718 Cayman GT4 is here – at long last.!

[Motorhead]

Although I sympathise with your view Paul, I doubt that you'll find many base spec Porsche sports cars around and I'll bet that most GT4s included a minimum of £5k of options - probably nearer £10k.

Your GTS was a very well spec'd car in the first place, as is the GT4, but often it's the small things that can make a big difference to ownership, and Porsche options are all very expensive. Personally I find it difficult to accept that in a £60k+ car basic things like cruise control, auto wipers and dimming mirrors, climate control, parking sensors and folding mirrors are optional items, but it's just the way the premium car market operates.

On another subject, here's a pic of the bulky silencing/emmision control arrangement on the GT4.

Jeff

 

[ralphmusic]

Jeff,

Some clearer images

Not all that complicated

 

[MrDemon]

but very minor - issues about gearing and weight.

Jeff

Gearing ruined the car, fullstop.

the new cars now torque limited on top of the long gearing.

I want to drive exciting cars not just great cars, the 992 GT3 will be base £120k, The GT4 at base £85k with a proper gearbox would be a none issue.

They again have made a class leading great product, alas it won't be a very exciting product. (it might be in PDK form though)

will they just add PDK or will it be an RS at the end of the run ?

 

[Motorhead]

Jeff,

Some clearer images

Not all that complicated

Thanks Ralph - that's much clearer.

Yes, I suppose that the arrangement looks rather odd because of the need to provide space for the diffuser under the silencer. I presume the rearmost cans contain the GPFs or a combination of cats and GPFs.

By the way, weren't we expecting some additional info (tech data/pics perhaps?) from Porsche today?

Jeff

 

[ralphmusic]

By the way, weren't we expecting some additional info (tech data/pics perhaps?) from Porsche today?

Jeff

What can I say, the vbloggers broke the embargo!

I understood that there were to be some serious road and track tests released today but can't be right all the time

There is a lot of "stuff" in the link I PM'd you although I haven't had time to plow through it all - I think there was an image of the new injector arrangement for instance.

Ralph

BTW, your avatar, did you miss the white block?

 

[Motorhead]

Yes, certainly there's a lot of info there Ralph, and thanks for sharing - a pity it's not categorised better. I was hoping for a pic of the rear suspension and maybe some engine power and torque curves.

I managed to miss the block by setting the rudder hard aport..!

Jeff

 

[ralphmusic]

Jeff,

Look for the PCNA Press Kit, some detail in there. Product Facts/718/718 GT4

Ralph

 

[Motorhead]

Many thanks Ralph.

There's not much in the Press Kit that hasn't been cut and pasted into the hack reviews, but I did notice a couple of snippets regarding the new engine:

"a generously sized crankshaft main bearing with a diameter of 67 mm (up from 63 mm on the 2020 911 Carrera S) provide a sturdy base"

"To make high engine speeds of up to 8,000 rpm possible, rocker arms with hydraulic valve clearance compensation operate the valves. The electronic engine management system adjusts the timing of the four VarioCam camshafts according to load requirement and engine speed"

So, a stiffer crank than that in the lower-revving turbo engine, rocker actuated valves like the GT3's, and although there's variable valve timing on inlet and exhaust this time, there's no mention of variable valve lift (I'm not sure if the GT3 has that?). On top of that, in the Catchpole interview I think AP mentioned that the cylinder block castings are different from the turbo engine, so with the heads being different too it really is a new engine. The single "saddle" rear silencer of course replaces the two individual units used on the 981 and will have had an effect on the exhaust note.

One other thing I've noticed: although the Chrono Package is standard on the Spyder it's a £336 option on the supposedly track-focused GT4. Very odd.!

Jeff

 

[Twinfan]

This was posted on Rennlist, created from press info etc I think so not entirely accurate but is maybe close enough?

 

[ralphmusic]

Jeff,

With a 11mm larger bore, you'd hope they used a different block. []

Below is a PCA Panorama article describing Sharkwerks' 4.1L GT3 engine upgrade where the cylinder walls were down to just over 1mm after the rebore from 3.8L.

I put this modification story in one of my pieces a while back in the Modified Section of PP.

Go to "View" in browser and enlarge the page/font a couple of times and it is possible read it if your sight is good enough to drive a Porsche [8|]

Ralph

 

[Motorhead]

Thanks chaps - I've got blurred vision trying to sort out the appropriate power/torque plots and trying to read the piece (in expanded view) on the Sharkwerks GT3 engine upgrade..!

Dave, certainly it looks as though the new engine's torque characteristic is more progressive than its predecessor, and stronger at higher revs, and is accompanied by a useful power increase at the top end.

