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Discussion Starter · #1 ·
Hey Guys....

Lurker here. Own a 2012 G37S Sedan (7AT).

I thought i'd open up the discussion on Q50 fuel economy with the following ratings from Infiniti:

20/30/23 mpg 3.7-liter V6 RWD
19/27/22 mpg 3.7-liter V6 AWD
20/29/23 mpg 3.7-liter V6 Premium and Sport
19/27/22 mpg 3.7-liter V6 Premium and Sport AWD
29/36/31 mpg 3.5-liter Hybrid RWD
28/35/30 mpg 3.5-liter Hybrid AWD
28/34/30 mpg 3.5-liter Hybrid RWD Sport
27/31/28 mpg 3.5-liter Hybrid AWD Sport

So some things that stand out:

1. This is a major shift in their rating of vehicles as in the past it was just RWD vs AWD. Meaning, the window sticker on base RWD was the same a fully loaded RWD with sport, prem etc. With the Q50 they break it out.

2. Previous G37 RWD's were rated at 19/27. Who knows what the real truth is as that was likely an average of the stripper RWD and my RWD S with heavy brakes and larger 18's. Can't imagine dealers stocking any NON-premium cars so 20/30 is likely not going to be the norm. However, 20/29, is up a few ticks from the last gen.

3. Why does the sport take a 1 mpg city and 2 mpg hwy hit on the Hybrid sport? 19's vs. 17's? Heavy brakes (they are heavy)?

4. What's up with the 4(!!) hwy mpg drop on the Hybrid AWD vs. the Hybrid AWD Sport?


When it's time I'd go Hybrid RWD Sport as I'm willing to drop a few mpg for Sport. That combo should be the fastest (or maybe a tick slower as the RWD Hybrid has better mpg - better mpg = better efficiency = less drag and faster). However, the sport summer tires would likely let it launch faster from a dig.

Mike S.
 

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AWD will take a hit regardless, it has extra bits poking out under the car, raising the coefficient of drag slightly. I think the AWD models ride an inch higher or so, maybe half an inch, which is actually down over the G37 if I'm not mistaken. While the AWD cars are rear-biased until they sense slippage, all that extra running gear adds weight and drag.

Now let's think about the sport model. Bigger brakes all the way around. Maybe 19's by default (built into the Sport trim level). That's more unsprung weight. 4mpg highway more? That's hard to reconcile.

How about you extract the weight of each vehicle and the coefficient of drag for each one and chart it out? You may be able to see a clear correlation there.
 

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Hybrid AWD Sport is about 200 lbs heavier than hybrid RWD sport due to extra AWD system as afrisheen posted in the previous post.
Real numbers will come out as more Q50s are independently tested.
 

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Discussion Starter · #4 ·
I get it. AWD more drivetrain loss (even if it is 0/100 most of the time). And I get that the sport has heavier bits that result in better handling and braking and possibly better 0-60 (more traction from a dig), but might be smidge slower when underway as it's just pulling more weight.

My confusion in the drop from the Hybrid AWD to Hybrid AWD Sport. Why drop 4 mpg on the highway from JUST adding the sport. Adding the sport the RWD Hybrid only drops it 2 on the highway.

Maybe its a mathematical thing as fuel economy grows. Meaning, adding heavy awd system to a 15mpg Tahoe might drop it to 14mpg. Adding the same system to a 50mpg Prius might drop it to 45mpg since it's the same percentage of loss just applied to a high mpg car, resulting in a higher mpg loss.
 

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Wow...truly pitiful numbers.

For comparison the 328d diesel got 32/45/37 and with AWD 31/43/35. The Audi A6 diesel is 24/38/29. The 5-series diesel isn't rated.

In Europe the Q50 comes with the MB 220CDI diesel...170hp. That would probably similar to the 328d in the US. The 328d is 184 hp in the US. MB is bringing in the E250CDI with about the same efficiency. It has 195hp in US trim (204hp in Euro trim, but the difference is probably testing procedure).
 

