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Porsche 911 reprogrammation moteur echappement ipe installation shiftech 22
08.09.2016Analyse

Porsche 911

991 GT3 RS

We had the immense privilege of welcoming to our premises one of the most powerful supercars of 2016, the new Porsche 991 GT3 RS.

If a Porsche 991 GT3 is already very rare, the RS version, the ultimate version of the 991, is even rarer, as its production is limited to around 2,100 units worldwide.

The question is: why a GT3RS?

One might ask what the GT3RS has to offer that the GT3 does not. The GT3RS is the nec plus ultra, with a 4.0-litre engine instead of the 3.8-litre of the standard GT3, and a revised intake just like the engine, which receives special treatment to enable it to cope with revs of up to 8800rpm. From an aesthetic point of view, the GT3RS is easily recognisable by its rollover bar, its imposing spoiler, its wider tracks, its 21-inch wheels at the rear (325 wide) and, last but not least, its front wing vents. All these changes bring considerable improvements in terms of handling and responsiveness. There's also a gain in raw performance, given the increase in power (+25hp) and the 10kg reduction thanks to the use of magnesium.

Finally, why not compare it with the 997 GT3 RS 4.0? Although the latter is an older generation car, it has the same engine as the new GT3RS, but is 80kg lighter! So is the 997 GT3 RS 4.0 more powerful than the latest GT3RS? Yes, on paper at least, because in reality the 991 GT3RS, thanks to its 21-inch wheels, better aerodynamic support and above all its 7-speed PDK gearbox, takes the lead with a 0.4sec gain in 0-100km/h (3.3 compared with 3.7).

The result: a lap of the Nordschleife in 7m20sec, 7 seconds quicker than the previous 4.0L.

To sum up: the 991 GT3 is intended for occasional track use, while the GT3RS is intended for occasional road use. And if you're not convinced, a quick road test with that stiff-as-wood suspension and roll bar will remind you.

Preparing for the GT3RS? Why not!

While the choice of the GT3RS over the GT3 is an obvious one, it's not always easy to see why it needs to be prepared. In any case, this is one of the reactions we regularly have to this type of vehicle. You should know that, whatever vehicle you have, once you've had a taste of preparation, it's hard to do without.the feel of the accelerator, the acceleration, the response and the performance in terms of acceleration are all very pleasant indeed.so, even if this latest RS is the result of extensive optimisation by Porsche, there are still possibilities in terms of preparation, particularly if it is fitted with an IPE exhaust system that frees up the flow of exhaust gases even more.

What parameters need to be changed to achieve a greater gain? With a naturally-aspirated engine, you unfortunately don't have much choice. You need to add more air, optimise the richness and possibly shift the ignition switch. That's mainly what we do. To increase air intake, we use a larger ignition, which will have the effect of opening the valves longer to obtain more power. In practice, this translates into a 1.5° increase in ignition in 98 octane. With regard to richness, to comply with European standards, the car runs fairly lean until the exhaust gases have reached a certain temperature. Once the temperature has been reached, the mapping switches from rich to richer, increasing performance with a more interesting air/fuel ratio. We then choose to run the vehicle richer before it switches to enrichment. This makes the vehicle even more responsive and reduces the gap between richness and enrichment, which avoids too large a delta in exhaust temperature.

All that remains is to increase engine speed. The standard maximum is 8800rpm. It is possible to increase this to 9000rpm, but in reality, the PDK gearbox will change gear at 8900rpm. in the end, 100rpm are gained, which is enough to squeeze out a little more power.

It is these different parameters, combined with the different load and torque limits, that enable our vehicle fitted with the full IPE line to develop around 28bhp and 28Nm more. A low score on paper, of course, but much more responsive thanks to the revised richness.

The GT3RS - the best buy?

When you consider that all the 991 GT3RSs were sold even before they were officially marketed, you have to ask yourself a few questions.

The first question is: how do you get this car? It's virtually impossible for the average person, even if they have the €185,000 required to buy one.

And why is that? Porsche is on a roll and prefers not to sell vehicles that could be the subject of speculation. As a result, to be able to buy a GT3RS you must first have had a GT3 or an older-generation GT3RS.

Despite this, you can find GT3RSs for sale on the internet where prices vary between €250,000 and €300,000, a good investment even if Porsche is against such practices.

The second question is: who would dare to drive a €300,000 car on a racetrack? Indeed, with such rarity, and taking into account the considerable added value on resale, one might wonder whether there are still purists who drive this type of vehicle on the track, which is ultimately its vocation. With limited editions such as these (and I'm not talking about the recent 991 R, where it's even more blatant, since it's limited to 991 examples), isn't Porsche ultimately forcing speculation to the detriment of driving pleasure? What's the point of selling ultra-sporty vehicles if you're just going to let them appreciate in value in a garage? Admittedly, that's a bit of an exaggeration, but I'm not sure you'll come across many GT3RSs on the track or on the road, even though there are over 2,100 of them in existence worldwide. So, even if 2,100 isn't a very large number, you should know that I have personally come across three Audi A1 Quattros on the road, albeit limited to 333 examples.

Conclusion

Be that as it may, this latest-generation GT3RS is truly an exceptional vehicle. It was a real pleasure to see it, to try it out and, better still, to prepare it. A pleasure also shared by the owner, who plans to drive this GT3RS and not leave it in the back of his garage. Sharing this with you is very difficult, which is why we have created a video that summarises the preparation of the vehicle and gives you an idea of the sound produced by this IPE line. Don't hesitate to watch it and share it if you like it.

Chrono

Porsche 911 991 GT3 RS ShifTech software tuning + IPE full exhaust