That's still a lot of work, time, and expense, so I feel for you. But look at it this way: you might get wind up with a better motor in the end if you discover the core of the problem!

BTW, do you have a windage or baffle tray in your oil pan? I'm not an engine guy but there seems to be some consistency in the same cylinder tossing the piston and lunging the rod out of the block. Couldn't that be a lubrication issue? If it was a build quality issue, I would expect less of a pattern. It's interesting that virtually all of the reports here point to the same basic failure mode, modified or not; they almost always let go in normal driving, not very often at WOT, and it almost always seems to be the #1 cylinder.

Point being, there MIGHT be an issue with the #1 cylinder not getting enough lube under full load so it wears faster (which should show up in UOA's). Then some freaky combo of relatively low RPM, and a corresponding lack of oil pressure, combined with some ECU weirdness under light throttle, conspires to stress an already weakened part to the breaking point.

Just a guess, anyway. I really don't know, but a pattern is a pattern.

As for the warranty, well I doubt you'd have gotten any love even 6 months ago. There's only so much a dealer hookup can do for you. Major repairs like this need to be approved by the factory zone rep, and they're the ones who are looking for any excuse to save corporate money on warranty reimbursements to a dealer.

Anyway, good luck, let us know how things progress.

Did you have any increased engine noise prior to the failure?

Many people experience this when they bend a rod under high load, which causes large imbalance that manifest itself as lots more engine noise. This usually leads to the rod failing and exiting the block during normal driving.

I still think there are a certain number of engines that are just defective (knock on wood). I'm not buying into the whole ' you have to shift before X rpms' or 'it's a partial boost' issue etc. Now with increased mods, I do agree one has to pay more attention to what's going on but for many who just have basic bolt-ons, it shouldn't be an issue.

I'm about to hit 50k, learned to drive stick on it, and have driven it every which way, and the engine just purrs like the day I bought it (knock on wood - harder this time ;) ).

I usually shift between 3000-4000 rpms and and rev the hell out of it at least 5 times a day to, during and from work. Yeah, I'm almost stock, but the story I'm hearing is even close to the stock motors are blowing. I think mods will increase the likelihood of an already defective motor blowing much sooner. Just my 2 cents.

I agree with you, I have over 51k now, and just add tmic and inlet, I shift when I feel like it, so no certain pattern, but between 2500 to 6k rpm...I tried over 6500 a few times to see how the car response...
I do worry about the said blown engine thread like this here...and people started to come out of the woodwork with blown engine.....lately my right foot is getting heavy with the gas pedal after the tmic and inlet install...so I try to enjoy my car without worrying about blown engine....I do hope we figure out though .....I hope that is just some bad apple....

My engine is blowing. I just know it. I read it on the internets that someones engine did!

Slight noise a day or 2 prior but to mee sounded like the HP fuel pump ticking. No Knock detected on dashawk. Fluids, AFR, EGT all good.

Once i heared the ticking noise i started to become anal about paying attention to parameters and gauges. No negative detection whatsoever

stock cars are not popping...99.9% have mods on them....and i agree that shifting anywhere in the rpm zone up to 6000 should not be a issue.....but i have taken the position of not playing around too much in the 3000 rpm area going into boost....i boost or i do not, and i shift by 6000 max as Mouse mentioned.....the car was designed to run out of breath there, why push it past the K04 power curve, plus the throttle closes...and indeed members with 50,000 plus miles on stock or lightly moded cars have been fine.. Lastly, i do believe that Jersey's car has great parts on it and a fine safe tune, but something with the full combination of all this with added boost has put the motor in distress...would it of blown if the car was running stock boost, and stock tune??? Hopefully we will find out soon, so others can be prepared and avoid this type of issue...

Many cars have had a very similar ticking to what you described prior to getting a hole in the block. The one guy that pulled his engine apart in time found a bent rod.

This is likely what your ticking was.

My car makes all types of nosies. even if I got a bent rod I'd never be able to hear it.

Nope, you sure wouldn't. But apparently you'll definitely be able to feel it through the clutch pedal.

:toothache:

Yeah your right. My days are numbered though I'm just waiting for the bent rod daemon to come claim me. Would be the perfect end to my MS3 career.

I'd like to add that if you blow a MZR DISI engine is probably a minimum of $2500.00 for a use long block...If you plan to mod heavy allow me to suggest building it with forged parts.

