+1 I have little faith in any electrical knock reading device. The more I read about knock, especially on the innovate forums, the more I believe that a well designed hearing aid with a head set will be the best way to go in detecting knock.

For fun, I have hooked up a wire from pin 78 on my ECU to my Innovate logging system. I will log the knock voltage and compare the changes to timing changes. My hypothesis is that increased voltage from the knock sensor pin will not overlap with pulled timing. We will see.

 

I agree with you

I think what has done though is to err on the side of caution which is a good thing

Better to have a few extra knock counts and some pulled timing here and there even if its not real detonation than to have a engine failure - IMHO

The evos have proven very reliable and I think the stock knock control is a great protection device even if it is very conservative

Keep in mind - VERY important - as you modify a vehicle it significantly alters the SOUND profile of the engine and makes the knock sensor less and less accurate at hearing knock as opposed to engine noise

Aftermarket clutches also greatly effect the sound profile


For example at the 900 plus whp level the knock sensor is totally useless

 

It is interesting to noite that the fuel trim readings it gives are far off from my very reliable Matco detertminator scan tool

I would say the jury is still out on the knock counts - them seem accurate to me so far but its still new

 

I'm also running into random knock encounters. I had my car professionally tuned. The thing is, I had adjusted my tune for racegas myself. During day time it's perfect, 100 Octane, 24psi tappering to 22psi by red line. During night time, it spikes to 25psi to 22psi by redline.

During daytime pulls I'm getting no knock, timing advancing perfectly.

But take a look at my night time log, there's random knock counts (third gear pull from out of boost range). Yet timing gets pulled little bit but as RPM climbs, it keeps the timing advancing. I'm seen some knock log of my 91 gas (Califonia), and I've seen knock where it becomes so bad, by it hit 6000~7500rpm, the timing stays at 4~5 degrees,

I've richened up a bit in thoes area, and it seemd to have solved the problem, could be the crazy hot weather here with 91, so I'm only running 100 octane now.

As of now, for my racing gas map, i've pulled the timing 1~2 degrees everywhere and richend up a bit.

Here's the night time log from yestarday w/ race gas and cool temperatures:



how many # of knock count is considered dangerous? over 3?

-PTune

 

That is why I said in another post regarding someone elses log that I am going to adjust my knocksensor filter to make it less conservative(Do not try this I will have my tuner do this as he has tuned 2 of my other turbo cars in past without a problem) and check the plugs after every run because I had a map loaded on my car made a 4th gear pull..log showed no knock..then 30 min later same map..log showed 1 count from 4200 to 5200 and pulled timing so I know it was a fluke because I made no changes. Good tuners use their ears, I have not learned that technique yet, but my tuner does it pretty well. For a lot of us diy amatuers we use the logger because we don't really know what knock sounds like.

 

Question. I noticed the Knock filter for the 05 is different than the 03. Will the 05 be a little less sensitive to knock?

 

Not sure have not taken a look at it yet.

 

i would take more timing out......your are knocking for a long time

 

Why is my tps 99.60784 not 100?

 

dj, thanks for advice, I've done that already, running the exact timing as my regualr 91 tune. just a bit leaner.

5k6, The TPS seems different on every datalogger I try. I also have pocket logger shows my max TPS to be 98.8. Only on evoscan it actually shows 100, I think there was a post to calibrating your TPS. might want to look into it.

 

A few comments:

1. It is very very normal for an EVO to pull timing as you approach peak boost. Peak boost happens around 3700 rpm. When you go WOT at 2000 rpm (as you did), your timing starts high and then gets gradually pulled until it reachs 3-4 degrees. On some tuned cars it might even reach 1-2 degrees. After that the ECU will gradually add timing and it will reach 19-21 by redline.

2. Looking at your chart I can see contradictions in that knock sum. Allegedly with knock sum increase your car is supposed to pull timing. But from 5k-56k your knock sum is at 4 and the ECU ADDS timing. That tells me that there is something fishy about this knock sum logging. I have seen this in almost all the logs that have been posted, which leads me to ask the question: Is knock sum reall measuring knock? The ECU then keeps on adding timing despite the knock sum being 3-4. That seems the opposite of what should happen.

3. Do you have a wideband o2 sensor? I know that the narrow band o2 tends to be off, but your narrow band voltage is WAY low. You need to be around 0.93-0.94 volts across the band. That might mean that you are running the car WAY lean. You MUST get a wideband and do some logging with it to know for certain. But from the look of the narrow band, you seem to be too lean.

4. Your timing should be higher from 6500 rpm onwards. I think that is where the timing is getting pulled since you MIGHT be running lean according to the narrow band O2. You should be around 15-16 by 6500 and end up with 20-21 at redline.

 

Man what gear were you in ?

 

Wow, only advancing to 10/11 degrees? I've NEVER seen that. I don't see timing being pulled either, just smooth advancement to 11 degrees. Which is VERY low. Is this with a stock turbo?

 

The datalog was done in 3rd gear. Stock 05 turbo. this knock shows up only during night time for odd reason. on daytime it's fine. Also this is with 100 octane race gas.

 

nj1266,

I have seen you make this statement countless times. Just because you see an increase in ignition advance, it doesn't mean the ECU isn't pulling timing.

The ECU is still going to follow your timing profile based on your ignition maps and what RPM/load you are at. It's just that the the ECU will subtract timing from the value that it should be.

For a quick and completely arbitrary example, let's say that your timing should ramp up like this from peak torque:

3 5 8 10 14 18 (completely arbitrary just to prove a point)

Let's say that you get 6 counts of knock where the 14 and 18 were. Then your timing will look something like:

3 5 8 10 12 16

Of course the ECU will still advance timing. It will just apply the knock correction to it. I just keep seeing you say that you see the ECU ADD timing when there are knock counts. Sure....it is just following the timing maps and correcting as needed.

Also, what was posted about the DSM ECU is incorrect.

The DSM ECU will pull .35* of timing for every 1 count of knock. The 1G ECU pulled a maximum of 15* (43 knock counts). The 2G was slightly lower than that, but I forgot the number.

But the DSM ECU would pull timing exactly proportional to knock counts, starting at 1. Roughly 3counts of knock to 1 degree being pulled. I don't believe that we have found out the exact formula for the Evo ECU yet.


Eric