I'm sure you have seen them clogging up Ebay on countless occasions, unscrupulous sellers offering power upgrades for almost every car you can think of. I have seen these sellers talking of 9 to 25 BHP gains on cars for a very low price.
Well they would be right, usually these are retailed for a mere £4.99 which is a good price.
If they worked as they say! which they don't.
What they don't tell you is that this 'chip' is a single resistor worth about 2p.
So Do These Resistors Increase Performance At All?
Er yes, partially. In the same way that emptying the rubbish from
the passenger footwell makes the car lighter and therefore quicker.
At most you are looking at maybe ¼ BHP if you are very lucky.
How Do They Perform This Amazing Power Hike?
Basically the resistor connects between the ECU and the air temp sensor.
The temp sensor is a thermistor (a device which changes its resistance with temperature so that the ECU can tell how much fuel to inject, colder air = more fuel).
The resistor is fixed at the same resistance that the thermistor has at very low temperatures, so 'tricking' the ECU into running rich all the time.
So You Can Get Extra Rubbish BHP For Only A Fiver, Any Drawbacks?
More cons than pros in this case.
Running rich will burn your spark plugs, block your catalyst, possible bore wash and affect your MPG. Turbo assisted engines tend to run slightly rich anyway so more fuel won't help.
Save your money and save your engine, don't buy one.
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