Damn! If someone offered me $2500 for my used longblock I'd sell it tomorrrow. It was running perfectly when it was pulled at only 22K miles..

i'll trade you my built motor plus your stocker and 750.00... We each pay freight

I'm no wizard, but that sounds like voodoo. For the engine to worse off under part load than full for a mechanical failure unless there is severe detonation sounds like belief in magic. I don't know for a fact what is going on with these failures during part load, but here's a conjecture:

The initial failure point is a piston or rod (pretty safe bet!)
The failure starts with a bend in a rod or a crack partway through a piston, most likely while at full load.
Either will fail completely, matter of time.
SO...
90+% of driving time is spent in moderate throttle, medium rpm. The zombie parts are going to fail, they need only a certain amount of normal usage to do so as the crack propagates (piston) or the bent rod mayhem unfolds. Now when part has worked itself close to failing with via *any* kind of driving after the fatal injury, a slight extra load will hasten its death.

So, you're just driving along and don't realize you're actually on a dead engine. Then you reach a hill, go up an on-ramp or whatever and boom it finally lets go. You might think the last thing you did killed it, when in fact it was already shot, bleeding and just waiting to die.

That's only an edumacated guess but I think it's more likely than there being a Bermuda triangle of modest rpm and boost that magically kills healthy engines.

theres no bermuda triangle lmao
its known that boosting around 3-4 the ecu has a tendency to stay in closed loop and run really lean which can easily blow a motor at only 5 psi

I think you mean open loop, but yes this is the issue.


I am ~13.5:1 in open loop under boost and quickly drop to ~11-12:1 in closed loop.

If I didn't already have a built motor that would be tempting... Unless someone has cash in hand, I'll just wait around until DCR comes up with something big and then send it to them to build using thier stuff.

Dude, look at all the blown engines. How many were at part throttle & how many were at WOT redline or some shit? Instead of calling it voodoo, maybe we should spend a little more time figuring out why. The entire CPU is fucking voodoo. It's not reading chicken entrails, its seeing people time after time blow at part throttle in open loop. Paying attention to the facts isn't superstition, it's called using your brain.

i honestly dont know of one blown engine at wot in the cars power band honestly

You gotta point, and combined with the lean spot bf360 pointed out I'm starting to be convinced. But you'd think more people would hear it if there is detonation severe enough to break things? It would have to be so severe that KR can't pull timing fast enough.


"its known that boosting around 3-4 the ecu has a tendency to stay in closed loop and run really lean which can easily blow a motor at only 5 psi "

-- Agreed. Detonation is a gravedigger and 5psi is a non-trivial load, it's more than WOT on a non-turbo engine.

Question: if you hit the pedal a bit more does that get it out of the danger area? I drive pretty moderately, but it's an MS6 and it goes into boost just pulling its weight around. I'm wondering if taking it easy with moderate throttle and rpm is actually riskier than WOT? I always use 93 and have never heard knock.

Edit: I hadn't seen this before
"i honestly dont know of one blown engine at wot in the cars power band honestly "

*That* points to the problem being the ECU programming, which means it can be fixed with a reflash.

i hate part throttle boosting, i always try to drive around in as much vacum as possible and if i need to i downshift instead of boost, going wot is a lot safer than part throttle boosting

My plan is to install an alkycontrol meth kit activating on a MAF voltage of ~2.8 and above.

This will richen up the AFR in open loop and greatly reduce any chance of detonation...

EXACTLY.... I SHOULD SAY IT AGAIN EXACTLY. Drive in vacuum or hit it in boost, no middle ground.... and IMO downshift instead of going hard on it in 5th or 6th from vacuum to boost...lugging sucks.
this simple boost gauge has kept me out of trouble and this issue is not a issue for me at all...this one is easily fixed thru correct shifting...so now the issue to be found is what else is happening to make our cars from popping....moded ones that is..LOL

http://i243.photobucket.com/albums/f...z/IMG_0238.jpg

this punny dick little turbo sucks for keeping out of boost big turbo ftw.

by the way i do not obey those rules at all...25.5k and going strong with great leak down, compression, and i scoped the motor and its fan fucking tastic.

Go WOT or baby the shit out of it? No middle ground? That sucks!

Like I said before, think about this for a while. Do you think that this motor was only calibrated to run in vacuum or full boost? You think there was no part throttle "boosting" as part of the testing? You think a bunch of people with dashhawks have better instrumentation and knowledge about what is going on than the people that designed, calibrated, and tested the drivetrain?

This smells like another forum myth spreading through the internetz.

i'll tell you this, i don't trust anything generic to read proper sensor values IMO if you want testing done it needs to be data streamed in real time from factory equipment, that the car was made to work with.

