CX-9 Skyactiv 2.5L turbo engine
- Thread starter CC58
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- RDX Aspec Adv.
Friend of mine drove one in the 90's. They still make that turd?
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- RDX Aspec Adv.
I understand. I'm just torn on ideology right now. On one hand, I miss all my other faster vehicles (this is the second slowest vehicle I've ever owned), but on the other, I did buy it to be a cheapskate, and using 91 octane exclusively kindof negates that. Not so much right now, but by election? Dunno what oil will be doing.
>Bumo-a-dump with thoughts, opinions, rants
This isn't really true, it is actually low-end torque (and thus low end HP) that really stresses driveline components, from rods to trannys, and the Turbo 2.5L is about as torquey and built as it gets for a factory stock engine. The thermal management Mazda had down pat with the 2.3L DISI. Of all the engines that should have been warping heads and roasting headgaskets, the L3-VDT was not. Bad tuned and narrow margins of error however DID bring to light new phenomenons like LSPI, and bent rods. IMO the L3-VDT was built with s*** components-- and big surprise bc for the first time in Mazdas history, they made a deal with the DEVIL (Ford) who, in exchange for the MZR engine design, offered to provide both Ford and Mazda lines with OEM components that were sourced by Ford. And Ford is about as cheap/greedy as it gets. Every part to fail on a Mazda MZR will be FoMoCo branded, from timing chains, VVT phasers to dipsticks and connecting rods. I mean, considering all of that the 2.3L DiSI was relatively very bloody reliable
Believe it or not, but Mazda uses the best ingredients they can possibly procure at the moment (even given their economic limitation). They are alloy and foundry masters. They've taught big bad FORD a LOT over the decades about machining, casting, forging. Have you ever seen Ford execs and engineers pine about Mazda's machine and foundry quality? For fun here is a direct quote "what we learned was that we were good, but our competitor (Mazda in that context) is damn good".
As for the high boost pressure on the 2.5T, the intention is certainly not about specific output, but efficiency.
The 17+psi will only occur during miller cycle operation. As with the Millenia, the idea is to compress the air as much as possible before the IC, and let the heat be shed in the IC, that way LESS COMPRESSION WORK needs to be done in the combustion chamber. And as you should know, doing all the compression in the combustion chamber liberates heat exactly where is it not needed-- as well as robs power to pump. When using the miller cycle on a FI engine, pumping losses are reduced both in the compression stage and the vacuum stage. The Miller cycle is not conducive to high RPM.
Other manufacturers are using atkinson/miller cycles on their NA and turbo engines as well, but they are technically unable to realize the higher mechanical compression in the real world enough to put it on the market, so they don't reach the thermal efficiency levels of the Skyactiv.
The Turbo Skyactiv, using high boost and miller cycle, is able to increase efficiency using the waste heat from the exhaust to compress the charge, rather than sacrifice to a supercharger as on the original Miller cycle 2.3 V6. This is one technical reason Mazda is so bent on quick spooling to 17+psig, the non-technical reason being initial response.
It's funny how every car manufacturer has jumped on the "downsized turbo GDI" bandwagon, mostly because of Mazda paving the way in the mid-2000s with the successful and relatively reliable 2.3L DISI. Mazda was pretty much the first TURBO GDI engine to make it to a global market.
Others played around with GDI before, but they were all NA and limited to small/domestic market. In fact, there was not another 4cyl automotive gasoline engine ~2.3L displacement of any type that was producing as much low-end torque as the L3-VDT (2.3 DISI). It took many years for Mercedes Benz to top it with their 2.0L, but they had to make those engine by hand. lol. Forget about daddy warbucks Toyota who has only very recently managed to cobble a 2.0L GDI turbo version out of their aged AR- engine.
It truly is sad, how other manufacturers have the money, (Toyota 30b dollars profit annually) but they don't have the engineering talent (or the desire to invest in engineering talent), simply because investing in marketing, promotion and advertizing pays WAY more. And don't forget how these companies are paying online shills in this age of social media to bash certain manufacturers and demean their products, simply because the innovation threatens their profits, and brand images. This form of nasty marketing is HUGE right now. Look around. These profit-mongers know advertizing and marketing = way more money than innovation and hard work; they wait for honest, dedicated, sensible and highly skilled engineering houses to do all that- the heavy lifting, then they swoop in and buy it and/or copy it, only to release it in about 5+yrs later due to their $peedy 'development cycle'.
It's kind of sad to see how shitted on Mazda and their innovations get by casuals/shills. Really, only the engineers in the industry can truly appreciate what Mazda is capable of, and trust me THEY KNOW IT. To most consumers/marketers though, sadly, it's straight up pearls before swine. If Mazda made 30 billion annually, they would literally destroy almost everyone else. That's the power of skill, integrity and resources, but sadly, as has been for the past few decades, the naive and trusting Mazda invites wolves into their house to do business with and can never, ever seem to get more market share, particularly in the cash cow known as North America, where marketing REALLY works on people. Mazdas are very popular in Europe, but they are an entirely different type of consumer.
