I tried to disable the knock control today with the address FAA set to (0x5658), and it didnt seem to do anything. Still ran off the high octane ignition map as normal, so maybe for my model it is hidden somewhere else in the maze.

I did some testing again today, and 0 octane appears to not use my low octane map. I managed to force the octane number down to 1. I left it off zero so that it is not sitting in a form of limp mode. At 1 it uses more retarded values than in any of the maps still, and that includes areas of the map I didnt hit while forcing the octane number down.

Also did some playing around with the Knock Filter 2 map (mine may be different to others). It is basically a map of zeroes with a number of 128 values used around 120 and 140 load and spread from 1500 to 6000rpm. It appeared to be related to the areas of the ignition map that are effected by octane number. I had an idea to enter a bunch of 128 values into some off-boost areas, and then see if driving in those areas could make the octane number go up or down. What it actually did was force the octane to zero and go limp whenever I was in that area of the map. Strange. I might try over the weekend putting zero for all of the map and see if it has the opposite effect... maybe disabling the knock in some way.

If anyone want to follow what I am talking about, grab a ROM and XML for the GT-A. (80700010).

 

https://www.evolutionm.net/forums/sh...=knock+disable

This is how I disabled knock control.

 

Re-writing the routine would be the best, but at the moment it would be a good goal to just know what all of the maps truly represent.

I generally trust my knock readings too, but I just dont trust it around the 2500 to 3500rpm range at low boost. Especially if it were truly knocking and a small amount of retarding of timing would stop it. But when I have been all over my car and also mic'ed the block to listen for what is triggering off the knock control and cant find a thing. Maybe on later models Mitsubishi "dialed in" the knock control a little better, but for the 7 GT-A I am tending to think they got it wrong. I drove more than half a dozen of these cars and they all had the same feeling of a massive lack of power in the low-end, with the car I purchased being the best of them. From what I have seen it seems to be a common theme on this model of car, making it all the more important at least for myself, to find a software based solution. With the knock control not playing games, the car feels alive and is a delight to drive around town. So I am dedicated to finding out how to work with this setup.

With regards to the zero octane being the low octane map. What I was doing for testing was tagging just about everywhere off-boost and setting it all to only 5 degrees, but leaving the high octane map untouched. That way I could see when it was trending towards using the low octane map. But in all my testing I never saw it move from the values in the high octane map. That is the part that is confusing me. Unless, whoever setup the definition for 80700010 got the low octane ignition map wrong? The original map by default runs identical values to the high octane map at every point, but with my tuning I have deliberately set it to what I would consider a good safe level (more retarded as load increases).

This is the reason for the experimenting. Not to say anyone is right or wrong, just to prove in real world conditions what is actually happening regardless. From what it looks like, we really need to find an unhappy ex-mitsubishi ecu worker and do some brain picking. :-)

 

Best. Post. Ever.

 

Unfortunately, with the Evo, it seems as if people jump into forged and built engines prematurely. If tuned properly, and that's a big if, the stock bottom end of the Evo is sufficiently strong for most of our applications. We already have forged rods, albeit smaller than most aftermarket rods.

In 2G DSMs, the rods were about the same exact size (maybe exact) as the Evos, but they were cast. I was running over 400 whp and sold the car running strong with 117,000 miles. I had a friend pushing 550whp on the same bottom end and running 10s in his DSM...all on the cast, tiny rod bottom end. The Evo bottom ends are much stronger and should be able to handle, and have been proven to handle, these levels and higher.

Most of these threads over the years of spun rod bearings and blown engines are no doubt people who either ditched the stock ECU for an aftermarket with inferior knock control or people who didn't tune for 0 or little knock on the stock ECU. Remember all of the tunes that were exposed when ECUFlash and logging capabilities came about for our Evos. How many people were running around with double digit knock sums every day by reputable tuners?

Of course, I'm not saying built engines are a bad thing. It's just that, as John mentioned, they are difficult to work with on the stock ECU, and for that matter even an aftermarket that uses our same knock sensor, for reasons explained throughout the thread.

I, for one, like the stock ECU knock control. It would be nice to be able to control it a little better and I hope this thread leads to some new findings, but I don't ever plan on changing from the stock ECU and knock control. I stuck with the stock ECU/DSMLink on my DSM and will stay with the stock ECU on my Evo, until something truly better comes along. In my eyes, that means pressure sensor knock detection.

 

Matt are you saying that your definition shows the low and high octane maps the same as stock?

Eric, I didn't realise our rods were forged. In the UK everyone is paranoid about exceeding 400 BHP and 400 lbft because they think the rods will break (although with the owner's full understanding I'm pushing one considerably harder on pump with a Green but watching the boost spikes, rev limit and knock). Some are changing just the rods and think the pistons are fine to 550 BHP.

 

I have never examined the stock rods under a microscope or anything like that, so don't take my word without question. I forgot where I received or read that information, but it was one of the things that I remember being most happy with coming from my DSM.

