CX-9 Skyactiv 2.5L turbo engine

[MikeM.]

Yes I know what they are referring to. I built my engine to handle more power, but it never "blew up" it did get torn down and rebuilt though (that is not the same).

Are you saying it ran fine and had no issues when you tore it down?

 

[Tbot101]

Hey, just relax. I'm just here to learn something. My question is completely legitimate and you only gave me an aggressive non-answer.

If you can strip away half the material as was used, say, in the 80s and still keep it stronger than it needs to be in order to accommodate a tune (what you are saying unless I am not understanding something), you can strip even more to make it just strong enough for normal use and make it even lighter. Simple math. No misinformation here. If you are not interested in giving me a straight, rational answer, just let someone else do it.

You're right, they could. That doesn't mean they always do. This entirely depends on the manufacture, engine, etc.
For example the Mazda protege, very weak connecting rods. They will snap even under stock power sometimes.
Or the Mazda MZR 2.3L (non DISI). Very long, weak connecting rods. They will snap when you add about 100 ft lbs more torque.

The closer the part is to the limit under stock power the higher chance there is for failures. Why would any manufacture risk that to shave a few grams off some rotating parts? You have to understand the casting, forging process is not perfect. Not even part that comes out will be identical or have the same tensile strength and fatigue limits as one another. If they add only 10% additional strength to a part vs what it can handle stock, there is a lot more chance for failure from the parts.

Another problem with that is the power rating is not always known when the part is created. They don't know what the engine power will be before it is made, they make the engine, and have the calibration done at different times, so if the company that creates the calibration makes too much power they blow the engine. They must account for all scenarios so they almost always create parts to handle more than what it is designed for.

It just "depends." But since we are talking about the skyactiv, we have already shown the con-rods can handle *at least* another 50 ft lbs / 100 HP over stock without failing.

Are you saying it ran fine and had no issues when you tore it down?

Correct, had no problems when I tore it down, but I tore it down to build it before it would blow up. I was pushing it pretty hard and was expecting a stock con-rod to snap. So before one did I tore it apart and rebuilt it with stronger components.

Yes, I'm a retired Software Engineer. I've worked with many electrical, software, and mechanical engineers. Seems many of the mechanical engineers (ME) started out as gear heads. You should consider harnessing your passion for cars and going back to school to get an ME. If you like basic Physics 101,102,statics, and dynamics, you will probably want to go the distance. They require simple algebra. If you make it past Trigonometric Calculus, you can probably go the distance.

I prefer the electrical side, and went to school for electrical engineering.
Learning about engines, fatigue limits, and all that really doesn't require a degree in mechanical engineering. Sure it helps, but not required to know.

 

[vroom]

You're right, they could. That doesn't mean they always do. This entirely depends on the manufacture, engine, etc.
For example the Mazda protege, very weak connecting rods. They will snap even under stock power sometimes.
Or the Mazda MZR 2.3L (non DISI). Very long, weak connecting rods. They will snap when you add about 100 ft lbs more torque.

It just "depends." But since we are talking about the skyactiv, we have already shown the con-rods can handle *at least* another 50 ft lbs / 100 HP over stock without failing.

Thanks Tbot101. That seems strange though, considering that under Skyactive Mazda engineers have been looking at every detail to reduce weight. I mean down to reducing wheel bolts from 5 to 4 on some models. The motor being a very large weight component, it seems they could save a lot... Maybe they will address this in future engine generations (making tuning more difficult and possible gains much smaller)?

 

[Tbot101]

Thanks Tbot101. That seems strange though, considering that under Skyactive Mazda engineers have been looking at every detail to reduce weight. I mean down to reducing wheel bolts from 5 to 4 on some models. The motor being a very large weight component, it seems they could save a lot... Maybe they will address this in future engine generations (making tuning more difficult and possible gains much smaller)?

I have a complete 2.0L engine that I have torn down, and have seen what is inside. They shaved weight sure, but they designed the rods different than the MZR engine and you can clearly see by looking at them they will be able to take more abuse because of the design.

If you think weight and size is the factor that determines strength, that's incorrect. A billet H-beam connecting rod is almost always lighter than a factory rod, yet due to it's design and material (billet) they will handle enormous amounts of power vs a stock one.

The DESIGN of the connecting rod is the key, NOT the weight or size. If the design didn't matter than lightweight H-beams or Aluminum rods would suck! but they dont.

Look at the difference, the DESIGN of the rod is the important factor, they shaved weight were it isn't as important and does not take as much stress, like the rod cap for example, the rod bolts, etc:

 

[NelsonLewis]

Hey, just relax. I'm just here to learn something. My question is completely legitimate and you only gave me an aggressive non-answer.

If you can strip away half the material as was used, say, in the 80s and still keep it stronger than it needs to be in order to accommodate a tune (what you are saying unless I am not understanding something), you can strip even more to make it just strong enough for normal use and make it even lighter. Simple math. No misinformation here. If you are not interested in giving me a straight, rational answer, just let someone else do it.

