[C6] Cold Air Intake

[Sweptclean]

Sometime ago I installed a BBK cold air intake with two low restriction cone filters, plus I changed the air bridge to a smooth one. Question: should I have also changed the air mass sensor or adjusted it (if there is such a thing) ?? I have a hesitation when I floor the engine from a dead stop, and I can hear the gush of air going in before the engine responds.

Second question, do I have to "re-tune" the engine to deal with the cold air intake ?? Who does that in the Tampa/Sarasota/Lakeland area ??


Thanks guys.

[Rich Z]

Well, generally speaking, any time you change anything related to the air passing through the mass air flow sensor, you need to recalibrate the table that the PCM reads that correlates the amount of air flowing in relation to the frequency value that the MAF actually reports to the PCM.

There will be no off the shelf MAF available to help you, because there won't be any off the shelf MAF tailored to your particular mods. And honestly, changing the MAF to an aftermarket one would likely just make matters worse rather than better, as the table I mentioned above would like be even further from reality. Replacing the stock MAF with an aftermarket one pretty much guarantees that you need to have the car tuned so the MAF can be recalibrated. Most people replace MAFs with aftermarket ones to get a larger MAF housing, so that guarantees that the MAF table will not be correct.

BTW, at some point GM went from an open tube type MAF to a cartridge style one that simply plugs into the air bridge housing. I'm not sure exactly when that took place, but I believe the cartridge type will be even more sensitive to air path housing changes than the tube style was.

Do you get any error codes? Realistically, if the MAF is REAL far out of whack, it flags an error and the PCM ignores the MAF thinking it is defective and goes into open loop mode.

As for your hearing a rush of air, have you checked for air leaks AFTER the MAF sensor? If the engine gets a big gulp of unmetered air, then yes, you can have hesitation because the PCM doesn't know about it to compensate with more fuel.

Anyway, hope my ramblings help somewhat.

[Kap142]

When I got my Z06 back in 2011 I, too, changed the CID to a similar unit as you and also went to a smooth coupler. I did no other changes to the air induction system. Have never received the first trouble code and she runs great.

I have never herd the air whoosh you speak of nor felt the hesitation you speak of. My "Peek" runs wonderfully.

[Sweptclean]

Rich Z: No, I have never had an error code. As to the initial rush of air, there are no air leaks but I will have to check that again. The "rush" or gulp is on the initial flooring of the gas pedal. There is a hesitation of about a second or a second and a half before the engine responds and spools up. That is in neutral, however, when I feel the hesitation and the sound of air gulping in. When in gear I do not hear the sound of air, but do feel the hesitation.

What I gather from your comments is that an aftermarket MAS will not help, but rather re-tuning the car so the car's computer can recognize that there is more air coming in.

Thanks.

[Rich Z]

Well, the problem is that I can't imagine a simple CAI mod causing so much of an improvement in air flow that you would be having this sort of a problem. CAI isn't forced induction, so it shouldn't increase the air flow THAT much.

Before the air intake mods, you didn't have this problem at all?

You know, you just might be fighting with torque management holding you back.

#PIP4112G: Sag or Hesitation on Acceleration (Normal Operating Characteristics) - keywords 4l60e 4l65e 4l70e 6l80 6l90 - (Aug 15, 2008)

Subject: Sag or Hesitation on Acceleration (Normal Operating Characteristics)


Models: 2007-2008 Cadillac Escalade, Escalade EXT, Escalade ESV

2006-2008 Cadillac XLR, XLR-V

2007-2008 Chevrolet Avalanche, Silverado, Suburban, Tahoe

2006-2008 Chevrolet Corvette

2007-2008 GMC Sierra, Yukon, Yukon XL

2008 Pontiac G8

Equipped With a Gasoline Engine and Automatic Transmission




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This PI was superceded to updated to remove models. Please discard PIP4112G.


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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
Some customers may comment on a sag or hesitation when accelerating under the following conditions:

- When coasting with a closed throttle and then aggressively applying the throttle. Examples of this maneuver include a rolling stop or a lane change maneuver. In this type of maneuver, even though the accelerator is applied aggressively, the throttle blade is opened slowly for up to 0.7 seconds to help minimize driveline lash and clunking.

Also in a 6L80 or 6L90 (RPOs MYC or MYD) equipped vehicle when making a hard, complete stop with a closed throttle, immediately followed by an aggressive throttle opening the transmission downshifts may not be completed by the time the throttle is opened. As a result approximately 0.5 seconds of "zero" torque may be commanded to allow the shift to first gear to occur.

Recommendation/Instructions:
Both of the above conditions are a result of Torque Management and both of these conditions should be considered normal and no repairs should be attempted.

There are some significant programmed-in controls in the PCM to try to keep an owner from damaging the car, especially while under warranty by GM. But if this is the case, a good tuner can take torque management out for you.

[Sweptclean]

Before installing the CAI I did not have this problem (air gulping noise), although the hesitation from what I understand is built into the accelerator pedal (and can be minimized by re-programing the PCM). From what you just described, and which I have experienced (the hesitation after slowing down or lane changing) could be the "Torque Management" doing its job.

R