That said, the P-engines (Skyactiv G engine code) are INCREDIBLY WELL ENGINEERED and their build quality is unmatched. Why don't Mazdas suffer as much oil consumption as Honda, Toyota et al?? It comes down to parts uniformity and more importantly surface finishes. Mazda plateau-hones their bores for instance. The Sky G pistons have a ductile iron top ring land cast into the allow FFS. Who else is doing that on a gasoline engine? That's diesel piston territory!
The 2.5L turbo engine OBVIOUSLY has more in it, however these engines need to be reliable for worldwide markets, need to acheive CO2 emission targets, NOx targets and economy targets. That means the end-user has to violate those requirements. And I'm pretty sure the 2.5T is low-tuned not only for it's application (soccer moms) but for real world testing as well. Remember, as usual, there isnt another engine on the market quite like it. Is there another gasoline 4cylinder producing 310ft-lbs on regular fuel @2000rpm? It's the 2.3 DISI all over again
As for tuning the NA SKyG's, yeah they have more in them too but they're pretty much self-tuning TBH while maintaining a PRESCRIBED margin of safety. You can change parameters up and unlock some more torque, but you remove a margin of the proactive safety net.
Now, I know some people pay big dollars to 'tuners', and it's really nothing you could not do yourself. I'm a little bothered that some user should have to PAY big money to PROVIDE THEIR DATA to a 'tuner' not only so that HE can learn his craft on the fly and get paid for that... but who will mostly only look at the optimization the user's own car ECU has done autonomously-- and simply enter those adjusted values as the default values in the ECU so the next time you start the car and it starts it's self-optimization, it does so in a narrower window closer to the tune THE CAR GAVE ITSELF PRIOR, reducing the time it takes for the car to re-optimize after each restart. IMO the end result is a driver who a bit sooner notices that the ECU has reached optimization sooner, rather than later. You can pretty much do this yourself TBH, especially if you were motivated by HUGE DOLLARS to have people throw THEIR OWN data at the tuner.
No one payed me to go to school.
The usefulness of that level of tuning is not bad, ie narrowing optimization windows based on data derived from the ECU. Raising the rev limiter, setting trims and tweaking the top end IV retard a bit is just the simplest s*** tbh, something I'd do myself.
CHCHCHCHCHCHEERS!!
This isn't really true, it is actually low-end torque (and thus low end HP) that really stresses driveline components, from rods to trannys, and the Turbo 2.5L is about as torquey and built as it gets for a factory stock engine. The thermal management Mazda had down pat with the 2.3L DISI. Of all the engines that should have been warping heads and roasting headgaskets, the L3-VDT was not. Bad tuned and narrow margins of error however DID bring to light new phenomenons like LSPI, and bent rods. IMO the L3-VDT was built with s*** components-- and big surprise bc for the first time in Mazdas history, they made a deal with the DEVIL (Ford) who, in exchange for the MZR engine design, offered to provide both Ford and Mazda lines with OEM components that were sourced by Ford. And Ford is about as cheap/greedy as it gets. Every part to fail on a Mazda MZR will be FoMoCo branded, from timing chains, VVT phasers to dipsticks and connecting rods. I mean, considering all of that the 2.3L DiSI was relatively very bloody reliable
Believe it or not, but Mazda uses the best ingredients they can possibly procure at the moment (even given their economic limitation). They are alloy and foundry masters. They've taught big bad FORD a LOT over the decades about machining, casting, forging. Have you ever seen Ford execs and engineers pine about Mazda's machine and foundry quality? For fun here is a direct quote "what we learned was that we were good, but our competitor (Mazda in that context) is damn good".
As for the high boost pressure on the 2.5T, the intention is certainly not about specific output, but efficiency.
The 17+psi will only occur during miller cycle operation. As with the Millenia, the idea is to compress the air as much as possible before the IC, and let the heat be shed in the IC, that way LESS COMPRESSION WORK needs to be done in the combustion chamber. And as you should know, doing all the compression in the combustion chamber liberates heat exactly where is it not needed-- as well as robs power to pump. When using the miller cycle on a FI engine, pumping losses are reduced both in the compression stage and the vacuum stage. The Miller cycle is not conducive to high RPM.
Other manufacturers are using atkinson/miller cycles on their NA and turbo engines as well, but they are technically unable to realize the higher mechanical compression in the real world enough to put it on the market, so they don't reach the thermal efficiency levels of the Skyactiv.
The Turbo Skyactiv, using high boost and miller cycle, is able to increase efficiency using the waste heat from the exhaust to compress the charge, rather than sacrifice to a supercharger as on the original Miller cycle 2.3 V6. This is one technical reason Mazda is so bent on quick spooling to 17+psig, the non-technical reason being initial response.