You're right, they can, and I apologize for coming off as aggressive. I just took your comment as additional weight = stronger, and that's highly incorrect. Having a warranty to stand by, and balancing issues are two things that come to mind why they wouldn't want to, but we all know some factory engines are already known to be weak from the get go, while others are known to be "bulletproof." I'm also new to the Skyactive technology, so some of it is a learning curve for me as well. OVT/TBot101 does seem to have great knowledge with it so far, and putting it to use is something that I'm definitely interested in...

 

[NelsonLewis]

I have a complete 2.0L engine that I have torn down, and have seen what is inside. They shaved weight sure, but they designed the rods different than the MZR engine and you can clearly see by looking at them they will be able to take more abuse because of the design.

If you think weight and size is the factor that determines strength, that's incorrect. A billet H-beam connecting rod is almost always lighter than a factory rod, yet due to it's design and material (billet) they will handle enormous amounts of power vs a stock one.

The DESIGN of the connecting rod is the key, NOT the weight or size. If the design didn't matter than lightweight H-beams or Aluminum rods would suck! but they dont.

Look at the difference, the DESIGN of the rod is the important factor, they shaved weight were it isn't as important and does not take as much stress, like the rod cap for example, the rod bolts, etc:

Ooooh! Engine porn...that Skyactive conrod is a thing of beauty...

 

[CC58]

I prefer the electrical side, and went to school for electrical engineering.
Learning about engines, fatigue limits, and all that really doesn't require a degree in mechanical engineering. Sure it helps, but not required to know.

I started out to get a BSEE, but switched over to software in my junior year, so have done all the math courses required. Understanding physics is critical to understanding mechanical components. BSME classes are fundamental to understand mechanical stress and wear.

 

[Tbot101]

I started out to get a BSEE, but switched over to software in my junior year, so have done all the math courses required. Understanding physics is critical to understanding mechanical components. BSME classes are fundamental to understand mechanical stress and wear.

Sure, just like quarter mile times are required to know if an engine makes more power. I don't want to argue about this. This thread is finally becoming peaceful with open talks of information.

 

[CC58]

Sure, just like quarter mile times are required to know if an engine makes more power. I don't want to argue about this.

Quarter mile times are a check on subjective dyno values. Everyone can run a quarter mile, and few have access to dynos to cross check. If your customers can make the numbers in the quarter miles, you are legit in your claims. Simple as that.

 

[Tbot101]

Quarter mile times are a check on subjective dyno values. Everyone can run a quarter mile, and few have access to dynos to cross check. If your customers can make the numbers in the quarter miles, you are legit in your claims. Simple as that.

Yet when I show you just that you dispel it???

 

[CC58]

Yet when I show you just that you dispel it???

Because they were wrong. They guy obviously was not stock to make 50-60hp.
You need a stock CX-5 with just a "tune", tested by a reliable third party.

 

[Tbot101]

Because they were wrong. They guy obviously was not stock to make 50-60hp.
You need a stock CX-5 with just a "tune", tested by a reliable third party.

the dyno sheets are wrong the 1/4 mile times are wrong. what's next?

 

[MikeM.]

Sure, just like quarter mile times are required to know if an engine makes more power. I don't want to argue about this. This thread is finally becoming peaceful with open talks of information.

Now that you are in a better mood, maybe you can tell us how to verify that a dyno chart hasn't been fudged just by looking at it?

 

[Tbot101]

Now that you are in a better mood, maybe you can tell us how to verify that a dyno chart hasn't been fudged just by looking at it?

coulda swore I answered that a few pages ago, but why should I give you the courtesy of answering your questions when you won't do the same for me?

anyways dyno sheets that show clearly humidity, correction factors, SAE, etc printed on it *usually* means it hasn't been tampered. The easiest and most common way to tamper with power is altering the CF (correction factor) to make gains look larger. As temperature and humidity factors don't make as much of an exaggeration.

i'll give you an example. There is a dyno here in town that has its CF at 1.3, while most other dynos here are around 1.2 - 1.24. I bet you can guess whose dyno shows the highest gains in the state! lol

On the dyno sheet for the Dyna Pack, look at TCF (transmission correction factor) if it is a 1.0 no correction is being placed, if it is not 1.0 there is a correction in place that will make the numbers look higher. Other ways are seeing axle power , axle torque, etc but those are a bit more in depth controls in the software that rarely is shown on a sheet.

You guys can dispel all my dyno sheets, 1/4 mile time as all BS, I dont care. I dont even wanna talk about it. I would much rather talk more about the skyactiv engine, design, components, and such like we have been doing. I really enjoy that. It may sound cheesy but I really love what mazda did with this engine. They did everything "just right." Except for one thing lol.. the intake ports.

 

[NelsonLewis]

coulda swore I answered that a few pages ago, but why should I give you the courtesy of answering your questions when you won't do the same for me?

anyways dyno sheets that show clearly humidity, correction factors, SAE, etc printed on it *usually* means it hasn't been tampered. The easiest and most common way to tamper with power is altering the CF (correction factor) to make gains look larger. As temperature and humidity factors don't make as much of an exaggeration.

i'll give you an example. There is a dyno here in town that has its CF at 1.3, while most other dynos here are around 1.2 - 1.24. I bet you can guess whose dyno shows the highest gains in the state! lol

On the dyno sheet for the Dyna Pack, look at TCF (transmission correction factor) if it is a 1.0 no correction is being placed, if it is not 1.0 there is a correction in place that will make the numbers look higher. Other ways are seeing axle power , axle torque, etc but those are a bit more in depth controls in the software that rarely is shown on a sheet.

