same money as a FAST/DFI/BigStuff.
For the money and ease of useage it's just as well to switch.
Just my openion.
Scott~
 
I totally agree with Dave and Scott.

Turbo Bob you have me confused:confused: , if you were going to build a FAST car what would you use?
 
How fast?

I was simply trying to clarify that the aftermarket boxes don't tune your car for you.

Bob
 
Like the picture of the engine there Sam! Looks great!

Mine's in Ohio... getting re-worked... Can't wait for spring!
~Scott
 
Bob,

As I see it the main advantages of an aftermarket ECU are:

The ecu can learn and adjust the fuel table (not at idle or WOT)
The ecu adjusts WOT fuel delivery based on WBO2 input
The user can easily record, review and make changes to the calibration.

Yes, aftermarket ECU's don't learn at WOT. It is still up to the skill of the tuner to calibrate the WOT fueling. But most current aftermarket ECU's adjust WOT fuel delivery based on WBO2 input and the limits of authority set by the user. This ability gives the tuner a "cushion" so that the ECU corrects for a lean condition and won't cause a catastrophic event.
 
Bob,

As I see it the main advantages of an aftermarket ECU are:

The ecu can learn and adjust the fuel table (not at idle or WOT)
The ecu adjusts WOT fuel delivery based on WBO2 input
The user can easily record, review and make changes to the calibration.

Yes, aftermarket ECU's don't learn at WOT. It is still up to the skill of the tuner to calibrate the WOT fueling. But most current aftermarket ECU's adjust WOT fuel delivery based on WBO2 input and the limits of authority set by the user. This ability gives the tuner a "cushion" so that the ECU corrects for a lean condition and won't cause a catastrophic event.


I understand and agree. I was just clarifying. As a note, the Translator Pro works the same way.

Bob
 
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