CAI .... Cold Air Intake

[nakata]

Originally Posted by ainarssems

Well you cannot get air cooler than ambient without some type of active cooling(something like extra high power aircon for intake) but that would not be practical and possibly rob more power to operate it that you would gain. Another option would be nitrous injection.

47p2 picture shows fuel cooler which is mounted in intake, that would make intake air even hotter as it cools down fuel.

Stock A/S8 already have 'cold air intake' as does all modern cars drawing air from the front of car unlike some old cars that used hot air from under the bonnet.

Well known 'tuning' is to put resistor in place of air temperature sensor to fool ECU of thinking it gets colder air and to inject more fuel at WOT and advance ignition.

The main reason for "poor" performance is the low octane fuel. Try with 100+ octane fuel. With 91 or 93 octane you have too much detonation, and ECU is correct advance timing of spark's to safe engine from detonation. As cold air creates less prerequisites for detonation.
Look abaout this articile for more performance.

pp Please read more carefully about methanol. It is very toxic fuel.

[Iyole]

Thank you for all the replies and advice ...

In South Africa we only get 93 & 95 Octane so I use an Octane Booster to achieve a 98 Octane ....

Some Tech comments from the Web ....

An engine that doesn’t have a turbo charger must rely on atmospheric pressure to supply air to the engine. That ratio is 14.7:1. Now if we use our example above colder air has more molecules, more molecules means more oxygen, engines burn oxygen, so the more you can cram in there the more power you can achieve. Since there is no turbo or intercooler on an N/A engine the only way to get colder air into the intake is to extend the pipe to the fenderwell or down below the engine where the air is cooler. On this example more oxygen is getting to the engine thus creating more power. On the flip side, you have extended the intake pipe about 3X the normal length meaning it makes it harder for the engine to pull the air into the engine. So a shorter length pipe would be ideal, but that would put the filter into the engine bay sucking in hot air. You would actually LOSE horsepower here because you are pulling in a lot less oxygen. In short, people using short ram intakes on an N/A motor are actually shooting themselves in the foot. The stock airbox is more efficient.

On the NA cars, the longer the intake tube, the harder it is for the engine to pull the air. That's only true, if your intake tube is A. too small, or B. has too many tight bends in it. If it's a well designed tube, there will be no restrictions. Most intake tubes I've seen for various cars, actually outflow the engine. As for NA cars, it would indeed be more beneficial to route the filter outside the engine bay. Then again, if it's just a 4 cylinder passenger car, you're not really gaining much anyhow. There's only so much pep you can produce, from a 4 cylinder passenger engine.

Overall, most of the time, the real benefit from a CAI, is the summertime, where there is a decent contrast between under hood air temps, and outside air temps. In the winter, (if you're in a cold state like myself) you're going to get your cold air regardless. Unless of course your engine bay is jam packed.

I am not trying to gain more power ...... just constant power .... yesterday it was 32 degC in Cape Town and
the S felt really flat....

[nakata]

Sorry, but do you know about variable intake in A8? If you have long intake runner you have more power in low rpm, with longer intake is increase power in middle and high rpm. You don't need CAI in A8.Is done enough about that.
When is cooled just no need a high octane fuel. ECU is responsable for timing correcting, to safe engine of detonation.

pp look about variable intake in 40V engine.

[Iyole]

Thank you for the Link ... very informative especially all the links to DIY 's at the
bottom of the page.

I am technically challenged .... and am not looking to go the route of CAI.

What I am trying to establish is if one was able to keep the Air into the
Airbox at an optimum temperature surely the motor would run optimally and the ECU would adjust accordingly ...

I also feel that the Dastek Chip I have might have some influence in not
allowing the ECU to adjust properly when intake temps increase .... ??

I will firstly check that the intake flaps are operating properly as per your link ..


PS: Look abaout this articile for more performance ..... link not working. Thanx

[nakata]

link again.

[sarg]

Originally Posted by ainarssems

Well you cannot get air cooler than ambient without some type of active cooling(something like extra high power aircon for intake) but that would not be practical and possibly rob more power to operate it that you would gain.

Stock A/S8 already have 'cold air intake' as does all modern cars drawing air from the front of car unlike some old cars that used hot air from under the bonnet.

^ ^ What he said ^ ^

All cold air induction kits do is get the air from outside, rather than under the bonnet - common mod on E39 M5s, but of little or no use if air is already coming from outside

[Dezzy]

Use the climate for cold air, take a supply vent to inside the cabin and route it into the bottom of the airbox.