What's your RPM at 65mph?

[M35x06]

I've only had my M35x for about 2 weeks and I've noticed that while i'm on the interstate and traveling 65MPH my RPM's are nearly 3K??? only reason i'm asking is because coming from my Cadillac STS with the northstar v8 and a 5 speed transmission I was running about 2200 RPM at 65. Are these cars really geared that low? no wonder the gas mileage is V8 like out of a V6. Don't get me wrong though, love the car.

[mazz]

I sold my m35 in July but I recall 3k on tach at 70 mph
Mazz

[Larz]

That sounds about right to me. My 07 M35 indicates about 3000 at 70mph as well, so your numbers make sense.
On a side note regarding gear ratios, my 1968 Fleetwood Brougham has a 7.7L, 375bhp engine and will do 70mph at just about 2000rpm. Not for long though because it weighs 2500kg (about 3 tons) and only gets about 8-10mpg at those speeds, LOL.

[nemeios]

Depends on the inclination of the road, but I have seen similar results about 2800-3000 for 70mph on a flat road. My wife's EX35 has lower rpms on similar speeds but that has a different engine (HR)

[agee]

My '10 with the 7spd transmission and HR engine gets about 2500rpm at 75mph in 7th gear.

[Partysan7]

08 M35 5spd transmission (vq35de) 3K rpm My car does at about 77-80 mph depends

[M35x06]

thanks for all the replys. interesting results. I'm at 3K rpm at 65mph on flat ground and you guys are closer to 70. does the awd have different gearing that would make mine rev higher at lower speeds?

[avishal26]

thanks for all the replys. interesting results. I'm at 3K rpm at 65mph on flat ground and you guys are closer to 70. does the awd have different gearing that would make mine rev higher at lower speeds?

Not sure if final drive ratio is different for AWD but I do about 3k RPM at around 120kph (which is about 72mph) and I have an 06 AWD.

I believe they ratio it lower to improve the 0-60 time. 'Issue' was fixed with the 7spd transmission in 2010.

[ColoJoe]

My 09 M45X is 70 mph at 2500 rpm - I don't know if the M45 is geared differently than the M35...

[The00Dustin]

How long are your drives? I've noticed that the RPM stays higher until the transmission warms up (at least that's my assumytion). IOW, if I'm parked outside overnight and it's really cold, I'll see what I have to assume are 4th gear RPMs for 10-15 minutes, which is long after the coolant temp is up to normal, but if I'm parked in a garage where it's not so cold (but it's still cold), I see normal RPMs in 5-10 minutes. In the summer, I see normal RPMs in 1-5 minutes.

[M35x06]

The00Dustin: that is great question, my morning commute is very short maybe 10 min at most. I have my car in a garage most of the time but sometimes it's not. I'll be driving this tomorrow about an hour and a half away to get my recall done and I'll watch the rpm after warm up to see if comes down.

[bejjutsu]

Nearing 3K is right. I've heard the rational for the high RPMs as "more passing power." So, you could theoretically go from 60-80 a little faster. But yeah, big waste of gas.

[bejjutsu]

My 09 M45X is 70 mph at 2500 rpm - I don't know if the M45 is geared differently than the M35...

The M45 gets power at lower RPMs, so that makes sense.

[M35xTO]

The final drive ratio is different for the AWD/non-AWD, and I believe even the 35/45. Your RPM seems very normal to me. I was a little surprised at first, and was initially too worried to go that fast because the engine was spinning so fast, but since then, I've done several long distance trips (6-10 hours of driving) at ~135kph (~84mph) with no issues at all. Engine noise isn't an issue at all, and the fuel economy isn't too horrible (low drag coefficient?), so I've just learned to ignore the RPM needle.

[M35x06]

this is all great info. this is why I join these forums, very helpful. thanks again.

[autoengr]

Just couple of quick notes for fun on engine speed...
Assuming your torque converter clutch is locked up, everything can be easily calculated from RPMs to speed. Engine rpms x gear ratio x final drive ratio tells you how fast your tire is rotating - then you use the circumference of your tires to get speed. Fun to do this with your grade-school age kids.

Returning to the TC clutch - when your vehicle is cold, this may not lock up. As you converter slips it will have a higher input than output speed. This shearing of the fluid creates heat and helps the transmission reach operating temp. Therfore depending upon operating temperature and throttle position, you could get variations in RPM at speed.

This takes us to fuel economy - RPMs do not determine fuel consumption alone. When combined with throttle position, you have a volume of fuel consumed per unit time based upon mapping programed into the vehicle. Adding speed gives you distance per unit time and allows you to get consumption in terms Americans understand on window stickers. Light throttle at high RPMs and high speed can be very fuel efficient.

[DeanM45]

2006 M45, 65MPH = 2388~2392 RPM as measured with Cypher.

[tomnan24]

2008 M35X, 2500 rpm @ 60, 2700 rpm @65 and 2900 rpm @ 70

[quinner49er]

That is one of the main reasons I bought the M45X. I test drove the M35X first and it was a nice car, but it was revving over 3000 rpm @ 120 km/h (about 75 mph). This was on level, open highway cruise. I found it noisy. Once I drove the M45X, the difference was like night and day. V8 power, with tons of torque available early and constant, makes for blistering acceleration and quiet cruising (about 2000 rpm @ 100 km/h and 2600 rpm @ 120 km/h).

The problem they had was with the 5-speed automatic in the M35. The car had the same engine as the G35, but weighed several hundred pounds more. To compensate and keep the acceleration acceptable they played with the final drive ratio. This was solved, as others have pointed out, with the 7-speed transmission in 2010.