The real reason people are breaking rods

[FORZDA 1]

Originally Posted by djuosnteisn knock frequency depends on structural characteristics of the block, not rpm.

Also the installation placement of the knock sensor....

[FORZDA 1]

Originally Posted by SRTie4k ......either the DISI is an insanely noisy engine with bad vibration problems, or our knock sensor just plain sucks. Which is it?

More FYI on knock sensing. When I took my car to the dyno, the tech let the rpm sensor touch the TMIC shroud (ETS 3.25). During the first run it vibrated against the shroud and caused a big timing retard that ruined the run. The rattling noise obviously tripped the knock sensor. He moved the pickup over so it couldn't touch the shroud and the next run was essentially perfect.

My point is that noise, ANY noise, that passes through the frequency that the sensor is tuned to trip on WILL cause perceived knock. If you have ANY underhood buzzes or rattles any one of them could pass though the sweet spot and trip the sensor to knock retard.

[asherstan]

interesting

[SRTie4k]

Originally Posted by FORZDA 1 More FYI on knock sensing. When I took my car to the dyno, the tech let the rpm sensor touch the TMIC shroud (ETS 3.25). During the first run it vibrated against the shroud and caused a big timing retard that ruined the run. The rattling noise obviously tripped the knock sensor. He moved the pickup over so it couldn't touch the shroud and the next run was essentially perfect. My point is that noise, ANY noise, that passes through the frequency that the sensor is tuned to trip on WILL cause perceived knock. If you have ANY underhood buzzes or rattles any one of them could pass though the sweet spot and trip the sensor to knock retard.

That's why I say a setup with full solid mounts and a balance shaft delete will likely cause more false KR since vibrations increase dramatically. That's also why I said I have a hard time believing the stock DI system could possibly cause more noise in the frequency of the knock sensor than a heavily modded engine bay.

Originally Posted by djuosnteisn knock frequency depends on structural characteristics of the block, not rpm.

But RPM will indirectly affect the frequency, if even by a very small amount.

[Ziggo]

As said before, the frequency that the knock read at is primarily dependent on the structural characteristics of the block where the sensor is attached.

RPM will simply affect how often that it is picked up. In the world of vibrations, RPM is a relatively infrequent occurrence. Its like the difference between the tempo of a beat of a drum and the tone of the drum. Both have a frequency and thus in theory could make a sound, but the knock sensor is looking for a specific tone of the drum, it doesn't care how often it beats.

RPM will affect how all of the tones interact with each other. At a certain RPM any number of things could combine to generate a wave form in the tone of the knock. Lower frequency vibrations each with their own set of harmonics, with proper timing generated by RPM, can be combined to generate higher frequency vibrations.

I have no idea if it is the injectors, that is what is different about this engine, so as soon as we encounter a strange problem that almost always gets blamed first. Any number of things could be the issue.

This type of issue takes a ton of time to resolve because the only effective way to do it is through testing which is typically late in the development cycle when both money and time are short, and I assume that the engineers are under similar situations to what I experience at work which means there is a bean counter standing over your shoulder the whole time telling you to not make it perfect, make it good enough, and for a stock engine, this knock detection system reeks of "good enough"

[ganque]

Does anyone has a picture/map/diagram of where the knock sensor is located?

[FORZDA 1]

Originally Posted by ganque Does anyone has a picture/map/diagram of where the knock sensor is located?

Will this do?

[darth vader]

Unplug that bitch, who needs it anyway....

[mituc]

Guys, where should I look for dangerously high cylinder chamber temperatures on my dashdaq? Or how can I figure them out? I just want to make sure I don't go anywhere too close to those high temps that can cause cracks on the rods and everything.

The only thing I can think of is to keep an eye on the the cat temp values, because there isn't any "EGT" (exhaust gases temp) parameter available. Will this be enough?

[06Speed6]

I have a catless dp and I have seen my cat temps go over 1700*, I am not sure how trustworthy those numbers are because that would likely put the chamber temps over 1800*. The best bet is to get a egt, its better for tuning than afr anyway.

[FreeFlyFreak]

Originally Posted by mituc Guys, where should I look for dangerously high cylinder chamber temperatures on my dashdaq? Or how can I figure them out? I just want to make sure I don't go anywhere too close to those high temps that can cause cracks on the rods and everything. The only thing I can think of is to keep an eye on the the cat temp values, because there isn't any "EGT" (exhaust gases temp) parameter available. Will this be enough?

Want to know for sure.
EGT probe exhaust runner 3.
Anything else is a waste of time.

[mituc]

Hmm.. I can't find this on my dashdaq. Maybe it has some other name?

[cpolly69]

the dashhawk displays egt, but it is only calculated egt and it's wrong -
there is no sensor that the ecu could read real egt from - so there is no way for your dashdaq to display it -
that's why freefly said to get an egt probe - and an egt gauge
there are some things that no data logger - or obd2 monitoring device can display - this is one of them - oil pressure or temp are some others

[Ziggo]

Originally Posted by 06Speed6 I have a catless dp and I have seen my cat temps go over 1700*, I am not sure how trustworthy those numbers are because that would likely put the chamber temps over 1800*. The best bet is to get a egt, its better for tuning than afr anyway.

Cat temperatures do not directly relate to EGTs. The catalitic process creates alot of heat and will be higher than the temperatures before the cat.

