How does Mazda CX5 GT 2016 compare with Nissan Rogue 2016 SL?

[Unobtanium]

That's not even an issue due to a common feature of turbochargers called a wastegate. In other words, boost is 100% controllable. So is valve timing. You greatly underestimate the ability of Mazda to do basic engineering.

<dt>Well informed people know it is impossible to transmit the voice over wires and that were it possible to do so, the thing would be of no practical value. <dd>- Editorial in the Boston Post (1865)</dd>

Yes, you can vary valve timing...but will it still be optimal to keep carbon off the vavles, then? There is more to efficiently boosting an engine than just bolting on a turbo. You need minimal valve overlap. I dunno how this reconciles with their desire to time the valves to keep them at a certain temperature, though.

 

[CC58]

I do notice that the small torque converter makes takeoff a bit delayed and jerky at say, 50 to 60 percent throttle. You get. Nooooothhhiiinng....yank! And you're off. Other than that, I'm a fan.

That said...cvt is the way of the future.

Yours sounds broken. I'll take it in and have it looked at. Mine has zero delay and certainly not jerky.

 

[MikeM.]

There is more to efficiently boosting an engine than just bolting on a turbo. You need minimal valve overlap.

There is more to boosting an engine than just bolting on a turbo?

You had better get this memo to the development team at Mazda quickly because I believe they are getting ready to release a turbo Skyactiv soon.

I dunno how this reconciles with their desire to time the valves to keep them at a certain temperature, though.

Key words here: "I dunno". I wouldn't expect you to know. Leave it to the brilliant minds at Mazda, they have many tools in their design chest to avoid carbon deposits. My point was, they can make the turbo function like a non-forced induction engine during any portion of the drive cycle that might cause carbon formation. This is only one tool of many. Believe it or not, they actually know what they are doing and the proof is in their products. I simply don't see why you would use your extremely limited understanding of this to doubt them.

 

[yrwei52]

Brilliant minds at Mazda had produced totally failed rotary engines in the past and problematic SkyActiv-D diesels in present. Naturally-aspirated, high-compression SkyActiv-G and forced-induction SkyActiv-G engines simply go to different directions in theory, and can't co-operate very well IMO. It'd be very interesting to see what kind of compression ratio will be on turbo-charged SA-G 2.5L when the spec is coming out.

 

[Chris_Top_Her]

Brilliant minds at Mazda had produced totally failed rotary engines in the past and problematic SkyActiv-D diesels in present. Naturally-aspirated, high-compression SkyActiv-G and forced-induction SkyActiv-G engines simply go to different directions in theory, and can't co-operate very well IMO. It'd be very interesting to see what kind of compression ratio will be on turbo-charged SA-G 2.5L when the spec is coming out.

The new sky g is basically 10:1, however there is a modified MZR that mazda uses for racing; 14 (or 13) :1 and like 30psi of boost.

 

[MikeM.]

Brilliant minds at Mazda had produced totally failed rotary engines in the past and problematic SkyActiv-D diesels in present. Naturally-aspirated, high-compression SkyActiv-G and forced-induction SkyActiv-G engines simply go to different directions in theory, and can't co-operate very well IMO. It'd be very interesting to see what kind of compression ratio will be on turbo-charged SA-G 2.5L when the spec is coming out.

Static compression is all but meaningless with forced induction. What matters is EFFECTIVE compression which is a function of boost and valve timing which are fully adjustable on the fly.

Every company has produced duds at some point in their history but to say the rotary engine development in the 1960's is a black mark on Mazda is just so wrong-headed I can't even imagine where your head is at. Mazda has done more than any other entity in history to further the development of the Wankel rotary and the fact that it's not commercially viable in the modern era does not diminish their award winning accomplishments. Have you no sense of historical achievement?