It's funny how every car manufacturer has jumped on the "downsized turbo GDI" bandwagon, mostly because of Mazda paving the way in the mid-2000s with the successful and relatively reliable 2.3L DISI. Mazda was pretty much the first TURBO GDI engine to make it to a global market.
Others played around with GDI before, but they were all NA and limited to small/domestic market. In fact, there was not another 4cyl automotive gasoline engine ~2.3L displacement of any type that was producing as much low-end torque as the L3-VDT (2.3 DISI). It took many years for Mercedes Benz to top it with their 2.0L, but they had to make those engine by hand. lol. Forget about daddy warbucks Toyota who has only very recently managed to cobble a 2.0L GDI turbo version out of their aged AR- engine.
It truly is sad, how other manufacturers have the money, (Toyota 30b dollars profit annually) but they don't have the engineering talent (or the desire to invest in engineering talent), simply because investing in marketing, promotion and advertizing pays WAY more. And don't forget how these companies are paying online shills in this age of social media to bash certain manufacturers and demean their products, simply because the innovation threatens their profits, and brand images. This form of nasty marketing is HUGE right now. Look around. These profit-mongers know advertizing and marketing = way more money than innovation and hard work; they wait for honest, dedicated, sensible and highly skilled engineering houses to do all that- the heavy lifting, then they swoop in and buy it and/or copy it, only to release it in about 5+yrs later due to their $peedy 'development cycle'.
It's kind of sad to see how shitted on Mazda and their innovations get by casuals/shills. Really, only the engineers in the industry can truly appreciate what Mazda is capable of, and trust me THEY KNOW IT. To most consumers/marketers though, sadly, it's straight up pearls before swine. If Mazda made 30 billion annually, they would literally destroy almost everyone else. That's the power of skill, integrity and resources, but sadly, as has been for the past few decades, the naive and trusting Mazda invites wolves into their house to do business with and can never, ever seem to get more market share, particularly in the cash cow known as North America, where marketing REALLY works on people. Mazdas are very popular in Europe, but they are an entirely different type of consumer.
That said, the P-engines (Skyactiv G engine code) are INCREDIBLY WELL ENGINEERED and their build quality is unmatched. Why don't Mazdas suffer as much oil consumption as Honda, Toyota et al?? It comes down to parts uniformity and more importantly surface finishes. Mazda plateau-hones their bores for instance. The Sky G pistons have a ductile iron top ring land cast into the allow FFS. Who else is doing that on a gasoline engine? That's diesel piston territory!
The 2.5L turbo engine OBVIOUSLY has more in it, however these engines need to be reliable for worldwide markets, need to acheive CO2 emission targets, NOx targets and economy targets. That means the end-user has to violate those requirements. And I'm pretty sure the 2.5T is low-tuned not only for it's application (soccer moms) but for real world testing as well. Remember, as usual, there isnt another engine on the market quite like it. Is there another gasoline 4cylinder producing 310ft-lbs on regular fuel @2000rpm? It's the 2.3 DISI all over again
As for tuning the NA SKyG's, yeah they have more in them too but they're pretty much self-tuning TBH while maintaining a PRESCRIBED margin of safety. You can change parameters up and unlock some more torque, but you remove a margin of the proactive safety net.
Now, I know some people pay big dollars to 'tuners', and it's really nothing you could not do yourself. I'm a little bothered that some user should have to PAY big money to PROVIDE THEIR DATA to a 'tuner' not only so that HE can learn his craft on the fly and get paid for that... but who will mostly only look at the optimization the user's own car ECU has done autonomously-- and simply enter those adjusted values as the default values in the ECU so the next time you start the car and it starts it's self-optimization, it does so in a narrower window closer to the tune THE CAR GAVE ITSELF PRIOR, reducing the time it takes for the car to re-optimize after each restart. IMO the end result is a driver who a bit sooner notices that the ECU has reached optimization sooner, rather than later. You can pretty much do this yourself TBH, especially if you were motivated by HUGE DOLLARS to have people throw THEIR OWN data at the tuner.
No one payed me to go to school.
The usefulness of that level of tuning is not bad, ie narrowing optimization windows based on data derived from the ECU. Raising the rev limiter, setting trims and tweaking the top end IV retard a bit is just the simplest s*** tbh, something I'd do myself.
CHCHCHCHCHCHEERS!!
No they are not self tuning........
What tuners are you talking about that take money to learn on the vehicle at the same time? Sure that happens, but not sure that has anything to do with anything that has been spoken about in this thread.
The car does not give itself optimized ignition, afr, vvt, etc. The only thing it does is Fuel trims, like any ecu since EFI originated.
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- CX9, Signature 2017
I have a 2017 CX-9 Signature.
I am currently on my fifth map file tune with OVT. Results are good. The next few files we are going to push the limits.
I am currently on my fifth map file tune with OVT. Results are good. The next few files we are going to push the limits.
