Why do our engines blow up?

[darth vader]

Not to be a bitch but, let's do the maths here: We have 10,000 Speeds in the US per year, there are about 30 registered blowups on this site, FROM ALL CAUSES. That's 1 in a thousand, including all forms of idiocy the car is heir to. Nasioc can only dream of that rate, they have 80+ for the 08 Gen Subie alone.

Sucks to be the one, no doubt but, odds are on your side, if you're smart in how you do things and don't get greedy.

[Target:STi]

your math isnt exactly accurate. no one has the exact figures on engine failure except mazda. your odds would be better if you compared the amount of blown engines reported on this forum compared to the number of registered users on this forum. even then its not 100% because not everyone reports theirs. besides, that list hasnt been updated in quite a while. and as i said before, i bet there are a ton more stock engines that have failed that we dont know about, because those cars belong to people who arent enthusiasts or dont care about forums.

the facts are out there. there has been a TSB or a Recall on just about every major component of the powertrain between the 3 and the 6. Clutch, Fuel Pump, PCV system, PCM, bypass valve, turbo, VTCS, rear differential, changing the reccomended oil used etc... take that into account when you see the rising number of blown engines and make your own conclusions.

if you look at all that and still say this is a great engine that wont cause you problems? denial, as they say, is not just a river in egypt.

[darth vader]

Of course there's problems with my maths, just as there's problems with people drawing the conclusion this engine is a ticking time bomb, from reading a few Internetz posts. That's what happens, though.

There will ALWAYS be error in drawing any conclusion based on questionably collected "statistics" or anecdotal reports. No matter how well you try to control the variables, it's not a laboratory experiment.

What is needed for a that is a good-sized batch of production engines, a series of controlled tests to determine failure modes, then analysis to determine failure mode causes. This would have been old hat to engineers in the 1940s but, is pretty much a lost art today, due to cost concerns. One hopes Mazda did SOME of their own homework before producing this engine, though....

[glocK23]

Originally Posted by darth vader Not to be a bitch but, let's do the maths here: We have 10,000 Speeds in the US per year, there are about 30 registered blowups on this site, FROM ALL CAUSES. That's 1 in a thousand, including all forms of idiocy the car is heir to. Nasioc can only dream of that rate, they have 80+ for the 08 Gen Subie alone. Sucks to be the one, no doubt but, odds are on your side, if you're smart in how you do things and don't get greedy.

Exactly the same way I see it as well.

But continuing this thread is pretty pointless now, the OP is getting rid of his car. Typical of an 08.5 model vehicle getting traded in for something 'newer".

Epic.

[trickytwelveinch]

Originally Posted by glocK23 Exactly the same way I see it as well. But continuing this thread is pretty pointless now, the OP is getting rid of his car. Typical of an 08.5 model vehicle getting traded in for something 'newer". Epic.

Agreed. Just to kill this thread all together (just in case anyone still reads it) I want to give my last input:

Half these engines blew because the driver has no clue wtf they're doing; period. I mean there's all these people doing "mods" and half of them can't even install a simple CAI/SRI! Then they come on here and post stupid threads like "just installed CAI/SRI and I have the following issue"....

Then you have others just go "way to fucking deep" into the reasons this engine is blowing and posting all of their "assorted" theories as to why that is; going as far as claiming there's a design flaw...give me a fucking break.

Not every engine is design the same; what is so hard to understand? If the MS3 engine could only support an additional 100-150 HP on stock internals were as your evo can support 200+ tough luck- people shouldn't come on here bitching how this motor sucks and shit. Overall, this is a fine piece of engineering in this motor.

If people don't know how to "mod" then don't mod or come on here bitching that you fucked your engine.

But that's sits differently with the plenty of self-proclaimed Mazda gurus.

Eh, it's pointless saying any more- sucks to say, but truth hurts.

[DaleNixon]

Because you touch yourself at night.

my engine will never blow up. even at 24 psi. its the people who dont boost alot that blow up.. our engine were built to boost to the moon. when u dont boost ur rods get pissed and pack there bags and leave hopefiully trying to find there way into a race car

[Target:STi]

well said.

[MS3pwr]

after doing a bit of research i noticed that our cars run a 9:5:1 compression ratio. I know that is a very common ratio for a lot of N/A cars. So i dont know if its just me but isnt it possible that once we hit boost the pressure gets to high and catasrophic failure occurs? Arent turbo cars supposed to run a lower compression ratio so when we boost we hit a 9:5:1 ratio vs whatever it is at full boost?

[Realgib3]

wow lol when you say a BIT of research you mean a REALLY LITTLE BIT. I wish you you the best of luck in your search for the answers...

