Are standback users seeing partial throttle knock?

[booya620]

Well?.....

Is the 2800-3800 rpm cruising knock showing up on tuned users? If so, more or less than stock? How modded is your vehicle? Thanks, I'm trying to see if engine management makes a difference or if this is truly nothing to worry about.

[subparpunk03]

I pulled a BUNCH of timing down low for anything over 30% throttle and I'm not seeing anything over 1* of knock before 3500 rpms. Anything less than 1* of KR is really nothing to worry about.

[AutoXRacer]

Bone stock, modded, and tune cars all see the "mystery KR" at partial throttle in the 3K-3.5K rpm range.

I don't see any KR at WOT running 19PSI...but I cruise in the 3K-3.5K rpm range and I'll see KR in the 2-7 range. No one knows what crooked crap Mazda did in the ECU. The only thing that will fix it is a flash to the ECU. Hopefully CP-E will figure it out and offer the fix in a flash.

[subparpunk03]

those random spikes when the engine is under very light load are really not anything to worry about.

As I mentioned, I pulled a bunch of timing down low, we're talking <3400 rpms and anything more than 30% throttle has timing pulled, and I am no longer seeing the random spikes after the car warms up. Still seeing it a bit when driving on a cold engine. I pulled this timing for another reason though: if I mashed the gas at anything <3400 rpms I would hear audible knock instantly, as soon as I hit 30% throttle.

I didn't believe that the random spikes were nothing to worry about until I pulled my spark plugs not too long ago (before I installed a FMIC and thats when the REAL trouble started) If you notice little white flecks peppering your spark plugs, those are pieces of your piston and its the result of the damage that occurs when there is harmful detonation. If you are only seeing the random spikes then you should not have any white flecks. Although the car is detonating and causing the knock sensor to "hear" it and pull timing, you aren't under enough load to be causing any real damage to the engine internals.

Modern cars are built to withstand a certain amount of detonation, thats why we have the knock sensor. This car knocks at low-load and part throttle, took me a while but I've just come to accept that fact and move on. Pull your spark plugs and look for little white flecks of your pistons on them, if you don't see that then you are all set.

[AutoXRacer]

So you are telling me that you were able to tune out the "mystery KR" in the 3K-4K RPM range at part throttle?

[subparpunk03]

well... yes and no. Mostly yes.

As I mentioned above, I pulled a good deal of timing between 2-4k rpms at anything over 30% throttle. I did this b/c my car would have AUDIBLE knock anytime I went >50% throttle in 4th gear or above. In order to get rid of it, I had to pull about 5 degrees, and to pull that much you have to pull a little extra to "step down" to it so you don't throw a CEL.

Well the side effect of this is a very noticeable lack in power down low. Does it knock? no way. Is it fun to drive and does it drive well? Not really. I put this map on so that I could do some WOT pulls without the car puking everywhere and then gradually pull timing where appropriate, as opposed to running with it knocking and trying to remove timing to fix the problem.

I don't consider this a solution, more of just a temporary fix. I'll upload my "pussy tune" for you guys to take a peek at this afternoon. You may not need anything as drastic as I've done, maybe pull 1-2 degrees in midrange - part throttle and see if it helps you too.

[subparpunk03]

Again.... this is overkill and it will make the car feel like crap and be super slow, but it will cure your knock



Thats what I started with and after some driving and logs I ended up with something a bit more aggressive:



The aggressive map still has a teensy bit of partial throttle knock, nothing over 1.5 KR which I'm not too worried about, but it cures all my issues with >50% throttle issues I saw down low.

[booya620]

so you pulled that much timing are and still see some knock? you did here audible knock so some legit knock was occurring. What is scary is that you're saying that the "mystery" 28-3500 knock can be tuned out (for the most part). This means that there is knock occurring and it's not phantom, which can affect the longevity of the engine.

[subparpunk03]

On that first map, essentially no KR on the dashhawk. Keep in mind that KR as read by the dashhawk and actual detonation are two different things. I don't think its been verified that the electronic "ear" on the block is the ONLY thing that affects the KR parameter. Also keep in mind that my car is kind of a freak. Other reworked turbo users aren't seeing the kind of knock that I am down low.

I'd like to see other standback users play with timing and see if they can eliminate the mystery spikes and validate that it is in fact true that the car is having legitimate detonation issues.

The other thing is that some cars are built to run with a certain amount of detonation as "acceptable" So while no detonation is ideal, having a slightly more aggressive tune and a very small amount of detonation that can be managed by the knock sensor is just fine.