Fuck generic shit, only time you get PROPER readings out of a generic tool would be your 6 and 7 thousand dollar machines or something comperable to factory equipment like the MODIS. that said i refuse the dashhawk never owned one never will.

not saying to go WOT...just saying to go more than hoovering in that area at part throttle...i very seldom go WOT FYI...i drive most of the time at way below WOT, but i do not pussy foot around the boost/vacuum line if i can help it.

as fpb mentioned, he has no issues at all with any of this open/closed loop issue so maybe this is all paranoia...but i drive conservatively and correct enough that i have never had a blow n engine in 30 years of driving.....and again going WOT all the time is not something i do...i probably drive car more conservativley than 99% of this forums members..ohla

but the dashhawk reads the factory sensors? its the same thing the ECU is reading...

oh don't get me wrong i have blown engines before, but th eones i did i shoved 35-36psi through a huge turbo through and i knew it was coming.

In my opinion this is mass hysteria but there may be something to it, with the way the EGR purges, and how it does, IMO if you drive part throttle boost OVER 1/4 throttle your fine, because then the egr does not purge at all, if your 1/4 or under it does, and thats where i see people blowing, once they get out of that, it goes back and spikes lean becuase its missing that inhert gas that was being injected from the EGR. and the ecm can't compensate enough for it.

Thats only a theory, that was tested using mazda's datalogging equipment just so you know. the numbers i know this car does i use factory stuff becuase as i said i don't trust generics.

As for the closed/open loop thing i dont' think its that, its just what the egr is doing, and when you have all that extra breathing mods on the car it could happen hell we are all operating outside of the factory ecm specs.

i have a block off plate sitting here i keep neglecting to put on i should probably do that.

no generic OBDII tool reads just like the factory, as it dosn't know everything the ECM is doing, the factory tool comes up with numbers differently and takes sensor values from other places.

heres a good example not a mazda but still, on a nissan quest with an adjustable TPS sensor, the correct reading is in the TCM not the ECM, the factory tool will give it to you, but a generic will not.

thats why they are generics they don't do even 1/4 of the shit a factory tool does.

so it appears that getting rid of the EGR is the next mod for me

Can you explain this further? I'm just looking for some info on the proper way to drive this car. Are you saying when the car is transitioning from vacuum to boost, you shouldn't be giving it less than, say, 1/2 throttle?

honestly it really is speculation, but until someone blows this motor at full throttle in the powerband, and people keep poping this motor in that dam 3-4mark and part throttle boosting, my speculation is as acurate as you can get for now

Nixon i would say try to drive out of boost, it uses less gas and is a lot safer than risking it, if you need to downshift, if your around the 3k mark i am usually going to go wot just because i dont drive anywhere in the middle like most people

+1


Other than some engines just being defective, this ^^^ seems to be the most plausible explanation for the bent rod induced failures IMO. I can guarantee that the majority of folks drive in that middle ground. If that was the cause, we'd hear of a lot more blown engines.

Alright, so since we're armchair quarterbacking, here's my .02 cents on WTF is going.

To me, it seems like there are two separate incidents in just about every blown engine case:

- bent rod event
- rod through the block event

Bent Rod Event:
The fact that rods are bending at all should point to some off-axis compression force. But how would an engine see ANY off-axis pressure? The most likely answer is the balance shaft, so that's what I'm going to go with. The past couple of blown engines have happened because of a severe overboost (35+ psi). In those cases, my hypothesis is that the BS is binding causing some deflexion in the cranshaft. = bent rod, vibrations through the clutch, metal knocking, etc., etc. It seems like that could happen at high rpms or any other high load situation as well.

That alone, however, does not grenade the motor, until...

Rod Through the Block Event:
The question that everyone should be asking is; why doesn't the event that bends the rod blow the motor? The answer is that even at high psi and high rpms, normal combustion is not the greatest force that an engine can see. Detonation is much more destructive. Depending on where in the compression stroke the detonation occurs, you can be talking about exponentially higher forces than under normal combustion. Even with the overactive knock sensor on our cars, the engine does still need to experience detonation before it can retard timing; no matter how quickly it does react. It seems like engines with straight rods can withstand those pressures fairly well, but it makes sense that a bent rod likely couldn't. Throw in the fact that the "bent rod engines" seem to be blowing in the same rpm range where just about everyone is experiencing random knocking and it seems pretty clear that is the catalyst that puts a rod through the block.
[/speculation]

Just my .02 cents; take it with a grain of salt as I've never personally looked inside the motor yet (blown or otherwise)...

So loading up the engine at low RPMs is bad. I've taken this and translated it into never loading up the engine hard below 3k in 5th or 6th. Even then, I don't mash the pedal to accelerate. WOT in 5th or 6th is for top speed runs I guess. Too bad the car magazines always brag about how there's no need to downshift to get power in this car. Everyone who reads that and buys an MS3 will be destroying their engine.

Edit: We should ask Cobb how they daily drive their MS3. It's seen a shitload of abuse and is still rock solid according to their blog.

