Speed Vs Rpm

[Rotty]

Hi Guys

Just back from my first long run since buying the car (1998 gs300)

Sitting on the motorway with the cruise control set at 60mph

and the sat nav saying 57mph all was good with the world.

Then i got to wondering about the revs,

The engine was spinning at 2000rpm at that speed

Can anyone tell if this is correct ?

does everyone's car sit at 2k rpm or there abouts at an indicated 60mph ?

Just shows i had nothing else to worry about in this great car lol

cheers

Alan

[Derek870]

I have a IS250 and it revs low as well, something that does baffle me is if I accelerate the revs rise to 2500 yet it it doesn't kick down, come on techies explain please..................

[LexIS200Sport]

My X-Trail does the same thing; it's basically the lock-up clutch inside the torque converter releasing under moderate acceleration and allowing some slip. Therefore the engine is somewhat decoupled from the driveline and allowed to accelerate to a higher RPM. When the vehicle reaches your desired speed and you back off the accelerator pedal, the ECU senses this and the lock-up clutch re-engages.

The reason for this is two-fold:

• NVH: reduces driveline shunt under sudden acceleration
• The engine is allowed to rev to a higher RPM (and produce more torque), thus allowing for quicker acceleration

Of course if you accelerated even harder, the lock-up clutch will release and the transmission will drop a gear (provided it is within the engine's rev range).

More information can be found in this patent by Nissan: http://www.google.com/patents/US5616100

Source: I am a powertrain engineer and consulting to an automotive firm in the Midlands :)

[Derek870]

Wow thanks, and I understood!

[coneybiller]

Also a by-product of this will be reduced fuel consumption as well (compared to if it didn't allow any slip at all) :)