I recently purchased a pair of resistors from ebay to boost the performance of my newly purchased 05 plate Ford KA.

With a set of lighter than the standard steel 13 inch alloys and carrying no spare wheel, tools or cradle and no passengers the car would accellerate from 0-60 in about 12 seconds. Thats with a totally stock 70bhp motor with 63000 on the clock shortly after a service.

The first chip/resistor to come through was from a seller called Dazzarooney. It came with pretty detailed instructions and diagrams of his own car to help get started. He also said that not all cars have a plug on the inlet sensor you could use so the temperature sensor could be used instead on those models.

I had to use the water temp sensor as I couldn't see a plug on the air inlet myself. I followed the instructions for fitting the resistor and these were the results. He claimed a 5-20bhp increase and I think that this should be genuine on most cars. His own mondeo 2.0 zetec gained 12bhp, my KA gained at least 5bhp!!

The only downside is that the choke doesn't work properly so the engine takes a couple of goes to get started in the morning. Once it has been run it is fine for the rest of the day, if it becomes a problem in severly cold weather I shall remove the resistor until next summer.

Fuel economy is the same as before even though I have generally been driving faster. The KA is still returning a healthy 45mpg which is now pretty impressive given the spritley performance.

I estimate that 0-60 times can be as low as 10 seconds and I have seen 105mph top speed (on a racetrack of course) which is 3mph up on before the resistor was fitted.

The gains didn't come completley straight away although I did instantly notice improvement. I think the ECU takes a few miles to totally adjust as the KA kept getting faster for a good 400miles or so.

The second resistor came a week or so later, but the instructions were poor compared to the others. Also the 2nd resisitor was of a different resistance to the first one and although this claims a 25BHP+ increase I have decided to leave well alone as the seller appears to have taken little effort with his product.

I showed my dissapointment with neutral feedback to which he destroyed my 100% feedback score with negative.

YOU HAVE BEEN WARNED!

Just to add that disconnecting the temperature sensor will also disconnect the fan so if in heavy traffic or very hot weather the engine could overheat. I've had no problem so far but will be rigging up a seperate switch for the fan for summer.