JCviggen

We're not arguing the fact that more displacement isn't better for eliminating unwanted turbo delays, but rather that the 2.5L would somehow be too laggy at the 400 horsepower level. Given the setup of the twin scroll single it should be every bit as good as the twin charged flat six at comparable HP/litre numbers.

What most people describe as lag is really a relatively high boost threshold, which is most of what I was talking about. Drive the 370hp Carrera and the 450 GTS back to back and the latter really feels a lot more "typically turbocharged" than the first. It's inherently subjective and your personal method of defining and measuring it doesn't really change that. Not going to go into yet another pointless back and forth though, we've done this already and my previous experience gives me a clue why you got banned here with your first account ;-)

RRDnA

Thats the whole point - its a sensible and reliable mitigation strategy - produces a broader power band and more linear overall response.

The lower the displacement and higher the boost the peakier the engine is and feels.

RRDnA

I know what turbo lag is - if you can't feel it or discern it, its immaterial and is simply food for internet forums - largely commented on and driven by people who don't own the cars.

Surprise, surprise one of us owns one (X51S) and one of us doesn't ...so frankly what you think you know and what I actually know are materially different (and have measured, to clarify as delivered by the SC system developed by Porsche whereby you can look at boost relative to throttle, relative to a GPS coordinate, or lineal G or lateral G or gear, or RPM.......).

I gave you the answer above - its the conclusion Porsche came to and unsurprisingly many other manufacturers managed to arrive at a similar answer (Ferrari, McLaren, MB etc).

E.g. you blend displacement with two turbos to produce a combination of low end torque coupled with linear response to the redline. You are simply arguing for a peakier non-linear experience.

There's really not much to go back and forth on - go and buy a WRX STI EJ257, add bigger turbo, add TBE and injectors and tell me what it feels like. It will be very peaky and very laggy even with a twin scroll. All of this has been done to death for over 20 years.

4nroots

Porsche have hit a home run with pretty much every GT car. They know how controversial the 2.x H4 has been. If the GT series is really going all turbo, it'd be pretty risky to start the era off with such a polarizing engine (especially without major changes) IMO.

RRDnA

Thats the marketing portrayal or often a view driven by journalists that don't own and never will likely never own a brand new GT car - however ask a 991 Series I GT3 owner how he or she feels - E and F series engines are still giving up the ghost, why are solid lifters back in vogue for one engine cycle or how about GT4 owners, check the thread on third gear failures - still happening and still being recorded.

BillC3

This raises an interesting marketing conundrum for Porsche: How are people going to feel about two separate engines -- a 6-cyl and a 4-cyl -- both making roughly the same horsepower? Will people think the 911 is overpriced because a "lowly" Cayman/Boxster makes as much (or more) power with fewer cylinders, or will people think the 4-cyl is on the ragged edge by being pushed to make as much/more than the bigger engine?

How Porsche manages the introduction of a 4-turbo GT4 and/or Spyder will be interesting to watch.

Yargk

I think this is actually the easy part. In 1982 you had the 924 Carrera GTS making 280 hp. That's not just a lot more than the 911 of the time, it was on par with the 911 turbo of the time (just a little less). That would be like a turbo GT4 with 500 hp nowadays. It would be viewed as a frenetic track special that makes hp with a crazy tuned motor, while the 911 makes hp in a more 'effortless' way consistent with people who want more of a tourer. These cars have different buyers so there's no conflict. (although there would be of course a conflict if the GT4 made 500 hp like the GT3, but just not if it made 430 hp to be comparable with a 911 GTS)

What I think would be the bigger image issue is a 4 cyl in some Caymans and a 6 cyl in others. It seems that choice would confirm the complaint that the 4 cyl isn't "good enough." I used to just trust that the next GT4 would be NA because AP said so a few times, but if one thinks of Porsche as a business, it doesn't make sense. If they built a GT4 with a turbo 4 that was amazing and all the car magazines agreed, then it would boost sales of the lower models because it's the same "type" of engine. I think a 6 cyl would distance the GT4 enough from normal 718 models that there wouldn't be as much of a halo effect. Also, it is relatively cheap and easy to get 400-430 hp from a turbo 4 based on the existing turbo 4 engines. I think a detuned GT3 engine would be much more expensive.

Porsche has made cars that make less business sense just for the hell of it before though, which is why we are fans, so we shall see.

GT4 981

^^ well said and I couldn't agree more!

zorgg

From a pure industrial point of view, it's sure that putting a 4 cyl. turbo in the next gen of GT4 / Spyder is the cheapest option. It's also a good way for Porsche to differentiate the Cayman / Boxster range from the 911 one, despite similar performances (the next GT4 will probably be faster that the current 911 GTS).

On the other hand, I understand that all fans would expect a NA engine in these cars, but I can't see Porsche spending a lot of resources in de-tuning their 4.0 NA engine - considered as the gem of their current production - to a point that its proper nature will be affected. If you think about it, a detuned 4.0 NA of say 410 hp will be less powerfull than the last 3.8 NA engine of the former 991 GTS, and probably at the mercy of a 718 GTS on a track... I agree that it's possible technically, but this would mean limited max engine speed for this 4.0 version (7500 revs / min?), a sound impacted by the OPF system etc. With probably a somewhat disappointing result at the end. Why would Porsche take that risk? Engineers like challenges, they want enhanced performances on next engine generations, not worse ones. And, regardless of the engine type that is finally installed in the GT4 / Spyder, the fact that it 'sounds' like a 4 cyl. turbo (if I refer to the Spyder video circulated recently) is not a very good sign, anyway...

This said, I also feel that too much significance is given to the engine that will be finally adopted (how many of us have actually SEEN the engine of their GT4/ Spyder ?). The only point that counts is how nice the car will be to drive. Yes, sound is a part of it, but is it that essential? I'd be more worried about some other elements that have been shown or mentioned: steering wheel controls, **** shifter activating a double-clutch system, maybe electric soft-top for the Spyder (who knows...) etc. All these new functionalities are steering these cars away from the initial concept of relatively simple sports cars. To me, even the electric hand brake system on the 981 was one step too much...

Crazy Eddie

shaytun

For me the sound is even more important especially on the road.

ExMB

You no doubt make a good point. But lets also keep in mind that PAG keeps very tight control of what gets written and released by the press. Not saying that kool-aid is involved but when have you ever read a review of a newly introduced model that wasn't glowing with praise?

Diablo Dude

No doubt about it.
The VISCERAL appeal of the 981 GT4 is HUGE!

VLJ

Amen, especially with a nice exhaust this car's sound is intoxicating.

Alan C.

Eddie, if you want to crank that up a notch add a set of Dundon headers and their tune.