 

[yrwei52]

Every company has produced duds at some point in their history but to say the rotary engine development in the 1960's is a black mark on Mazda is just so wrong-headed I can't even imagine where your head is at. Mazda has done more than any other entity in history to further the development of the Wankel rotary and the fact that it's not commercially viable in the modern era does not diminish their award winning accomplishments. Have you no sense of historical achievement?

You're not the only person on this forum know automotive history. People can google it and know everything, true or false. You don't have to use such wording to insult people with different opinions.

Mazda almost collapsed in 1970's due to its fully commitment to the Wankel rotary engine. The company was insisting for production of rotary engine for RX-8 through 2011, when less than 1000 were produced. With poor fuel efficiency and high oil consumption from the nature of rotary engine, compounded with high emission and unreasonable failure rate, the rotary engine is simply not suitable for the 70's, not to mention for current modern era. A picture in my head with a pile of broken rotary engines in a Mazda dealer's backyard is the testimony to major failure of a commercial product, no matter how infamous it was in the history!

 

[fdew]

Brilliant minds at Mazda had produced totally failed rotary engines in the past and problematic SkyActiv-D diesels in present. Naturally-aspirated, high-compression SkyActiv-G and forced-induction SkyActiv-G engines simply go to different directions in theory, and can't co-operate very well IMO. It'd be very interesting to see what kind of compression ratio will be on turbo-charged SA-G 2.5L when the spec is coming out.

My son, mother in law and a good friend all had rotary engine Mazdas. The
Loved them. Each one bought more then one. There experience plus my driving there cars is what drove me to look at Mazda for myself I never associated failed with the rotary.

 

[MikeM.]

My son, mother in law and a good friend all had rotary engine Mazdas. The
Loved them. Each one bought more then one. There experience plus my driving there cars is what drove me to look at Mazda for myself I never associated failed with the rotary.

True, they were very well regarded. There were even write-ups about the breakthrough Wankel rotary in many popular publications like Popular Mechanics. My cousins had one as did my brothers best friend. People who had them loved them. When you asked them about the seal life (40-60,000 miles), they would say it's the price of admission and totally worth it!

In 1970 GM acquired a license to produce Wankel rotary engines. 17 manufactures in total held production licenses. Licenses cost $49 million. Mazda had more expertise on the technology than any other manufacturer. These were boom years for Mazda which was quite profitable. Mazda produced many different rotaries but the most popular was the 13B which was in production for over 30 years. It was used in coupes, sports cars, even pick-ups.

Anyone who lived through those heady days knows without a doubt, the Wankel rotary was not a failure. No engine in production for over 30 years is a failure!

 

[piotrek91]

Static compression is all but meaningless with forced induction. What matters is EFFECTIVE compression which is a function of boost and valve timing which are fully adjustable on the fly.

I have to disagree with you here.
Static compression * engine size determines the size of the combustion chamber at the top of the piston stroke.
A 14:1 2.0L engine has just 35.7ml of space at TDC. 500ml per cylinder/14
meanwhile an 8.5:1 2.0L engine has 58.9ml of space at TDC.

even if you lower the effective compression ratio by delaying valve closing, you still end up with the same tiny combustion space.

This mean that the combustion volume of a 8.5:1 2.0L engine is roughly equivalent to a 3.3L naturally aspirated 14:1 engine.

If we were to ignore intercooling, it really wouldn't matter if the air is compressed by the cylinder or by a turbo. What really matters is how much air can you squeeze into the combustion chamber without getting knock.

 

[wlong01]

True, they were very well regarded. There were even write-ups about the breakthrough Wankel rotary in many popular publications like Popular Mechanics. My cousins had one as did my brothers best friend. People who had them loved them. When you asked them about the seal life (40-60,000 miles), they would say it's the price of admission and totally worth it!

In 1970 GM acquired a license to produce Wankel rotary engines. 17 manufactures in total held production licenses. Licenses cost $49 million. Mazda had more expertise on the technology than any other manufacturer. These were boom years for Mazda which was quite profitable. Mazda produced many different rotaries but the most popular was the 13B which was in production for over 30 years. It was used in coupes, sports cars, even pick-ups.

