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Disappointed in 7mt gear ratios

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Old Apr 17, 2013 | 09:21 AM
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Originally Posted by ChuckJ
Totally agree. I had always wondered why they did that. They actually had to spend money to do that. I would be a good question for someone going to the factory tour (or someone who knows a PM or engineer in Porsche) to ask.

ChuckJ
+1. While I'm not affected by this personally (and I don't do time trials in my non-existent 991), I am curious about this.
 
Old Apr 17, 2013 | 09:32 AM
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Hi Pete,

Unfortunately, the rpm drop is most pronounced when you're shifting at redline. I didn't notice much of an issue during the break-in either.

Originally Posted by CarreraPete
Hi, Sergey,

I was thinking about what you'd told me at the meet while driving around yesterday: I did notice the drop between second and third gear.

I'm still under the 1K mark so I haven't really been pushing the car to red-line, but I'm hoping this annoying drop in RPMs doesn't really hurt overall performance; especially while trying to shake a competitor from a standing start ...
 
Old Apr 17, 2013 | 09:35 AM
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I saw a quote form Porsche somewhere that said that 7mt was derived from pdk with a higher third to improve fuel economy.
Originally Posted by ChuckJ
Totally agree. I had always wondered why they did that. They actually had to spend money to do that. I would be a good question for someone going to the factory tour (or someone who knows a PM or engineer in Porsche) to ask.

ChuckJ
 
Old Apr 17, 2013 | 09:46 AM
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Originally Posted by SxxB
I saw a quote form Porsche somewhere that said that 7mt was derived from pdk with a higher third to improve fuel economy.
... Because there is a lot of cruising around in 3rd for the mileage conscious?

They had to hit that 'city' rating.
 
Old Apr 17, 2013 | 10:29 AM
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Originally Posted by jaspergtr
... Because there is a lot of cruising around in 3rd for the mileage conscious?

They had to hit that 'city' rating.
The tech manual does say that 3rd gear has a higher ratio to reduce fuel consumption, but that's a little hard to understand given the city test procedure (attached). Perhaps it's better suited for the German fuel consumption standards.

ChuckJ
 
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Last edited by ChuckJ; Apr 17, 2013 at 10:33 AM.
Old Apr 17, 2013 | 10:45 AM
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Originally Posted by ChuckJ
The tech manual does say that 3rd gear has a higher ratio to reduce fuel consumption, but that's a little hard to understand given the city test procedure (attached). Perhaps it's better suited for the German fuel consumption standards.

ChuckJ
lol! Thanks for attaching that. This is actually one of the reasons, over the last two/three years of owning a dual clutch car for almost 5 years, have I started preferring to shift manually, because I'm tired of the gearbox racing to top gear by 32mph (quite literally).

Mileage be damned!

I understand EPA ratings, federal laws, etc... - but who the hell buys a sports car for its mileage (I know there are more than a few of you here)?

Yeah, because with my $200k Porsche Turbo S, I'm concerned with saving $30 a month vs buying a Jetta. That will equal out in about 80 years, just in time to trade it in.
 
Old Apr 17, 2013 | 12:51 PM
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Originally Posted by ChuckJ
The tech manual does say that 3rd gear has a higher ratio to reduce fuel consumption, but that's a little hard to understand given the city test procedure (attached). Perhaps it's better suited for the German fuel consumption standards.

ChuckJ
I will say that when I had the 991 C2S Cab 7-speed manual press car, I was in 3rd gear whenever I did city driving under 40 mph a lot. But part of that was to make sure I could gear the glorious PSE.
 
Old Apr 17, 2013 | 03:48 PM
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I only have 500 miles on my 991 C4S so I am shifting at 4000 rpm. Every shift seems to be just a blip with RPM's dropping about 700 to 800 in all gears. Don't want to put those number in concrete...but I think that's pretty close.
 
Old Apr 17, 2013 | 04:37 PM
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Originally Posted by T-Mac
I only have 500 miles on my 991 C4S so I am shifting at 4000 rpm. Every shift seems to be just a blip with RPM's dropping about 700 to 800 in all gears. Don't want to put those number in concrete...but I think that's pretty close.

That's because the higher the wheel rpm is, the bigger the gap will be due because different gear ratios are multipliers. That's why it isn't that noticeable at lower rpm shifts.
 
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