groundhog

Around 510 but thats just splitting hairs

arter

430/(370/450) = 522.9

groundhog

Assuming peak is at same rpm - thus losses are similar
370=450-80
450+60 gain = 510
430=510-80

510 at the crank is a respectable gain as peak - but the more interesting gain is that measured across the whole torque curve

Has yours in stock form ever pulled timing or boost during a hot track session? as yet mine hasn't.

arter

Understand your calculation, but....

You used a loss factor of 60 for the base (310 wheel on MAHA), 70 for the S (350 wheel MAHA), and 80 for the GTS ( 370 wheel MAHA).
So I would expect an increase in loss factor at 430 wheel hp MAHA to say 100? (310 to 370 jumped 20)
So again crank now is 430 plus 100 equal to 530hp?
Okay, just playing with you.....

I will go by the mustang dyno adjusted to look like a Dynojet that COBB is using as that is what we use here in the colonies...
I would be what I wouild use to check permformance with.... using delta over stock.

Last question, no sign of pulled timing or boost at the track. Oil temps never got above 248F (120C) even on a very hot day (103F).

groundhog

Actually you're right I probably should have used something like 90

Mine has never pulled timing or boost at similar temperatures - it generally gets up to 120C if a track is dominated by third gear and thats running pretty hard - drops quite quickly when off the ham. Haven't gone past this but its starting to get up there (I'd be getting twitchy at 130C/~266f).

From the track perspective I wonder how much extra heat is generated as a function of the new tune, plus the loading on the stock intercoolers, plus engine/transmission oil temps - something to think about. In fact, gut feel is cooling may be behind Porsche limiting the crank HP of the next gen GTS to 475HP (supposedly and inline with the hardware being unchanged).

Wont matter for the road guys but the track guys may need bigger intercoolers and an additional oil cooler.

arter

I added the 3rd front radiator to my car. Not sure I need it, but should help.

Used to overheat my cayman on track in the summer......


GT2RS has a misting system for its intercoolers..... good for 40 minutes, then it drops 80 hp when it runs dry.
Dont think I will go there.....

groundhog

Sensible move, very cheap insurance

LavaGTS

If you could ever find this article please post it up here somewhere. I'd really like to read that.

Cobb, can you chime in on the accuracy of the stock boost gauge? How far off is it?

tango131

I'm with you nino. All I've seen indicates the internals of the engine are identical between carrera and S models, including information straight from Porsche's "Technical Service Manual":
***
p. 11:

Connecting Rod
The connecting rods of the 911 Carrera model year 2017 are forged, and cracked
with a length of 138 mm. At 22 mm, the diameter of the connecting rod eye is
unchanged compared to the predecessor.

p: 12:

Aluminum forged pistons of 91 mm in diameter are installed in the engine of the 911 Carrera model year 2017. The diameter of the pin eye is 22 mm, the same as that of the predecessor engine. The first ring groove is hard anodized due to the higher loads. The part number, tolerance class and installation position are marked on the piston crown.
Repair
The procedures in the Workshop Manual relating to the position of the arrow marking and the data matrix code must be observed during installation.
Piston rings
The piston rings are CrNi reinforced to increase resistance to wear.
The piston has three rings:
1 Steel plain compression ring
2 Stepped taper-faced ring
3 Three-piece oil scraper ring

****

There is nothing in the technical service manual noting any differences for any internal engine components (crank, rods, pistons, cylinder linings, cylinder heads, etc.) between regular and S models. the displacement, bore, stroke, compression ratios and throttle body are all identical between engines. The manual does note throughout any other differences between models for turbo size, brake calipers/rotor size differences, etc. the S does have a 3rd radiator with PDK,and is standard in hot climates (ie middle east, tropics, etc.)

So if there are any engine differences between models, they are not noted in Porsche's technical services manual (and I suspect they would be).

Cheshi143

Here you go, link to the genuine parts catalog, let me know if you need help using it.

https://www.porsche.com/usa/accessor...originalparts/

groundhog

Go to 6 minutes 30 seconds - If I have time I'll track down the article.

There are two part numbers for pistons - each come as a set of six
these are 9A2 103 930 00 x identification and 9A2 103 930 50 x identification

COBB Tuning

It seems to be pretty accurate.

-Mitch

tango131

Interesting. the parts manual does show two part numbers. But the Sunset porsche parts website (https://www.sunsetporscheparts.com/o...on-9a210393000)
shows the following for 9A2 103 930 00:

THIS PART FITS
MakeModelYearBody & TrimEngine & TransmissionPorsche9112017Carrera, Carrera 4, Carrera 4S, Carrera S, Targa 4, Targa 4S3.0L H6 - Gas

So seemingly both regular and S models.

I wonder of the 9A2 103 930 50 part is just an updated part number for both regular and s models?

windblow

If you look closely at the parts catalog, 9A2 103 930 00 is just for the set of pistons and 9A2 103 930 50 is the complete set of pistons + rings + circlips. Sunset says the Base, S, 4, and 4S use the same pistons part number.

Valvefloat991

I have compared the stock boost gauge with the OBD readings using the Torque App. The boost gauge is pretty accurate, unlike the water temperature gauge and, to a lesser extant, the oil temp gauge.