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Anyone here with experience with the Fabspeed performance tune on a 991.2. Have been considering the GIAC option. But wondering how the Fabspeed compares. Also seems as if we are on the cusp of many options being offered as more tuners crack the security on the ECU.
Disclaimer - no experience but just interested in this space. Also - I'm not challenging anything with malice.
For the NA cars - the gains from a tune are greater; although less substantial than the boosted cars, in the S. Higher hp and % gain in the S over the base.
For the #2 cars - The Fabspeed tune shows the greatest gains in the base then S and smallest gains in the GTS. This is interesting to me since word on the street is that they all have the same engine with the only difference being turbos and a tune. With the minimal difference in power from Porsche - I expected the gains to be greatest in the GTS then smaller % in the S and even smaller in the base but Fabspeed is showing the opposite. With only 20 or 30 hp difference going to larger factory turbos, should there not be bigger gains in the higher trims?
I have a different experience. In my experience, the tune result on turbocharged cars is significant and there is much less of an effect from a tune on NA cars.
I moved from a 991.1 to the .2 recently, and never even considered a tune for the .1, the gains were just not worth the price of admission.
I have a base .2 and figure that Porsche de-tunes these cars to show a bigger gain for the S, etc. The aftermarket tunes allow them to exceed the performance of the S for sure. The tune on my base car is very interesting to me for this reason.
I did not compare the Fabspeed and the GIAC, but wonder if the Fabspeed tune is their own, or if they are a GIAC Distributor.
Lastly from what I have read, it sounds like we are right on the verge of many other options coming out that may not require ECU removal. This possibility along with my concern about voiding my warranty have kept me from moving forward at this time.
Absolutely interested in hearing from others on this subject. Hoping to not incite the "pissing match" I have seen on threads with similar topics.
Disclaimer - no experience but just interested in this space. Also - I'm not challenging anything with malice.
For the NA cars - the gains from a tune are greater; although less substantial than the boosted cars, in the S. Higher hp and % gain in the S over the base.
For the #2 cars - The Fabspeed tune shows the greatest gains in the base then S and smallest gains in the GTS. This is interesting to me since word on the street is that they all have the same engine with the only difference being turbos and a tune. With the minimal difference in power from Porsche - I expected the gains to be greatest in the GTS then smaller % in the S and even smaller in the base but Fabspeed is showing the opposite. With only 20 or 30 hp difference going to larger factory turbos, should there not be bigger gains in the higher trims?
Anyone else have opinions about this?
Just curious about your second line and it may be my interpretation of the wording: "greater but less substantial" seems contradictory.
I have many years experience with modifying turbo motors from back in the Toyota Supra days and the gains from a simple boost increase + exhaust back pressure reduction would far exceed anything we could do with a NA motor. (Used to be referred to as a BPU: basic performance upgrade - prior to going too crazy with injectors and big turbos etc).
Disclaimer: i do not own a 991 of either flavour (yet). Over ten years in my 997 Carrera (non-turbo).
The decreasing results in tuning the 991.2 line (from "base" to "S" to "GTS") may be due to the fact that they all run the same intercoolers: you will reach a limit due to intake charge temperature - and need bigger intercoolers to get the same gains in the GTS.
My wording must be off..... Gains from a tune on turbo cars are pretty universally higher than NA cars. My intent was stating the the gains on a 3.8 are higher than a 3.4 yet in the #2 cars the gains on the base are higher than the S and GTS trims despite the same block and larger turbos on the higher trims. Sorry for the confusion.
Should have said the tune is less substantial in the NA cars but a greater affect on higher trims. On the turbo cars the biggest impact is on the base.
I'd bet money fabspeed is white labelling the GIAC tune.
My wording must be off..... Gains from a tune on turbo cars are pretty universally higher than NA cars. My intent was stating the the gains on a 3.8 are higher than a 3.4 yet in the #2 cars the gains on the base are higher than the S and GTS trims despite the same block and larger turbos on the higher trims. Sorry for the confusion.
Should have said the tune is less substantial in the NA cars but a greater affect on higher trims. On the turbo cars the biggest impact is on the base.
I'd bet money fabspeed is white labelling the GIAC tune.
Now I understand - and I agree with your observations.
I am just guessing but i believe there will be a practical limit to what the intercoolers can support - more boost heats the air more (and the base would have the most headroom given they share the same parts) and the same can be true for the fuel injectors. This could explain how the biggest gains are available for tuning the base model. Time will tell.
How about we just stay on topic and focus on facts?
Fabspeed's own power gain estimates would suggest the biggest gains from stock numbers are in the base car. While a tuned S and GTS will be faster, respectively, the state of tune in the base is much lower and will see the most gains. The overall capacity of the turbo's increases as you move into the S and GTS, which will ultimately result in higher numbers. From a tuning perspective, the best option in terms of performance vs. cost is definitely the Base.
The situation with Mercedes AMG GT and GTS is exactly the same. The motors in the GT and GTS are almost identical, with the exception of a dry sum, etc., the RennTech tune produces the exact same power on both models even though the GTS comes in a higher state of tune from the factory.
