Anybody else wondering why we spin such high RPM's in 6th gear? I've had my '04 6MT Sedan for a month now (1,400 miles), & that's the only real question/concern I have.

Example: May, 2004 issue of Motor Trend Magazine (where we win the comparison again says '04 G35-5AT spins 2250 RPM @ 60 MPH, while smaller-engined ( 3.2 Liter) '04 Acura TL-5AT spins only 1750. Even the much smaller-engined (2.0 Liter turbo) Saab Aero spins only 2000 RPM @ 60 MPH !!

We'd get better mileage on long hauls, & have less wear and tear on the engines internal components to boot. With first gear being nearly a "granny gear" now in my 6 MT, surely they could find a slightly lower final drive ratio that would still allow acceleration at or near present levels?? During average daily driving I go 2nd to 4th to 6th gear as it is - the car is a "torque monster" and the engine is very smooth and tractable at low RPMS, so why does a car with so much torque need to rev so high in 6th ?? Maybe the proposed Quaife posi for the Sedan discussed on another thread could be had with a better final drive ratio and be my (our?) answer?

Any thoughts, here, fellow G35 fans ??

Sport Sedan Fan

 

The problem with dropping rear ratio is what it does to 1st and second and third gear multiplied ratios and how it affects zero to 30, 60, and quarter mile times.
A 10% reduction [via diff change] will [cube root of 10%] reduce acceleration by 2.3-3.0%......roughly equal to 0.3-0.4 seconds in quarter mile.

Most buy the G for performance..........not sure that a blended 10% reduction on highway .....netting 5% annual average for most drivers = 1 mpg improvement [2 if all highway]= 50/60 gallons per year.........a $100-$120 per year.


Engines tuned to turn high rpm and produce above average power always are compromises at 50-60 mph at cruise. You must chose between turning enough rpm to deal with AC and hills without a downshift.
Also RWD has a disadvantageous driveline loss [2%] vs a FWD so the same engine must turn 2-3-4% faster in any case in RW applications just to deliver the same power at cruise.