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6th gear under 70 mph?

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Old 01-16-2013, 02:02 PM
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perryinva
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Default 6th gear under 70 mph?

Saw a comment about this, never heard it before. Don't use 6th gear under 70mph??? Ho did I miss that discussion?
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Old 01-16-2013, 02:18 PM
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alpine003
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For what reason? I don't really see the logic. Link to post?

Although I have been somewhat lazy to diligently shift to 6th and have known to hold 5th, I'm sure that will change after I install my new cans.
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Old 01-16-2013, 02:49 PM
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Steve's MLC
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Someone posted about not running under 2k rpm due to oil flow a while back. Related ? You would be well over 2k at 70 tho.
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Old 01-16-2013, 02:54 PM
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Macster
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Originally Posted by perryinva
Saw a comment about this, never heard it before. Don't use 6th gear under 70mph??? Ho did I miss that discussion?
The concern is that at too low a speed in a higher gear causes the engine to lug which is over time can be harmful to the engine.

I do not know what rpms the engine in your car runs at at 70mph in 6th (or top gear if fewer gears than 6)) -- heck I can't even remember what rpms my 996 Turbo engine runs at in 6th gear at 70mph but if I had to guess between 2K and 2.5K but that's as close as I can come.. wait let me check my pics....

Ok, I found a photo I snapped at 75mph and the tach indicates 2600 rpms.

Anyhow, on a relatively flat stretch of road I use 6th gear to reduce rpms and improve gas mileage.

What I avoid doing is doing this when the engine is cold and I avoid giving the engine very much throttle.

If hard acceleration is called for I'll downshift to 5th or even 4th but in the Turbo 5th is almost always enough. Heck acceleration in 6th is ok as long as I don't get piggy about it.

It boils down to mechanical common sense. You wouldn't drive around in too low a gear to keep the engine near or at redline all the time and on the other end of the scale you shouldn't drive around in too high a gear at too low a speed that the engine is barely above idle.
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Old 01-16-2013, 03:21 PM
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ivangene
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Originally Posted by Macster

It boils down to mechanical common sense..
what we have here is a recipe for disaster
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Old 01-16-2013, 03:51 PM
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MiamiC70
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We have a 6th gear?
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Old 01-16-2013, 04:03 PM
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alpine003
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I'm just glad we can downshift all the way down to 3rd at that speed if we have to for us folks that don't have a turbo.
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Old 01-16-2013, 06:25 PM
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mmahon04
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My car was designed specifically for one of the 'Fast and Furious' movies; consequently, I have 23 forward gears that actually accelerate me more the higher I go.
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Old 01-16-2013, 06:27 PM
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SSST
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You drive under 70mph?

I generally leave it in 5th if I am under 70, but only because I get a little droning cruising under 2200 and 70 in 6th is 2300.
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Old 01-16-2013, 06:29 PM
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MiamiC70
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5 of those are over-drive, right?

Originally Posted by mmahon04
My car was designed specifically for one of the 'Fast and Furious' movies; consequently, I have 23 forward gears that actually accelerate me more the higher I go.
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Old 01-16-2013, 07:04 PM
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Originally Posted by MiamiC70
5 of those are over-drive, right?
No, the over-drive gears bring it to 28. The first 23 allow you to live life a quarter mile at a time.

This box was originally the testbed for the 7-speed 991 gearbox; Porsche gave it to the 'Fast and Furious' production crew stating it was "too cumbersome for daily use."
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Old 01-16-2013, 07:06 PM
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Yes, becasue everyone knows the quicker you throw it into overdrive the fast you go :/
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Old 01-16-2013, 08:47 PM
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6th gear is one of the best economic stimulus plans I've ever experienced. My Wife holds 4 Land Speed Records in a 996 and the slowest is 152 MPH. She NEVER used 6th gear.

As always, opinions will vary and everyone has a different answer.
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Old 01-16-2013, 09:08 PM
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Yes RPMs is the answer here not the gear. Keep RPMs over 2500 in all gears. For normal daily driving in traffic I run between 3000 and 4000 RPMs. If no one is in my way and the conditions permit then over 4k we go.
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Old 01-16-2013, 09:45 PM
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Generally 55mph is the lowest I'll go into 6th (unless in an American car with a T56).
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