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The 991 GT3 leaves the factory with 475hp and 440Nm in 3.8 form (991.1) and 500hp and 460Nm as the 4.0 (991.2). Our Stage 1 calibration takes the 4.0 to around 525hp and 485Nm, and the 3.8 to around 500hp and 470Nm, with the main gain felt in mid-range response rather than a headline peak. Paired with a valvetronic exhaust you keep a quiet setting for the road and open it up when you want the flat-six heard. Every car is baselined and proven on our 4WD linked dyno before it leaves.
PORSCHE 911 GT3
EXHAUST & TUNING
911 - 991, 991.2
At JF Automotive, we focus on maximising your Porsche’s performance. Our ECU tune for the 991 GT3’s flat-six engine 4.0L unlocks the power you expect from a GT3 model, while ensuring smooth drivability. Though some critics say early 991.1 models lacked punch or reliability, we can fix that! With our professional tuning, you’ll enjoy better responsiveness and an exceptional driving experience. Let us enhance your Porsche’s performance and take your driving to the next level.
We use the latest technology and our extensive experience to fine-tune every engine, providing a custom solution tailored to your needs. At JF Automotive, we are passionate about cars and committed to delivering the best possible results for our clients. Trust us to enhance your Porsche’s performance and upgrade your driving experience.
JFA Stage 1 Tuning + Valvetronic Exhaust - 520BHP / 525PS
Our calibration increased both power and torque across the entire rev range with noticeable an extra 50Nm at the wheels in the mid range.
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- Porsche GT3 Tuning Dyno Graph
Please note this dyno graph shows raw data measured at the wheels. Our system then calculates drivetrain losses to produce engine power figures.
Porsche 991 GT3 Stock Results
Porsche claim 500BHP and 460Nm for the 4.0L, yet the initial dyno runs and data logs revealed that it is actually producing around 501BHP and 466Nm torque. Let’s also not forget this engine is produced by Porsche’s motorsport division, hence it’s a stonker of an engine!
We recorded the power figures on our Mustang 2000BHP AWD linked dyno which measures wheel horsepower and torque, and then we apply our estimated drivetrain percentage loss to these figures which gives an estimated flywheel power.
Porsche 991 GT3 Engine Tuning Options
Direct ECU Remap: We developed a direct ECU calibration to the engine’s Bosch ECU. We download the factory engine and gearbox software from the ECU’s and get to work re-calibration many map tables to unlock more power. Alex Branch one of our in house software engineers gets to work making a few adjustments while maintaining all the safety maps built in by Porsche.
Porsche 991 GT3 Engine Tuning Tuned Results
520BHP and 473Nm! Enough said.
Ok so that’s the peak numbers we have seen on the dyno and while they might look that impressive the mid-range torque increase is 50Nm at the wheels….thats where the magic happens!
Eoghan May and Alex Branch run the vehicle on the dyno and on the road while data logging and checking how the tune performs ensuring it’s safe. The engine is running beautifully and the car drives like a factory-finished product.
Questions we get asked
How much power does a remap add to a 991 GT3?
The naturally aspirated flat-six is already highly tuned, so gains are modest compared with a turbocharged engine. Expect around 25hp on the 4.0 991.2 and a similar figure on the 3.8 991.1, with a stronger mid-range from revised ignition, cam timing and throttle mapping. We always confirm the figures on the dyno rather than quoting a number.
Is the tune done through the OBD port or does the ECU come out?
The 991 GT3 ECU can be programmed through the OBD port, so there is no need to remove it. We read the original calibration, keep a copy on file, and can return the car to standard at any time.
Can the valvetronic exhaust be fitted at the same time as the tune?
Yes. We fit the exhaust first, then calibrate the engine with it in place so the fuelling and ignition suit the new back pressure. Fitting and tuning are normally completed in a single visit.
Do you offer a 12 month warranty?
Yes. Warranty plans are available to buy separately: see our warranty page. Every remap also comes with lifetime software support.
What is motorsport use?
Motorsport-exclusive components are explicitly designed for track use. While they can be installed on any vehicle, it’s important to note that using such parts renders the vehicle unsuitable for road use and may result in MOT failure.
Will the lifespan of my engine be reduced?
No! Our remaps are designed specifically to improve the performance of your vehicle whilst remaining within the tolerances of your vehicles’ components.
Sadly, in attempt to achieve ‘big numbers’ some other companies over tune engines, placing excessive stress on the engine, transmission, cooling systems, etc, leading to reduced life span and reliability of the vehicle. We pride ourselves in producing reliable remaps which do not over stress your vehicle but still produce impressive results.
What is covered with the 30-day money back guarantee?
In any case where a customer is dissatisfied with any remap software covered by the guarantee, within thirty days of the supply date, the customer can request their money back. In order for any refund to be processed, the customer must present their vehicle to our workshop and allow our technicians to restore the vehicle to its original state. On successful completion JF Automotive will refund the cost of the remap to the customer.
No refund can be granted unless the vehicle is returned to the original state by JF Automotive. The 30-day money back guarantee covers Stage 1 remaps, EGR, DPF and AdBlue software deletes, gearbox tuning (not BMW xHP) and economy remaps. It does not cover Stage 2, Stage 3, pops and bangs, xHP gearbox tuning, parts (including plug-in modules such as the Speed-Buster) or dyno sessions.
If another modification is purchased alongside a tuning file, which relies on a remap to operate, only the cost of the file is covered by this guarantee. We reserve the right to withdraw this 30 day money back guarantee.
Can the remap be reversed?
Absolutely. We offer this service free of charge if the vehicle is brought back to us. We’ll be very surprised if that’s what you want after taking one of our remap products, however in the case of lease cars some customers prefer to put the car back to standard before returning the car. You might want it back to standard if you are visiting a dealer for warranty or service work, again we will do this for free. Should you lose your tuning files due to dealer actions or parts failure we will be happy to re-install the map onto your car free of charge where possible.
What if a main dealer wipes the map with a software update?
No problem, simply bring the vehicle back in and we will take a fresh read of your ECU and write you a new map file free of charge. We offer this as part of our lifetime software support.
Do I need to notify my insurance company?
Whilst the remap is undetectable to dealer equipment, you should notify your insurance company of any modification to your vehicle. Many insurance companies do not penalise you for upgrades of this nature, particularly if you’re tuning for increased economy however a failure to disclose modifications may invalidate your policy. You may wish to enquire with your insurer if the modification will affect your policy prior to choosing one of our services.
Why we don't you offer ECU remapping for £200?!
We get asked, “Why do some tuners charge as little as £150?” There are a few factors as to why we do not offer remapping for £100-£200!
We supply custom written files for each vehicle that we remap that take in to account condition, milage and customer request of each vehicle. Our services are fully insured with a 30-day money back guarantee and lifetime support for the tuning software supplied. We constantly invest in the most up to date tuning and diagnostic equipment and software and we offer a quality service to all our customers.
Overall our custom supplied tuning software is of the highest standard that we know of, so if you want the best of the best, choose JF Automotive.