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Wow...truly pitiful numbers.

For comparison the 328d diesel got 32/45/37 and with AWD 31/43/35. The Audi A6 diesel is 24/38/29. The 5-series diesel isn't rated.

In Europe the Q50 comes with the MB 220CDI diesel...170hp. That would probably similar to the 328d in the US. The 328d is 184 hp in the US. MB is bringing in the E250CDI with about the same efficiency. It has 195hp in US trim (204hp in Euro trim, but the difference is probably testing procedure).
Newsflash...we aren't in Europe and these aren't diesel engines...
 

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Guess you haven't read much but this is a performance car. Europe prefers diesels due to taxes. If the gas tax dropped to zero tomorrow they would all drive smooth, powerful gasoline engines. Also there's a chance the diesel will make it stateside in a year or two.
 

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Guess you haven't read much but this is a performance car. Europe prefers diesels due to taxes. If the gas tax dropped to zero tomorrow they would all drive smooth, powerful gasoline engines. Also there's a chance the diesel will make it stateside in a year or two.
This car has a relatively antique, by Infiniti standards, port injection NA V6. It is exactly the same engine tested in 2009 by Car and Driver: 2009 Infiniti G37 vs. BMW 328i, Audi A4, and Acura TL – Comparison Test – Car and Driver

If anything, the Q50 is a bit heavier. The performance would slot between the Audi A6 and BMW 535. Behind a 335i. To 60mph, it is barely faster than a 211hp 2.0 turbo 4 A4 (5.6sec vs. 5.4 sec on the G37). And that was with a 6-sp manual.

My point is this is a mainstream sedan, not some high performance sports car. By 2004 standards, maybe. Not by 2014 standards.

Next Infiniti needs to bring this engine up to date. direct injection. Maybe a turbo (the BMW and Audi 6s are 3L turbos) or just with a much more solid power curve. At the 1-2 shift, about 42mph, the Q50 has about 250 hp.

This isn't the say the Q50 isn't a great sports sedan. I think it is the class leader. However, it isn't really 'high performance', just average performance.

Europeans like diesels because they are much more efficient, their fuel costs are much higher, and they are much poorer. Even Germany or the UK would be among the poorest US states.

Also the power curve for diesels is much flatter and better suited to street driving. People usually comment that diesels feel like much stronger engines than more powerful engines that turn in better 1/4 mile numbers. The reason is we don't do wheel spinning acceleration to 100+mph ETs on the street. Typically, it is part throttle acceleration to 30, 40, 50, or 60 where an automatic transmission shifts at 4000rpm or less. In that environment the diesel dominates.

BTW, our current car is an E320CDI diesel. All of the other cars we are considering are diesels: A6 TDI, 535d (really 530d, but 535d is US nomenclature), and probably the leading candidate, the E250CDI which delivers acceleration barely ahead of a G25.

What ever it is parks next to a QX56, a Supra TT, an S2000, a Port City offset super late model, and a 1938 Buick Special.
 

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Every thing that comes to market today is always antique ( so to speak) but antiques have proven value/reliability. In USA most cars are driven lot more miles(KMs) than in Europe and most Americans buy lot more cars in their life time. Man you are comparing apples and oranges.
 

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Let me add to that. The Audi S4 is 2" shorter on a 1.5" shorter wheelbase. It has about the same peak power, but a much fatter power curve. It is faster to 60 (4.9 vs 5.4) and much faster in the 1/4 mile ([email protected] vs [email protected]). The Premier Plus version with nav and keyless entry is about the same price as an Q50 AWD Sport with all the packages.

That isn't to say the Audi is the better car, but simply to show the handicap imposed by the Q50's antique engine.

Note, the AWD Q50 is more nose heavy than the S4.
 

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Diesel fanatics, why didn't I see this coming?