Anyone who lived through those heady days knows without a doubt, the Wankel rotary was not a failure. No engine in production for over 30 years is a failure!

Owned a 86 RX-7 (purchased new) for 11 years. Had some minor electrical problems, drivers side door lock that would stick once in awhile but other than that the rotary was rock solid. Did not consume much oil either, maybe 1/4 qt between changes.

 

[MikeM.]

Owned a 86 RX-7 (purchased new) for 11 years. Had some minor electrical problems, drivers side door lock that would stick once in awhile but other than that the rotary was rock solid. Did not consume much oil either, maybe 1/4 qt between changes.

Nice! Did you know Mazda was the only manufacturer to win the prestigious and grueling 24 hours of Le Mans with a non-piston engine? The rotary produced so much power for it's displacement and weight the race organizers banded together and banned rotary engines from future races following their historic win.

The rotary was very profitable for Mazda until the Arab oil embargo of 1973 caused gasoline prices to skyrocket and the more efficient piston powered engines displaced the rotary. Hardly a negative commentary on Mazda's engineers back in the day (let alone currently). I just don't get the irrational negativity exhibited by a few members here.

 

[MikeM.]

If we were to ignore intercooling, it really wouldn't matter if the air is compressed by the cylinder or by a turbo. What really matters is how much air can you squeeze into the combustion chamber without getting knock.

True. And if you re-read what I actually wrote that is exactly what I said! The very technologies that prevent detonation from happening in a high compression engine are applicable to an engine with forced induction. Yes, static compression of the turbo engine will be lower than the NA engine but the turbo will still have an effective compression just as high (if not considerably higher). And if I know how these engineers think, boost will come on very low in the rev range.

 

[SugarMouth]

The CX-5 is a reliable, competent, effective mode of transportation.
The Rogue is a POS.

^ What he said!

 

[fdew]

Fun story. Back when my son was 17 he found a Mazda RX7 for sale for $300 He and I went and looked at it. The owner told us the body and suspension was in great shape but the engine was shot. "They all did that."

My son cranked it over while I looked around under the hood. There was raw gas pouring down the carburetor throat. I told the guy I thought it was flooded and he got mad. Told us he had been a certified Army mechanic for 20 years and when he said a engine was shot it was shot.

I apologized and asked if he would give us a half hour while we drove around and thought about it. Drove to the nearest Mazda dealer and asked for the rotary guy. Told him the story. He asked the year, Yup, they all do that, The float sticks, gas washes down the carburetor, washes all the oil off the seals until the engine loses all compression (The oil is the seal) He said, buy it take it home, remove the plugs, take the crab apart and fix the float and leave the gas line disconnected. Then take it out and tow it down the road in gear until the no more gas comes out the spark plug holes. Put everything back and enjoy.

We did and it ran great. His second RX7 was bought with the same problem. It turns out that some people trouble shoot, others just go by what they have heard.

Frank

 

[axel2078]

I don't know much about the Rogue, but I originally wanted a 2016 Nissan Murano because I really loved the styling and features....but then I realized it had a CVT, which I hate, and there were numerous consumer reports of Nissan CVT failures around 40K-60K miles. That quickly turned me off to the Murano. Since I already have a Mazda 3, I decided to look into what Mazda offers in a similar class and came across the CX-5 and after reading about it, I really liked it. I did more research on it, which seemed to be mostly positive and my wife surprised me with one for Christmas.

 

[wlong01]

Nice! Did you know Mazda was the only manufacturer to win the prestigious and grueling 24 hours of Le Mans with a non-piston engine? The rotary produced so much power for it's displacement and weight the race organizers banded together and banned rotary engines from future races following their historic win.