Everything is supposedly bad. Theres no exact way to do things. You drive the car the way you drive it. If it blows you were doing something wrong if it doesn't blow you were doing something right. Or trade it in and you won't have to find out the answer either way.

Fuck it. I love this car. I'll drive it til it pops and hope I'm doing things right!

+1 lol

The question is, at part throttle/low boost, how much torque is being generated at around 3k rpms? I bet it's no where near the 280 ft/lbs. It's probably well under 200 ft/lbs. Does anybody have a dyno showing boost? Just cruising around I'm in vacuum most times.

Also somebody mentioned the cx7s before. With their automatics hunting for the highest gear possible at a given speed, they're probably loading their engines a whole lot more than we are. Yet they're aren't suffering from tons of blown engines. Also they are a good bit heavier which puts even more strain on the engine.

Well, CX7s have a different turbo, and are not being modded like ours are.

till DCR, Haltech, Cobb, CP=E. etc etc give us a real definitive answer to why these moded engines are having issues than it makes sense to me to drive in balance...by that i mean enjoy the car in all rpms up to 6000 and at all throttle positions, but have common sense...the guy that's boosting at 18=23psi and running 320whp fully bolted car who is running WOT on a daily basis on most drives is pushing the common sense a bit....on the open/closed loop issue, IMO it's best just to boost thruu it at a reasonable throttle position and shift....my car feels good shifting at 4000-5000 rpms with the HKS BOV so i frequent that zone quite a bit...the turbo is not taxed, and it's not over -boosting.....and again downshift to acclerate if you want any pull, if not lay back and drive in vacuum for gas mileage... Lugging taxes the engine and is bad...especially with turbo cars like this one. This may be all voooodu as some have mentioned, as many high hp cars have not blown...Woosh, Laloosh. Tizi, etc, etc, but many have so i would side on the conservative side on this one till......and i am not a conservative person on life.....just trying to do the things that i have learned and makes sense to me...so far it's worked, my car runs friggin great and is still exciting to me 28 months later.....

The torque converter is probably keeping CX-7's from seeing as much engine load as they would see doing the same on a manual. CX-7's aren't that much heavier than an MS6. Out of curiousity, what kind of loads do you guys see at WOT?

I'm insulted... :rippedhand:

Well, I stand corrected!

ANY LAWYERS OUT THERE? we need to get a class action lawsuit going.
there is no good reason all these motors are blowing up at such a young age and low miles.
especially since mazda isnt standing behind their product and warranty.

jesus guys how many times do i have to say it, im not saying your blowing your motor at 3000rpm because of load necessarily, its like this, say you only part throttle boost by accident, and boost 5psi, that doesnt sound like much but if the ecu stays in open loop and your boosting and running lean

Well if you noticed, I quoted someone else but anyway....


Again, without having an idea of how much torque is being produced during that lean period, it's just a wild guess. For example, at 5psi, let's say the engine is making 180 ft/lbs (doubtful) and hits a lean spike to 250ft/lbs, that's still less than the max the motor is capable of. Realistically, it's not going to be that high. Now as the rpms rise, this becomes more and more dangerous.

I'm not sure what cx7s dyno at but it's likely the torque converter will sap some power but not a crazy amount. As for weight, they're close to 4000 lbs with AWD. That's almost 900lbs heavier than the ms3.

They dyno about 170 whp/200 wtq stock. Honestly, with everything I've done so far, I'm lucky if I'm over 225 whp. I refuse to dyno though... :D

Yeah, weight AWD CX-7 vs. MS3 is no comparison...

No, bf360 had it right... well, partially. Closed Loop is normal driving mode using the O2 sensor for AFR feedback, and Open Loop is conditions where the ECU relies on its tables only with no O2 feedback. The car does seem to have rather lean Commanded AFRs while in Closed Loop and under boost. To me, I really don't give two shits in which mode my ECU is operating. What I care about is Commanded AFR. An ECU could easily run in Closed Loop all the time and just have much richer AFRs for conditions that warrant rich(er) AFRs.

Any ways... 3-4 PSI... shit, that's weak!!! ;-) Try 15 PSI and a Commanded AFR of 12.6:1 while still in Closed Loop. YES... I mean Closed Loop. Or, how about 5.95 PSI with a Commanded AFR of 14.0:1??? Want more? Take a look at my attached pictures.

What turbo do they run?

As long as you are meeting the AFR targets I don't see a problem

Informative thread, thanks everybody! Sounds like I should get at least a good boost gauge, any recommendations?

FWIW, I have a 2009. It has never knocked or pinged at all, not even in lugging conditions or WOT driving. I also get bad city mileage, which says something about how I drive it - not like a wimp.

