cai.....too lean? (possible engine trouble?)
 

first i gotta say what a great forum this is.... i've been checking this site daily (well almost) since i got my P5 about six months ago. awesome info.

anyways... my brother installed a cai on his WRX a few weeks ago...he works at a shop that customizes cars... anyways, he loved the results but found out yesterday from both cobb and from subaru that some people using aftermarket intakes have been experiencing engine troubles with the WRX . well actually some people have ruined the motors in their WRX using cai... the problem they say is that the intakes are running the engines too lean...causing major problems for the engine. (i'm not talking about the cheap intakes either, i am talking about aem, injen etc...)

anyways, i wanted to get an injen for my P5 but was wondering if anyone has run into any such difficulties or have heard of any of these problems with aftermarket intakes on the P5. i was under the assumption that reseting the ECU during install would automatically adjust for the increased airflow.

thanks

never heard of anything like on a Proteges

it should be well withen the computer's parameters to adjust for a cai.

99+ Proteges already run too rich at WOT in stock trim. Installing a CAI will actually IMPROVE the situation. :bt:

i have a modded wrx too, and on that car you want to use the factory box with a K&N dropin filter and remove the resonator. anything else will require a/f setting changes. the MAF is overly sensitive on that car.


now on the pro5, i noticed that my mazdaspeed muffler's bore
is almost black from the carbon deposits. its running quite
rich from the factory. i would assume adding a CAI would
lessen that out and perhaps even improve the longetivity of
the plugs and motor. but i dont want the extra noise as
its a clunckin slow car and dont wanna start sounding like a
boggin civic with noise, but no kick.

Well you have to remeber that a WRX is a totally different issue from our Protege's ,
they are running turbo's ... so more air .. and cold air intakes can have an affect which can be adverse... I would think it would be possible that a WRX could run lean off a Intake (cold air etc.) .. But then I would also figure that your brother or other WRX owners would have an exhaust which adds to the fury ...
But finally I would also think that he would know well enough that he has a turbo and he should keep an eye on this things... ie: feul pressure gauge.......

I would basically try and add more feul to the fire....


p5:
Mazda's run rich from the factory ... An intake won't hurt ..
We are lucky in that manner... We also use a MAF... and VAF
Bruce

wrx issues, yah, FI cars you need to becareful. exactly what
you mentioned.

i might try that intake. :)

Lean?? Not Rich??
 

With colder air, wouldnt the engine run rich? Or, is it the opposite with Turbos? I know that our car gets allittle worse gas mileage with the CIA because of this. Also, cant keep my foot out of it with the sound and feel with the CIA and Exhaust:rolleyes:

Mickey

Colder air = More dense = More oxygen per volumetric unit

I think our engines running so rich is half of the low fuel economy issue. But better rich than lean.

Thats what I thought.

Obviously not since you said the exact opposite in your post. More oxygen and same amount of fuel makes a lean mix. Not rich. Turbo's need more fuel because they pack more oxygen in (again raised density). But I would be amazed if a CAI was able to shift our engines from rich to lean.

Hummmmmm
 

kc5zom

Maybe my wording was vague:rolleyes: , with colder air the ecu then corrects with more fuel. Yes the volume and the speed of the air is increased with the CAI however the fuel is also increased with the decrease in temperature (I dont think the the ratio is linear), think of a choke. Thus, we get worse mileage. NOW, with the turbo motor increasing the pressure as well as cooling the air with an intercooler, I was asking if the turbo engine acted the opposite of the N/A motor and ran lean. This was a simple question. With a CAI on a N/A motor COLD AIR Intake, meaning colder air and more fuel. I think that the volume doesnt offset the increase of fuel (Nonlinear curve), Thus the N/A motor runs rich. DOES the turbo motor act the opposite because of the increased pressure and the colder air from the intercooler? Can the WRX ECU compensate for the change with the turbo?
By the way this is the same question as before, just better worded I hope:D .

Mickey

i have an A/F gauge and after i put in my CAI my engine burns richer at all RPMS.. even idle..

It's impossible to run too rich. The fuel is computer controlled by the ECU and the only way you'll run lean is if you have MASSIVE amounts of air going into the engine (FI for example) without upgrading the injectors. For all intensive purposes though, even for most FI applications, the stock injectors are fine.

pr5owner- really? thats kinda hard to believe. do you have a wideband o2 sensor or one that's just hooked up to the ECU?