Another advantage I can think of in terms of tuning a stock N/A engine involves changing the cam timing to get rid of the EGR function at part load.

Your MPG might take a hit, but I didn't really find it amounted to much for the gains.

On my A4 AVK 3.0 V6 (which had exhaust cam timing) I found that eliminating the exhaust cam retard at low RPM made major improvements to throttle response when you were cruising around town in real driving conditions.

You can achieve the same thing on an engine with single intake cam phasing by setting it to full advance (so earliest IVC) from just off idle to about 4000 RPM.

Anyone else tried this approach?

I've read plenty on EFI, trust me...

You know as well as I do that no EFI tuning book is going to tell you what the net effect of these types of modifications will be.

That's why I'm taking the time to post this stuff up and get feedback from members who know Motronic works.

So my next question is this:

Let's say I set the initial knock pull to 0.75 and the engine needs 1.5 degrees to control the knock event, what's preventing the engine from pulling the additional 0.75 degrees if it sees that the knock event wasn't controlled by the initial pull of 0.75? I see no reason that the ECU wouldn't be able to correct the timing accordingly after it sees that the knock activity hasn't subsided after X number of combustion cycles.

I should add that in my experience, I haven't seen any excessive timing pull or knock activity on my own vehicles that I've tuned this way.

As I mentioned earlier, I think that the initial delta of 2.25 degrees is unnecessarily aggressive and is meant for worst case scenarios of drivers running WOT in 50C heat, up a hill with a trailer with 85 octane fuel.

OK great, so will you please answer my previous question

Let's say I set the initial knock pull to 0.75 and the engine needs 1.5 degrees to control the knock event, what's preventing the engine from pulling the additional 0.75 degrees if it sees that the knock event wasn't controlled by the initial pull of 0.75? I see no reason that the ECU wouldn't be able to correct the timing accordingly after it sees that the knock activity hasn't subsided after X number of combustion cycles.

Although a bit prickly, prj 9.9/10 backs up his claims with reasonable assertions when prodded.

Correction, it's an engine that's managed by a computer.

Further to your response, then it appears that I'm correct in my understanding that the ECU CAN pull additional timing after the initial ignition correction.

Now, back to the original point of how much ignition timing needs to be pulled out to prevent a runaway detonation condition.

If I understand correctly, your position is that 2.25 degrees (or so) is required if the ECU senses that the engine is beginning to suffer from pre-ignition. If not, then the cooling of the combustion chamber surfaces is insufficient and either 1) the ECU will need to pull out MORE timing overall in order to control pre-ignition (than if it had just pulled out 2.25 degrees in the first place) or 2) the ECU will be unable to control the pre-ignition and your piston will do a meltdown.  

My position is that 2.25 degrees initial timing pull is unnecessarily aggressive and that this calibration is done in anticipation of a worst case scenario. My presumption is that if I lessen the initial ignition delta, I am doing so with the understanding that the vehicle owner will always be filling up on 91 octane or higher (94 octane fuel is common in our neck of the woods and I would always advise someone to use it whenever possible).

To see if my position was tenable, I dug up the data logs to compare the stock vs tuned ignition tables and ignition correction as well as the lambda actual vs requested. Here's a summary of what I found.

1) When I compare a WOT log of my tune (top) vs the stock tune (bottom) you can see the ECU juggling timing on both logs. However, with the ignition delta set to 0.75, the ECU is only pulling out as little timing as required to stabilize ignition. Whereas in the bottom graph, with the delta set to 2.25, the ignition timing is much more unstable when the ECU starts sensing knock.

stock vs tuned touareg 5000 rpm ignition by zimbu themonkey, on Flickr

I should add, remember that I'm talking about N/A engines here. With the additional pressure of F/I, I will concede that prj's point becomes much more of a concern. Proceed with caution.

2) Contrary to the position that a stock V8 can't take much more ignition advance Advance the timing, you hit knock -> you lose power due to timing pull. , I found that it can take much more than the stock tables call for. At full load, I was seeing up to 7 degrees more advance.

stock ignition
stock touareg ignition table by zimbu themonkey, on Flickr

tuned ignition
tuned touareg ignition table by zimbu themonkey, on Flickr

3) When I examined the ignition retard on a cylinder by cylinder basis, the ECU was requesting little to no ignition retard which suggests to me that the extra ignition timing can be added safely.

cyl 1
tuned touareg ignition retard cyl 1 by zimbu themonkey, on Flickr

cyl 2
tuned touareg ignition retard cyl 2 by zimbu themonkey, on Flickr

cyl 3
tuned touareg ignition retard cyl 3 by zimbu themonkey, on Flickr

cyl 4
tuned touareg ignition retard cyl 4 by zimbu themonkey, on Flickr

cyl 5
tuned touareg ignition retard cyl 5 by zimbu themonkey, on Flickr

cyl 6
tuned touareg ignition retard cyl 6 by zimbu themonkey, on Flickr

cyl 7
tuned touareg ignition retard cyl 7 by zimbu themonkey, on Flickr

cyl 8
tuned touareg ignition retard cyl 8 by zimbu themonkey, on Flickr

4) Contrary to the position that Adjust the fueling -> gain absolutely nothing because they already run best power I found that the stock fueling tables took much more throttle for it to make best torque (lambda 0.85) vs my revised fueling tables, where best torque was made as soon as you tip into the throttle.

stock lamba actual
stock touareg air fuel ratio current by zimbu themonkey, on Flickr

stock lambda desired
stock touareg air fuel ratio desired by zimbu themonkey, on Flickr

tuned lambda actual
tuned touareg air fuel ratio current by zimbu themonkey, on Flickr

tuned lambda requested
tuned touareg air fuel ratio desired by zimbu themonkey, on Flickr

While all this goes a little beyond the scope of your response. I think it provides some pretty solid evidence that there ARE gains which can be made safely, even on a stock V8.

5-7 degrees of extra advance and lambda 0.85 at tip-in vs WOT is going to make a substantial difference to how the vehicle responds, especially in transient throttle conditions. I would also submit that the extra timing will result in absolute gains through most of the RPM band at WOT.

Based on what I've seen, most N/A engines are tuned for fuel efficiency, emissions, driver 'comfort' (read: numb throttle) and worst case scenarios.

Getting the most power and response seems to be a distant second, especially in the case of a big heavy sport ute with a massive V8.

Unlike the case of some of the more sporting model V8s like the S4 and RS4,  the North American V8 Touraeg was most likely calibrated with the understanding that whoever is driving it will be filling it with 87 Octane and running it hard in hot humid conditions.

Further, as the stock fueling tables show, the calibrators' main concern was fuel economy. To knock it out of lambda 1.0, you pretty much have to push it into kick-down.

With that said, I see no reason to make it that resistant to adding fuel. All you need to do is take a good representative log, find out which map areas you use for cruise and static part throttle and keep them in lambda 1.0.

From there, my preference is to get right into best torque (lambda 0.85) ASAP. Again, it makes a MASSIVE difference in how the vehicle responds to throttle inputs.

I don't have time to read this.
But my data is based on personal experience on my dyno.

0.75 timing pull "controls" nothing at all in any engine - why, I already wrote.
Do as you want and melt your shit if you want to, not my problem.