[darth vader]

Awesome......yeah....it's just you....

[DaleNixon]

Holy shit! Call the Mazda engineers before we all blow up!

[JumpingJackson]

ZOMG I THINK MAZDA FORGOT THEY WERE USING 9.5:1!!!

[bf360]

WoW -_-

[cost0305]

Just wanted to chime in and say I've been a lurker for years. I know its like a decade later but lets dig this guy up for a 10-year update lol.

Owned my 2008.5 Mazdaspeed3 since new.

105k miles with aftermarket Shure Motor Mount, Cobb SRI, Cobb TIH, Forge Motorsport BPV, Cobb Accessport running OTS Stage1 tune and a short shifter (factory fuel pump). Had four problems ever over 100k miles.

First, a couple of injector seals went at about 35k as I tried some higher boost AP maps. I replaced with the Shure injector seals which are a much more substantial design and zero problems since.

Second, the Gen1 Cobb SRI bracket mount broke as we all well know. It's still broken and I run a few zipties to keep it from rattling around too much. Cobb has since changed their mounting design to avoid overstressing that mount point on the car anymore.

Third, right at about 100k miles the pivot shaft seal failed and I replaced that the other day (and made a video of the replacement https://www.youtube.com/watch?v=vdFXj7mo0cE).

Fourth, the front end is starting to get a bit noisy on bumpy roads when the car is cold. I have yet to investigate the cause but I'm guessing end links or the like.

I've got the original clutch, which I attribute to my manual blipping because it certainly isn't because I've babied it. Expecting to replace that soon just as regular maintenance.

Absolutely f*cking legendary car in my book.

Motor hasn't blown up and I agree that some of these 'kids' (I was a kid when I got mine also) were so mod happy they simply threw the motor out of balance and caused themselves all of the headaches they are blaming on the platform.

Especially true with Japanese performance cars, "STOCK IS BEST".

I did upgrade to the 18x8 rims from a 2012 MS3 and slightly larger tires than stock mounted to them just to keep the meat on the ground at WOT. Personally I love the torque steer, but I know that's an acquired taste. I'm not trying to mod to get rid of that.

All of these people who replaced suspension parts I have no understanding. This car is plenty stiff from the factory for anything. I think its mostly driven by companies trying to sell parts rather than actual drivers pointing out flaws in the platform.

The Stormtrooper has earned every mile. I have not been nice to her. LA traffic stop & go, weekend canyon runs, road trips LA to Denver and back thru the Rocky Mountains 5 times. I once drove straight to San Antonio TX and back to LA in two days.

Now that I've written this I'll be sure to update everyone when I blow my engine next week. LOL

[MSMS3]

“Threw the motor out of balance”? Haven’t heard that one before except for the “balance shaft delete” mod. Don’t think that accounted for any blown engines though.

Most blown engines were from bad tunes, incompatible mods (big catless downpipe with no high pressure fuel pump upgrades, and once again, bad tunes). Many wanna be tuners using Cobb AP self-tuning when it was available made tragically stupid mistakes.

Another cause was going wide open throttle below 3,000 rpm. Connecting rods do not like that.

[Jeff23spl]

Not sure the ''out of balance'' from cost0305 was about a mechanical statement for crank shaft or like you said, more about tuning to be out of balance...?

I agree one part of blown engine (crank bearing issue with little to no mods) is related of driving them like a low torque n/a below 3000 rpm. it is even worst with cx7 owners with lack of maintenance expecting it to handle it like a v6...low grade oil etc...

Cheap filter hosing that may crack or leak and take the crank bearing with it if not replaced after few changes and carefully torqued. (spin on for peace of mind)

a lot of turbo problems from cheap design already pushed from factory up to peoples trying to make them hold high boost to redline...no cool down after high load conditions....i heard often peoples telling: because it is liquid cooled it wasn't needed. It is true for normal boring driving but after a spirited drive, give it a chance on the last few miles or let it idle a bit...
And then, all other related problems because of tuning or modding errors.

These days, you can get a speed at very low cost without any idea of what happened before you got it. high mileage without much maintenance...We did also see here peoples doing cheap repairs that won't last......etc...When you earn much money to buy a sport car, you take more care of it than actual kids that get their speeds for the price of any other beater....There is a reason to pay just 1/10-1/20 of the original price...it is because it gonna cost....If getting it at this low cost already take your budjet, you won't be able to afford the repairs and will blame the car...

As said above, when you get it new and take care of it, it is a very strong engine, i used my factory engine like a test lab to learn tuning and i won't complaint. i was even surprised that my first engine lasted so long. I was ready to rebuild it even before blowing it, i knew it would happen soon or later...