Cayman GT4: Where are we up to now?

[Motorhead]

ORIGINAL: spyderman

ORIGINAL: chrisH The GT4 maybe the last model to have a NA engine assuming its the detuned 3.8, as from next year they are moving to 2.9 and 3.8 Turbos to meet the 2016 EU Emission Regs.

Whatever is has, it will need to produce about 400hp to be competitive against the existing homolgated cars. A turbo I think is highly unlikely. I think it's going to be very interesting. Chris.

Chris & ChrisH, I’m still convinced that it’s going to be a N/A rather than a turbocharged engine, especially if it’s going to arrive well before the rumoured flat-4 and flat-6 turbo engines arrive on the scene for the Boxster/Cayman and 991.2 Carrera. Although MrD’s insider info is saying that it will be a 3.6L, I’m still banking on it being the 3.8L which would have the added bonus of allowing more scope for race development. It would also ease the production engineers’ headaches by just having two blocks for the N/A engines: 3.4L and 3.8L with bore/stroke ratios of 97mm/77.5mm and 102mm/77.5mm respectively. The last 3.6L [non-DFI] engine was used in the 997.1 Carrera which had a 97mm/81.5mm bore/stroke, ie a completely different crank, so it would be odd if Porsche reverted to these engine dimensions for the GT4. Having yet another bore size for the DFI engine doesn’t really make sense either, especially since the N/A 2.7L and 3.4L will soon be dropped in favour of the flat-4 turbo engines and the turbo flat-6 engines are reputed to be 2.9L and 3.8L. It would be much simpler from the production engineering viewpoint to have just 2.9L and 3.8L 6-cylinder blocks, with the latter being used for the GT4, Carrera S, GT3 and Turbo. One question remains however, and that is: if Porsche plans to make the GT4 a permanent member of the Cayman family, how long will it continue to have a N/A engine? If an initial 2-year production run is guaranteed, presumably the next generation of GT4 could well be turbocharged. Jeff

 

[spyderwhite]

The dfi 3.6 was/is the same stroke as the 3.4/3.8 also cannot see it being a 3.6. Here is also hoping its 3.8 but fear it will be 3.4

 

[Motorhead]

Was there a 3.6L DFI Carrera? I thought that, as now, there were only the 3.4L and 3.8L engines available. Jeff

 

[spyderwhite]

ORIGINAL: Motorhead Was there a 3.6L DFI Carrera? I thought that, as now, there were only the 3.4L and 3.8L engines available. Jeff

Yes it was 345hp in the 997.2 and then cc was reduced to 3.4 and350 hp in the 991

 

[Motorhead]

So Porsche could reinstate the 3.6L tooling for the GT4. Rather a limited production run though and it would be much simpler [and cheaper?] just to detune a 3.8L to ~380PS. For what it's worth, I can't see Porsche tuning up the 3.4L to that sort of horsepower, Jeff

 

[ralphmusic]

If the GT4 were to be turbocharged, it would release tuners to more easily offer remapping via piggy back devices such as http://www.fabspeed.com/porsche-991-turbo-engine-tuning-power-kit The 9x1 ECU has still not been cracked and I would guess is unlikely to be broken anytime soon so perhaps there is an upside to turbo future...

 

[Motorhead]

Agreed Ralph. Tinkering with the DME on N/A engines appears to deliver ~20hp at most, but turbocharging presents a significant opportunity both to the manufacturers and engine tuners. Incidentally, I thought that Softronic had cracked the DME encription for the 9x7.2 DFI engines, although I believe one tuner somehow piggy-backs the base DME to effect the sofware upgrade. Jeff

 

[ralphmusic]

Jeff, Softronic have ECU flash software for 987.2 http://www.softronicsoftware.com/987-2-boxster-performance-software so not a piggy back arrangement, but not the 9x1 generation Siemens ECU. I think on 9x7.2 it was a simpler Bosch unit. and this for 991 models http://www.designtek.eu/Porsche/991-MKI--911--2012--/ECU-Remap---Tuning-Tool/pt2425_2426_-cma1633-cmo2427/ does not exist per a call this morning... Too many questions currently for me on the reliability of performance claims and 'ease' of installation of these normally aspirated ECU tunes.

 

[Motorhead]

Yes Ralph, Softronic have cracked the coding for the 987.2 DFI engines, but it seems that the 981 is still work-in-progress. Actually, I think that the 9x7.2 DME was also supplied by Siemens rather than Bosch which may explain why it took so long to produce a remap for that series of engines. Buiding on that experience, I'm sure that their 981 remap isn't too far off. The DesignTek remapping looks like a piggy-back device and best avoided. Jeff

 

[spyderman]

If they are going to downsize and turbo all 991 models, surely the 3.8 will disappear - perhaps to become 3.6 or even 3.4 ...? Chris.

