CAlexio

I do remember now chris Harris mentioning about pdk sucking drivetrain power. If try this is amazing that a car with same engine but with a manual, is faster. Would be a first and bodes well for 991.2 GT3 (assuming what we are assuming)

Bartron

Besides the wider body and more aero slowing the RS down, as well as the extra weight of sound deadening, do we know if there is a gear ratio difference to make the car faster? I couldn't care less either way but interesting to think of the variables involved.

GrantG

The gearing advantage should favor the RS for acceleration (7 ratios vs. 6 with similar top gears). 911R is 7 mph faster due to less drag (not gearing) - this means the RS is shedding quite a bit of effective horsepower through aero drag (and PDK friction which accounts for about 1 mph of the 7 mph difference). It takes a lot of hp to go 7 mph faster near 200 mph (unless I screwed up the math it's about 56 hp). And the loss due to PDK at top speed (if the 1mph loss of Vmax is accurate) is about 8 hp of the 56 hp total. Note: This 56 hp effective difference at 200 mph would be WAY smaller at normal legal speeds (the aero drag is proportional to the cube of the speed, so under 4 hp spent to overcome the extra drag at 100 mph).

I got the 1 mph difference based on the Vmax of the new GTS Manual being 193 mph and the PDK version of same car being 192 mph (though I thought I remembered a 2 mph difference for some models) - specs attached here:

Guest89

Do they have the same final drive?

GrantG

The two cars have different gearing (partly because the RS has larger diameter 21" wheels and a slightly lower theoretical top speed), but both cars have gearing that is designed to maximize top speed - All GT models hit top speed in top gear very close to peak hp (8,250 rpm in this case) - the optimum conditions for Vmax). There could be a slight benefit to one car or the other, but it's small...

If I remember right, the RS has slightly lower gearing than the GT3 but after taking into account the bigger tires, it's something like 1% taller overall effectively geared than the GT3 (which goes faster than the RS, despite the 25hp deficit).

The RS's design purposely traded drag (and therefore top speed) for better downforce and higher cornering speeds.

turbofreeFLAT6

911 GT gearing.pdf

GrantG

Thanks for posting!

isv

Just a question. The 4litre has a shorter 6th gear but lower top speed than the 3.8RS?

GrantG

No, the smaller number (gear ratio) makes for a taller gear. You're talking about 997 models, right?

Edit: I think maybe the speeds at 7,000 rpm may be swapped in the second chart (seems reversed from top chart) - I agree there might be a typo

turbofreeFLAT6

You're right, they should be reversed. I'll check them all as soon as I have time.

turbofreeFLAT6

Now corrected. I have the speed at 7,000 rpm in 6th for the RS 3.8 but not the 4.0 so had calculated it from the relative ratios. However I had divided the 4.0's ratio by the 3.8's instead of the other way around.

I've also included the GT4's ratios. Their length compounds the power deficit relative to recent GT3s. 997 RS ratios in the first few gears would have helped give proper GT thrills without usurping Carrera power figures.

GrantG

Thank you! PM Sent...

BusDriver

Due to its lighter weight (-50 kg), lower rotating masses (gearbox, wheels, etc), lower aero drag - the 911R accelerates quicker than the 991 GT3 RS in every gear. But because of the RS's launch control and much quicker gearshifts, the RS gets off the line about 0.5 sec quicker and makes up ground on the R at every gear shift. Therefore, in actual acceleration performance, the R has a sustained advantage only from 3rd gear or ~75 mph onwards.

With all that said, the RS and R serve different purposes and maximum acceleration is neither cars raison d'etre. If maximum acceleration is important, then the 911 Turbo is a better choice than either the RS or the R. If track performance and lap times are important, then the RS is the right choice. But, for ultimate road driving pleasure and if the concept of a modern day road-oriented hot-rod appeals to you - then the 911R is the car. Very fortunate to have one as there is nothing else like it.

Footsoldier

As above ^ !

rosenbergendo

Besides a plaque, what is impressive about this car? And no I'm not a disgruntled RS owner. I just don't get the R. And yes I have a 997 GT manual car and a 73 Viper Green coming soon so I get a the allure of a manual.