GT3 gear ratios

I had a 97.1RS and currently have a 97.2 RS.

I find the ratio's too short in the 97.2, I would estimate that on a lap of Silverstone you need about 5 extra gear changes, say each change costs you a 10th, that's half a second lost which is lot of time to find from acceleration.

I'm not saying it's necessarily slower, the 97.2 is definately quicker but it does have more power.

What I am saying is that a gear change costs time, going from 5th to 6th towards the end of hanger straight will cost you a couple of miles per hour because you are off the power for a fraction of a second as you make the change, therefore more gear changes more time lost but that's got to be balanced against better acceleration but in a race I would sacrifice a bit of acceleration for fewer gear changes.

My preference would have been to have the 97.1 ratio's in the 97.2.

Fioran0 do you by any chance know what a 997.1 C2S on the ratios for comparison as well please?

Why do people give MrDemon so much stick, I'd have thought shorter gear ratios equal faster acceleration, especially in lower gears and as such you could have to equal cars but with just different gear ratio's and the one with the shorter ratios would accelerate quicker within each gear. Its just getting the balance right, too short and drivability won't be so good and you will loose loads of time constantly changing gear and too long will just result in slower acceleration.

gibbo205, Exactly the same as the 996C2. Ratios are very slightly different but speeds calculate to the same due to 19" rims.

Here is some data that demonstrates the point I'm making.

The data was from Oulton Park, I'm driving both cars, the red line is the 97.1, the blue 97.2. Over the straight highlighted on the data the 97.1 gains 10th despite it being down on power compared to the 97.2. You can see how much time is lost by gear changes (it maybe that I'm crap at changing gears).

Whilst the 97.1 lap is a second quicker, I did not get a clear lap in the 97.2 and I'm convinced that overall the car is quicker.

I ran two identical race cars last year except one had a standard box, the other close ratio, this year both will have the standard box.

steve, apologies, i totally missed your post. absolutely agree (once you get over and then adjust to the whoosh that is first gear lol)

I agree with you dad about first gear, but I've got used to it now and have learned to use it to my advantage in the odd launch start.. I have also driven a 7.2 rs lately and again agree that I found it to have the perfect box, what a car!! see you at oulton!

ade

Yes I had a better entry onto the straight in the 97.1 and you can see the 97.2 accelerating better in second and third, the 97.1 holds third for much longer and once the 97.2 is in fourth there is no difference in the acceleration. As you say if the straight had been a little longer I would have been grabbing fifth in the 97.2 whilst the 97.1 would have held fourth for much longer.

The longest straights in the UK are Silverstone and Snet, I've never neaded sixth in the 97.1 but have in the 97.2. The only time I think you would use sixth in the 97.1 would be on a full lap of the ring.

On that lap the data is indicating that I had traffic coming upto point 11, I'll see if I can find another lap without traffic.

The data logger was made by a mate of mine, it's much more accurate than most commercial systems.

Hi Ken,

Are all your RS's standard cars suspension wise?

Ade

After spending so much time looking at 997 cup traces, its shocking to see the time lost through manual gear changing. A typical 997 cup trace shows almost linear acceleration. You can flat shift in a manual GT3 but it is very hard on the box. Not surprised to see the speed of the 996. The 997 keeps up with the 996 on bhp alone. It's such a shame. it's a superior chasis blighted by PASM. A 997 fitted with passive would be substantially quicker and give similar feel to the 996. I think that It is essential for a chassis to telegraph as much information to the driver as possible on the circuit, up to and beyond the limit. In my opinion, this is a fundamental failing of the 997 generation GT3 chassis. i am happy to jump into a 996 GT3 and go for a 10/10ths time because i feel in front of the car at all times. It gives so much information that the trick is to filter out what you dont need. The 997's that 'ive driven feel generally vague on the limit, especially the way it telegraphs oversteer which is a major problem because you are working the nose during turn in so hard to counter the pasm that rear grip is always compromised and if you dont have a very high degree of feel in the chassis the car can easily snap into oversteer before you can counter it. I know of 2 very competent 996 GT3 drivers that had suffered heavy oversteer offs in 997GT3's for this reason.

With the 996, you know well in advance what the car is about to do and can adjust your inputs accordingly leading to a smooth and predictive lap. The 997 is more of a lottery and - for me at least - leads to a driving style based around a reaction to a loss of grip (mostly oversteer) and leaves me feeling that the car is working against me and not with me.

This is in sharp contrast to driving the 996 and 997 cup variants. Although they are both predictable, the 997 is an easier car to drive on the limit providing more physical grip and requiring less effort to drive.