Agressive tune = more power

The stock ecu will not allow an overly agressive tune - unless you isolate the knock sensor from the block

 

Shiv, as someone who used to be quite the computer nerd (tried IT and hated it) I find it hard to believe this whole pro-active knock control. Your knock sensor hears pre-ignition and compensates to alleviate the problem. The EMS uses the same knock sensor. So, what are you talking about? Both systems are going to react to the knock sensor, you just happen to have a lot more options of how the system will react with the EMS.

 

Good point - IMHO

When I examined the Exede system it's knock control adjustment was merely reducing the knock signal - or maybe I was looking at it back wards

 

Agreed - I made 521 whp with the AMS gt35 kit last week on a reflash with stock maf sensor

 

They do not realize that they are substituing years of research and development by in setting knock controls with some estimates and predictions made by a "tuner" shop in a few minutes

Even AEM itself failed to conduct what I would consider "extensive" testing and development of its system on the Evo platform

I love my AEM - its a great unit

However - many people do not realize the quaility and capability of the stock ecu

 

The diference as far as I see it is the AEM reacts to knock by end user / "tuner" defined settings and controls - e.g. the knock threshold - amount of timing pulled and fuel added per knock event and the rate at which its restored

After the AEM is set up - it has to wait for knock action to react to it and then it only reacts for a limited time frame while the knock is occuring and a short time frame thereafter

By contrast the stock ecu has a entire method of predicting the future knock activity based upon past knock activity which has been set up by engineers based upon years of experience and research - e.g. testing in Alaska and Death Valley etc

What is going to be really cool is when Ecutek releases its Evo flash version - (soon) which will offer us the ability to make slight massaging to this factory set up to give a slight performance gain while keepng the frame work of the factory system in place

It will be even nicer if the Ectek flash incorprates the end user map switching and map adjustment of its current WRX flash

 

The difference is that the factory ECU is constantly logging historic knock activity predicting how much ignition retard (if any) is needed for the next engine event. That is, if it determines that octane conditions aren't good as they should be for the application, it will have already pull back timing well before the detection of knock. This is called adaptive/pro-active knock control.

Aftermarket stand alone ECUs operate in a very different way. They typically have the following parameters (if not a few more):

Threshold-- Noise level above which knock is counted. Often this threshold point configurable as a function of RPM (to account for extra noise as revs increase)

Rate of Retard-- The amount of ignition retard applied the next engine event when knock is counted/detected. Usually this is set from 1 degree per engine event to 3 degrees per engine event. Too little and it wont supress knock fully and too much and it will over-react and kill power.

Rate of Advance-- The amount of ignition advance put back (per engine event) when knock is not counted/detected. Rate of advance, naturally, is going to be a lot less that rate of retard due to the nature of knock hysterisis. This may only be set to 0.25-0.75 deg per engine event. Too little and knock retard is going to be too obvious and intrusive. Too much and you're going to ping poing in and out of knock.

RPM/Load above and below where knock detection is inhibited-- This basically establishes the rpm and load ranges at which knock detection is enabled. Beyond these ranges it is assumed that knock detection is inaccurate (due to excessive valvetrain noise, piston slap, resonances, etc,.)

Maximum Retard-- Maximum about of timing retard allowed. Pretty self explanitory.

While these parameters provide the tuner with a lot of options, they don't exactly nail the solution on the head. I started my career back in the mid 90s tuning nothing but stand-alone ECUs. In fact, a stand alone ECU was my first product. But after a decade of tuning them, there is no doubt in my mind that they are, in most applications, an answer to a question that few are asking.

Just my 2c,
Shiv

 

This is getting old fast Al. Everytime you state this misinformation, I correct you. Yet you continue to misinform time and time again. First of all, it's spelled XEDE. Second, it does not simply reduce the knock signal. In fact, it actually amplifies the signal in some rpm/load combinations. It also induces a nifty filter that helps attenuate all the high frequency noises and rattles that occur when you install stainless steel exhausts and headers-- something the factory doesn't take into account for obvious reasons. The knock adjust feature makes the factory knock sensor more accurate in distinguishing between knock and noise-- especially in more modifed cars which, in simple terms, make very different types of noise. Our approach was to improve upon something that already works well instead of disabling it and designing a comprehensive knock control strategy from scratch with a limited budget. Judging by the lack of knock-related failures with the XEDE, I think it's working out quite well for us. And that's with hundreds of them on the road.

Regards,
Shiv

 

Thanks for the info on the Pro-Active Knock Control of the Stock ECU, definatly a nice feature i was never aware of.

im going link this thread to the AEM forums, who knows...perhaps they can incorporate this feature in a future upgrade.

 

It seems the Stock ECU is very capable but the bottom line is that the AEM has made more power is is also a great everyday driveable car. no better than the Stock ecu. So just accept the facts.

 

I stand corrected - thanks for the more detailed explanation. All I saw on the cpu screen when I looked at the tuning calibrations on your product was a set figure of 20. I guess there is more going on behind the scenes - thanks

Still - I think the stock knock set up is very accpetable for my pursposes

I think at least we can agree that the reliability record of stock ecu based tuning solutions on evos appears to be much more favorable than that of stand alone systems

 

Correct were not giving it all away. No one should be in those Knock correction fields except for Shiv and a few others. I agree with you Al about the proper way to tune a standalone. It takes lotsa time and the Chiptorque guys section off two full days (16 hours)minimum dynotime for special application full standalone cars. Of course the AEM is EVO specificish so YMMV. Good points though Al

David

 

Which facts? I've not seen you post any. Here's one to get you started:

https://www.evolutionm.net/forums/sh...d.php?t=104771


The bottom line is so long as one can adequately control fuel and spark at a given rate of airflow, the difference is in the discretion of the tuner.

 

Yeah, sure the idea is to tune and the tuner should be competent enough to tune it, the trouble is that they often don't tune or can't tune but they do anyway. The now infamous George Malinov from the late unlamented Busted Solutions is a perfect example of the over-confident, incompetent and irresponsible idiots who push and sell the AEM EMS as a panacea and screw-up peoples cars.

Should and ought to are fine concepts, but the actual reality is that "they" often wont or can't and the client ends up holding the bag

 

The facts are that outside of one ill-fated dyno run by Georges POS, never run reliably car with a huge turbo and thousands upon thousands of other peoples dollars, the highest power levels I've ever seen posted by EVOs with a DD dyno were all done with the XEDE and other Vishnu mods.

I was never a big Vishnu fan but the truth is the truth and I know first hand a good bit about EMS's and mods, etc. I've spent some time at Dyno4mance (great place, good guys ) on several occasions. I've seen with my own eyes the comparisons of AEM EMS cars and XEDE cars. Sure, results can vary and I've not seen everything, but I've seen plenty and learned a lot.