AEM EMS Series 2 vs Chrome ECU

[AdamVR4]

I know this has already been discussed but I've spent a good deal of time thinking about it today and want to make sure I'm not off-base.

I assume both the Chrome ECU and the AEM EMS Series 2 adequately control fuel, timing, no-lift shifting, 2-step, etc. Functionally, they seem similar, which is why so many are opting for the cheaper, simpler to tune, chrome ECU's.


For my application, the Chrome ECU's KEY advantage relative to EMS:
- stock knock sensor / algorithm


For my application, AEM EMS s2's KEY advantage relative to Chrome:
- better datalogging


If I make the jump to E85, something that's always simultaneously tempted and scared me, that eliminates use of the knock sensor, effectively eliminating the Chrome ECU's key advantage.

I've got a local guy that I trust to dyno tune my car with the EMS. He doesn't mind me standing over his shoulder questioning him and he's willing to show me the ropes with the software.

What would you do?

[familyMAN]

From your build thread, I'll post it here as well...

I like my AEM series1 but would love to have series 2. Flex fuel and many safety features that should've been included years ago. (AFR lean limit by load, FP to load, etc). If you have the sensors and data, you can prevent catastrophic failure from common problems.

For example, what happens if one of my two fuel pumps fails or I spring a leak on the submersed line with Series 1 or chrome?? I'll have enough fuel to keep it running and toast a motor...

What happens on a series 2? Either FP safety feature or AFR will kick in and it will automatically cut fuel, ignition or boost (almost positive you can define response)....

[CoopKill]

I believe with the proper sensors that all can be accomplished in Chrome as well?

[Alex3000gt]

You've got a local guy, with a dyno who is willing to tune your car - with the caveat that it has AEM EMS.

I would go AEM EMS, it would be a great learning experience. I'll let other people chime in with technical reasons for and against.

[familyMAN]

Since I am only experienced with AEM my input is biased, only because I am not familiar with the pro's of Chrome.
Here is another pro for AEM...
Real-time tuning, no flash and retry. Very useful when trying to get big ass cams and injectors to idle well. Also useful when cruising down the interstate and trying to get something better than hummer gas mileage on e85. I made a ton of progress real-time on my 2 hr cruise to NG that I wasn't making with logging my cruising, making changes and uploading.

[AdamVR4]

You've got a local guy, with a dyno who is willing to tune your car - with the caveat that it has AEM EMS.

I would go AEM EMS, it would be a great learning experience.

That's a very good point. My biggest concern would be learning on a $10,000 3.5L 6G72. I could reduce that risk considerably by installing it on my original 3.0L...

Real-time tuning, no flash and retry.

That is a fairly significant advantage and one that I've really benefited from over the years with the lowly e-manage.


It may seem like my mind is made up, but this morning I was hell-bent on the Chrome ECU. Now I'm just confused.

Thanks guys.

[TurboSinceBirth]

The lack of real time tuning is a big strike for me since I've relied on that heavily in the past with different piggyback controllers. Chrome doesn't require nearly as much tweaking as an AEM starting from scratch with either system so effectively you will reach a point where it will be a moot point. I doubt Chrome will ever have SD since it isn't as accurate of a tuning method at least with the technology our cars were made with. There are new features always on the horizon for chrome but I doubt it will ever accomplish more than some of the most expensive standalones. If I had a trusted tuner that would help teach me what all the tables did I would probably go with that option. I've debated a long time about ponying up for a ProEFI and have threatened before to go standalone. I owned an AEM EMS v1 once before despite barely getting to use it on a 3.5L 5857 build.

I wouldn't be scared of running ethanol. You know what you're doing enough to understand the pitfalls of it. That's all there really is to it. I guarantee you'll love the extra torque switching fuels and probably won't want to go back. I couldn't stand pump gas levels on our piss poor 91 here. It was too slow. Lol. Conservative timing is what it's all about. If it really bothers you and I know you're one to get it done right, then you'll rent a dyno to tune for MTBT. Watch for the torque curve to stop increasing, back it off for a safety margin, and you'll be good as gold. I'm honestly not too sure I would consider messing with timing even using VD as a tuning tool. There's no way to real-time view the torque which I guess you can't do on a real dyno either but at least it feels safer to do a pull there.

[Greg E]

If I make the jump to E85, something that's always simultaneously tempted and scared me, that eliminates use of the knock sensor, effectively eliminating the Chrome ECU's key advantage.

You're confused because you keep filling your head with crazy ideas.

The same issue with tuning e85 is the same with an AEM and Chrome. You effectively get around the octane limitation of your fuel and reach into the realm where cylinder pressure becomes a danger. Neither chrome or AEM have an effective way to detect cylinder pressure.

Detonation is only one form of cylinder pressure. Excessive compression from too much air and too soon of a spark (too much timing) also causes cylinder pressure. As awesome as a microphone on top of the motor is, it can only tell you detonation is happening and by then it's too late.

Remember my thread about Ion knock detection? It effectively monitor cylinder pressure and can detect the pressure levels. Get really good at monitoring that and it can detect knock before it even happens.

Too bad neither chrome or AEM have the capability to utilize this technology. Believe me, it's something I very much want to add but just don't understand electronics well enough.

[Greg E]

Another large misconception is that you *need* live tuning... Wtf???

If you got a sensor that reads air mass (GM) or air volume (stock/EVO MAF) and the scaling/comp tables are setup properly, then the sensor will report correct airflow to the ECU and thus you'll have a running motor with stock or aftermarket cams. The closed loop feature gets around the fine tuning part and the fuel trims tell you what to do from there. It just works without the fuss... It's nothing like fucking around with a piggy back. You don't tune chrome. You calibrate the MAF sensor and injecors, set your desired AFR, flash and turn the key. It just works...

As for tuning for power. You don't tune while your foot is to the floor! You let the motor idle/cool then spend some time reviewing the logs. What's waiting another 10 seconds to flash the chip?

A major advantage to chrome is you always know your real time HP and Torque. I'm not talking about dyno calcs or any of that over engineered crap. The MAF itself is a true measure of air. So much real time useful data can be utilized knowing that key information. How else can a guy take a full second off the 1/4 mile time and gain over 6 mph without changing a single part under the hood???

[familyMAN]

Another large misconception is that you *need* live tuning... Wtf???

Attitude, WTF???

Never said it was a "need." I have just found it useful on my setup which is SD.

**Tuning idle and cruise on stock cams (or street cam regrinds) and reasonably sized injectors is quite a bit different than race cams and fire hoses when you are trying to get some streetability below 3500 rpms. Weird stuff happens to AFRs (even bank to bank differences) due to overlap, dead times, etc. Only sharing my experience and what helped me.

Maybe Chrome would be better but to my knowledge no one has tried to tune 280 cams and 1450 injectors on chrome? If so, I would love to hear their experience!!

Maybe a large MAF is the ticket. Obviously worked for Matt M.

Never looked into it personally, but doesn't AEM work with a MAF also if that is preferred?