The rotary was very profitable for Mazda until the Arab oil embargo of 1973 caused gasoline prices to skyrocket and the more efficient piston powered engines displaced the rotary. Hardly a negative commentary on Mazda's engineers back in the day (let alone currently). I just don't get the irrational negativity exhibited by a few members here.

Although the 86 only had apprx 150 hp it had guts. I remember one morning on the interstate I looked at the speedometer and it was tooling along at 115 mph. Felt like I was only doing 60. I could chirp the tires shifting from 2nd to 3rd. If I had a three car garage instead of two I would of kept it for weekend fun.

 

[Chris_Top_Her]

Although the 86 only had apprx 150 hp it had guts. I remember one morning on the interstate I looked at the speedometer and it was tooling along at 115 mph. Felt like I was only doing 60. I could chirp the tires shifting from 2nd to 3rd. If I had a three car garage instead of two I would of kept it for weekend fun.

You can chirp your cx5 going from 1-2 with a tune too. I chirp mine under right shift condition with awd, and larger/wider wheel even

 

[efini]

The rotary produced so much power for it's displacement and weight the race organizers banded together and banned rotary engines from future races following their historic win.

Hilarious! You know absolutely nothing about that car or the race, completely ignorant and repeating junk you've picked up from ignorant people! I guess I shouldn't be surprised...

The rotary was not "banned" and no the organizers didn't "band together" to put a stop to it. And there most certainly wasn't anything about winning because it "produced so much power". The car won on reliability, after other manufacturers fell near the end of the race. An absolutely great thing to win on, but so far from your claims. The FIA had declared new engine specifications that began to go into effect in 1991 and fully into effect in 1992, they wanted engines that were similar to F1 engines. Most engines at the time did not fit into the specifications, Mazda obviously included. Mazda knew the rotary wouldn't be racing the next year well before the race began. There'd be absolutely no point in anyone banding together to put a stop for it, it was already done...at the time. The rotary later briefly returned in the hands of privateer teams after future revisions to the specifications.

 

[MikeM.]

Hilarious! You know absolutely nothing about that car or the race, completely ignorant and repeating junk you've picked up from ignorant people! I guess I shouldn't be surprised...

That's a great start for someone who has their facts wrong (not to mention for someone who only has 12 posts in total).

The rotary was not "banned" and no the organizers didn't "band together" to put a stop to it.

The rotary was not banned by name, it was EFFECTIVELY banned by a change to the engine regulations which made it impossible to field a competitive rotary engine.

And there most certainly wasn't anything about winning because it "produced so much power". The car won on reliability, after other manufacturers fell near the end of the race. An absolutely great thing to win on, but so far from your claims.

24 hour endurance races are ALWAYS won on a combination of power/reliability. It's difficult to separate the two. For example, the rotary that Mazda won with was capable of making 900hp they wisely de-tuned it to 700 hp for the Le Mans event to insure reliability. Their competitors didn't fare as well. My apologies if I didn't elaborate enough on this to satisfy you. The rule change that effectively banned rotary engines was by the FIA and, anyone familiar with the politics of racing knows that one person doesn't dictate the rules - it's a political process. So I stand by my characterization. The 1991 race was the first and only time a Japanese manufacturer won. If you don't want to believe me, maybe you'll believe Wolfgang Karl Kopp:

https://www.facebook.com/wkoepp/posts/10204345997959860:0

The rotary later briefly returned in the hands of privateer teams after future revisions to the specifications.

Are you sure? Were they competitive? They may have revised the rules to save face but that doesn't mean a rotary could ever be competitive under those rules.

In any case, I don't see your point (except to unfairly attack me). This entire off-shoot of the discussion began when someone used the fact that the rotary engine fell out of favor during the Arab oil embargo as evidence that Mazda engineers were not very talented. I think Mazda's Le Mans win and the development of the rotary engine is prima fascia evidence of their exceptional talent over the years.

Read more about the development of this amazing engine here:

http://www.rotaryeng.net/Mazda_R26B_US.pdf