The real reason people are breaking rods
 

I have looked a lot at these blown engine issues. In the end it was all under our noses. The rods are plenty strong for this application and I have compared them dimensionally to both EVO X and SRT4 rods. They are no lighter and although the bolts are a mm smaller in diameter, the DISI engine was not designed for high RPM and we are not breaking rod bolts. I have looked at binding issues, hydrolock etc ... nothing was concrete.

So then I looked at the rod construction and noticed the small end is tapered. Interesting. Diesel engines taper the small end so that the bearing surface is lower so that the rod takes a high load. The rod I have seems to have some good wear on the bottom of the bearing caused by cylinder pressure. Interesting. Perhaps poor oiling. Perhaps too much pressure.

http://www.mazdaspeedforums.org/foru...apered-end.jpg

I then looked at how similar cars produced power and as it turns out no EVO or SRT4 motor makes as much torque as we do at such low RPM. Period.

The way this Mazda is calibrated is more like a truck than a performance car. We don't need more than 300 ft lbs of torque to make well over 400whp but Mazda didn't want that for this motor.

Everyone has been looking at hp gains for this car and have completely ignored the torque and where it is at its maximum and that it doesn't carry into the RPM band.

Further torque is the one that is DIRECTLY proportional to cylinder pressure.

Case and point, look at the tq and hp on this 450whp evo
http://www.pure-tuning.com/images/dy...-S256-PUMP.jpg

Now look at Darksun's dyno. Again look at the torque he made.
http://farm4.static.flickr.com/3140/...94ff486c_b.jpg

Take a look at this recent DISI dyno. 375 ft lbs at 3000 RPM.
http://www.mazdaspeedforums.org/foru...ue-maf-cal.jpg

Cylinder pressure is what causes the "force" that is then back calculated as torque by a dyno. The gases that cause the cylinder pressure as a result of combustion expand at the same rate no matter how quickly you engine is spinning. This is the reason that you advance spark timing - so that the flame front occurs at the appropriate time to provide as much force to the downward moving piston as possible.

Now, as RPM rises, the piston moves much faster. So then amount of TIME it is subject to the pressure of the expanding gases is less per each power stroke. The reason cars make torque during a certain part of the RPM band is because there is a relationship between how you can control the burn rate (which depends on air/gas inflow, mixing, lighting mixture) with respect to piston speed

So when you are making 300ft lbs of torque at 2500 RPM, the motor sustains the force required to makes that torque for longer each power stroke than if you made the torque at 4500 RPM. Let's not even talk about the fact that a dyno takes an average force applied which favors high RPM to low RPM. It's pretty damn hard to make the torque we do at such a low RPM. The principle is similar to lugging.

So our engines making 300 ft lbs of torque at 2500RPM and only 280whp are under a lot more mechanical stress than an F/I honda motor making 300 ftlbs of torque at 5000RPM and 400whp at 7500RPM.

Once RPM increases too much, inertial loads of the rod and piston break rod bolts. The counterpart is extreme torque at low RPM. Oil pushed out of bearings and extreme connecting rod loads are the result. This load applied again and again eventually results in bent rods and holes through blocks.

Once you open up the flow path to this car it makes MUCH more torque at an even lower RPM instead of breathing better at higher RPMs.

Have you seen the rods on a diesel? Here is an example of a TDI (yes diesel) dyno. Look familiar?

http://i615.photobucket.com/albums/t...-10-25Dyno.jpg

Here is an example of a 1.9 TDI rod and piston that makes 170 ft lbs of torque and 100hp from the factory. The rods are bombproof compared to us because THEY WERE DESIGNED to take high torque at low RPM.


http://image.dieselpowermag.com/f/91...ecting_rod.jpg

Nuff said. I don't think anyone should be wondering why we break rods anymore.

Solution? There are many factors that affect how an engine produces torque and power. In order for the stock bottom end to stay in one piece, change the stock tune so that you don't hit 21psi at 2800 RPM. Help the motor breathe and move the torque curve further in RPM. Not only will the engine survive longer, but it will also make more whp. And everyone will be a hero, not just whoosh, who certainly didn't make the power he did by chance.

EDIT: This is an addition further explaining the low load rod breaking phenomenon:

I know that people are concerned with the part throttle blow-ups. These are certainly explainable - and I think the short article below from Hot Rod magazine clearly explains how fatigue and material impurity can lead to brittle fractures when components are under high stress. Brittle fractures start at a point of imperfection or impurity in the metal and propagate through. This is why some guys last longer stock and some don't. When a brittle fracture starts to happen, you won't feel anything until that fracture has grown enough to cause the rod to snap. The fracture will most likely let go under vacuum or when engine RPM changes (gear changes) since the rod is being "pulled apart" at that point if you will.

Cylinder pressure, high RPM, etc all play a part in exploiting a material flaw if it exists in the first place and bring it out of the wood work faster.

If you look at MS3 rods, you clearly see that the surface finish is not smooth (machined) like it is in aftermarket forged rods.

