GKR Performance

09/06/2026

05/06/2026

Mahle air filters trusted by GKR. OEM-quality fitment, reliable engine protection, and excellent filtration for everyday driving.

31/05/2026

BMW F31 335xd (2014) — 403.5hp With The DPF Still Intact

A lot of people will tell you that 400hp+ on a 335d means removing emissions equipment.

This car proves otherwise.

📈 Independently tested at Surrey Rolling Road, producing:
🔺 403.5hp

All while retaining a fully functional DPF system.

Modifications are straightforward and sensible:

✅ Intercooler upgrade
✅ Engine calibration
✅ Transmission calibration
✅ EGR optimisation
✅ Swirl flap optimisation
✅ DPF retained and fully operational

No smoke maps.
No disabled DPF strategies.
No shortcuts.
Just a properly calibrated setup designed to make reliable power while retaining the systems BMW engineered into the vehicle.

One thing often overlooked is that a healthy DPF is not the restriction many people assume it is. When the engine, turbochargers, sensors and calibration are all working together correctly, there is still plenty of performance available without removing it.

This result was achieved with the DPF remaining in place and functioning exactly as intended.

Independent dyno figures are always nice to see because they remove any doubt and provide a completely unbiased result.
403.5hp.
DPF retained.
Verified independently.
Real calibration.
Real protection.
Real results.

+

18/05/2026

BMW F31 320d LCI (B47) — Stage 1 Calibration
Stock hardware. Stock drivability. Just done properly.

This 320d LCI came in completely standard, factory rated at 190hp / 400Nm. Before calibration, we carried out full logging and dyno testing to confirm the car was healthy mechanically and performing as expected.

📊 Results:

Stock:
🔹 189hp
🔹 413Nm

GKR Stage 1:
🔺 226hp
🔺 513Nm

The virtual dyno data and dyno printouts correlate extremely closely, which is always a good sign of a healthy setup and accurate calibration.

This car also received our usual supporting calibration work including:

✅ Correct torque model calibration
✅ EGR optimization with DPF regeneration strategy retained
✅ Swirl flaps left fully active
✅ Factory safety and thermal protections retained.
✅ Additional enhanced protection strategies where beneficial

No disabled safeguards.
No “flash and hope”.

Just smooth, factory-like drivability with a substantial increase in usable torque and power throughout the rev range.

The result is a car that feels exactly how a 320d should have left the factory — responsive, efficient and properly calibrated.

Real calibration.
Real protection.
Real results.

08/05/2026

Something that’s been interesting recently…

We’ve had a few customers contact us lately who are now well over 100,000 miles on their GKR calibrations without issues — including a couple still running software originally done back in the GBW days.

Considering how much discussion there is online about tuned cars “not lasting”, it got us thinking.

It would actually be really interesting to hear from people running our software:

📍 How many miles have you covered?
📍 How long have you been running the tune?
📍 What vehicle is it on?

Whether it’s a daily driver, weekend car or full build — drop it in the comments 👇

(GKR or GBW software both count 😄)

01/05/2026

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24/04/2026

The fastest x1 previously virtual dyno ran at 360hp was on our new 4wd linked dyno today.

This is the tune it's been running the past year. M50d injectors next, watch this space 😎

24/04/2026

BMW 3-bolt fl**ge to 90mm V-band turbo adapter for GTD2056, GTB2260 & GTB256. Fits M47, M57, N57 engines. For turbo conversions & builds.

20/04/2026

We now offer live chat on our website 👋

Visit us here: https://www.gkrperformance.co.uk/ to speak with our team or leave your details if we’re not available, and we’ll get back to you as soon as possible.

GKR Performance is an established tuner based in Oswestry. We've built our reputation from groundbreaking work on Diesel BMWs. We serve clients across the UK & Europe with our premium-quality service and complete customer satisfaction.