Skip advert
Advertisement

This is how to make your M135i sound like an M4

This M135i owner hacked into BMW's synthesised system to make his car sound like a 425bhp M4

Whether we like it or not, the practice of synthesising engine noises is becoming increasingly common in new performance cars. Sticking a turbocharger into the exhaust pathway and improvements to sound proofing have lead to a significant decrease in engine noise, much to the disappointment of many enthusiastic drivers. To claw back some of that aural involvement, manufacturers have resorted to this controversial system.

BMW's synthesised engine noises are played into the cabin through the car's speakers, so in theory, disconnecting your speakers should remove their influence altogether. But it was only a matter of time before someone went a step further and actually modified the synthesised sound.

Advertisement - Article continues below

>Read - BMW M135i review and pictures

In this case, a tech-savvy M135i owner has managed to hack into his system and upload the soundtrack used in the new M4. It swaps the typically smooth straight-six soundtrack for a rougher, harder voice. You can hear it in the video above.

>Read - BMW M4 review, price and specs

If you want to listen to the M135i with its factory fitted synthesiser working, watch our track battle video below. What do you think? 

Skip advert
Advertisement

Recommended

BMW M135 v Mercedes-AMG A35 – which is the best £50k hot hatch?
A35 v M135
Group tests

BMW M135 v Mercedes-AMG A35 – which is the best £50k hot hatch?

BMW’s M135 xDrive has found some much‑needed focus with its new M Dynamic Pack, but is it enough to give it the edge over Mercedes‑AMG’s A35?
11 Jan 2026
BMW M135 xDrive review – all-wheel drive hot hatch eyes Audi S3
BMW M135 xDrive
In-depth reviews

BMW M135 xDrive review – all-wheel drive hot hatch eyes Audi S3

The M135 has lost an ‘i’ and gained chassis revisions and a restyle. Is it enough to make it a benchmark hot hatch?
4 Dec 2025
Skip advert
Advertisement

Most Popular

Citroën C5 Aircross review – quirky, honest SUV offering Range Rover comfort on a budget
Citroën C5 Aircross
In-depth reviews

Citroën C5 Aircross review – quirky, honest SUV offering Range Rover comfort on a budget

When is a generic family crossover not the dullest thing on Earth? When it’s a comfy Citroën glazed in weirdness
9 Apr 2026
Looking for a used performance car icon? Try these – car pictures of the week
Used performance car icons
Features

Looking for a used performance car icon? Try these – car pictures of the week

Does price, a lack of personality and irritating mandated nannying in new cars put you off? Look to the stars of the past…
11 Apr 2026
Honda Civic Type R (EK9, 1997-2000) review – 1990s JDM icon makes a Peugeot 205 GTI look agricultural
Honda Civic Type R EK9
Reviews

Honda Civic Type R (EK9, 1997-2000) review – 1990s JDM icon makes a Peugeot 205 GTI look agricultural

The EK9 was the beginning of the Civic Type R story, but Honda never officially sold it in the UK. Unicorn status on our shores is a given, then
13 Apr 2026