That's not to say that my source wasn't incorrect. I'll try to find some info on it and post some links if I can still. I forgot if I read it on a website, in a magazine, from Mitsu, some forum, etc. Wherever it was, I was under the impression for quite a few years that our stock rods are forged. I've seen pictures, at least, of the stock Evo rods and the stock 2G DSM rods and they look pretty much identical. I know the 2G rods are cast. The 1G rods are bigger and cast. The stock 2G was rated at 210HP I think, so using the same size rod, but forged, made sense to me and somewhat, for me, verified what I have been reading. I don't think Mitsu would use such a tiny, cast rod in the Evo, but who knows.

 

5658 should turn off the knock control and the rear O2 CEL, and 5652 should be just the knock sensor. I have done this and seen 0 knock all of the sudden and the car appear to run on the low octane maps based on idle timing differences. I went from intermittent knock with a bad clutch at 20psi to NO knock ever all of the sudden. Difference in the USDM rom maybe? I wouldnt think it would be but I am not sure.

 

Matt, the thread I linked to included the addresses for JDM Evo 7... you might want to check your values at the same address.

 

Well i've just read all 3 pages and there is some very interesting posts in there.

I myself have an evo 6, with an evo 8 forged engine, balance shafts removed, gsc s1 cams and now a green, on a stock evo6 intercooler. Boost is sorted out via my AVCR.

I have been out logging it today, running 2.3bar of boost and I get the odd knock counts of no higher than 3, and it isn't sustained as the octane level stays at 100.

I use a JDM evo 7 ecu with the tephra v5 patch, and I have just had the ecu rescaled to 320 load (from 300).

Before I had the forged engine fitted, again I wouldn't get very high knock counts, but was running 1.8bar on stock internals (even stock cams), and producing 380bhp and 390 lbft.

Anyway I just thought I would post up, just to throw a spanner in the works, with reference to the balance shaft removal and forged engines

As for Mattjin and your GTA, I have to ask (silly question I know) but have you actually tried a new knock sensor attached to the block and removed the current 1 that is giving issues ?

I know you connected a 2nd one to the rocker cover, and that was fine, just wondered if you had bolted it to the block to see if you still get the same knock readings ?

 

Just for future reference, what forged pistons do you run?

 

Wiseco with the revised (22 thou from memory) 2nd ring gap

 

Yes, my GT-A came standard with the low and high octane ignition maps identical. All other stock ROMS I have downloaded for this vehicle have the same exact map as mine has too. It is a JDM 2002 Evo 7 GT-A. Bought it a couple of months ago as a second hand import. At first inspection I thought it very strange to have the same values for both maps, so maybe somewhere along the line the Mitsu engineers decided not to use the low octane map. Maybe purely relying on the RAM based knock retard. First thing I did was to start with a more retarded low octane map but as my experimentation has shown me it never uses it even on zero octane. The ROM and definition can be found anywhere for this car, but the definition needs the data endians all changed to big otherwise the scales are all garbage. So please grab a copy and check it out.

With the octane on 100 it uses purely the high octane map that is for certain. I have so far been unable to do anything to make the ecu use the low octane map. So you can see some of the confusion I have over this. Maybe the reason why the knock control didnt disable is because I entered 5658 and the GT-A model doesn't have a rear O2 sensor. I may have done the wrong thing and please correct me if I did, but to make FAA adjustable I just copied over the line out of the definition for one of the EVO9's. OEM my ROM has a value of 56D0, but I might try 5652 next time I am online with it. I know virtually nothing about assembly, but thanks for the info JCS.

I actually do want to try to put the new knock sensor on the block in the original position. However, this vehicle is near impossible to get to the knock sensor. Cant from above and cant from below even with the proper 27mm tool. It has to have the intake off or the motor out to get anywhere near it. But actually what is happening with the car is a bonus because it makes it easy for me to play with the knock control setup. If the car ran perfectly then I would not be able to easily force the motor to truly knock with any form of safety. So for now it is a good way to experiment. I am not so sure about the sensor being faulty. It behaves correctly at WOT, with too much advance causing it to register knocking. Its just the part throttle low boost areas that ruin the fun.

To make it clear, I am not a newbie to tuning. I have been tuning for almost 20 years and in most parts of the world. The thing I am new to is working with this exact unknown knock control setup. The tune in the car is relatively safe so I have no fear at all of engine damage. I too believe most people should leave the knock control alone, but when it is playing games and there is some knowledge to be gained, I am all for experimenting with it. I tend to believe that those that have damaged their engines when not running the knock control have nothing but themselves or their tuners to blame. If the motor was damaged from knocking then it can only mean the mapping was wrong and it was heavily relying on the knock control to keep things together in the first place.

What would be great is to still have the knock feedback, just have the ECU not retard the timing. In a perfect world.......

Rods are a bit off topic. Thought I would be a thread **** for once. :-P