I've learned to row the six speed and keep it between 3500 and 6000rpm. Not good for mileage but it's smooth and safe and fast... and it keeps me pretty busy.

Oh the freeway though, traffic usually limits me to about 65 which is roughly 3K in 6th gear, but I always drop a gear (or two) for passing.

I was reading Road and Track's long term test, which was still running fine at 40K. They had the usual 2007 problems but were happy with the fixes provided, and never had another problem with the engine. Then Mazdaspeed gave them a bunch of parts, including a CAI, and they ran it to 50K without blowing the motor.

No doubt it was a favorite of younger staffers and interns, but also got driven by their older, more conservative drivers, who probably drove it like any other car. Their long term fuel burn was better than I ever get, but I'm guessing it includes a lot more open road highway driving than I do.

Anyway, point being, they have a wide variety of drivers driving it differently for various reasons (road, and track) and it never throw a rod through the block. Good for them, I'm just saying that it's another data point to consider, and a pretty good one at that.

It's good to notice a pattern though, and y'all did a pretty good job. The lesson I'm taking from this is that cruising for MPG on level ground at low revs is OK, just downshift at least one gear if you want to do anything differently, and work the motor in a pretty narrow rev range when you wanna go fast.

Which I do, I just have to shift a lot more than I'm used to, and it burns a lot of fuel. Given the soot that collects on the exhaust tip, my shitty MPG, and total lack of pinging or knock, I don't need a monitor to tell me that it runs pretty rich in stock tune. If it has any lean spots I haven't found them yet, and I've never heard so much as a minor ping, running 91 octane, 10% ethanol CA gas since it was new.

Doah! I just reviewed my logs and you are correct.

This is the DashHawk code translation in the bottom right corner of the display:
Fuel System Status (C = Closed Loop, O = Open Loop, L = Open Loop due to Engine Load, F = Open Loop due to a Failure/Trouble
Code, P = Closed Loop with Problems, - = Data not available, U = unknown status)


When this value is displayed on the screen or on the PC from a data log, the following values are used:
0 = Unknown
1 = Open Loop
2 = Closed Loop
4 = Open Loop due to Engine Load
8 = Open Loop with Fault
16 = Closed Loop with Fault


I am typically in 2 until 3000-4000 RPMs, which is closed loop (usually with a ~13:1 AFR), then go to 4, which is Open loop due to engine load and my AFRs usually drop to ~11:1.

I just don't understand why our car aims for ~13:1 under 10+ PSI of boost after reaching full boost...

I understand running lean with retarded timing during spool up, which pumps a lot of heat into the turbine to accelerate the spool up time; however, I would feel much better if the AFR was < 12:1 under heavy load.

kwsmithphoto.....i totally agree dude, as i have read that story as well back a couple months ago....stock cars or slightly bolted cars on stock tunes, stock boost have been fine...as the Road and Track Mazda Speed3 test car revealed..Even Cobb's mule is still kicking, although having a in-house tuner and dyno for 1000 pulls is handy Also True=Boost is for sure not easy on his car.. It's alway's cars that have mods that somehow are not in total balance or putting out to much TQ or boost, with a questionable tune , which cuts the safe window down quite a bit...It seems like the car stock is tweaked pretty good from the factory in torque with not alot of play room for upgrades..as per internals giving out......definetly some room to improve, but when the combination puts pressure, load, extra boost, etc etc the combination of all this has the car running on parameters obviously it can't handle, and then......Something will be figured out, and the cat's trying to make this a better car doing all these upgrades are feeling it...I feel bad for anyone thats gone through this, but at this point they no what you are getting into. Ask any woman...she will tell you some things just take time for a good outcome. and if rushed can lead to a un-wanted pop, Doh!!!!.

Well some stocker's have blown too, so there might have been (or still is) a tolerance issue with the con rods. But ya, I agree, in stock trim these motors are already pretty wound up from the factory. It's just a re-worked older engine, not a new one that was designed from the ground up for DI and turbocharging.

Heck, what do you get from a Mazdaspeed CAI, 25hp and 30lbs? That gets you to 288bhp and 330lbs. Not too shabby. Which works out to 125hp per liter, and 143lbs per liter, which is in the big leagues in terms of specific output. Personally, I'm gonna stop there and leave well enough alone!

you could count the stockers that have failed on one hand, in fact i have not heard of more than 2. But anyway, i agree with you at this current time that less is more, but i have been running the CP-E CAI and TBE since 3/07...4 months after i bought my car...and let me tell ya, if i had to give those two minor mods up, i would probably trade it in...to me it has made a big difference...In performance and indeed sound, 40 hp probably... and i do believe the CP=E CAI or SRI is a better air intake than the MazdaSpeed...in fact the original Speed intake was pulled off the market early on because of issues...Also i TOTALLY agree that running 300+bhp and 320 TQ is not shabby....coming from a Honda SI, my test drive in the Speed3 was downright thrilling, reminded me of the STI in mid range power for 10 grand less...lastly folks HAVE to remember that this is a 22,000+ car and it was designed to give you what it was designed for.....i wish it had more, but it is what it is...and i am at peace with it as is.