Edit July 30 2009: I am adding this reply I made to a member to the first post so it doesn't get lost.

We have seen some bent rods and some blown engines at wot or on the way to WOT that were outright compressive failures. The rod likely had no damage prior and simply was overwhelmed by compression forces. These are the "my line popped off and I made 30psi failures"

A rod that lets go during accel/decel lets go at that time because they are points where the rotating assembly is accelerated. F = MA remember. However, the rotating assembly goes through these transition points all the time on a normal motor without failure. So what can you conclude?

1. The rotating assembly has locked at that point due to hydrolock or mechanical lock.

2. The rod developed a gradual crack. Due to imperfections in manufacturing and high torque output, a crack is formed in the rod grows eventually letting go during these transition points.

I find #1 less likely than #2, but when the last guy that blew his engine tells me the hot side of his intercooler was filled with oil I do wonder. Remember that people blow doing stupid shit they don't mention as well so take it with a grain of salt.

So what have we learned here?

The pure MECHANICAL design of the rods and motor is fine for the power levels we are making on these engines given the rods have no flaws and nothing strange locks up. This is what DCR has been saying as well. If the actual mechanical limit was exceeded we would not have the whoosh, laloosh, darksun, and many others running in the 300-350whp/350 ft lbs of torque range for a long time. Pretty much everyone would blow and they would blow at WOT.

HOWEVER, something locking the assembly OR the more likely manufacturing flaws of the rod COMBINED with high cylinder pressures makes some of the "weaker" motors let go. This is why the failures happen at random times. You may be lucky or you may not be. High torque, especially high torque at low RPM will push you over the edge if you have a weak motor. So take your chances - or better yet tune and drive sensibly.

The SRT4s, DSMs all had similar issues, but after the car being around for 5+ years the weak ones were weeded out and the people that lasted were the ones that treated the car with respect and had a proper calibration.

STIs blow ringlands at stock power yet some make 450whp safely.

Don't be surprised by this. Parts have a tolerance. Let's say that at stock power 1% of cars blow. At 50% over stock power 4% of cars blow. At 100% over stock power 40% of cars blow - etc.

Interesting thread Lex! I was thinken the Stanback gives you variablr boost control might ajust...

with the standback you can adjust boost by rpm. im gonna give it a shot. maybe keep it a little lower from 2500-3500 then taper it up.

This does make a lot of sense actually. But. you arent going to be lowering much torque by tapering the boost, thats for damn sure.

You can cut the ignition timing down to accomplish lower torque below 3000, but the trade off is, the car is going to be slow as shit.. and then bam, a shitload of torque hits the cylinder when you meet back to the ignition advance.

thread of the year.

Just thinking out loud. IIRC aaron found a difference in the way the 07-08 load maps vs the 09 load maps. One requested more load in the lower rpms vs the other requesting more load in the upper rpms. Load in this car equals boost. This car is load targeting. How about changing the load tables?

Then again, this engine was designed to make the grunt power under the curve. Mechanically it wasn't designed to make power up top.

Just thinking... :drive:

Well the proper way to do it is with valve train mods. You could port/polish the heads, enlarge the valves, then regrind the cams to move the power upwards in the rpm.

However, once you build the lower with forged, it doesn't even matter anymore.

just out of curiosity, has anybody blown motors with upgraded fuel pumps?

Yes, and with meth.

Is this suppose to be news of some sort? Darksun dyno is a not a good comparrison, he spiked the shit out of his turbo.

Want another comparrison, the caliber is making 530 lbs of tq down low on a reworked turbo.....no boom. all my standback tunes ramped boost up from day 1. TQ down low is the most over rated, dangerous thing imo. However, this motor is still to weak.

Lex, thank you very much for this post, still, I have some questions just to figure out how should we drive this thing, what we should not do, and so on, with mods or just stock.

Some of the guys with blown engines said that the rods bended under low boost/light acceleration and around 3k rpm. 3krpm is not high at all. 6500 yes, let's just say it's a bit high even though the rev limiter is at 6700 or 7000, but 3000?

While driving around town I find myself cruising at quite low RPMs (like, going with constant speed in the 1st or 2nd gear around 1200-1800rpm, or in the 3rd gear at 1800-2200rpm), and it's quite dangerous to hit the gas hard at such low RPMs - dangerous at least for the turbo but seems like it's dangerous for the rods as well. But at 3k RPM all should be just fine, no matter the boost level, pedal position, load, and so on.

P.S.: did anyone blow his motor at over 6500rpm?

Excellent write my man ... makes sense ( of course someone had to shit on it ) Sooooooooooooo .... what ever happened to all the csutom cam testing that was going on 6 months ago .. I never saw any results on here about them .. looks like one way to go would be a diff. cam setup for sure.

I try to make it a habit NOT to nail it at low RPM (anything below 3) and when I catch myself doing it, I usually let out a, "FUCK". :yikes: I tend to ease into it a bit. Not really the ideal "fix", but hopefully my motor will last longer. Granted, I'm lightly bolted.

