How many RPMs in what gear?

[HarryBMW]

Hi all, I inherited and fully restored my father's 1976 2002 four speed. Is there a rule of thumb as to what gear I should be in as it relates to RPMs? I want to make sure I don't wear out the gear box being an unexperienced (but learning!) driver. 

 

Thanks

[Conserv]

The '02's M10 engine was designed to run continuously, and has virtually all its power, in the range of 3,500 to 5,500 rpm's. That's where you should keep revs: it is a sweet and responsive engine in that range.

 

Sadly.... many '02 owners don't agree with me -- I've been an '02 owner since 1973 -- and they prefer to keep revs low, so as not to disturb their image of a modern engine running quietly and peacefully at 2,000 to 2,500 rpm's. At 2,500 rpm's, your '02 is cranking out about 50 of its 100 horsepower.

 

That's all I'm gonna say... ?

 

Regards,

 

Steve

 

 

[ray_]

There's some related info in the owner's manual regarding speeds in gear during break-in, etc. The manual is downloadable in the tech articles section here. 

 

The shorter answer is drive the piss out of it; the motors are bulletproof and the gearboxes are as well, if not abused;

 

The longer answer is that the cars were designed to cruise at red line. 

 

And if it breaks the part needed replacing anyway!

 

Cheers,

[adawil2002]

Maintain it well, the engine & transmission will last for 50+ years

 

Keep it under 6500 rpm in 4th or you'll most likely get a speeding ticket.

 

5500 is ~80 mph in my '68 1600.

[TobyB]

There's nothing wrong with loafing along at 2200- the M10 makes a nice torque bump around there.

 

Don't lug it much lower than that, though.

 

But to go fast, shift when it runs out of power, or hits about 6500, whichever happens first.

 

t

 

[Mike Self]

All California-bound 76s used a 3.64 differential; that translates to about 74 mph at 4000 rpm.  IIRC 49 state 76s (but I may have this backwards, not either living in CA or owning a 76) were fitted with 3.90 diffs to make up for the loss of power due to all the emissions stuff.  That will bump up the revs at a given speed; That's why a lot of folks who fit an overdrive 5 speed use a 3.90 diff, as the 5th gear will be about the same revs at a given speed as 4th gear mated to a 3.64 diff.  

 

mike

[NYNick]

Sure, the fun begins around 3500 RPM's, but there's no shame in driving around town and shifting earlier. Shifting later is more fun and exciting. Neither will hurt your engine. Many of us go with the 'more exciting and fun' driving. 

 

Don't worry about hurting the car, worry about hurting yourself and you'll be fine.

[fjord-tii]

IMHO, redline at least once per drive.

[Son of Marty]

IMHO take it out for a long hard drive before any tune up you'll get more consistent results that way.

[John76]

A Calif. '76 with a 3.64 diff cruises nicely at 65mph at 3500rpm...which is the sweet spot where the M10 reaches max torque (efficiency).

I always thought the last batch of '76s came with the 3.90 diff to attain the 3500 max torque closer to 55mph when the Feds reduced the maximum speed limit to 55mph and mandated 85mph speedometers. Anyone remember those days? 

 

[BarneyT]

1st 4500

2nd 5800

3rd 5800

4th 4500...

[2002FjordBaur]

4 hours ago, John76 said:

A Calif. '76 with a 3.64 diff cruises nicely at 65mph at 3500rpm...which is the sweet spot where the M10 reaches max torque (efficiency).

I always thought the last batch of '76s came with the 3.90 diff to attain the 3500 max torque closer to 55mph when the Feds reduced the maximum speed limit to 55mph and mandated 85mph speedometers. Anyone remember those days? 

 

 

Sorry to hijack with an off topic... but what is that phone app you have there, if i may ask?

I need to check my speedo accuracy and was thinking an iPhone app but not convinced how accurate they would be to calibrate to?

[NYNick]

WAZE is spot on.

[TobyB]

Oh.  But.  Before you take it much over 3500, make sure it's well warmed- up.  Like, 10 minutes of driving warmed up.

 

Cold is quite hard on the pistons, and cold oil doesn't do much but pop off oil filters when the pressure regulator sticks.

 

t

[John76]

9 hours ago, 2002FjordBaur said:

what is that phone app you have

 

There are many speedometer apps to choose from. 

The one I use has speed limit settings, altitude, compass direction, trip recording, etc. All work using GPS, so the accuracy is excellent.

Even works on airplanes, boats, bullet trains, or just walking.

Check the Apple App for "Speedometer"...there are dozens!