Ralph, I think the new engine's bore and stroke mimic those of the 4.0L GT3, requiring a significant over-bore compared with the 3.0L turbo engine and necessitating more meat in the block.

A 1mm wall thickness after the 997 GT3 engine rebore sounds alarmingly marginal to me, but I'm sure Sharkwerks know what they're doing.

Jeff

 

[Brian_Innes]

For Brian, What do you think of this lap of Knockhill?

[tube]https://youtu.be/p58a00SzytQ[/tube]

Ralph,

Thanks for posting yet another brilliant video clip, this time with none other than Walter Röhrl at the helm of the 982 GT4 at Knockhill. Nice smooth relaxed laps.

Walter's lines are pretty much spot-on. I noted he used 3rd gear for turn 3, Scotsman corner, as I did when competing in the sprint championship with my Cayman R. If Walter had been going for a lap time, he would probably try 2nd for turn 3 with the GT4's long gearing. This has the disadvantage of a tricky down-change to 2nd at the bottom of the dip while changing direction for turn 3, followed by an equally tricky up-shift to 3rd at turn 4 approaching the chicane. I have tried both with the manual gearbox, and allotted to stay in 3rd as Walter did. With PDK it's an entirely different lap. The quick flick down-shift to 2nd at turn 3, followed by a full throttle up-shift to 3rd approaching turn 4 makes it an easy corner combination to gear for.

I thought Walter Röhrl as a newbie did a pretty good job of Knockhill. As you would expect from a world champion driver. I timed his lap at 58.8 seconds. Not bad for his first acquaintance at this challenging track. I wish I had been there to see this track test.

Brian

 

[ralphmusic]

Brian,

Older guys Rule!

 

[ralphmusic]

Jeff,

A video discussing the engine..

[tube]https://youtu.be/kD2V_Wa7fic[/tube]

Ralph

 

[MrDemon]

Jeff,

A video discussing the engine..

[tube]https://youtu.be/kD2V_Wa7fic[/tube]

Ralph

So close , all that work on a new engine, to then have the same gear box !! very frustrating.

Spyder wins as a buy this time round, we will have to wait to see what the GT4 PDK brings, might even be an RS.

GT4 seems to lack that magic GT D&A this time, before it was the manual choice in a PDK world, this time round I don't get it.

Now the Spyder been given a bit of GT D&A

Engine sounds a great unit though, held back AGAIN by the gearing now more so as torque limited :-(

 

[ralphmusic]

The 981 GT4 has torque limiting, as do the Base, S and GTS 718 and 981 series versions

 

[Motorhead]

Quite so Ralph, and thanks for the link. So it's a 982 clutch with the GT3 DMF coupled to the standard Getrag transmission - much to D's chagrin.!

Fabian Zink provides some useful insight into the challenges of raising the rev limit by a relatively small 500rpm and confirms where a significant part of the new GT4's development budget and engineering effort went - and it wasn't into the transmission.! Most of the details he mentioned were known already but he described something about a bearing which is a mixture of series production and GT technique (?) - unfortunately the recording is a bit garbled and he reverts to German so I couldn't really get the gist of what he was referring to.

Also, he all but confirmed that the engine will definitely be used in other cars, so expect to see it in the Boxster and Cayman and maybe in a 992.

Jeff

 

[ralphmusic]

Jeff,

I didn't get the full meaning of the bearing reference. When he referred to vibrations, I thought 'harmonics' which talks to better balancing of internal reciprocating parts.

Another aspect of the new/old car - gearing - I thought Brian's comments about Walter Röhrl's gear selection at Knockhill versus Brian's Cayman R was interesting. I have to say it rather supported Mr D's preference for the greater involvement with a manual gearbox, you have to pick the right gears for the circumstances and one 70mph corner might require one gear and another 70mph corner might require a different gear.

 

[Motorhead]

Could be Ralph. Maybe we'll get more insight when production begins and Porsche issue more engine-specific details.

Gearing's always an issue/compromise when you have a fixed set of ratios and the latest PDK transmissions now have 8-ratios compared with the 7-ratios of the previous generation. It's the same with other manufacturers and I believe that the next VAG DSG transmission will have 9-ratios; all emissions and fuel ecomomy-led of course.

I reckon we're seeing the beginning of the end end of the manual 'box (who wants to try shuffling 7 or 8 gears manually?) and it's unlikely that it'll feature in any hybrid car. Mind you, it all becomes irrelevant with EVs.

Jeff

 

[ralphmusic]

Looks rather nice.. makes you wish Porsche were more adventurous with styling..