Issue With AirRaid CAI

[tko125]

I installed and AirRaid CAI on my 2010 this weekend to pair with my Flowmaster exhaust. After installing, I drove the car to Buffalo, NY (about 5.5 hrs). I average 14.6MPG which is horrific!

Prior to the install, I was averaging about 17.2 with my Thule Rack on top and my 275's (Cooper A/T 3's). I was expecting the same mileage with the CAI (if not a little improvement) when compared to stock. I've disconnected the battery another two times to reset the ECU in an attempt to help clear the problem but no luck!

My next thought is to take the MAF sensor off and clean it with (CR MAF cleaner).

Has anyone else had a similar experience when switching to a CAI? If so, any suggestions? I'm really starting to regret this!

 

[4Rager]

I have a K&N CAI with stock exhaust, and I did not experience what you are explaining. I never disconnected the battery or anything. Shortly after I installed it I drove from Reno to Palm Springs and got 21.8 MPG (best ever) and I just filled up this morning and got 16.9 MPG on my last tank which included 120 miles of towing of 17' fishing boat. Usually I get between 17.5-18.5, so you've definitely got something going on. No CEL or anything I'm assuming? I would double check all the connections of any sensors you unplugged for the install as start.

 

[tko125]

I have a K&N CAI with stock exhaust, and I did not experience what you are explaining. I never disconnected the battery or anything. Shortly after I installed it I drove from Reno to Palm Springs and got 21.8 MPG (best ever) and I just filled up this morning and got 16.9 MPG on my last tank which included 120 miles of towing of 17' fishing boat. Usually I get between 17.5-18.5, so you've definitely got something going on. No CEL or anything I'm assuming? I would double check all the connections of any sensors you unplugged for the install as start.

Done and Done....I already checked the pressure line and all other connections to the new CAI, the only thing I can think of at this point is the MAF sensor...something is definitely not right here.

 

[05Rrunner]

Put it back to stock and check your mileage you'll know for sure what's going on. I know it's kind of a pain but that's the price of admission when modifying.
Seems unlikely the cleaning will change anything , the odds of it showing up right when you did this install is pretty slim

 

[Antman]

I installed and AirRaid CAI on my 2010 this weekend to pair with my Flowmaster exhaust. After installing, I drove the car to Buffalo, NY (about 5.5 hrs). I average 14.6MPG which is horrific!

Prior to the install, I was averaging about 17.2 with my Thule Rack on top and my 275's (Cooper A/T 3's). I was expecting the same mileage with the CAI (if not a little improvement) when compared to stock. I've disconnected the battery another two times to reset the ECU in an attempt to help clear the problem but no luck!

My next thought is to take the MAF sensor off and clean it with (CR MAF cleaner).

Has anyone else had a similar experience when switching to a CAI? If so, any suggestions? I'm really starting to regret this!

The cold temps/warm ups are probably what's causing the poor mileage, not the CAI.

You need to average the fuel mileage over time and different temperatures if you want a more accurate representation of the difference.

 

[dproberts]

My guess is:

1) the outside temp is cold
2) something with the new CAI isn't seated or sealed right - a hose or the MAP sensor.
3) defective CAI
I bought a K&N CIA for Honda about 6 months ago and the MAP sensor mount was welded wrong (probably didn't get seated in the jig right during manufacturing) and car wouldn't run for more than 30 seconds. Crazy but true.

 

[tko125]

My guess is:

1) the outside temp is cold
2) something with the new CAI isn't seated or sealed right - a hose or the MAP sensor.
3) defective CAI
I bought a K&N CIA for Honda about 6 months ago and the MAP sensor mount was welded wrong (probably didn't get seated in the jig right during manufacturing) and car wouldn't run for more than 30 seconds. Crazy but true.

I took the MAF sensor out and cleaned it. I also checked all the seals and connection points and am still getting shit mileage. I'm going to contact AirRaid and ask for my money back and the ability to return this.

 

[PopsSmith]

The whole purpose of a CAI is to get more oxygen into the engine. The MAF determines the O2 content through a membrane which induces a electrical current that is proportional to the O2 content. The MAF is important because it ensures that the ratio of fuel to O2 is correct or issues will arise. Not enough O2, the vehicle runs rich. Too much O2, the vehicle runs lean and has the potential for detonation (aka destroy your engine).

Now that the fundamentals are there, what might be happening is that your vehicle is compensating for the O2 increase by adding more fuel which equals better performance but worse MPG. Similar thing happened with my 370z. When I put the 370z back to stock, I lost some hp but gained about 2-3 mpg. This is just a theory as further diagnostics are needed to determine the exact cause.

 

[mo_mo]

The whole purpose of a CAI is to get more oxygen into the engine. The MAF determines the O2 content through a membrane which induces a electrical current that is proportional to the O2 content. The MAF is important because it ensures that the ratio of fuel to O2 is correct or issues will arise. Not enough O2, the vehicle runs rich. Too much O2, the vehicle runs lean and has the potential for detonation (aka destroy your engine).