Let me add to that. The Audi S4 is 2" shorter on a 1.5" shorter wheelbase. It has about the same peak power, but a much fatter power curve. It is faster to 60 (4.9 vs 5.4) and much faster in the 1/4 mile ([email protected] vs [email protected]).
First, we already know the Germans lie about horsepower figures to dodge taxes, so you can never compare 1:1 without dyno sheets from both cars. If Audi says the engine has 333 horsepower, that's what it's putting to the pavement; crank horsepower is more in the neighborhood of 370, assuming ~15% drivetrain losses. All other manufacturers give you crank horsepower and wheel horsepower is that number minus 15-20 percent depending on configuration (full time AWD etc.). So there's one orange to an apple.

The Premier Plus version with nav and keyless entry is about the same price as an Q50 AWD Sport with all the packages.
With nav and keyless entry on the premier plus, the Q50 crushes the S4 on features alone. Real leather ($1250 option for full Nappa leather on the S4), customizable drive by wire steering, Infiniti Intouch, no $475-$1075 tax for paint colors other than black or white, full LED high/low lights, rain sensing wipers, around view cameras, distance cruise control with full stop and restart, adaptive headlights that pivot, 19" wheel/tire package (a cool $800 for the S4), lane guidance...I could go on.

So we take an S4 Premium Plus and match it up feature for feature to the Q50 AWD Sport (loaded) and what do we get? $57,150 for the S4 and it's still missing features the Q50 has. Oh and we're still stuck with black or white color choices for the paint. And then there's that legendary Audi quality, which JD powers predicts a rating of 2 out of 5 stars for the 2013 model. Suddenly the absolutely bulletproof, ancient VQ37VHR engine doesn't look so bad, considering you will spend more time driving it to where you want to go than back to the dealer again to replace a water pump.

I will concede two points. The S5 is faster, and the VQ is due for a major overhaul. The VQ mileage has always been a sticking point and the only thing that improved it this time around was a higher final drive ratio which keeps the revs down at highway speeds.

My crystal ball says the Renault/Mercedes/Nissan tryst is about to pay off with engine choices straight from Mercedes and Renault possible for future Infiniti models, but then again, Nissan is definitely no stranger to turbo engine design. Mythical powerplants like the SR20DET, RB26DETT redtop and the skull-crushing VR38DETT in the current Nissan GT-R all show Nissan's engineering prowess. The VR38 is an evolutionary engine based on the VQ, so if a drop in engine size and boosting is warranted to keep up with the competition and increase fuel economy, they won't have much trouble.

I know my tone came off as harsh, but in the end I did a bunch of googling to form a halfway-coherent response and I learned alot, so thanks for your counterpoint, it is appreciated. ;)
 

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Base on the build site on both car:

Audi S4 premium plus with MMI® Navigation plus package, Dynamic steering and adaptive damping suspension, Audi advanced key (keyless access), Fine Nappa leather seating surfaces, and Bang & Olufsen® Sound System is $57,200.

A Q50 Sport AWD with all option (Nav, Deluxe Touring and Tech package) is $52,900.

That's about $4300 cheaper and got much more techs then what the S4 have to offer.

You can't just compare S4 premiere plus with just nav and keyless to a fully load Q50 Sport AWD and say they are about the same price. You need to compare option per option. If you into purely performance, then S4 is a good choice. But if you wants great value and lots of cool techs, the Q50 is a definite choice.

The Premier Plus version with nav and keyless entry is about the same price as an Q50 AWD Sport with all the packages.
 
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I will grant that the Q50 is less expensive, just not a lot less expensive...they are close enough that most people could consider either.

Second, people dont' lie about power. There are standards they have to conform to. Differences come because peak values don't determine acceleration. For the engine, it is power under the curve, which to some extend depends upon gearing. Then their is rotational inertia...both the wheel/tire assemblies and the the engine internals. Shift speed can be another factor. To some extent driveline power losses. And for 0-60 times and even 1/4 mile times in cars with lots of power, traction is another.

For example, the Q50 tire is an inch large in diameter. In the same model (say PSS) it would way about 1 pound more. However, the RFT may be 5 pounds more than that. Undoubtedly, it is one factor hurting BMWs in acceleration comparisons.