So, with this theory, it really doesn't matter how much octane or meth you're running, because this isn't being caused by knock, just extreme cylinder pressure.

Good writeup. I still think our compression ratio is a good part of our problem. 9.5:1 is too high for a high boost application, especially when throwing rods have proven to be a problem. If you compare our motor with the CSRT, their compression ratio is 8.6:1. They even have a longer stroke than our cars (3.82 vs 3.7) with approximately the same bore which theoretically should put more pressure on their rods. They make 265ft lb torque down low (~2000 RPM if I remember right) and they aren't having these problems from what we have heard.

I hope we can find an easier way out, but it sounds like lower compression, stronger rods, or both may be required.

I'm hoping aaronc7's throttle smoothing fix will give me a little more control over this high boost in low rpm's business.

I absolutely refuse to lay into it on my car until 4K RPM.

Just to clarify a few things here.

The strength of the internals is what it is. I am not claiming they are EXACTLY as strong as an EVO or SRT4. No one knows that without doing some extensive and expensive testing and the end result won't help anyone anyways. So what if those cars can stand 30 more ft lbs at the wheels? Our internals and their internals are comparable in the long run.

Further, add to that the fact that our fueling system is more failure prone than a regular tested and true port injection system. On top of this there are always the failures that are due to manufacturing flaws, mis shifts, water hydrolock through the CAI etc and you have the whole picture.

The point here is that the bigger horsepower cars that last on stock internals are making that torque much further up in the RPM band. This is the whole point of why they are able to make the higher hp numbers.

We make similar torque stock to a CSRT4 and just 1 or 2 breather mods push the MS3 to the 300 ft lbs at the wheels mark.

Here's driver311s old dyno with just a test pipe. There are many more similar to this.

This also goes hand in hand with why people that race and beat the crap out of their cars don't have a problem. No one starts street races at 2500RPM.
http://i24.photobucket.com/albums/c4.../newpix240.jpg

I have been thinking on the fueling issue for awhile now and would like to see what you think LEX. I have the SB with the pro-fuel controller which is able to control meth or extra fueling. I was thinking of adding one large injector in the intake manifold freeze plug location. The way I was thinking of using it was since with the Sb you cantrol it by RPM, I was thinking of having it come on around 900 rpm (which is above idle) ramp it to full (or where it needs to be found by trial and error) by say 1500 than when the regular fueling starts to catch up start ramping it back down starting around 3000 rpm. I would love to hear some thoughts concerning my idea.

i like it. I used this same concept to add extra fuel to my turbo 240sx running 6-50lb injectors. I used a SDS additional injector controller at the time.

So ... what can we do "tuning" wise to control this ... the throttle maps are obviously a start to limit that in the lower end, I guess lowering the WGDC in the lower rpms would help too.

Anything else to reduce torque / slow the spool on this small turbo.

interesting take lex. but this doesn't really explain why people blow at part throttle in LOW RPMs', unless I'm missing something.

If people were nailing it, going WOT in 3rd gear at 2k rpm, then ok. but what about the guys that blow at part throt?

Yeah none of this really explains motors taking a shit crusing at -5 vacuum.

holy shit, great fucking thread lex. i have some pics to post up about fueling "issues" as well. but i'll save that for another thread.

The damage done to a rod may be done PRIOR to exiting the block. Perhaps on a previous WOT pull from low RPM doing damage to the rod ... then the added stress of a bent rod eventually sends it out the block.

This thread is exactly why I just did this:

http://www.mazdaspeedforums.org/foru...uys-think.html

I'm hoping this gives me a big extra safety margin... the car definitely doesn't pull hard until right around 3500 rpm now, no matter how low in the RPM I get on it.

Nice work Lex !!!.

If you have any more words of wisdom to keep this motor out of trouble....please post up...

so too much torque at too low of an RPM ?

So.... If I strap a retarded huge turbo on my car that doesn't even spool until 4.5k I'm golden ? *rhetorical*

:thinkerg:

I see. that makes sense. So, it's from previous metal fatigue.

but don't most with 3076 on stock bottom end still end up throwing a rod even though they have a turbo that spools much later?

there not big enough, idk anyone that blew with a 3076 maybe a 3071

Essentially the metal fatigues. The rods don't have a completely even structure - there may be inclusions, the metal lattice might have interruptions or distortions and we know the surface is not polished. These all lower the tensile strength and yield strength of the metal. So after the rod is "impacted" enough times close to the yield limit it starts to weaken or cracks develop. At that point it will end up breaking or bending.

If you look at streeunitmark's blow-up and jimmymacs you see the exact phenomenon. Mark had an uncontrollable spike of cylinder pressure and so did jimmy before a rod finally yielded.

This simply tells us that the rod is operating close to its yield strength and after a certain number of cycles it fatigues and gives in. Material science is very well detailed in describing this phenomenon and the strength of a part can go right down to the cooling/heating rate of the part during manufacture. Seeing as these are mass produced there will be some discrepancy.

