mcpiaseczny

Really? Wanna dump that laborious C2S in my garage? It could be arranged...

911C2

I usually skip 5th and go 4 to 6. Im in 6th as much as I can. Interstate driving I get 27MPG. Shell keep a steady speed, need to pass just shift.

jimbo3

If the terrain is relatively flat and I can hold a minimun 75MPH, I'll cruise in 6th. 28MPG+ on a 300 mile trip with a very slight headwind, which is marginally better than my '06 Taurus was on the exact same run.

Leander

We kind of DO have to go back to the optimum rpm thread. If we agree that the car runs best at close to 4,000 rpm, then you will never use 6th gear at normal highway speeds. I never use it now, and I drive to Los Angeles from the Bay Area several times a year.

I'm thinking of having my 6th gear removed...

993-C4S

Here is one of the old threads. Still looking for more

https://rennlist.com/forums/showthre...ht=optimum+RPM

race911

Huh???? Maybe a 2.0S needs to maintain that to keep the plugs from fouling. Anything larger, or with more streetable cams or fuel injection? Never have in almost 30 years.

993-C4S

And another..

https://rennlist.com/forums/showthre...ht=optimum+RPM

jimbo3

I recall someone saying that cam chains settle down at engine speeds of around 3,000 RPM and greater. With a US trans, that comes to almost 80MPH in 6th, IIRC.

hddude

There is a correlation between SAI issues, low RPM's and use of 6th gear.

Leander

Here's the most recent discussion, which refers to the 4K.

https://rennlist.com/forums/993-forum/380296-keeping-the-revs-up.html

race911

OK, I've got the definitive answer now. Took the yellow car out to the grocery store just now. 4K in 6th didn't really get me ahead of much of anyone. Got a little blip up to 6K in 6th on the way back. So just go regear your transmissions!

Leander

Ha Ha! Your grocery store must be a short hop down the autobahn!

race911

Autobahn 13! Little rough now v. 20-25-30 years ago, but what do you expect in Oakland. Or California.

The Brewmeister

Interstate cruising only.

clubsport1

Surely it depends on which gear set and final drive ratio you run