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cut air can affect petrol mixtures?

Posted: Fri May 28, 2004 2:01 am
by androoz
as topic says.. can a cut air can affect my petrol mixtures and make the car run rich..?

Posted: Fri May 28, 2004 5:45 pm
by decoy
the more air you get in through the sensor, the more petrol gets injected to match the air. so maybe it was running really crap before, not much air going through hence not much petrol? just my guess :P

Posted: Fri May 28, 2004 8:20 pm
by coop1er
Cutting open the air box certainly affected my car. It would
run like crap at idle and I could feel it surging at cruise.

I went back to an original setup but with a larger intake, it
has worked well.

Posted: Fri May 28, 2004 8:41 pm
by mr mark
well even no alot of people do cut there box its a pretty stupid thing to do cos all it sucks in is hot air from the engine bay. but i do have to say that i have done it to a starion before i knew better!!!

Posted: Fri May 28, 2004 8:45 pm
by tmz_99
i think a far better idea is to replace the air filter with an aftermarket job and then run some ducting to the standard intake (or make the intake bigger if u think u can) and run it under the car, to force in cold air, had it done on my car for a while and have to say that it DID make a difference, esp on freeways, engine would rev nicely and stayed cooler for one reason or another.

Posted: Fri May 28, 2004 11:31 pm
by SpidersWeb
Ok I cut my air can, and it gave a great change.

Faster response (hit throttle, instant juice and boost) was the biggest.

My car idled a bit easier. Ive had no bad issues, only good ones.

Since the cut air can doesn't allow air to bypass the MAF sensor, its impossible for it to effect the fuel mixture.

If the car runs like crap after cutting the air can, chances are you have buggered your MAF in the process, or not connected it back up securely.

Its a good idea not to cut too much, or put in a heat shield. Otherwise at idle, your car will be sucking in lovely hot radiator air which is probably stagnant (e.g. been sitting there heating up). On mine I made the largest holes on the panel side of the filter near the original cold air intake. I also left the actual cold air intake still in tact.

I also made holes in my Galant air can, and it too has given this car greater response. Although in the Galant I can actuall fit an MAF adaptor and pod filter. Just too poor. I did buy it some Iridiums though - yummy :D

Posted: Fri May 28, 2004 11:36 pm
by androoz
hehe JC poor but can afford Iridiums huh?

basically im just asking because i feel im getting bad kms for the amount of petrol i put in.. ill have to wait till i put a full tank in to make sure.. my uncles JA can get around 400kms with a full tank.. im hoping mine would be around there.. maybe a little less as his is completely stock.

Posted: Fri May 28, 2004 11:38 pm
by androoz
forgot to mention that the cut air can is not causing any problems that i know of.. im just asking to see if it affects the petrol mixtures thats all

Posted: Fri May 28, 2004 11:54 pm
by SpidersWeb
haha well ignition was more important. It was mis-firing sometimes.

I had $100, so it was a choice, 8mm leads or plugs. I chose plugs, turned out I needed leads. Also turns out I have the wrong sized spark plug bit :glare:

..

Posted: Sat May 29, 2004 12:15 am
by Project2501
The AFM only measures the airflow at vacuum. Once you hit boost, the MAP provides the signal for the ECU mapping. Hence itll only be rich/lean at idle. I reckon if anything, it will be lean, because of air going past the afm instead of through it.

cheers

tom.

Posted: Sat May 29, 2004 10:09 am
by SpidersWeb
the cut air can does not allow air to go 'around' the MAF. It *has* to go through it. So it can't run lean.

All the cutting does, is allow more air to easily enter the air filter. We're not removing the can here, or cutting behind the MAF. Its all sealed up like normal.

The only possible effect it can have, is on whatever runs off the vac lead that goes to the side of the air can <--- I *seriously* want to know what the hell that is for. When Im not so lazy, Ill follow it and have a look :)

In all circumstances the MAF is always on vac because its placed before the turbo. This is why the MAP was used to read boost, and gets its vac feed from the throttle body not the air intake.

Posted: Sat May 29, 2004 1:32 pm
by coop1er
Early mitsubishis use the karman vortex air flow sensor which
has ultrasonic sensors to detect air vortices.

These vortices are proportional to the air flow through the
sensor. So the air flow sensor doesnt understand vacuum or
boost, it just measures the amount of air passing through.

These ultrasonic sensors on the early mitsubishis listen
for the sound of the vortices. I think that cutting the air box open
confuses the sensors somewhat as well as letting hotter engine
air in.

...

Posted: Sat May 29, 2004 2:16 pm
by NachoMan
I've done it
It was a big improvement
No ill effects
'Nuff said

Posted: Sat May 29, 2004 7:23 pm
by SIRIUS
400k on a full tank for a stock JA...doesnt sound to good...i got around 570-580 k b4 the orange fuel light come on, was driving sensibly just givin it a squirt every now an then...have spoken to other ownsers an therez is around the same...

Posted: Sat May 29, 2004 8:24 pm
by androoz
are you serious.. :glare:

ill have to wait till i can afford a full tank, and see what i get..