ECU remapping attracts a lot of second-hand opinions. Some are based on bad experiences with poor tunes, and some are just out of date. Here are the questions we get asked most at our Hertfordshire workshop, with straight answers.
Does remapping damage your engine?
Not on a healthy engine with a properly developed map. Every engine has safe limits for boost, fuelling, timing and temperature, and a good tune works inside them.
Where problems do appear after a remap, they usually come down to one of three things:
an underlying engine fault that was already there
poor maintenance, such as overdue oil changes or worn parts
a sensitive engine that needs the power dialling back slightly
That's why we check every car over before tuning. A remap won't cause a fault on a healthy engine, but it can make an existing one show up sooner.
Will a remap void my warranty?
It can affect it, so check your terms first. Some manufacturers may decline engine or gearbox claims on a modified car, while others look at each claim on its merits. We save your original software before every tune, so the car can always be put back to standard software. That doesn't mean a remap can't be detected, and we'd never suggest hiding one.
Does a remap always use more fuel?
No. It depends on how you drive. On many turbo diesels the extra low-down torque means the engine works less hard at cruising speed. Use the extra power all the time and consumption will go up. If fuel use is your main concern, our economy tuning is set up for that rather than for maximum power.
Is remapping only for performance cars?
No. Some of the most common cars we tune are everyday models: BMW 320d and 120i, VW Golf GTD and 2.0 TDI, and Audi A3 and A4 TDI, along with vans and pickups. Turbo diesels and turbo petrols respond best. Non-turbo petrols gain much less.
Are all remaps the same?
No, and this is where most bad experiences come from. Many cheap remaps are generic files loaded onto every car with the same engine. Mac Tuning has developed its own software for most vehicles over years of testing and research, and every tune is custom-tweaked for the specific car in front of us. You can check the expected figures for your car on our power gains check.
Is remapping illegal?
No. ECU remapping isn't illegal in the UK. A remap is a modification, though, so you must tell your insurer. A properly developed Stage 1 map on a healthy car with all its emissions equipment working should pass its MOT as normal, because the test checks emissions, smoke and warning lights rather than the ECU software.
Is an AdBlue, DPF or EGR delete the same as a remap?
No. A remap changes how the engine makes power. A delete is a separate software solution that switches off an emissions system: the AdBlue delete, DPF delete or EGR delete. Each one takes 45–60 minutes. A DPF delete also needs a physical exhaust modification, which is carried out separately. With deletes you get what you pay for, and we often put right poor ones done elsewhere.
AdBlue, DPF and EGR deletes are intended for off-road and motorsport use.
Is tuning complicated or risky?
There's a lot going on in the software, but the process itself is straightforward. We check the car, read and save the original software, write the new map, then check everything is running as it should. A Stage 1 remap takes 60–90 minutes. If your tune is ever wiped, for example by a dealer software update, our software warranty covers reinstalling it.
Can a remap be reversed?
Yes, always. We save your original software before writing anything, so the car can be returned to standard whenever you need it.
Get honest advice in Hertfordshire
We're based in Ardeley, Hertfordshire, near Stevenage, Hitchin, Letchworth, Hertford and Welwyn, and we see cars from all over the UK. We've tuned over 5,000 cars and have over 300 five-star reviews, which you can read on our reviews page. Klarna and Clearpay are available through our finance page.
For more on what a remap involves, read our guide to a Stage 1 remap in Hertfordshire or see our performance tuning options. Got a question we haven't covered? Get in touch or book online.
