Hi,

I am seing knocksums of 4-5 and want to lower the ignition advance a bit, how are the 3 ignition maps related to each other? Which one should have the highest values? When does the ECU change to use another ign map other then the one with most ign. advance? In my current setup ign map #1 has the highest ign. advance..


Knock, how hich knocksum is normal? Should I aim to have 0 knocksum all over the rpm range or what is considered OK?

Thanks.

 

Your desired sum should always be zero. But unfortunately too many variables keep that from being a possibility ALL the time.
First of all how much boost are you running and what are you list of modifications done to the vehicle. Preferably the ones done to the engine compartment and exhaust.

 

what ignition maps are you reffering to? There are only 2 ignition maps in your ROM that can be seen in ECUflash. A high octane ignition map and a low octane ignition map. The ECU also has whats called a octane flag, which is measured from 0-100%. At 100%, the ECU is looking at the high octane map completly, this goes for fuel AND ignition. If you experience a lot of knock, and the ECU has to keep pulling timing VIA it's knock retard protocols, the octane flag counts back from 100%. As this happens, the ECU will start to look up fuel and ignition values from the low octane maps. If it goes to 0% octane flag, the ECU is looking up values on the low octane map completly, with no interpolation between the two(high and low octane maps).

You want to shoot for 0 knock sums at all times, but conditions don't always allow for this(i.e.bad gas, certain weather conditions, ect.) So, it's normal to experience 1-3 knock sums at certain conditions. Tune for 0 though if at all possible.

Also, it is possible to experience whats called phantom knock. This is when certain sounds are exhibited that sound similar to knock. The knock sensor is nothing more than a tuned microphone. It's tuned to hear the frequencies that are associated with detonation and pre-ignition(knock). Unfortunatly, there are other things that can happen under and around the hood that sound a lot like knock to the knock sensor. If you have a downpipe that is hitting your lower control arm supports, this may cause phantom knock. There are others as well. This will cause the ECU to pull timing if knock sums go over 6 counts. This hurts performance, as pulling the timing effects power alot. It's important you find the cause of knock. Pull timing and run high octane gas (100 or more octane) and see if the knock goes away. If it does, then it was the result from over advanced ignition timing. If does not go away, it's phantom knock or possibly mechanical knock.

I will explain what mechanical knock is later. I got somewhere i gotta be, and im LATE!!

CJ

 

Thanks for the reply.

Actually I have 6 ignition maps in ECUFlash.

High octane ign map1
High octane ign map2
High octane ign map3
Low octane ign map1
Low octane ign map2
Low octane ign map3

My question is.. what is the relation between high octane 1-3, when is it using high octane 1 and when is it using high octane 2 and 3? Which of these should have the most ign. advance?

I know pretty well what knock and phantom knock is but i'm wondering why there are three high octane ign. maps.. I will iam for 0 knocksum but want to know which of the three high octane maps to change..

 

I had the same question yesterday and asked my tuner... he said map 1 is used when the engine is cold, map 2 is used for normal operations, and map 3 is used when there is a malfunction (limp mode).

I had the question because all 3 maps were the same on a previous tune I had, but on my new tune (with a different tuner) they are different.

 

It is obvious that he as an Evo IX which have 3 high octane maps and 3 low octane maps representing. Cold start, Normal operating temperature and DTC operation.

You are incorrect on multiple accounts.

Even one count of knocksum is able to pull 1 degree of timing away.

 

+1

ps. I_tune. VIIIs only have 2 ignition maps, IXs have 6.

 

I stand corrected, i was under the impression he had a VIII. I have never tuned a 9, so you learn something enw everyday.

I have NEVER seen 1 knock count pull timing, not on the VIII at least. It takes about 5-6 counts to start pulling timing.

CJ

 

You are still wrong. 1 count can pull timing.

 

I am glad to have this confirmed again lately cause there was a thread here a few days ago that a evo 9 high oct ig map was being discussed in detail and after 2-3 pages of posts about weather it was a good map or overly agg nobody seemed to question that it was high oct map 1. I thought maybe there had been a discovery in the code that I hadn't heard of so I didn't comment.

 

Like i said, not that i have seen.

Could you be so kind and tell us all, how much timing is pulled with only one count of knock??

CJ

 

Go reread my post.

 

I did, and it says nothing about how much timing is pulled at 1 knock count. Please, enlighten us.

CJ

 

I think you may be the only one that has overlooked the post, so I will enlighten you:

https://www.evolutionm.net/forums/sh...51&postcount=6

 

instead of being an ***, you could have wasted less of your time by just giving the correct info the first time i asked. Thanks! This will be the demise of this forum.

For instance, if you could of just pointed me to the CORRECT post, it would have saved a lot of time and uneeded posts. Cute.......



CJ