So I just installed the K&N rx4990 (as seen in the "home made CAI" thread)...it fits and sounds great. However, my car lost the "pick up" it had with the stock air box!?!? It just feels less responsive after the K&N filter install....and yes, the scoop is open for fresh air, and filter is never very hot...even after driving 1hr+...

Any ideas???

I'm thinking the air/fuel ratio might be too lean...? Since the turbo already compresses extra air into the cylinder, adding even more air might be overkill??
Anyone have experience or data on this?

 

There is no such thing as too much air. An engine is nothing more than an air pump. The more air you can pump through it the more power it will produce. The eec will adjust for the increased flow.

 

I agree. I'd check to make sure you did not accidently unplug the MAF or something.

 

nope...everything is connected. Did a sanity check with a buddy.

My educated guess is that maybe by installing the filter directly in front of the MAF, the air-flow over the MAF sensor is altered (somehow distorted) from what it was previously...as in the MAF is not detecting the true amount of air being sucked in. If the vacuume of the intake is strong enough, than the flow (due to less restriction) past the MAF is fast enough for this to be true. Hmmm.

I will be installing a silicone tube elbow between the filter and MAF (therefore altering the flow characteristics)...wonder if that will change anything...?

Anyhow, still puzzling.

 

If you're talking about low end torque, you almost always lose a little low end when installing an intake. That's the trade off for higher end horse power. Well, on a natually aspirated car at least. Since the MCS makes it's torque so early, I don't know if this would be an issue or not.

 

Did you remember to press the Sport button?

 

Also takes awhile for the car to adjust to the better airflow, car needs to learn

 

That's true, but shouldn't take more than a few minutes of operation. I installed the K&N straight-replacement filter and even with this subtle difference in air flow, the car ran like crap under 2500 rpm for about 5 minutes. By the time I had clocked 10 miles (quick run to the store and back), it was happy as a clam and mixing well.

 

Damn....maybe I got a slow learner!

 

lol. Ritalin?

 

The engine may operate at in a very narrow band of parameters in order to get the low end torque increases they got out of it.

It could be the lower vacuum resulting from the higher flow rates is outside the operating parameters the ECU needs to make the torque curve they beleive the engine should be running at.

The low end torque may just take serious hit when this happens.

Juse taking a guess here.

 

Reset your ecu. Anytime you do an engine mod you should reset your ecu. It helps to recalibrate it to your new mod.

 

I think it's not run time, but start/stop cycles that help the ECU adapt.

wrxdriver-easy way to reset ECU on R56?

 

^^Disconnect your neg. battery cable then press down the brake pedal for a few seconds to waste away any current left over. Then reconnect your neg. cable and start your car. Thats it.

 

Is this the same as the dealer resetting your codes? Or does it completely clean the clock?...as in erases radio presets, etc?
Any drawbacks to doing this?

 

It completely resets everything. I have done this to every car that I have owned with no consequences and it allows you to get more off of your modification rather than just bolting it on. If you have a reflash im 95% sure it will erase that as well but will not reset a piggyback or standalone. Your ecu learns off of your driving along with what variables that are playing with your engine.

 

wrxdriver this would clear prior codes as well?

 

It will not change the ecu or radio. It only resets the adaptive portion of the ecu.

 

thanks scottinbend

 

NP !

 

Anytime you disconnect the neg. cable it resets your radio stations and clock, well from what i have experienced.

 

I hope everything works out.

 

I'm not so sure about this, it sounds pretty risky...having to reset all my radio presets and all!

 

Until you exceed the volume of fuel that the stock fuel pump or injectors can provide. Not saying that's happening here, but that is a case where too much air requires further adaptation

 

^^ Agreed. It will happen if a turbo upgrade is in order. Then fuel injectors should be purchased at the same time or at least installed at the same time. If not then detonation occurs, and that's no bueno.