The Q50 is a great sport sedan offering an extremely well finished interior, a large number of features, a high quality/high service dealer network at very reasonable prices.

However, it doesn't walk on water. The engine is antique offering middle of the road acceleration and both of the field fuel economy. The runflat tires are a curious design decision and will, IMHO, lead to a variety of problems, primarily in the 19" size. All would be made better with a switch to top of the line non-runflats. And some features are missing: ventilated seats, side view cameras. The active steering is just takes manual inputs. No dynamic shocks are offered. The automatic high beams are not (or at least don't appear to be) adaptive high beams. The nav screen is on the small side. It lacks the touchpad input of the Audis and BMWs. No heads up display. No hold feature. No stop-start feature. No torque vectoring.

But none of the cars in this class are perfect. None offer every feature. Most have interiors no where near as nice as the Q50. Most cost more, although not always under a lease (a $60k 3-series leases for about the same as a $50k Q50). As an Infiniti owner (QX56), I can say many features are well thought out. Build quality is very good. Dealer quality is very good. At its price point the Q50 is very compelling.

With an updated engine (note, Nissan updated the V8 used in the M56 or QX56) it would probably be a fair bit better, both faster, smoother, and more fuel efficient. It is common for manufacturers to update the engine a year or two after the chassis, and that is what will probably happen here.
 

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Every thing that comes to market today is always antique ( so to speak) but antiques have proven value/reliability. In USA most cars are driven lot more miles(KMs) than in Europe and most Americans buy lot more cars in their life time. Man you are comparing apples and oranges.
Actually, not.

A modern engine is defined by direct injection and variable valve timing. Forced induction, usually turbocharging is also common. Add to that the uncoupling of power accessories (water pump, A/C compressor), intelligent alternator management, a deep discharge battery, start/stop and for larger engines cylinder disabling are common.

You need DI to gain the engine management functionality necessary for efficient operation. This shows up in higher static compression ratio because the DI allows the use of variable valve timing to manage the dynamic compression ratio while maintaining a high expansion ratio.

BMW seems to have the lead here. EPA numbers for the 535 are 20/30/24 vs 20/29/23 on the Q50...however the BMW weighs 400# (10%) more. The 528i is 23/34/27. The 335, usually viewed as the Q50 competitor, is 22/32/25.

The 5.6L V8 got its update a couple of years ago. I'm a bit surprised the V6 has the same specs as 2009, really the 2008 coupe. Then engine is unchanged although the transmission has gained 2 gears. BMW and Audi have 8-speed ZF autos. MB currently has a 7-speed, but has been introducing a new 9-speed.

Chrysler is also using the ZF 8-speed. GM and Lexus are struggling a bit here. Lexus has an 8-speed in some RWD models. GM seems stuck on 6-speeds. The expectation is most cars will end up with CVTs, 8spd, 9spd, or 10spd transmissions in the quest for fuel economy.

Net, the Q50 is very impressive, but does have some weaknesses. The G37 was already a good car. Even the G25 although the loaner I had this week had a terrible shock setup.

One note, not necessarily Q50 related: expect a lot more diesels in the US. Three factors have come together. First, large trucks are being converted to LNG/CNG freeing up diesel capacity for passenger cars. Second, Euro 6 standards, which come into effect in 2014, are close to US standard for NOx enabling Euro diesels to be relatively easily certified for US use. Third, fuel economy laws favor high mileage which the diesels provide.

In 2014 diesels and spark ignition engines have similar engine management. Diesels are no longer the noisy, smelly, rough, and loud step children. In Europe there are two Q50 models: the hybrid and one with the Mercedes 170hp 2.2L turbo diesel also sold in the C220CDI and E220CDI.
 

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13.4? Wow that's realy bad. How long is your average comute?
Is it calculated mpg or you just reading the info screen?

So far I'm (actually my wife) at 16.4 (calculated) mostly city. We are only on the 2nd tank, so I hope it will get better.
 
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