Anybody wanting peace of mind with their mods (especially those with extensive bolt-ons and piggybacks)should go with stronger internals and be done with it imo. There just doesn't seem to be a lot of leeway in terms of rod strength. And the tuning seems to be very complicated which could easily lead to a boost spike or lean condition. Why play russian roulette?

Mazdaspeed's first CAI was an AEM unit. It worked, but threw some CEL's so they pulled it from the market. Then AEM developed an airflow straightener, which stopped the CEL's, so Mazdaspeed recently put the new version back on the market with their name on it.

The reason I waited for the new Mazdaspeed version is to help avoid any warranty nightmares. It's also less noisy than the SRI because of the extra plumbing.

Exhaust, I'm leaving alone. From the look of things, the factory did a pretty nice job, unlike the intake, which appears to have been designed by, uh, well by Ford.

good luck with that brother. mazda is the man at finding bs reasons to void warranty and sorry that intake wont save you.

Maybe not, but it certainly helps. I've done battle with corporate zone reps before and know how to deal with them (being nice actually helps). Since it has a Mazda part # and label on it, and they market it, sell it, and install it as a for-profit accessory, virtually any judge in the state would back me up without hesitation. Lacking any signs of abuse, of course, or proof of track or competition use.

IOW, Mazda can't really say please, buy this part from us, but we aren't responsible if your engine blows as a result. Well they can try, but it's a losing argument in court. If they try to deny a claim they have to prove it was your fault. Adding one of their own parts, and lacking any other evidence that the car was used normally, you have a winning case if you handle it properly.

Zone reps are always the people who make the call on a major warranty job, not the dealer, and their inclination is always to say "no." But they can be motivated to change their mind, especially if you let them know you'll take it to court if necessary, and have a solid argument. Will they spend $5000 of lawyering to fight a $5000 case? Not likely, it's easier and cheaper for them to just fix the damn car, and the zone reps know that.

So just, as a n00b to clarify, the stock MS3 driven like it was intended, should be fine. It when you start modding it that things start occuring and Mazda gets bitchy. Is that about correct?

No your toast either way.

Except for a few unlucky individuals who claimed to have blown their stock engines, you're pretty much correct.

Don't the Cobb AP maps eliminate any lean conditions caused by the open/closed loop switch delay that the stock map has?

I'm not going to panic about this car... I still love it. The only thing these blown engine posts do is make me minimize mods to keep the car easily swappable in case of an issue... and I may trade it in right before the powertrain warranty is up.

The more reports come through, the more it seems like there is a manufacturing flaw with these cars. Some people rag on them and nothing lets go. Most that let go are at low load conditions.

KR under WOT has A LOT to do with the fuel used. Example, the 94 octane where I'm at is shit and knock like a mother. 91 Octane just over the border knocks a lot less.

I have noticed a difference with different gas too.

Im in cali. so highest grade is 91.
But I notice a difference between gas stations.
As close as I can tell so far, the ones with the ethanol sticker run much worse.

I have had the best luck with the gas from the 76 and picking a pump that has previously poured 91.

This car is very very sensitive to gas quality. Mazda has made the knock sensor sensitive enough so that it can deal with poor quality gas. Not ideal, but it can and does deal with it.

Like I said, some water injection will cure all that up. That or pulling 4-5 degrees of timing.

Last time I checked, all gasoline sold in CA has ethanol in it, about 6% on average, year-round. 10% by 2010. Some regions have to increase the amount of oxygenate (more ethanol) where CO is more of a problem in the SUMMER, as you can see on this chart:

Summertime Gasoline Use-By Dates

So, basically we're always using "winter" gas, except in the summer when it gets even more "winterized." :) Welcome to California. But wait, it gets even stranger:

All gasoline sold in CA must be refined in CA, using a tightly spec'd formulation. There are only 21 refineries owned by a handful of companies, many of whom aren't associated or owned by a particular brand. In fact, "76," the retail brand name for Unocal, was bought and fully absorbed by Chevron in 2005.

