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@ Chris - naturally the graphs are an avarege of several runs - we did things thoroghly!
If you gain 2 hp you can travel at a given speed pressing LESS on the accelerator => save fuel.
On some cars, theres a good gain to find on FE by derestricting the intake system - on other none. It's enegine and model specific.
I for the moment don't belive theres an much extra pumploss on cold air, but theres extra arodynamic drag to overcome in cold condistions. I think, that throttle valve resistance is far greater, which appears to be why HAI work, as throttel has to be open further to produce same amount of energy to move the car at a given speed.
What we are all trying to do here is to get the max Kilowatts out of every unit of fuel. Depending on the specific engine this can be improved in several ways.
- All engines will benefit from a derestricted intake system until a certain limit.
- Some will benefit from a cold air intake
- Some will benefit from a hot air intake.
So you can't really conclude this or that. Further more what is right at one rpm, might not be so at an other rpm. So it's complicated stuff, and it would take many hours on the dyne to dertermind the best for each car, and each speed.
Everything is a compromise - what you gain in one end you usually lose in the other end. So better FE at low rpm, will mean less power and FE at higher rps, and vise versa.
I've been working with CAI and derestricting intake systemes for four years some time ago, and at the time we saw significant gains on both hp and FE.
But things has changed in the past 10 years, and car manufactors and the ECU programs has changed a lot, so now things might look different, because of changed demands on emmisions.
I'm not saying that HAI dosen't work - I'm saying that it will be different from engine to enegine what works best, as the engine, car driver etc. are different, and thus you are optimising for different situations each time.
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