Further to the gains the tunes are releasing, the numbers should increase considerably when coupled with sport cats or bypass pipes. Ive also heard that there are upgrades planned for IC's as well so these cars, in any trim, should really be monsters. I'm wondering what the limits are going to be with the clutch and transmission components?
The link to PB breaks down the target boost and turbo sizes as follows;
FABSPEED tune:
Base - +105hp and +135tq
S - +90hp and +110tq
GTS - +75hp and 80tq
From ************:
9A2 3.0 991.2 Carrera
Horsepower: 370
Torque: 332 lb-ft
Boost Pressure: 13.1 psi
Bore x Stroke: 91mm x 76.4mm
Redline: 7500 rpm
Compression Ratio: 10.0:1
Intercooler: Air to Air
Turbos: 49mm compressor/45mm turbine
9A2 3.0 991.2 Carrera S
Horsepower: 420
Torque: 369 lb-ft
Boost Pressure: 16.0 psi
Bore x Stroke: 91mm x 76.4mm
Redline: 7500 rpm
Compression Ratio: 10.0:1
Intercooler: Air to Air
Turbos: 51mm compressor/45mm turbine
9A2 3.0 991.2 Carrera GTS
Horsepower: 450
Torque: 405 lb-ft
Boost Pressure: 18.0 psi
Bore x Stroke: 91mm x 76.4mm
Redline: 7500 rpm
Compression Ratio: 10.0:1
Intercooler: Air to Air
Turbos: 55mm compressor/48mm turbine
Now I understand - and I agree with your observations.
I am just guessing but i believe there will be a practical limit to what the intercoolers can support - more boost heats the air more (and the base would have the most headroom given they share the same parts) and the same can be true for the fuel injectors. This could explain how the biggest gains are available for tuning the base model. Time will tell.
This is mostly true, but not entirely. There are two sources of heat - i) the absolute compression of the air forces more air molecules into a smaller space, so it's warmer (more molecules with thermal energy in a smaller space). The act of "beating up" the air to compress it adds even more heat. In general, smaller turbos spool faster but beat up the air more at higher boost. Big turbos spool slower but add less heat at higher boost. The marginal returns get worse and worse because every incremental bound of boost adds a higher proportion of "extra" heat, and it also gets harder and harder to manage with small turbos.
So, going from 13lbs to 16lbs in the base adds a lot of "easy" power because the extra heat function is not too bad in that range. If the Base and the GTS were both running the same 16lbs of boost, the GTS would still produce a bit more power because the compressed air is cooler due to better turbo efficiency. But if you increase boost beyond 16lbs, the difference will widen in favor of the larger, more efficient turbos.
They should publish the before tune and after dyno charts. . The peak boost figures that you quoted are also incorrect for example my X51S has peak boost of 21.7PSI.
Another limiting factor in many turbo cars is the fuel system and its ability to supply adequate fuel to maintain a safe A/F ratio when adding substantial air flow / boost. I don't know if this is the primary limiting factor for 991.2 3.0L engine, but if it is not, it will certainly be a secondary limiting factor.
No experience with them or axe to grind but I find the Fabspeed always has these over the top claims for HP. Same crazy claims with just an exhaust.
I have had Giac on a former TT, a custom tune from EPL on another TT and Cobb on my previous 991.1 4S Look for the known tuners with track record that make real life gain claims.
Turbo cars are much more tune friendly. NA tunes basically help with throttle response and a little earlier kick in the Power band.
As usual you muddy the waters in 991.2 tuning threads. It's unfortunate this continues.
The reason the 991.2 base car sees the greatest gains is because it is in the lowest state of tune. Only 13 psi compared to the S at 16 psi and the GTS at 18.0 psi.
Despite the larger turbos the GTS is in a higher state of tune and therefore will hit higher peak figures than the base or S but not as large of max gains in comparison.
Care to back up your claim with evidence for once?)
I always do Fancy as I did with Sticky....
1Hz data logging from Porsche SC. Red line is boost, scale on left hand side. So a peak boost of 21.9 at an elevation of 600ft for an effective compression ratio of 24.8:1. Carrera SX51 and this is not a fast track.
Heres another one delta time graph X51 Vs S (peak boost 19.8PSI)
And to reinforce a point, the dyno chart for the GTS/SX51
At the end of the day you can't fully unlock the ECU so you can never deliver the full Porsche experience which includes linkage with PDK and PTV-E, along with linear power delivery.
the reason is it’s the lowest state of tune? So.... the tune is the only difference and not the smaller turbos?
This is my impression. Not sure if I am mis-informed.
My impression is that Fabspeed's specialty is performance exhaust, not chip tunes. Additionally the reported gains are similar to what GIAC claims. This leads me to believe that they are simply a re-seller for GIAC.
Would love to hear some real world reviews of the Fabspeed offering if they are out there.
11-29-2017, 11:23 AM
Fabspeed Tune for 991.2
. The peak boost figures that you quoted are also incorrect for example my X51S has peak boost of 21.7PSI.
