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I thought about a 991GT3 or GT4RS but decided to tune my 981GT4 first with great results
All measured on the same dyno but obviously a few weeks in between. I measured OEM, Softronic tune only and final dyno with all hardware fitted. Runs done on 98 octane (your 93) petrol
OEM 385pk at 6,400rpm; with Softronic tune 396pk at same RPM yet 30NM torque and impressive mid range. Engine breathes through 74mm OEM throttle body which doesn’t allow power to rise beyond 6,400rpm…
Result STAGE 1 tuning at the end of last year:
981 GT4 OEM as measured at JD Engineering: 385.5hp (manufacturer's specification 385hp), torque 433nm (manufacturer's specification 419nm)
So OK but could be better!!
991.1GTS with the same 3.8 engine has 430hp after all…
- OEM lambda value above 5,500rpm good, below that adjusted a little too lean
- Throttle valve all the way 100% open (not restricted by Porsche)
- torque has significant dips at 3750rpm and 5000rpm
- maximum power very early at 6,400rpm (manufacturer specification 7,400rpm) and therefore does not build up to 7800rpm
- Inlet has negative pressure from 4800rpm which is probably due to restricted throttle body/valve 74mm which is 82mm on 991.1 GTS and 991.1GT3
STAGE 1, Softtronic tune only. Result 396hp (385 stock) and 452.5nm (419 stock). This software update is made for stage 2 adjustments including Soul Performance Exhaust Manifolds, Race filters, IPD Plenum throttle body with 82mm throttle valve.
Installed the above “hardware” YESTERDAY and now the engine finally gets 20% more air…
Result stage 1 of first tuning (pure software)
- as you can see torque builds up much more aggressively at low revs; do you really notice when accelerating
- much more ignition advance; 25 to 30 degrees at 4800rpm. This gives approximately 30nm extra torque in the midrange and you can feel it!
- torque and power dips at 3,750rpm and 5,000rpm all but gone
- engine of course continues to lack airflow and there is underpressure in the intake at higher speeds above 5,500rpm despite professional fans placed 20cm from side air intakes
Went to JD Engineering / dyno YESTERDAY to measure the result of stage 2 tuning with the following hardware adjustments:
- engine is OEM mainly restricted by smaller 74mm air intake compared to 82mm GT3 throttle body (valve); only now does the engine also continue to gain power above 6400rpm towards the red line!
- Larger aluminum IPD plenum distributes air over cylinders
- High flow BMC air filters give just a little more flow
- to give the engine more torque, Soul Performance Long Street Exhaust Manifolds were needed with 200 cell cats; great fit and finish, reasonable price and high quality 200cell HJS cats
It took 12 hours to assemble everything combined with a major service, new spark plugs etc.
RESULT:
- 434.7 HP was 385.5 HP so 49.2 HP extra at 800rpm higher
- 480.7 NM torque was 433NM so 48 NM more (and 62NM over OEM spec)
- massive torque dip at 3,800rpm completely gone; about 75NM gain (also at 5100rpm)
- engine delivers max power now at 7200rpm (was 6400rpm)
- under pressure in air intake much reduced beyond 5,500rpm and therefore engine breathes so much better
- ignition advance max 33 degrees; standard 25 degrees.Torque now well above 991.1 GTS and GT3!
- Sound; 10% more sound with PSE/valves closed; 25% more sound with valves open. Much more character, almost sound like engine with carburettors at times
valves open automatically at about 90mph so you have full sound control with OEM backend exhaust!
Super satisfied with 435PK output at 7,200rpm (was 385PK at 6,400rpm) and massive 481NM torque (standard 419NM) at 6200rpm (991.1GT3 440NM also at 6200rpm). Look at impressive 75NM torque gains at 3750rpm and 5100rpm resolving OEM dips)
Thanks, I was also impressed. Torque very good indeed and this really translated in real-world performance
The Softronic tune was flashed while on the dyno late last year so would likely have had a more impressive showing if had given the ECU some 30-50 miles to adapt
I think it really is the combination of a lot more airflow into the engine, the long-tube street headers with cats for optimized torque and the tune to allow for it all to come together
one last detail and something that nicely shows the massive torque:
80-120km/h in just 5.9 seconds in 6th gear
I recorded a 80-120km/h in just 5.9 seconds in 6th gear
for comparison:
- Sport Auto (German) magazine recorded 6.7 seconds 80-120km/h on a stock car so I gained almost a second
- The latest 992GT3 in the Sport Auto test does 80-120km/h in 8.1 seconds in 7th gear, 6.9 seconds in 6th gear and only just matches with 5.7 seconds 80-120km/h in 5th gear. Impossible to compare gear ratios but my GT4 now makes over 400NM from 2.500rpm onwards, latest GT3 reaches 400NM torque only at 4700rpm and takes off like a rocket afterwards….
- GT4s have always produced good low-down torque and I am glad gains made are not only above 6,500rpm
(2.2 seconds as per above screenshot 80-120km/h in 2nd and 3rd gear matches the latest 992GTS turbo engine: light weight will play a role here…)
Now this is a real value thread - very well done. Feel like I need more punch on the track and been debating whether headers/tune is worth it, this provides some nice clarity.
Hello,
Great post with information!
The tune alone dyno that was set up for the mods would have done better as you mentioned since it wasn't driven 30 miles or so and flashed on the dyno. This is done so the DME adapts again as when the Siemens units are flashed they basically eliminate the learned data and start over. They start out low and work there way up and typically it is about 15- 20BHP or so for the stock cars The TQ increases also yet 10 or a bit less. Running it without the driving or learning starts out at the base for the file and increases in which the first dyno shows. The race cars with 100 octane add more yet there is more timing and TQ changes etc for it. In any case its still great increases as shown for with and without the mods and software.
The second dyno worked out well as the car was able to learn with the file being in it and the mods when it was driven to adapt.
Porsche Interseries programmed along with teamed owned Tudor and World Challenge cars in an exclusive with Softronic.
Porsche PCA racing binary check by Softronic for compliance.
Thank you so much for not only choosing us for your upgrades, but for doing testing, tuning, and producing dyno information! This is outstanding all around!
-Mike
__________________ SOUL PERFORMANCE PRODUCTS Quality Exhaust Solutions, Fair Pricing, and Outstanding Service
John Gaydos- Owner, Performance Specialist
Cell - (484) 883-6197 johng@soulpp.com
Nicely done ... love seeing real world data! We are planning the exact same build with the addition of Dundon Intake Headers ... so hopefully we can get similar results. We'll be hitting the track to see how much of a difference the extra 50-60HP will yield!
I was wondering who else tuned their 981GT4 the same way and what their gains resulted in?
happy Easter
Hey, I just wanted to say that I replicated your setup based on this post. Thank you. The thought of having 10NM more torque than a 2022 GT3RS sounded like a good place to be!
I sent my ECU file out to Softronics yesterday, will get the tune back in a few days and then can do some acceleration time testing and maybe a dyno pull eventually.
Looks impressive @LuckyX222
Seems you even replace some of the other exhaust? What did you choose?
would be great if you did a “before” and “after” dyno as well
It's mostly just the Soul street headers. I also replaced the "T" pipe at the exhaust tips with an "X" pipe but that doesn't do much. Otherwise, it's the stock muffler.
I didn't get a dyno before installing everything so I can't do a direct comparison, just after vs the other stock dynos we have as baselines.
01-07-2022, 07:11 AM
Real data: 981GT4 tuning Softronic + IPD Plenum 82mm TB + BMC filters + Soul Headers
