Well I can tell you first hand the "OLD" gen GT4 clubsport MRs are fast as hell on track...soooooo any update will be murder for us to compete with next season

With the Spyder falling so closely on the heels of the GT4, it got totally lost in all the fanfare surrounding the GT4 and the tsunami of well-deserved praise heaped on the GT4 in the automotive press. Talk about an under-the-radar intro that got totally buried, recall that Spyders sat on dealer lots and were offered at a discount while the GT4 at points reached levels of unobtainium with ADMs not uncommon.

I'll be surprised if Porsche again introduces both the 982 GT4 and Spyder in such close proximity, but what do I know. I would have bet the house the next Spyder would be NA and now that appears less than certain.

If they did the same HP/L as the base 2.0 718 with the 2.5 engine that's already 375hp. Very slight increase in boost with a larger turbo and you're there. People have already tuned 718s easily and conservatively well beyond 400. Ehresmann even did 450. Porsche uses their 3.0 H6 for the base, S and GTS going from 370 to 450 with nothing but different turbos and boost. They're not going to significantly alter the engine for no reason. With a turbo, boost level is what makes the difference and what holds back and the limitation lies in the strength of components like connecting rods how much you can get away with, not how much displacement you have. A higher boost threshold is the biggest drawback but relative to what has been done before (and other manufacturers) a 2.5L is plenty for 400+

I just don't know who is going to pay lets say 100K for GT4/spyder with 4cyl banger. You can easily tune 718s or GTS to 400HP for couple of grand or even less.

In the 991.2, the Porsche engineers took the base 3.0L motor with 370hp and raised it by 80hp to make the GTS with 450hp - just bigger turbochargers and tune...

They'll squeeze more out of the same motor in the 992 as well...

And in the 991.2 GT2 RS, they took a 991 Turbo motor with 540 hp and juiced it by 160 hp to arrive at 700hp with very little changed other than turbochargers and tune.

This wait is too long! And, this is just to know what will exist. If history repeats itself, there will be another long wait to determine if your dealer will get enough allocations, and then again, whether or not you will be given one of those allocations. All this waiting is frustrating.

Meanwhile, other manufacturers are talking new, neat stuff - like track focus monster Corvette, maybe even a mid-engine Corvette, a 700hp+ Mustang, and who knows what else?

So, for me, anything less than a reasonably priced 4.0 ltr car will be a let down.

I dont think the 2.5L 4 banger has the room for a larger turbo let alone two turbos and being a small displacement it will be harder to get bigger gains like that seen on the 6cyl. models regardless of turbo size.

The GTS is 365hp based on a tune of the 350hp 718 S. Sure it can go higher.
Although, Porsche have engineering decide how much hp their engine can withstand for public use with emmissions, fuel consumption and warranty considerations. So it is generally conservative and detuned by xx%. Indeed one can tune the 2.0L or the 2.5L engine to 400-450hp, but what is the threshold of this block and internals? Driveability? How about factory fuel consumption, emmissions? You can only tune so much until these things drop off and same thing with increasing turbo size. They bumped the base model from 2.0L to 2.5L in the S model for a reason im thinking that same concept applies to taking the engine to 400hp within porsche's conservative approach. Therefore I think displacement will be increased if they go turbo in Spyder.

The 3.0L 6cyl has the two turbos therefore the gain jump will be easier to achieve over the 718 with its single.

Why would that be? That's not really how turbocharging works. It's easier on a flat 6 to use two turbos since you have 3 cylinders on each side of the engine and it allows you to put the turbine close to the exhaust ports with easy packaging. With a 4 cylinder you only have two on each side which isn't enough for good drivability so you need a more complicated setup with the exhaust manifold to combine both banks before sending the exhaust into the turbo. Larger single turbo instead of smaller twins is not a disadvantage at all.

The reason Porsche tunes their engines to a certain point is primarily to put them exactly where they want them in their range. 718S has to be below 911 base etc. This is also evidenced by the fact that they gave the 2.5L S a twin scroll turbo with variable vanes but not the 2.0L - the car with the lower specific power output getting twin scroll for reasons of hierarchy. If Porsche considers the drivability 150 HP/L on an old fashioned single scroll turbo just fine then 160 on the twin scroll should not be an issue either.

The 6cyl with two turbos will make a larger jump in power when turbos are increased (with driveability) compared to the 4cyl with a single turbo if it has its turbo increased.
This was in answer to claim that the if the 3.0L 6cyl can jump from carrera, to carrera S to GTS power, why cant the 4cly do just as large increases between the 718 models....

Yes, porsche tune their engines to a certian point to put them where they need to be in their model range. But they also detune them for durability, emissions and fuel consumption. Which aftermarket tuners work around. This is why Porsche wont overtune a motor even though it is possible.

No...sorry. As far as the engine is concerned intake pressure is intake pressure. Two smaller compressors or one bigger being responsible for it does not change the amount of air that goes in. A larger single turbo has more mass that needs to be accelerated by the exhaust but a single turbo gets twice the amount of exhaust gas going through it which compensates. The reason for 2 rather than 1 has to do with the layout of a V (or H) engine, not that more of them is better.

Im saying that with two turbos Porsche can get the power increase they desired with the driveabilty etc (as pointed out on the 3.0L) when compared to trying the same thing with the 4cyl with single turbo. Which is what somebody thought was apples to apples earlier in the thread.
If they pump up the single turbo too much in the 4cyl, driveabilty will decrease.

I think this is based on a slight misconception (also see https://www.turbobygarrett.com/turbo...between_turbos )

People have noted that the 3.0 with the power kit/GTS turbos is actually getting to be a bit laggy, even though it is "only" doing 150 horsepower per litre same as the 2.0 in the 718. I think the 718 actually has the superior setup for drivability because its turbocharger has four exhaust pulses to work with rather than three. A 400 horsepower 2.5L with a slightly larger twin scroll turbo with variable vanes will almost certainly be as (if not more) responsive than the bigger flat six in 450 horsepower trim.

When playing with twin and single turbo set ups on my MKIV supra I had a chance to see the pros and cons of both.
Driveabilty was one. And lag of course.

I havent heard of any real notable lag issues with the any of the 3.0L turbos to date.

It is interesting however if the responsiveness would be better in a 400hp 2.5L as you have pointed out. Im curious myself on that.

And you would be wrong - lag is a non issue on the S/X51/GTS (unless you want to lug around in 7th) - the reason Porsche move from 2 to 2.5 to 3 is to give better response at the bottom end of the torque curve. Subaru went the same route with the EJ207 to EJ257.