Of course the stock turbo is too small on the car to really take advantage of a late spool. However having it spool at will as calibrated stock with full bolt ons and beating on the car (always working the rod close to the limit) will eventually result in loads which fatigue the rotating assembly.

My point is that if you're going to make 300-350+ ft lbs of torque, it's best to make it at a higher RPM where it will also give you a nice WHP result. On the stock turbo, I would eliminate the boost spike in lower RPMs and ramp load instead of having it hammer like a freight train. Your butt dyno won't be as happy but your internals will last longer.

Throw in the fact that high load/low rpm is also likely to detonate and you have a mixed bag of fail waiting to happen.

Bigger turbo guys have it easier because the slower spool time actually helps and you get better top end.

Remember the tuners from Puerto Rico and how they end up with really high hp cars on the stock bottom end? You know their secret? They bolt big ass turbos on their cars, make torque late, and make tons of horsepower. Traction is better and they are less likely to blow than when making all that torque down low and ALL of us with stock turbos make a ton of torque down low at 25% throttle.

You think its too high? I think you are a little off your rocker. DI is designed to be able to withstand high compression because of the fuel being sent into the chamber directly as it adds a cooling effect.

Lower compression gives you a greater ceiling for tuning thats about it. My port injection motor runs 9.5:1 compression. I have assembled a few motors that use 11:1 even 12:1 compression for boost. Now they are running Q16. But the compression is not our problem here at all. I mean if compression is just the issue here, then get a thicker head gasket and cal it a day.

I would look more too a stronger rod and a larger turbo. This engine needs more room to breath than mazda gave it for it to perform the way a performance minded enthusiast would want.

At low rpm and low load the engine also runs as high as 60 degrees of timing, thats alot of stress right there.

We arent talking about detonation, we are talking about torque vs compression ratio

This has NOTHING to do with compression ratio.. Its about cylinder pressure.

Take a concrete sidewalk. Depending on the size of the rebar used, will determine the weight it can carry. 1/4 inch rebar may be able to support 1 cars weight in a 6 foot section, but the second you place a big rig truck on the same section, the concrete cracks and breaks. To support that truck, you needed 1/2 rebar and a little different mixture of crete that can withstand a larger psi.

Same thing with rods, rods are rated for a certain psi, even forged. Mazda did not design the car with much overhead in it. Meaning, they have 15% over their rated power and thats it.

lex is this a kinda good description of where tq should hit? this is my dyno using the boost table to slowly raise boost.

the first dyno was with no tuning so the car would hit boost instantly. the second one is tuned.

http://i683.photobucket.com/albums/v...g?t=1248120397

http://i683.photobucket.com/albums/v...g?t=1248120333

So the next question is this- has anyone w/ aftermarket forged rods blown yet?

Man I might retune but I love the 21psi meth induced torque wallop right around 3k...:sad:

How does hour rod length and piston bore compare to the EVO, Neon, and Cobalt engines? I think the speed engines have a long stroke than bore size. Doesn't this result in a torquey engine?

Ive noticed on a few speeds that after accelerating and getting into either 5th or sixth and then pulling your foot off of the gas that the large amounts of KR that people see is due to the fuel stopping and the spark still igniting which in turn makes the KR and still doesnt show up as a misfire because it still sparks. It seems that at times the engine isnt completely in tune with itself (go figure)

This woukd explain why people like jumping jackson have blown with the gt28 and people like whoosh survived on the 35.....

what would this explain
http://i38.tinypic.com/2mzmgow.jpg
that this is just another theory with no proof?

You are driving a BMW with a better designed rod?:worthless:

This is really interesting info. My friggin head is spinning when I read about all of these threads about why engines are blowing. Although this does seem to be the most likely idea yet, (and the oldest) I'd still like to see a little more conclusive evidence to set my mind at ease. But thanks for the info!

thats not a bmw dyno. Thats a caliber srt4 dyno, making 200 mroe wtq than we are and not blowing like we are....sole reason, the engine is stronger.

We've gone through so many theories already its not even funny.
manifolds blow cars
balance shafts blow cars
oil flooding? lmao idiot
no meth equals boom?
no fuel down low equals boom
spiking down low equals boom
i agree that these contribute to blown engines, but they would blow in the first place if the motor was stronger.
Add rods, no boom period. The internals suck, end of story already.

Ok ... lets say the internals suck ... lets say it ... instead of being a dick and harping about it ... how about some tuning suggestions to MINIMIZE the risk until one is ready to build their engine.

case in point ... here is the WGDC map for this car ... WHY is it requesting it open MORE in the lower rpms. Seems to me thats a good place to start to limit it's opening.

http://i548.photobucket.com/albums/i...o/Untitled.png

What theory is without proof? The fact that people are blowing motors? Or the fact that the MS3 makes a lot of torque at very low RPMs? Or the fact that low RPM torque is putting stress on the internals?

