- #3 of 139
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Re: 2008 M [bruceomega]
by pearl
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Feb 22, 2007 (3:19 pm)
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Replying to: bruceomega (Feb 22, 2007 2:44 pm)
Bruce, I agree. The benefit of a six speed is that it gives you high enough gears (numerically) to enable quick acceleration, but then sixth gear is low enough (overdrive) to provide lower rpms for highway cruising and better mpg. So far, Infiniti seems to have chosen to use a high (numerically) rear axle ratio, AND a five speed auto trans with high numerical gears, meaning you get lots of torque multiplication for acceleration in just about any gear including fifth - the drawback is that you end up cruising at something like 3000 rpm at 70, when most of the competition is 2500 or less. A six speed should provide better mpg but not hurt lower gear acceleration ((there is a lot more to this subject, but all else equal, what I just wrote is true)).
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- #4 of 139
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Changes For 08
by ocim
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Feb 22, 2007 (7:03 pm)
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So, is it the general belief that the 08 M35X will have a different engine that the current model, regardless whether it is a 3.7 or 3.5? I am looking to purchase the car however, I would prefer to wait until fall if more HP is on the way.
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- #5 of 139
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Re: Changes For 08 [ocim]
by pearl
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Feb 22, 2007 (7:45 pm)
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Replying to: ocim (Feb 22, 2007 7:03 pm)
While I don't think there has been anything official put out yet, Infiniti replaced the 3.5L VQ engine in the G this year with an improved version that puts out more horsepower and is slightly more fuel efficient. Many people on these boards wondered why they didn't also put it into the 07 M? We don't know, but some months back, someone posted that they had learned that Infiniti had trademarked the designator "M37", so of course the speculation started that they would use an engine of this displacement in the 08 M. Obviously, none of us know yet; however, the competition is starting to run away from Infiniti in terms of gas mileage, power and more advanced auto transmissions, so it seems at least possible that we will see some changes for 08.
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- #6 of 139
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2008 M
by kals
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Feb 23, 2007 (1:20 pm)
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I don't see how the new V6 in the 07 G is going to make that much of a difference in performance and fuel economy in the M. What the wonderful VQ series V6 engine lacks is low end torque. Does anyone think Infiniti might go to a CVT transmission like Nissan has in the Altima. This would offer better performance and economy.
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- #7 of 139
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Re: 2008 M [kals]
by james27
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Feb 23, 2007 (1:25 pm)
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Replying to: kals (Feb 23, 2007 1:20 pm)
No idea on the cvt. They do seem to be able to scale up the design to handle more power than they used to, but there seems to be a limitation when it comes to all-wheel drive. I know that Audi offered it, but only on their front-wheel drive models. Haven't followed it close enough to know if they've changed, or even if it is still available. They do offer this transmission on the 270HP 3.5L in the ALtima.
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- #8 of 139
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CVT
by buddybrad
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Feb 25, 2007 (3:56 pm)
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I don't think adding a CVT tranny is instant improved gas milage. It all depends how the engineers "set it up" like with final drive ratios on conventional transmissions. The idea of a CVT on an M doesn't excite me. Considering Lexus is up to an 8 speed auto tranny, Infiniti is a few behind.
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- #9 of 139
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Re: CVT [buddybrad]
by art234
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Feb 26, 2007 (2:02 pm)
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Replying to: buddybrad (Feb 25, 2007 3:56 pm)
I have a 2006 M35X and the problem is the gearing. No high powered car should be turning 2500 RPM at 60 MPH in the highest gear, or 2800 RPM at 70. Adding one or two longer gears would address this issue. RPM's should typically be 1500-1700 at 60, and remain under 2000 at 70. I believe the difference in fuel economy would be substantial, without sacrificing performance.
Regarding CVT's, I have experience with 2 CVT's. I had a 2003 Murano with the first gen CVT, and I also have a 2006 Lexus RX400h which has the Toyota CVT. The main advantage of the CVT is that it "locks up" at much lower speeds than a conventional transmission. I believe the Murano's torque converter locked up as slow as 10 MPH, while a typical multi gear tranny does so above 30-35 MPH.
The M's fuel economy is embarrassing for such a technologically advanced vehicle.
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- #10 of 139
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How Many Gears Are Enough
by buddybrad
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Mar 03, 2007 (2:51 pm)
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You're right, the M35 and probably the M45 should have much better gas mileage. I believe they could achieve it by tweaking the computer and changing out the final drive ratio to something higher. 5 speeds with the 5th being overdrive is easy to get 2,000 rpm at 60 mph out of.
I have a '71 Buick with 350 4bbl and 3-speed transmission and I can get in the high teens cruising at 70 mph. It has a 3.08 rear end.
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- #11 of 139
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Re: CVT [art234]
by james27
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Mar 03, 2007 (9:56 pm)
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Replying to: art234 (Feb 26, 2007 2:02 pm)
I get in the low 20's on my M35x at a steady 70-75 or so using the cruise on an interstate. I average around 19 or so in my 40 mile commute unless the traffic backs up. The traffic is often running between 70 and 80. The car could get probably considerably higher mileage if the top gear was higher. Someone else mentioned running the transmission in Manual mode which can help. They have the transmission programmed to downshift at the slightest provocation. Putting it in M, means that you control that. Fine on an interstate, but maybe not for stop and go traffic. Try it and see what you think.
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