My son tells me tonight that he has fitted a device to his MG ZR by pulling the plug off the air intake sensor and fitting a small unit he bought on the internet for £9.95. He claims that it increases BHP and engine efficiency, I am very sceptical, as it was cheap it's not a problem but the question is can it do any damage to the engine. Cheers Barry

i think its just a resistor which tells the ecu the intake temp is lower soit enriches the fuel mixture.
He paid about £9.90 to much for it!

That wont help mpg one little bit!!

Dismantle and investigate, i did that any way when i was a kid. I think thats what made me the way i am. a bloody nusense!!!

The only damage is likely to be the hole it'll create in the pocket of whoever pays for fuel!

It's an unintelligent bodge, I.e. It has no idea what it is doing to the fueling it just makes the very intelligent ECU make judgments on the wrong information.
You get what you pay for.
Worse case bore wash you will however coke up the engine and exhaust cat with carbon soot.
Ask your son how much a new cat would cost then ask if the mod was worth it.