Sources for the gasoline stock are generally defined by the station's proximity to a particular refiner's distribution network. Basically, whatever makes the most sense logistically is what you'll get at the pump.*

For example, if you pull off I5 in the middle of northern nowhere and find 4 different stations on each corner, they almost certainly got their basic gas from exactly the same refinery; it doesn't make sense to run multiple pipelines and distribution centers to serve a low density population. In higher density areas, where the refineries are concentrated and the pipelines more "diverse," you're more likely to pump gas from a refinery owned by the same company.

*The only real differences in a given region between different brands of gasoline are the additive packages, which are added when it's pumped into the truck! The actual refiner, though, just isn't very important.

The additives they use, primarily detergent blends, are important differences though. But the basic formulation and octane content is identical. Personally, I just stick with any of the "Top Tier" brands (Top Tier Gasoline) available in my area, 76, Chevron, Shell, and Texaco, and don't notice any differences in how the car drives.

For more information, here's a handy pamphlet:

http://www.energy.ca.gov/2008publica...0-2008-008.PDF

Which has nothing to do with blown motors, sorry for the thread drift, just thought some of y'all might find it interesting.

i no some folks feel running different gas in this car does not matter, but i think it does so i stick to 1 brand and have since day i Shell 93 octane. I have swithched on one tank and used Amoco 93 another fine product IMO...These would be the only 2 i would put in my car if i can help it...But Shell has been in 99.9% of my fill ups and i generally go to the same gas station......if anyone has ever bought a bad tank of gas...the car will feel it especially gas with water in it or 89 octane that was sold as 93....this is not a documented thing, just that this car is finicky and taking bad gas out of the equation can't hurt...Now my Honda CRV.....i put anything in that sucker and it does not matter.

Oh ya, contaminated fuel changes everything! And there's no way to tell until it's too late. But it's one of the reasons why I try to use newer stations or, ones that have replaced their tanks recently.

That was the silver lining of the MTBE debacle here in CA - when it started showing up in ground water, the state started looking for the sources, and it mostly coming from leaky underground storage tanks at specific gas stations. So, even though they banned MTBE, they told the stations with leaky tanks to replace them or shut down. It's an ongoing process, but many independently owned stations are being forced out of business because they can't afford new tanks.

Selling 89 as 91 is illegal, and the corporate stations are careful not to do it. But it does happen by mistake, sometimes. And who knows what's in the tanks at some places, I've seen unbranded gas stations I wouldn't use to fill a lawnmower.

Just punch it only after slightly letting off the gas at 3500 rpms and all is good. Don't let off the gas between shifts or shift really fast. Keep the carbon deposits at bay with seafoam or comparable. Upgrade your fuel pump. Monitor your EGT's and don't race it if the EGTs get above 800. You'll should never pre-ignite in this case.

Huh?

What part don't you understand?

I highlighted it. I'll highlight it and italicize it and underline it!

Ah, cause between shifts the car temporarily goes closed loop if you shift slow. The faster I shift, the smoother the car accelerates. If I take too long to shift, I get a high AFR spike (stoic) between shifts.

Are these engines so bad that they really need that much attention??

I don't think so. At least I hope not.

I can understand if a modified car with an aftermarket ECU flash or piggyback tosses a rod, but seriously, this is a production car from a reliable company. I'm not going to babysit it with with aftermarket gauges and extraordinary driving techniques.

I'm glad I have a 2009. Given my shitty gas mileage and sooty tailpipe, I'm guessing they're just dumping lots of fuel into the motor during closed loop city driving now, which is what I mostly do.

Mine:
2006 Mazdasspeed6
Miles :78k on the clock
Cylinder# 3
Rod: #3 bended at first, Clutch pedal vibration like an old man couldn't walk....
Kaboom at 3500Rpm 3rd gear @15psi, the BS sticking out thru the oil pan
Front of the block have a hole also rear of the block where the oil drain line have a hole ,but the rod nowhere to be found....
Warranty: you kidding me!!!!!!!!!! :17:
And yes i do have pics........
As matter of fact my own thread is here : The moment of truth....... The Kaboom thread - Mazda6 / Atenza

Were you modded or stock?

If he was stock he wouldn't have a cry smillie next to the warranty question.

I thought that was because he has 78k miles.

Found his mods:

GT28R
41mm Tial EWG
DNP with dump pipe
Cpe Catted DP
Cpe HPFP
CPE nano SRI
CPE stand back v2 pnp
cpe FCF throtle and fuel cut flash
CS FMIC modded
CS CBE
Perrin EBS...
2 Step colder plugs
HKS twin power ignition...

