GT4 Dyno Runs 981 & 718

[ralphmusic]

Posted in Rennlist from BGB who have been modifying and running track and race Caymans for 10 or more years.

First 718 v 981 road GT4 (Stock GT4 on chart). 718 engine showing much more even power line holding up better at high revs.

...and below 718 road v Clubsport versions showing new 4.0L closely tracking higher tune level old 3.8L.

 

[Twinfan]

Thanks for this Ralph. I think that explains why I find that the standard 981 GT4 feels 'strangled' - that torque curve says a lot.

It also shows what I, and I'm sure you, feel with the new 4.0 engine - linear power throughout the revs.

 

[Motorhead]

Yes, the 981 vs 718 [and by implication the Clubsport] comparison is illuminating and highlights the 'holes' in the 981 power and torque curves. How does the 718 power delivery compare with your modded 981 CS Ralph?

Clearly the race car tune has influenced strongly that of the 718. I presume Porsche plan to use the 4.0L engine in the next Clubsport provided durability can be maintained?

Jeff

 

[Twinfan]

I've just seen a post on Rennlist showing these charts, and they have some extra info:

718 GT4 Clubsport Race Car (98 Octane) vs. 718 GT4 4.0L Street Car (93 Octane)

So the race car is on higher octane fuel, has no GPF and less restrictive catalytic convertors. I'm glad we got the new 4.0 rather than the old 3.8 + X51 in the road car!

 

[Motorhead]

Dave,

As you're probably aware the US uses a different octane rating (PON) from Europe (RON), with US 93 octane being the equivalent of our 97/98 super unleaded. Presumably their 98 octane is race fuel, making the 718 vs race car comparison even more impressive.

Jeff

 

[Twinfan]

Yep, indeed.

At the first time of driving the new 4.0 at PEC I could immediately tell it was a 'better' engine - I think it's a really good unit and I suspect those folks picking up GTS 4.0s in the near future are going to be very impressed!

 

[AndrewCS]

Thank you for the information, as a new (700 miles) 981 owner I see that I have a few `holes` to manage Has not been that obvious so far, I certainly feel the kick off at 3800rpm but not really the dip thereafter.

 

[snowy999]

This also done by BGB shows its stage 1 GT4 (headers, air filters, IPD and throttle body) vs standard. Shows how much Porsche left on the table, I understand that the tune is a big part of it. Still a big drop off at the top end vs the 718 and clubsport. On the 718GT4 clubsport they use difft cams and intake I think....the dynos above show why the new GT4 is beating the old one in standard form, such a flat torque curve.

[attachment=BGB stage 1 GT4 vs std June 18.jpg]

 

[MrDemon]

3.8 x51 for the win then.

Such a shame Porsche did not offer this to punters.

 

[Twinfan]

3.8 x51 for the win then.

Such a shame Porsche did not offer this to punters.

I've just seen a post on Rennlist showing these charts, and they have some extra info:

718 GT4 Clubsport Race Car (98 Octane) vs. 718 GT4 4.0L Street Car (93 Octane)

So the race car is on higher octane fuel, has no GPF and less restrictive catalytic convertors. I'm glad we got the new 4.0 rather than the old 3.8 + X51 in the road car!

 

[ralphmusic]

Chaps,

The 3.8L will not meet Euro 6d-Temp regulations never mind Euro 7 required for certification of new models from end-2021. It was at the end of it's life, the 4.0L is at the beginning. The 4.0L technology changes v 3.8L are for both manufacturing and efficiency benefits and as such are common among the current 992 generation.

 

[MrDemon]

3.8 x51 for the win then.

Such a shame Porsche did not offer this to punters.

I've just seen a post on Rennlist showing these charts, and they have some extra info:

718 GT4 Clubsport Race Car (98 Octane) vs. 718 GT4 4.0L Street Car (93 Octane)

So the race car is on higher octane fuel, has no GPF and less restrictive catalytic convertors. I'm glad we got the new 4.0 rather than the old 3.8 + X51 in the road car!

the 3.8 x51 will do 435 BHP all day long with Cats and high torue if the gearbox was not limited lol.

the engine the 981 should have had, I agree the 4.0l is maybe a better unit now, but the 981 needed that 3.8 X51, the cars far to over rated as it stands.

really looking forward to the GT4 RS PDK and see if Porsche dare unlock the cars.

because atm the 4.0 GTS PDK is the car to own over a GT4, even on track !! which is daft.