Not even that CSRT makes 325 ft lbs of torque at 3000RPM. So what's your point?
http://i24.photobucket.com/albums/c4...nocaivssri.jpg

im sorry, but at 3600 it makes over 400...mute point if you ask me.

btw keep in mind where the runs were started grasshoper. start that caliber run at 2k and i bet my ass its gonna make more tq down low

Great thread lex :)

Get new rods and our engine wont fail (period)

fixed.

So that's it? Just get some forged rods and let the car knock like a motherfucker and push 15:1 AFR at 20PSI? Can I install these rods under a tree with my screwdriver set?

yes.

The reason the WG duty is higher at lower RPM is to promote spool in the stock configuration. The car was calibrated to have very little turbo lag and give you the kick in the pants when you punched it even at lower RPMs. Once you add flow mods you need to recalibrate this. Start by taking 10% off and see what effect it has. This will depend on your breather mods. You can also try limiting boost using the throttle based boost limit table.

You see Ladouche, the issue that you can't get through your thick skull is that even if the car has weaker rods than a CSRT4, people want to make the best out of it. With 350 ft lbs of torque in the right place on the RPM band the car can be safer and make more whp. WTF is your solution? Sell the car? That doesn't work for everyone.

So here, we are solving the real issue of current (and future) Mazdaspeed owners. You opted out, no one cares, k, thanks, bye.

There is no tuning on the market that is going to fix this issue for you... You need to replace the weak components, period.

So pretty much everything Palerider and Darrel Cox Racing are saying about this car is bullshit?

Im not sure what they are saying, but if you replace the internals with forged, you are good to go assuming your additional fueling is secured for higher hp levels.

Personally, i wouldnt build a forged bottom end unless i could easily get to 500hp.

I remember dcr saying they think the ms3 bottom end is stronger than the caliber

I think Mrlilguy broke a piston, and Palerider spun a bearing, but no catastrophic failures...

The MS3 rods are quite heavy ... as heavy or heavier than SRT-4 ones. They are 630 grams without bolts. So there's certainly some good meat on them. I consider them on the same playing field as most other modern turbo 4 banger forged rods.

Lex, what year MS3/6 rods did you get to inspect? I'm curious if Mazda had made any changes over the years..

all this makes sense to me... ATM For folks that want to drive there Speed for longevity...are we saying now the best thing to do is to gradually build speed to 3000 rpm then hit it hard to 5500.....rather than going WOT from low rpms??

Lastly..and i have felt this from day 1... that there is not much room in tis platform to make big power in its stock form unless the engine is moded for it.....everything stock is calibrated to run damn near its level for longevity.....as Lex mentioned add a few bolt-ons and a mild tune and indeed you are at 300 TQ or better....and this engine has told us it can't take it for extended runs over and over again till finally something gives..
LaDouch may have some keen insight and really most welcome it... i do... but why the fuck does it have to be so friggin negative on every post...Brother you have lots of good shit to add, why do you feel it necessary to remind all of us you think this car sucks??? How many times do we have to hear you call out cars shit??? Mazda did not design it for 300 Whp they designed it to be a reasonably safe car at stock 265hp levels...and judging by the engine failure rate...stock cars are holding up rather well Maybe this car in stock form is not as strong as a Caliber, BMW, Subbie....and does not have the room for that much HP/TQ improvement in its stock form,,,..but if built right i do believe it can be made to be reliable, with a good deal more power and also last a long time...i for one would be very happy with a 300-350 WHP caR...IN FWD this would be fine indeed.more than that would be pushing it as a DD in FWD..TQ steer.......Now i am hoping that we can at some point with the help of LEX, OTHER MEMBERS, YOU come up with a positive approach to make moded cars stronger in the right area to take away a good percentage of the engine failures ...If it is as simple as the rods being replaced...damn thats great and i certainly would do this FIRST before i go for bigger power again.. before i take the big power journey and give up my warranty....i would sleep better at night knowing i was doing it right .

Some of us have telling people for years that part throttle boost is the devil, and not to go WOT until >3000 RPM.

These were from Mark's motor that he built. He can chime in if he knows. I have not seen any difference in any of the rods from one year to the next that members have posted.

agreed...LaDouch mentioned this as well well over a year ago....and i certainly took his advice...but by part throttle boost.....how do we avoid it without going WOT all the time?? I drive the car pretty lame usually and then take it up a little bit and shift or hammer it to 5000 rpms and shift..No problems so far...And my style of driving is not to go WOT all the time///it does not work for me as i like to drive most of the time a little over the speed limit, but i do like to get to the speed limit quick if possible..is this bad?? and lots of cops in my neck of the woods and i really do not like to get tickets...or hassled

I've wondered for awhile if there isn't something in the mfg process that is biting on a few of these cars weakening the rods. Obviously its not affecting many cars in the grand scheme of things, but it seems to be affecting more than one would like.

Powder Rod process is extremely strong and cost effective for whatever their tolerances are
built for. However, there is no marginal room for more power like on other engines out there.

