BMW M135i & M235i TUNING

326 to around 390PS and 525Nm on the F20 LCI (2015 to 2019), and 320 to around 385PS and 520Nm on the earlier F20. On the four-cylinder F40 M135i it is 306 to around 345PS and 540Nm. Those are our own dyno figures, not a supplier's estimate.

A downpipe with a sports cat, and ideally an intercooler and intake, then a file written around what you have fitted. The hardware on its own is worth very little; almost all of the gain comes from the map that follows it. Send us the list of what is on the car and we will tell you what it will make.

Yes, and noticeably so in the mid range rather than only at the top. The factory 0 to 62mph figure improves, but what owners comment on is the way it pulls from 2,500rpm in a higher gear. We can put it on the dyno before and after so you have the graph.

Mechanically, near enough. Both use the same straight-six turbo and the same 326PS state of tune in the F2x cars, in different bodies. They tune identically and to the same figures.

Not for Stage 1. These cars use the ZF 8HP automatic, which has its own torque limiter. At Stage 2 the limiter starts clipping what the engine makes, so the gearbox tune pays for itself, and it also gives faster shifts and a manual mode that holds a gear.

Stage 1 changes no hardware at all, so the car keeps its catalyst and every emissions component and stays MOT-ready and road legal. We keep your original file so it can go back to standard at any point.

Yes. Warranty plans are available to buy separately: see our warranty page. Every remap also comes with lifetime software support.

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.

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.

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.

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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.

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.

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.

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.