What you really need to worry about is the detonation that you can hear or feel. Thats the stuff that will eventually kill your engine. I was getting that at a very specific point in the powerband and it was easily replicated, unlike the phantom knock which was impossible to create conditions that would duplicate it, it would just knock now and then. Seems that pulling the timing has fixed this though, at the cost of having the car run like doo-doo.

[booya620]

whats crazy about knock on this car is that the usual fixes, such as; upgraded intercooler, colder plugs, upgraded fuel pump don't seem to be helping. there are people that have done all three and haven't seen a substantial decrease in knock. Why???? What the hell is the ecu doing. It'd be nice to get a substantial answer to this from one of the major companies working on our ecu's as to what they've found so far. it'd be pretty ballsy of these companies to tune/ make tuning product if they didn't understand the ecu.

[subparpunk03]

Originally Posted by booya620 whats crazy about knock on this car is that the usual fixes, such as; upgraded intercooler, colder plugs, upgraded fuel pump don't seem to be helping. there are people that have done all three and haven't seen a substantial decrease in knock. Why???? What the hell is the ecu doing. It'd be nice to get a substantial answer to this from one of the major companies working on our ecu's as to what they've found so far. it'd be pretty ballsy of these companies to tune/ make tuning product if they didn't understand the ecu.

Its funny you say that b/c my car ran like a CHAMP until I installed my FMIC... then the car became essentially undriveable b/c the combination of the reworked turbo, downpipe and IC was just flowing WAY too much air into the engine and the pcm couldn't keep up.

Colder plugs won't fix detonation, they do help prevent pre-ignition which is another matter entirely, and FAR more serious.

The fuel pump allows us to send more fuel to the engine, but unless you can tell the PCM to send more fuel, its not going to be able to take advantage of the pump and run any richer without something telling it to.

The colder air charge from an intercooler *should* help, but the problem is that installing an IC that flows so much better than the stock IC is that you're getting much colder air, but you're getting a lot more of it, again, the PCM has a hard time adjusting for this big of a change. The fuel trim adjustment technique is meant to compensate for slight differences in sensors/calibrations, minor boost/vacuum leaks, and changes in temperature. Its just not built to handle drastic changes.

Any sort of sustained / REAL detonation in open loop can be managed by the standback by either adding fuel or pulling timing. In closed loop your only option right now is to pull timing.

I still think someone should get another knock sensor, hook it up to a knock light, and see if the two knock sensors agree with eachother.

[jmhinkle]

I didn't have any partial throttle KR until I hooked up my SB and it seems to be getting worse lately. If I'm off the gas coasting and then just barely touch the gas again my DH turns green which I have set to do over a KR of 3. It slowly diminishes and then does not do it again for a while. Weird shit.

[subparpunk03]

Originally Posted by jmhinkle I didn't have any partial throttle KR until I hooked up my SB and it seems to be getting worse lately. If I'm off the gas coasting and then just barely touch the gas again my DH turns green which I have set to do over a KR of 3. It slowly diminishes and then does not do it again for a while. Weird shit.

Can you replicate this on command? Sounds to me like an actual issue with detonation, and something to worry about. How quickly does it diminish? If it persists at all its probably an issue. Does the engine bog or stutter at all?

[jmhinkle]

No bogging or sputtering at all. I cannot replicate when it does it, but when it does it it is the same every time if that makes sense. If instead of just gently getting on the gas I punch it and build some boost then it goes away quickly, otherwise it kind of tapers down to 0 KR. I just got a new tank of gas and did the Seafoam treatment to the vacuum lines and gas tank. I'll let you know if it goes away.

[subparpunk03]

Originally Posted by jmhinkle No bogging or sputtering at all. I cannot replicate when it does it, but when it does it it is the same every time if that makes sense. If instead of just gently getting on the gas I punch it and build some boost then it goes away quickly, otherwise it kind of tapers down to 0 KR. I just got a new tank of gas and did the Seafoam treatment to the vacuum lines and gas tank. I'll let you know if it goes away.

Please do let me know. I seafoamed my car a while back, phantom knock didn't go away. I put in a bottle of octane booster, still got phantom knock. Pulled timing with the standback and it seems to have worked but its not an optimal solution. I think in the end whats going to be the real solution is a pro fuel controller and water injection.

[jmhinkle]

"water injection"

I'm headed that way in the near future anyways.