You guys forget that Dodge did their homework. They would be at irwindale speedway EVERY thur night for well over a year, testing the combo on what was to become, the SRT4. Weve seen them splatter engines on stage 2 packages before beefing up their rods. I use to harass them to roll that slug srt-10 off the trailer and run it for pinks :)

I would guess Mazda also did their homework...I think if it were an inherent problem with the rods we'd see a lot more cars blowing up...fact is we're not seeing a whole lot of them given how many are out there and plenty of people drive them hard and I would guess thousands go WOT without downshifting...you'll find this is common practice amongst non enthusiast individuals because they think revving the motor is hard on it, but got WOT in 6th at 55mph isn't :rofl:

So I think its obvious there's an issue with the rods and as you said there may not be a whole lot of tolerance for modding, but I don't think its from lack of homework...I wouldn't be surprised if Mazda has already found the issue, fixed it and didn't say anything figuring many of the motors popping will be modded to hell and void the warranty and the ones that blow that aren't modded and were maintained are so few and far between that its better to just fix it going forward as opposed to making any sort of mention of it.

is there anyway we can inspect the differences in ecus between the 07-08 and 08.5 and 09? i feel like they changed the ecu calibrations because from what ive noticed the newer cars dont have that huge torque spike like the others do maybe they changed the wastegate or load settings down low in the newer models? take a look at dynos between the different years

I think Aaron has looked into this a little...

I was thinking of trying this on a set of rods. I believe our rods are forged but I dont think they have been to the extent they need to be. Cryogenics is supposed to help take out or fuse some of the imperfections in metal if done correctly. Although it might not be cost efficient as you would need a new set of stock rods and than the cost associated with the cryo process might make it more cost effective to just buy a good set of forged rods. The only reason I was thinking of this is the pistons themselves seem to be fine.

Cryogenic Processing, REM Gear Polishing, Powder Coating, Ceramic Coating, Sandblasting

http://i381.photobucket.com/albums/o...cobaltdyno.jpg
http://i376.photobucket.com/albums/o...c/DSC01508.jpg

cobalts make the same torque we do around the same spot but tend to make that and hp alot easier, btw did i mention no blowing of their motors? not putting you down lex but i think our issue is more a tuning issue than an actual part issue

First, let me say, I agree with you Haltech and many others...its pretty obvious that the rods are the weak point and precious little is going to protect us against this limiting factor when striving for more power. Like Lex said, they are what they are.

Here is why I brought up our static compression ratio in this discussion. 1 psi of boost doesn't equal 1psi of added static compression. When you increase the static compression ratio of a motor by 1 psi, the cylinder pressure (i.e. load) goes up exponentially during the compression stroke. It's much more efficient to add the linear pre-cooled boost pressure as you can't remove the heat created by the higher compression ratio in the cylinder, its too late. I can't recite the equations off the top of my head, but I remember that if you compare 1psi of added static compression vs. 1 psi of added intercooled boost pressure, the static pressure will generate a shite more cylinder pressure (like 5 times more for that one psi), not to mention some serious temperature increases during the compression stroke. Yes, DI will help lower the temps, and so will meth, but it probably won't overcome that 1 psi of added static compression.

Who can say this isn't a participating factor in the differences between, say the CSRT motor and our motor and what their limitations are? In my mind (please prove me wrong if you think I am off my rocker), this is the difference between reliably running 15psi vs. 24psi during spurts on these internals...provided we have enough fuel and the tuning to make it work.

On a positive note, at least we have that 9.5:1 compression ratio to carry us through when we lower our boost at lower RPMs to protect our motors.:boggled:

interesting read lex. thank you.

How long are these guys lasting at those power levels? I can't find much info on the SS TC since GM went under and SS was disbanded early in production. The LNF engine is a nice one.

idk well see but ive seen a ton of cobalt dynos and there all up there around those numbers and havent heard of anyone blow, honestly i think your theory is right, but ecu also is playing a major role in the problems were having

Well with all this talk of caliber srt4s and evos and the like; we are comparting apples to oranges. Lets start comparing a DI motor to a DI motor instead of a port iinjection motor to a DI motor. I mean lets compare static compression ratios.

CSRT4 is 8.6:1
EVO 8 is 8.8:1

Cobalt SS (TURBO) 9.2:1 and the achiece a max pressure of about 17-19 psi stock
Fiat 1.8L DI turbo motor 9.5:1
Ford 3.5L ecoboost 10:1

I mean they didnt just throw high compression pistons in there because they thought it was cool one day. These engines are engineered for higher compression for a reason. Its not the compression. It weak rods and very little headroom in their design. Until we replace the item that fails time and time again...these will remain nothing more than theories. When someone has the gaul to replace the rods with a better set we will know the next limiting factor in this engine. For now thats the only concrete thing we have are broken/bent rods over and over again.

http://emob135.photobucket.com/album...no01/dyno2.jpg

I think I'm making the latest peak torque of any stock turbo car

thats because christian knew what he was doing when he tuned your car, haha

Make big torque later in the powerband. I get it. So how exactly do we do this with ATR?

