Heard a boy racer telling his mate the other day "just fitted a chip to my xxxxx car (non turbo) yesterday, and its loads faster!". Well that is just NOT possible.
I asked him how and he didn't know, but said it was about 20mph faster flat out! Now since it takes 4x the power to go twice as fast, that equates to a simply huge power increase! So he was obviously lying...
First of all, a noticeable increase in power is simply not possible with a naturally aspirated car (no turbo) by fitting a "chip" or having it "chipped". As we said in the first few pages engines breath air. If you do not increase this flow somehow it cannot make more power than it already is doing! That chip simply tells the fuel system how much is the CORRECT amount of fuel to add! The manufacturers stock settings are usually optimum for peak power. It also controls the Ignition timing, but again the stock settings will be about perfect for full power. It is only possible to get tiny gains in "drivability" rather than more real power.
t is possible to gain a few percent here and there at different rpm's and throttle plate positions, because the manufacturers tailor the fuel map to give optimum economy, smoothness and low emissions. But these gains are pretty small. They "may" result in better drivability, but definitely not enough extra power to notice!
It is possible however to chip a turbo car for more power in many cases. The max boost level is often controlled by the engine management system. So in this case reprogramming, or rather remapping the ECU or chip can bring power increases. Be careful though because the manufacturers set these things as they are often for good reasons - usually reliability!
By allowing the turbo to make higher boost the engine gets more air and therefore can make more power, often considerably more.