 

[Motorhead]

Chris, According to Georg Kacher, CAR's correspondent who seems to have good Porsche contacts, both 2.9L and 3.8L turbo engines will be available in the 2015 991.2: http://www.carmagazine.co.uk/Secret-new-cars/Search-Results/Spyshots/Every-Porsche-911-to-go-turbocharged-in-2015-with-9912/ Apparently the smaller engine has tax advantages in the rapidly expanding China market. With all 991s except the GT3 being turbocharged, I'm not quite sure where that leaves the 991 Turbo. Quite possibly the lesser 991s will just have a relatively low-pressure single-turbo arrangement. All part of the process of having turbocharged engines available across the Porsche sportscar range in the next couple of years. If that's the case then assuming the GT4 will be N/A, it may well only have a 2-year production run unless Porsche plan to extend building the N/A engines specifically for the race oriented GT3 and GT4 cars where target emissions and fuel consumption are perhaps less critical to the purchasers. Jeff

 

[dpoynton]

ORIGINAL: Motorhead With all 991s except the GT3 being turbocharged, I'm not quite sure where that leaves the 991 Turbo.

There are currently three cars in the Macan range, all have turbo charged engines.

 

[Motorhead]

Agreed David, but I did explicitly say "All part of the process of having turbocharged engines available across the Porsche sportscar range in the next couple of years". Good though the Macan SUV is, somehow I can't personally see it as a sportscar but it does further illustrate Porsche's march down the turbo route. Jeff

 

[dpoynton]

I didn't mean to interrupt the thread, my point was that the Macan (which, I agree, is not a Porsche sportscar) has three derivatives, all are turbo but only one is badged as such. This, I thought was in line with your remark; "where does this leave the 991 turbo". Shall we move on? David

 

[Motorhead]

Apologies David - I misunderstood the point you were making. Presumably the "Turbo" tag will become irrelevant and just signify top of the range cars. Jeff

 

[flat6]

ORIGINAL: Motorhead You might be interested to read Georg Kacher's impressions of RUF's 3800S Boxster here: http://www.automobilemag.com/reviews/driven/1311_2013_ruf_3800s/ Jeff

Thanks Jeff. The conclusion was interesting. I guess it depends what you're looking for out of a £100K car: The 3800S calls for even quicker reflexes with RSM deactivated. Communication between steering and throttle is more of a shouting match than a dialogue, and the speed window is more in line with that of any rear-engine Porsche. The means with which to induce understeer, oversteer, or a four-wheel drift can blur and overlap. Small variations in driver input can result in major changes of vehicle attitude. Exciting, yes. User-friendly, less so. Is a 3800S a better buy than a Carrera S cabriolet? Yes. It is quicker, more special, and more demanding to drive. Is it worth twice the money to upgrade from a Boxster S to a 911-engined Ruf? Probably not. The 315-hp ragtop is so sweet, smooth, and special that all it takes to narrow the performance gap is the optional PDK. From Ruf's model range, it's more worthwhile to drive one of the crazier efforts that leave the donor car well and truly grumbling in the dust. The Specs Price: $132,895/$139,695 (convertible/coupe) Engine: 3.8L flat-6, 420 hp, 332 lb-ft Drive: Rear-wheel

 

[Motorhead]

Courtesy of PH, an iffy Google "translation" from the 17th October issue of the German magazine auto-motor-und-sport: In the Cayman GTS uprated to 340 hp and 380 Nm 3.4 - liter boxer working . The GT4 goes even further and comes thanks engine capacity to 3.6 liters and is likely to be somewhere at 360 hp and 400 Nm of torque. The power engine is combined probably with a seven-speed PDK . The chassis and driving dynamics systems are adapted according to the new application. The new drive package should be good for a sprint time of just over four seconds and a top speed near 300 km / h. The maturity of the Porsche Cayman GT4 tests suggesting an early debut. In addition, the GT specification defines ambitions close racing. Perhaps because Porsche brings so a new Cup vehicle in position. More unfounded speculation, of course, and I'm sure that the manual rather than the PDK 'box will be the standard fitment. A 360PS motor sounds a bit puny and disappointing, if true, especially if Porsche has "racing ambitions". But if it retails around £65k I suppose you get only what you pay for. Jeff

 

[ralphmusic]

Jeff, This is where the wibbly wobbly web reinforces apparent "data" If I might 'out' the poster, 'twas I. A poster had breathlessly reported a source which on the face of it was recent, but more likely was an October 15 piece in Auto Motor und Sport, see http://www.auto-motor-und-sport.de/news/erlkoenig-porsche-cayman-gt4-sportliches-top-modell-im-anmarsch-8362301.html Your German might be better than Google's - I can just order a beer..

 

[Motorhead]

That's certainly the source Ralph. Maybe some different pics of the same car(s) again - in one set of pics the car has steel brakes (red calipers) whereas in another it has PCCB (yellow calipers). My German's not much better that yours, although I can go one better - Noch ein bier..! Jeff

 

[ralphmusic]

Prost!