No, they didn't just throw in higher compression pistons because they thought it was cool. They threw them in because they wanted to have their cake and eat it too. The problem with these new generation higher compression DI engines is that they are built for efficiency while still claiming to get the power of a larger engine. This is the DI marketing hype. It's a fact, DI or not, higher static compression exponentially raises cylinder pressure and heat. My point is that we would have a bit more legroom in our factory block if it wasn't for the greedy design of this engine. This type of design may work fine for well planned stock configurations, but when power modding begins, there is less room for error and growth than in a classic lower compression turbo engine. Some engines are built stronger, but ours doesn't appear to be strong enough and that is why we are here discussing it. If we understand the weakness of our design, only then can we even try to prevent against it.

The 3.5 Ecoboost only runs up to 12psi stock for a reason. I couldn't find any boost info on the new Fiat 1.8L. The Cobalt is obviously built pretty well, but even they were smart enough to scale back static compression a tad and seemingly threw in better internals. Only time will tell.

So tune out the tq spike and throw in a double stacked copper HG. I guess that doesn't really lower the static CR all that much...

Oh, and remember when the Cobb AP came out? the v101's may have been a joke but the v102's were a bit better. The big complaint everyone had was that the Cobb OTS maps put the "Wild Child" on Ritalin lol. For the V103's, everyone wanted the wild child back and they wanted the kid jacked up sweet tarts and pixie sticks...We asked for it, and we got it. Christian gave us back that mid-range tq spike. Is it a coincidence that the time frame in which that happened up until now is when we've seen the majority of our motors blow? (obviously this excludes users of other tunes).

Maybe, just maybe, Christian knew what he was doing. Not a sermon, just a thought. (lulz).

^ Does that correlate directly to the throttle smoothing in the 103 beta maps or is there more to it than that?

+1 on this...the first OTS maps were, in my eyes, improvements over the stock tune as it moved the power up the rpm range enough that you'll still get power when you stayed on it (like on a road course) but civil enough that you can putter around town like the regular Mazda3 and stay stealth and incognito (I live in a large urban centre where any form of street racing/stunt driving = automatic 1-week impound + fines).

The big hp guys bitched and moaned and haltech jumped in to create the "hotter" MSF maps with the "boost spike" and "boost taper" to bring the wild child back. It was such a huge dif that on the shoutbox, haltech told me to take a week or so to re-adapt my driving. Mind you, this was also about the time that Cobb realized the 1.01 maps were had bad tables in them.

In the back of my mind, I always wondered what would happen if Cobb could have stayed the "high road" so to speak and tuned it the way they wanted to rather than what the HP junkies dictated. Or maybe have 2 strategies, as Cobb road raced their car...rather than just for power/roll racing/drag racing.

Guys, this is not intended to make you think the rods are the weakest mechanical link in our engine. They clearly are. They are probably the weakest link in most engines as this is the MOST common high power type of engine failure. This was intended to point out that in order to make the best of the internals we have, not be at risk, and make more usable power, the torque we generate at the low RPMs should be ramped up slower and moved further down. Of course putting in aftermarket forged rods moves the overhead much higher up - this is not to argue that it won't help.

The first problem you're going to run into is that the stock turbo won't flow enough to make the torque late in the power band if you are shooting for power on stock internals, so the first thing I would do is get a properly sized turbo with a properly sized exhaust housing (read bigger). This will slow spool and move torque up the RPM curve at the same time.

If you're still on stock turbo, ramp up the boost so that at the low RPMs you don't spike (especially in 4th gear and above that as they are high load gears). I wouldn't want to spike more than 17-18psi when getting on it in the low RPMs and work the boost up from there. Follow this up with enough fuel and timing such that KR is low to none. This type of tuning is much more forgiving compared to a stock tune car with many flow mods.

i guarantee you, Mazda has not fixed the rods. They built the rods to spec.. If a customer blows a rod, they know why it happened and will deny the warranty. Why would Mazda redesign the rod to be stronger when the dont want the car to be modified to begin with? They will deny the warranty and be done with it.

Ford did the same thing with the lightning. What came out of it was, when the Terminator was introduced (03/04 cobra) they went straight to forged rods/pistons because they KNEW the after market would push those cars to huge limits. Ford wanted that recognition and all of their SVT vehicles now, have built lower ends. Mazda could give 2 shits less about notoriety at this point. There fastest sports car is infact, a Mazdaspeed 3, not an RX8.

You have to fix the problem on your own. Everyone knows about it, so it comes down to, if you arent willing to pay to play, dont touch the car. Be a man about your mistakes and own up to the cost.

Hal, at the same time you and other have been running well at up to 50% more power than stock.

When are you going to realize... that car companies do NOT build the car so enthusiast can make 200-300hp over their design? It comes down to money.. What kind of car can we build for the average guy, that makes power, but is still PROFITABLE? Thats the bottom line, MONEY. They do not sit around the table and say " we need to build the motor to take 600hp for these enthusiast guys. " We account for less then 5% of their total sales, who mod the vehicle after purchase.