You guys can dispel all my dyno sheets, 1/4 mile time as all BS, I dont care. I dont even wanna talk about it. I would much rather talk more about the skyactiv engine, design, components, and such like we have been doing. I really enjoy that. It may sound cheesy but I really love what mazda did with this engine. They did everything "just right." Except for one thing lol.. the intake ports.

Good information here...I'm behind you with the tuning aspect, I too want to learn more about the Skyactiv engines...

 

[NelsonLewis]

Because they were wrong. They guy obviously was not stock to make 50-60hp.
You need a stock CX-5 with just a "tune", tested by a reliable third party.

A stock CX-5 with just a tune wouldn't yield but .2-.3 tengths anyhow, and that could be easily skewed even on back to back runs. too many factors, however, I'm just as interested in the datalog from the run as the time slip...merging on the highway as well...

 

[MikeM.]

coulda swore I answered that a few pages ago, but why should I give you the courtesy of answering your questions when you won't do the same for me?

anyways dyno sheets that show clearly humidity, correction factors, SAE, etc printed on it *usually* means it hasn't been tampered. The easiest and most common way to tamper with power is altering the CF (correction factor) to make gains look larger. As temperature and humidity factors don't make as much of an exaggeration.

i'll give you an example. There is a dyno here in town that has its CF at 1.3, while most other dynos here are around 1.2 - 1.24. I bet you can guess whose dyno shows the highest gains in the state! lol

On the dyno sheet for the Dyna Pack, look at TCF (transmission correction factor) if it is a 1.0 no correction is being placed, if it is not 1.0 there is a correction in place that will make the numbers look higher. Other ways are seeing axle power , axle torque, etc but those are a bit more in depth controls in the software that rarely is shown on a sheet.

You guys can dispel all my dyno sheets, 1/4 mile time as all BS, I dont care. I dont even wanna talk about it. I would much rather talk more about the skyactiv engine, design, components, and such like we have been doing. I really enjoy that. It may sound cheesy but I really love what mazda did with this engine. They did everything "just right." Except for one thing lol.. the intake ports.

I am already aware of all the variables you mentioned that can affect measured gains (and a number of variables you didn't mention). However dyno charts NEVER have all the correction factors and variables that affect results printed on their face. Your claim was that you could tell by looking at it whether it had been fudged which is clearly not always the case.

I'm all for you discussing Skyactiv engines, design components and the like. But try to avoid the type of brash statements that are inherently false (like dyno charts don't lie, you can tell whether they've been fudged by looking at them, etc.) and other sneaky tricks like using dyno charts from engines that have modifications added to them when trying to support gains of 25-35 HP on a bone stock setup. Because words do matter and trust is earned, not assumed from the beginning.

And trust is important because, as you have finally admitted, taking a dyno chart as an accurate representation of reality is a matter of trust, not inherent scientific fact as you argued initially. Those types of statements can only work to reduce trust, not build it.

 

[Tbot101]

Oh god here we ******* go again... actually many dynos do publish those but whatever. MikeM im just going to stop responding to you so us adults can have an intelligent coversation.

You're a forum clown, nothing more. You cant even answer my simple questions yet you want in depth coherent responses from me to satisfy your galaxy sized internet ego. Go google some more.

All I have ever seen you do is rip info off of google or other articles and present them as your own. How dumb do you think we all are? We know the game you're playing here.

Now please, let us continue this discussion about the skyactiv engine. MikeM you are more than welcome to present your google information in our discussion if you can do so without injecting your massive ego into it.

 

[MikeM.]

Oh god here we ******* go again... actually many dynos do publish those but whatever. MikeM im just going to stop responding to you so us adults can have an intelligent coversation.

You're a forum clown, nothing more. You cant even answer my simple questions yet you want in depth coherent responses from me to satisfy your galaxy sized internet ego. Go google some more.

All I have ever seen you do is rip info off of google or other articles and present them as your own. How dumb do you think we all are? We know the game you're playing here.

Now please, let us continue this discussion about the skyactiv engine. MikeM you are more than welcome to present your google information in our discussion if you can do so without injecting your massive ego into it.

You accuse me of plagiarism (ripping off articles and presenting them as my own)? I have NEVER done that and it is just this type of hot-headed and baseless accusation that has caused your loss of credibility. Please support your false accusations with something more than your word. Because your credibility is in tatters!

You know what I used Google for? To support my claim that dyno charts are well known to be manipulated to sell products/services. This is common knowledge and yet you denied it. So I linked to an article discussing the fudging of dyno numbers. Yes, I found the article with Google, so what? Why do you feel so threatened by Google?

And what's with this accusation that I've ripped off articles and presented them as my own?

 

[Tbot101]

Dude, like you said earlier, go smoke a bowl or something. You're having another google induced temper tantrum.


At least start adding some citations to all the info you rip.