[cpolly69]

Originally Posted by Ziggo Cat temperatures do not directly relate to EGTs. The catalitic process creates alot of heat and will be higher than the temperatures before the cat.

yup and that # the dash hawk displays is really closer to cat temp instead of actual egt

[urville]

I've read through this thread and I do think the following info and thread are also a good resource to all this and thought I'd give a link through to them for informational purposes.

Check this out:
http://forum.mazda6club.com/speed6-e...disussion.html

I thought it was worth mentioning, especially this from in the responses.

Everything is debatable at this point as to why the fueling is so rich. Because it is, I think a catch can is an absolute must, Pennzoil Platinum is the oil of my choice, and blocking off the EGR like Whoosh should seriously be considered. When I pulled my intake mani off to put the new pretty red one on, it was covered in thick black soot. My old mani was spotless (b/c I cleaned the hell out of it) when i reinstalled with the catch can and I was definitely surprised to see more gook in there and it all came from the EGR.

[06Speed6]

Welcome to the forum

Running slightly rich isnt a bad thing, it hurts power slightly, but it has been proven to save your bottom end over time.

Catch cans are bandaids for a pcv system design problem. They work, but it is a ghetto fix.

The EGR does need to be blocked off.

[Frequentflyer]

Slightly rich is one thing, but being down in the high 9's and low 10's like the stock tune at WOT is WAY too rich. Slightly rich IMO is low 11's. I notice that I don't get nearly as much soot on the back bumper of my CWP tuned to 11.8 AFR with the AP as I did when I was stock.

[urville]

I just thought as far as the subject of thread goes it would be a useful link. I think the point they were making is that the combined effect of all the buildup from the EGR mixed with the situation from running so rich, that being the fuel that was shown to be causing the oil in the cylinders to be for lack of better terminology, diluted. These two issues are suspected thats all.

[06Speed6]

I never ran 9 or 10:1 stock lol.. Ide dip into the 11s sometimes, but it was mostly 12s at wot. Right now I am tuned to run low 12s to high 11s at wot. Running 9s at wot would probably sheer the oil and eventually score the bore which would lead to blowby problems, but it wouldnt break a rod.

I do remember those oil sheer threads on 6club though, we just hadnt torn down enough engines at that point to know what was going on. We now know that it is a pcv problem that was causing the oil to do that.

[darth vader]

So...you say block EGR but how do you keep combustion temps down if you block it off? Mazda tunes the car rich for this reason, I'd bet and, chucking EGR on top of that signals that there is an issue with combustion chamber temps. Deleting EGR will increase combustion chamber temps and bring on pre-ignition and detonation....

[aaronc7]

egr only active in non WOT conditions... i have blocked off the EGR it's been a great mod IMO. keeps stuff a lot cleaner..less knock.

[Frequentflyer]

Originally Posted by 06Speed6 I never ran 9 or 10:1 stock lol.. Ide dip into the 11s sometimes, but it was mostly 12s at wot. Right now I am tuned to run low 12s to high 11s at wot. Running 9s at wot would probably sheer the oil and eventually score the bore which would lead to blowby problems, but it wouldnt break a rod. I do remember those oil sheer threads on 6club though, we just hadnt torn down enough engines at that point to know what was going on. We now know that it is a pcv problem that was causing the oil to do that.

I dunno. My ATR shows my stock map running OL/WOT AFR's at 10.6 down to 9.8 from 4,500 to 7,000 RPM.

[mrQQ]

sorry for raising dead, but..

i've always thought that "we're now past bent rods" was the "low rpm/high load" thing.. but after reading few last pages of this thread, that doesn't seem to be the consensus?

so what was it in the end? fp shitting pants?

[Ziggo]

As I was poking at in the thread it's just simply management of the torque peak and avoiding knock, independent of the RPM.

I tuned my K04 to spool as soon as possible, and do the same with the BNRS3, I just keep the torque peak below 400, and only add timing in areas where the boost cannot make the desired torque alone.

If we were seeing bearing failures it would point more to a low rpm loading issue where the motor was loaded up before the oil pressure was sufficient.

Zigatapatalka

[mrQQ]

got it.

is there any reference as to which RPM is a safe turning point to no longer limit tq?

or, let me rephrase

what are safe psi/load values for 1.5k/2.0k/2.5k/3.0k rpms?

[Lex]

Woah old thread is old. The principle still applies - too much cylinder pressure and a lot had to to with the gen1 OEM tune/mapping that generated detonation before we had tuning solutions.

[nrankin01]

great write up!

[Playaj]

Thread necro'd again smh

Sent from my SAMSUNG-SGH-I337 using Tapatalk

[Enegem]

Good Info ..... The thread keeps going and going , Just like the eveready bunnie .

[mxlplx71]

There is no need to throw your 2¢in on an old thread...


Please just read and gtfo

[ms6mil]

Originally Posted by mxlplx71 There is no need to throw your 2¢in on an old thread... Please just read and gtfo

This isn't his first, he's being a post whore!

Originally Posted by Enegem Newbie Alert!!! 2011 MS3 All stock , upgrades soon (tis the season) Looking froward to the support , tech help , member pics , secure purchases and just plane good reads all around ....... 2 post down , 148 to go

@Enegem; Bad noobie..... bad!