DI is not a weak design, nor the higher compression or higher boost ability. Look at the ecoboost technology as an example. If SVT gets a hold of a Ecoboost engine in a car, they will forge it and design a healthier fuel source at the same time.

At least today, Ford has recognized the enthusiast market and builds their SVT line for those people. Thing is, you do end up paying for the primo parts, but it does yield anywhere from 50-70% increase power over the stock power levels. This is new to Ford, but not to chevy. Chevy has overbuilt their engines for quite sometime starting with the LT5, then to the LS1, LS2, etc.. But that technology does trickle down from the Vette engines. Ford has just recently caught onto it and it saves a lot of warranty issues.

I think out of all the JDM gook muscle, DSM with their EVO platform affords a lot of power without going into the lower end and rebuilding. Scoobies on the other hand, do not, just like many of flavors of gook muscle. Nissan use to have some stout bottom ends as well, but i dont know about their current models aside from the GTr.

True, but im a car guy with a lot of experience. I dont flog the car on hot days, or constantly beat the shit out of it. I change my oil freq, i check my plugs weekly and i take care of the car.

I also dial my tunes in, which is key to success. I also dont load the car up down low to often. But, i can suffer the same fate as others have. It comes down to experience and how you respect the car.

Also, one thing to bring up here. People who start blown engine threads never come clean about WHAT they did. They are embarrassed and dont want to be called a dumbshit. So, they act as if the car just blew. 8 times out of 10, it was owner induced, but they wont own up to it publicly. Theres only been a few guys who have owned up to it since 2007.

If you run a big turbo on a stock bottom end, i hope you got money put away because you are ticking away with a bomb. It costs you more money to build when you blow, then the build the bottom end before you strap a 1300 cfm air pump on the car.

Does anyone know what happened to JimmyMac? He was in the process of building his motor with Carrillo rods and the stock pistons last we heard because he bent a rod from overboosting on his gt28(?). Palerider, I know you hung out with that kid before. where is he at? what happend? someone should give that kid a call and tell him to update us...

Last time jimmy posted was March 9th and his last forum login was March 16th.

Here are all 18 of his threads...

http://www.mazdaspeedforums.org/foru...earchid=713064


He may have sold the car, who knows.

If I were to do anything about this bottom end as a precautionary step, just replacing the rods with Carrillos would be it so he was on the right track.

"New to Ford" Right. The company that built at least a +50% blowup margin into the 5.0, the nearly indestructible, if very tractorish, 2.3 Turbo, The 2.0 Cosworth, etc. They have a long history of overbuilding performance engines. You're right that companies today building a sub 30K car don't have as much monetary headroom to build what they like. The cheaper the car is, the more compromises are in it; especially these days, when consumers expect so much but don't want to pay for it.

I wonder how much FoMoCo design is actually in this engine. Legit question, I don't really know. There's FoMoCo on all kinds of things on the engine. The chassis is Euro Focus, too.

the MS3 in stock form is a winning formula (back-to-back C/D 10Best, 2007 and 2008)...once you start fucking around with any one of the variables in that formula, you can't expect the car to be the same. Who knew you'd fuck your warranty when you start making 100whp over stock in a 35K CDN grocery getter...

so basically this is wen you go WOT in a ms6
http://img37.imageshack.us/img37/521...daspeed604.jpg

YUP! LOL

Well you cant count the older ford tech from 80s and early 90s in this one. Their modular platform was major dogshit until 2003 when they grew a set of balls and did shit right. They finally listened that people arent going to keep buying mustangs that got walked all day long by huge cubed camaros.

The MZR was definitely a feeler engine for both Ford and Mazda. I highly doubt they thought they would get a huge market from this platform because of the low build numbers.

QFT!:notworthy:

Come on man, you are preachin' to the choir on this subject. Who said anything about expecting 200-300 HP for free? It sounds like most of us agree on the basic principles here. You said it was about cylinder compression. I agreed and told you how and why they could have made it better by lowering the static compression. Do you not agree with this assessment? I am simply pointing out another reason why we aren't one of the lucky platforms that does have some room to grow without often witnessing the epic fail tale. I am one of those that would be happy with a reliable 300whp on this little FWD. I am content with this car for now, but I am a little disappointed...I'm sure this is a common feeling around here. Hell, we even have some close to stock cars blowing up with only 25-50 added HP/TQ. For a car that is setup to spike 17-18psi stock, I expected a little higher tolerance until failure. Without much of a cost difference at all, they could have lowered the compression and relieved some of the stress on the engine. This wasn't smart at all as a manufacturer if they were in it to make money as they are going back to fix their problems quite frequently from what I have been reading. Even if they don't fix it, it gives them a bad name whether they are in the right or wrong. And yes, you are very right that many companies know better when they put their racing division stamp on their product.