Re: EBAY mod Chip Power Increase UPTO 20BHP VariPower etc.
RED_75SX said:
the way i see it putting this mod to make the car richer is worthless as the car will get slower and gas consumption will rise.Now leaning the car will have good effects like lower gas consumption and more power.Now that is why i am hooking my "variable resistor" on the MAP sensor.Now this must be checked on wideband lambda(air/fueal ratio)equipment to make sure the car does not run to lean.Car should make most power around 12.5 afr
Running very slightly richer will give more power, but not much.
If it's running weaker it will most likely hesitate, too.
Running weaker will give a slow burn so the exhaust gas is still on fire as it leaves the combustion chamber, and if it happens to an extreme can burn out exhaust valves and cause overheating.
Putting a variable resistor in the map sensor wiring. Hmmm. Chances are it won't do anything at all, never mind anything good. The reason you can fool the air temp sensor is because it is a temperature dependant variable resistor, with the current flowing through it being used as a signal for the ecu. Adding resistance makes it think the air temp is cooler.
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The MAP sensor however uses a different principal to measure. It's resistance doesn't change with varying manifold pressure, but it sends a varying voltage signal into a fixed impedance input in the ecu that you can't just shunt in the same manner. If it was that easy, then you wouldn't need to go to the lengths of fitting electronic fuel cut defenders to turbo cinqs - they limit or 'cap' the signal from the sensor so the ecu doesn't have a heart attack and shut the whole job down.
Similar principal for the lambda sensor signal.
If you're investing in a wideband lambda to log your results, you're looking at a lot of cash - enough to have the ecu remapped by someone who can actually optimise it and make it go faster.
**** What happens here is well documented within this site, but we'll go through it briefly again:
You try to fool the ecu into thinking it's got cold air. It adds a little more fuel. Lambda sensor says "oi oi, too rich matey" and weakens the fuelling again. Net result - you're depriving the ecu of one of the sensors it needs to make your car run the way you want it to, and you get no more power.
Couple of questions.
If it was as easy as sticking a 5p resistor in to get more power, wouldn't the manufacturers just do that and save the cost of a very expensive sensor?
Are the ebay resistors calibrated to the car? Do they work at a value which will give the correct results, or are they just a guess - "It runs 5 k ohms at 5'c and 1 k ohms at 30'c, so we'll whack a 4 k ohm resistor in to make it think the air is 25'c colder". You think your ebay power seller has any idea or interest as to what car or engine you have?
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Summary for those of you who can't be bothered to read the above.
Remapping by a professional will give more power. The fuelling and ignition advance curves can be optimised for your setup and give more fuel economy and more power.
Fiddling about with 5p of components from Maplins to try and fudge a signal will do no good whatsoever.