I'm looking to move to a new turbo (from a 997.1TT) to a 991 Turbo. Are there material differences between a 2016 and 2017? I know there are for the C2 and C4, but I don't know how the engine for the Turbo was changed between the years. Any help would be appreciated.

 

yes , 991.2 tts turbos are different, fuel injection is different, to what extend i do not know.

 

They changed quite a bit , higher pressure injectors , new fuel pumps , revised air intake, revised head work in the motor, new larger turbos , and an anti lag system which is active in sport plus. (holds boost for around 3 seconds after lifting, very effective and noticeable . ) The .2 is considerably faster from a roll and traps higher than the .1 as well. My baseline testing showed it does a 7.5 sec 60-130mph and 10.49 @131mph and 159mph 1/2 mile trap all on zero slope . Heat soak in stock form is a non factor as well, as i showed no degradation in performance even after 3 consecutive 1/2 mile runs on a warm day.

 

Interesting changes on the .2 for sure and even better with the real world data you provided. I been tossing the idea around of jumping from the 997 to a 991. The .2 seems to be the ideal platform.

 

Don't mean to jack the thread but
Curious if anyone can shim in on the difference in pdk from
A 997.2 to 991.1 or 997.2.

The price delta of 997.2TTS & 991.1TT preonwed is tighning up if you don't care about ceramic stoppers.

 

I wonder if they can retrofit the antilag into the 991.1 Turbo/Turbo S

 

Not sure about the antilag but all the other changes I'm sure can be retrofitted. Antilag may be software change though.

 

There are sensors directly on the larger .2 turbo as well as elsewhere to monitor flows / pressure to make the system work as well as mechanical changes to make the engine tolerate more heat , including inconel valves and a higher heat tolerant turbo wheel alloy . Obviously the ECU tuning is vastly different as well. Not really workable and definitely not cost effective IMO .

 

Excellence Magazine June 2016 pp 56 & 57

 

Good read. It's neat to see that a 2mm diameter increase in the compressor wheels make the extra 40HP in the turbo S. It's good to know that both the TT and TTS have the exact same maximum boost pressure which tells me that I can put after market parts on a TT and not worry about over boosting the engine!

 

[QUOTE=HotHonda;4577081]Excellence Magazine June 2016 pp 56 & 57

Thanks hadn't seen that. The .2 is def all about refinement of the .1. Other "hidden" improvements ive noticed are lining of the plastic inter cooler tracks, I suppose to minimize heat. Also additional air inlets within the intake air box to name a few.

 

I read it differently - and I may just be misreading your post. I understood it to say the S is programmed to build an extra 0.2 bar of boost, TT->1.0 bar and TTS->1.2 bar, and both cars additionally have +0.15 bar of overboost.

Since atmospheric pressure is about 1.0 bar, the TT manifold pressure would peak at 2.15 bar vs. 2.35 bar for the TTS. The pressure ratio is 2.35bar/2.15bar=1.093, but the rated engine power ratio is 580hp/540hp=1.074. So the TTS uses 9% greater manifold pressure to make 7% more rated power.

While the turbocharger has been tweaked, it looks to me like the ECU programming is where the S finds nearly all of the extra 40hp.

 

I went back and re-read that article, and realized that I've misread something. If I'm understanding this correctly, the only big difference in the two turbos, TTS vs. TT, is that the compressor on the TTS is 2 mm greater in diameter (56mm vs 58 mm). The turbine is the same size on both turbos at 50 mm. Due to the TTS's greater compressor size, its maximum boost pressure is 17.4 PSI vs. 15.5 PSI on the TT (this is the part that I've misread-the difference in the max boost pressure). My understanding, according to this article, is that the extra 40HP on the TTS is produced by the "bigger turbo" (in this case, extra 2mm compressor). Can the extra 1.9 PSI boost pressure increase the HP by 40 horses on a 3.8 liter engine? I believe so. My S6 has a 4.0 TT engine and with a 5 PSI increase, I've gained an extra 80-100HP/100ft-lbs of torque. Porsche engineers may or may not have tweaked the TTS's ECU as there's no mention of it, so I just don't know.
Another interesting thing that i'm seeing is how minor the gains (40-50 HP, if that) are with a stage I tune on these vehicles, which leads me to believe that the Porsche engineers are nearly max performing these engines and it's components to achieve such stellar performance. On other VW group (and others) vehicles with turbo & supercharged engines, there's quite of bit of room for improved performance using simple ECU/TCU tunes and piggyback modules.
Interesting and fun things to ponder for the gear heads!

 

Sounds like you had fun with the Audi!

Sadly, while the 991.1 TTS had +40bhp over the TT the hardware was identical, so a reflash makes the power of a 991.1 TT and TTS equal. The pay-to-play is very strong. Because of the numbers, my suspicion is the impact of the 991.2 TTS turbocharger difference is quite minor and the different boost targets (ECU program) are still the primary reason for the extra power over the TT.

With the 991.1 the stock TT/TTS exhaust system was the bottleneck, and the intercoolers were the next thing to upgrade after it. Since those were largely carried over I expect the situation won't change.

Some power figures for you, Cobb is similar:
http://rennlist.com/forums/991-turbo/917596-991-2-tt-vs-tts-specs.html

 

If that's the case (ECU doing the work), that's even more reason to save the $$ and just buy the TT. With the $20-30K savings, I can spend that money towards mods.