GrantG

Hmmm, I haven't seen many vids where speed continues to very high speeds (would be necessary to see the full effect of ram-air and aero drag). But remember that the GT3 also has ram-air scoops on the rear deck (if not Touring). I admit that RS has better ram air, but I bet the difference in HP is very small and only really noticeable at very high speeds. Also, the big rear wing on the RS should slow the car MUCH more than the little bit of extra ram-air effect can offset (beyond the differences between the engines when the cars are not traveling fast).

Aero Drag is a much bigger deal than HP at high speed. Mathematically, it's a Cube function. So to go 2 times faster with a given amount of drag, you need 8 times as much HP...

I know Trakcar says at the faster tracks, the .1 GT3 would beat him on the straights with his .1 RS (when the RS was rated 25hp and 4% torque higher), because of the extra aero drag...

catdog2

Could it be the PCCB's on the RS vs. Iron brakes on the GT3?

Do we know if that's worth any difference on a pull between to similar GT3's with different brakes?

Taffy66

I'm very sceptical on the parasitic losses on the PDK, until i see some comparable dyno figures taken at the same time in identical conditions..I'm guessing its no more than 1-2% which makes sense as there's only a 1mph higher top speed with the 37lbs lighter manual.People seem to compare a PDK with an auto.A PDK is a manual box with a computer operated twin clutch connecting to the engine..A proper torque converter auto has no clutch and no direct mechanical connection between gearbox and engine..

robmypro

Grant we need to go to Bandimere. .1 vs .2 GT3. PDK vs Manual. Let me know when you are game and we will get some video. If I get flogged, that is fine. Love the car regardless!

GrantG

A couple issues with this post. The 1 mph difference is not a fair comparison, since the gearing is quite different between PDK 7th gear and Manual 6th. The difference may have been greater with equal gearing. Next, additional weight (37 pounds in this case) does not affect top speed - it only affects how long it takes to get there. The relevant variables for top speed are power (at the wheels, which is affected by things like gearing and drivetrain losses), rolling resistance (no difference) and aero drag (no difference). If you search, you will see that there is a firm pattern between PDK and Manual dyno runs with Manual indicating more than 2% (10hp) better efficiency.

Taffy66

This should account for some of the difference although only minimal..The PCCB has 37lbs less rotational mass on the wheels.Since all the power is transferred to the wheels directly and its the wheels that take the car with it, then reduced rotational mass to twist has to make a slight difference..

GrantG

I would do it, if not for my will to preserve my clutch

Buteo

GrantG

You'll beat us both

Might be interesting to compare speeds at end of straight at HPR. My best so far is indicated 140mph (137 on Harry's GPS lap timer). Not a perfect test (if not same entry speed and braking point), but still interesting.

Speed is higher than 1/4 mile at Bandimere, so you start to see influence of aero a bit more.

Buteo

GrantG

Gaining 5 mph is a big improvement. Definitely means you increased power a meaningful amount

I had RE10 brake pads and Endless fluid on my GT4 which gave me the confidence to brake later in the GT4 - just stock brakes on GT3 so far...

robmypro

Dual clutches do have their advantages lol.

That would be a good one. .1 GT3 vs .2 RS.

drdonger

GrantG

If the GT3 is under-rated and if the RS makes 30hp crank more (let's estimate 540hp crank or more), then they are really pumping out lots of hp per litre (more than reigning champ, 458 Speciale which has advantage of smaller cylinders)

AutoQuest MS

HAHAHAHA