Blew the engine
 

Mazdaspeed 6 2006 with 83000KM. I had CAI,BOV,Magnaflow exhaust amd ujnichip plug and play.
I was cruising at 110Km in 6th. I downshifted in 5th to accelerate and then I experienced a lot of jerking. I was 1hr away from any civilization. It jerk often and then at a certain point I started to feel a vibration in the clutch ionly when slightly press, Fully press there was no vibration. Brought it into the dealership, they changed a maf sensor. Got out of there same problem. I went to see the mecanic and I told him to ghet in with me. On our way to the car he said that they found a code for overboosting. Anyway got on the road. I jerk and boom....Blew the engine. Thrust bearing was gone. All of my rod were bented and one piston melted...Does anybody think I should sue my dealership for letting me go with a code without telling me anything?

good luck with that....

As long as you weren't heavily modded when you arrived at the dealer, at the very least they should offer to replace or rebuild the motor since you went in there before it blew. And they had an opportunity to take care of the issue and apparently misdiagnosed it. I guess you have a case but you should think of a lawsuit only if they decided to fight you on it.

Nichodemus - Mazdaspeedforums
Car; 2006 Mazdaspeed 6 with 43445 miles.
Cylinder; #4
Damage; Rod through block
RPM; 4kish
Mods; CS FMIC, CS TBE, Fuel pump internals, Greddy type rs recirc , CPE Standback EMS tuned at 18 psi at a 12afr, CPE Pro Fuel for Devils own meth(meth had only been on for a few weeks, but suspected a rod failure was coming when my clutch started to pulsate, stupid me for taking it for one last drive)
Exhaust Manifold; stock
Situation; Blew on a freeway onramp when shifting from 2nd to third at around 4k rpm. No audible sound, just engine stalled oil light followed by battery light followed my CEL . Look under hood and aluminum chunks and oil everywhere.
Warranty; Negatory Ghost rider, the pattern is full. Voided due to aftermarket parts, no other reasoning given.
Oil; 5w30

good thoughts thanks. can you be any more detailed showing how to check for this?

The crank thrust tolerances on this car are fairly large. It wouldn't surprise me if you were completely right about a lot of these failures. Whether it's by design or poor manufacturing remains the question. If this is the case it has to do little with the power run through the motor as well.

Further, changing the thrust bearing means pulling the motor apart which is no fun.

wow if you did measure this, and there was too much play, pretty much useless trying to show the dealer huh?

lol. Trying to be preemptive with dealers never works out. it usually end with drive it till it blows when it does bring it in for a crate motor.

ha so I guess measure it, too much play, sell it, buy a leftover 08-09 (not the 2010 because its ugly) and measure it again and hope its good lol

Forzda, your theory works well with cars that just bent a rod, but what about Wisedom's burnt piston? I still think it has some to do with detonation and/or pre-ignition. It would be interesting to see how many blown engines happenned after EGT's were high.

For example, I get on it a few times and EGT's are ~850F, I'm accelerating lightly now at stoic AFR, shifting up, and lightly giving it gas. Boost starts to come on and boom. Normally, the extra load due minimal crank play is manageable, but add in a bit of detonation or a pre-ignition event and a rod gives....

Oh, and your point on the BS helical gears is dead on. From Wiki:

"A disadvantage of helical gears is a resultant thrust along the axis of the gear, which needs to be accommodated by appropriate thrust bearings, and a greater degree of sliding friction between the meshing teeth, often addressed with specific additives in the lubricant."

For anyone wanting to jumper their clutch switch, simple stuff and if the bearing is indeed an issue it just might save you, otherwise just peace of mind and less wear. It's the verticle plug behind the little plastic rod the top of peddle makes contact with, bust off 2" of paperclip and bend in half, should do the trick as Forza said. You can snap the assembly off the metal by pulling on the piece closest to the firewall, gives easier access.

Unfortunately, I do not know the details of my friend's thrown rod in his speed 3, but here is the mods.

2008 Mazdaspeed 3, Metallic Silver
HID 6000K LIGHTS !:
EBC Green Stuff Brake Pads ))))
Rotora Slotted Brake Rotors )
COBB FMIC
Tanabe Lower Front Brace
KW SUSPENSION VARIANT 3 COILOVERS
Enkei Racing RPF1 limited edition black 18" WITH carbon fiber center cap
MazdaSpeed 3 COBB SF
TurboXS Bypass recirc valve
Vibrant Exhuast,
TurboXS Downpipe
COBB AP: CUstom tuned at 17.62 PSI
DDE angel eyes
Motor Mount

I'll ask him, the next time I see him, as to how it occurred and which cylinder.

I gave up filling in the list cause its depressing but i believe it should be up to 36 by now. Also there are alot more of these cars blowing up that aren't on any forum or who just lurk and don't post.

So you are saying that the balance shaft assmbly does contribute to the failures in a way? So removing the BS relieves some of the stress on the thrust bearing. the problem is not necessarily fixed, but helps show why there are no blown motors with the balance shaft assembly removed right?