Now that the fundamentals are there, what might be happening is that your vehicle is compensating for the O2 increase by adding more fuel which equals better performance but worse MPG. Similar thing happened with my 370z. When I put the 370z back to stock, I lost some hp but gained about 2-3 mpg. This is just a theory as further diagnostics are needed to determine the exact cause.

Theory only:
The ECU should respond to the O2 sensors in the exhaust to ensure the air fuel ratio is stable. Of course the O2 sensor is post combustion so during engine load / speed changing it lags the MAF as an input.

The CAI is there to fundamentally delivery more oxygen / air to the engine. It should do this by reducing the pressure drop through the intake. This has two benefits. One is it takes less sucking of the engine pistons to draw the same volume of air into the chamber. The throttle (our foot on the pedal / drive by wire) should close to prevent the engine from getting to much oxygen and this puts more load back on the sucking of the pistons. Two is at wide open throttle you're going to get more air into the engine if the system is efficient.

My guess is you're romping on the throttle more or traveling at higher speeds as 2-3 mpg is significant. Is this a measured at the pump mpg or a Toyota estimated mpg? If measured at the pump, some pumps shutoff earlier or later than others so you might have to average a few trips to really know what's going on. I'd be surprised if a CAI changed your mpg by more than 3% (that's about .5 mpg on our vehicles) unless it is placing a very large restriction on the inlet then all bets are off.

Was there a sensor or any other electronics that got touched during your install? Might want to check for leaks and make sure the MAF is measuring 100% of the air and that the CAI isn't drawing in hot engine compartment air.

 

[PopsSmith]

Theory only:
The ECU should respond to the O2 sensors in the exhaust to ensure the air fuel ratio is stable. Of course the O2 sensor is post combustion so during engine load / speed changing it lags the MAF as an input.

The CAI is there to fundamentally delivery more oxygen / air to the engine. It should do this by reducing the pressure drop through the intake. This has two benefits. One is it takes less sucking of the engine pistons to draw the same volume of air into the chamber. The throttle (our foot on the pedal / drive by wire) should close to prevent the engine from getting to much oxygen and this puts more load back on the sucking of the pistons. Two is at wide open throttle you're going to get more air into the engine if the system is efficient.

My guess is you're romping on the throttle more or traveling at higher speeds as 2-3 mpg is significant. Is this a measured at the pump mpg or a Toyota estimated mpg? If measured at the pump, some pumps shutoff earlier or later than others so you might have to average a few trips to really know what's going on. I'd be surprised if a CAI changed your mpg by more than 3% (that's about .5 mpg on our vehicles) unless it is placing a very large restriction on the inlet then all bets are off.

Was there a sensor or any other electronics that got touched during your install? Might want to check for leaks and make sure the MAF is measuring 100% of the air and that the CAI isn't drawing in hot engine compartment air.

Your theory on the throttle needs to be improved. The throttle is typically a butterfly valve that adjusts it position based upon the amount the accelerator pedal is pushed. The throttle does not prevent the too much O2 going into the engine, it is there to act as a restrictor. Supercharged/turbocharged vehicles have been known to destroy engines due to detonation (too much O2 vs fuel) not because the throttle didn't prevent it. Also, pistons do not suck, they "push" the crankshaft.

Also, the O2 sensors in the cats or headers (depends on the vehicle) are for emissions. The CAI allows more O2 into the engine by reducing the amount of turbulence (eddies, etc) in the intake. This basic fluid dynamics.

The change in MPG that I saw was directly related to the modification (putting back to stock) I made to the vehicle. Basic science: you change one variable at a time, record your results, interpret the data.

 

[mo_mo]

Your theory on the throttle needs to be improved. The throttle is typically a butterfly valve that adjusts it position based upon the amount the accelerator pedal is pushed. The throttle does not prevent the too much O2 going into the engine, it is there to act as a restrictor. Supercharged/turbocharged vehicles have been known to destroy engines due to detonation (too much O2 vs fuel) not because the throttle didn't prevent it. Also, pistons do not suck, they "push" the crankshaft.

Also, the O2 sensors in the cats or headers (depends on the vehicle) are for emissions. The CAI allows more O2 into the engine by reducing the amount of turbulence (eddies, etc) in the intake. This basic fluid dynamics.

The change in MPG that I saw was directly related to the modification (putting back to stock) I made to the vehicle. Basic science: you change one variable at a time, record your results, interpret the data.

I think we're saying the same thing but Ill clarify a bit.

I agree that the throttle acts as a restrictor. What I am trying to point out is that the restrictor will limit the air which will modulate power. If the inlet is 'more better', then the restrictor will be 'more restricting' and closed except at WOT (you won't depress the skinny pedal as much to get the same power).

O2 sensors are for emissions. Agreed. Do you not think that the ECU gets feedback and adjusts the fuel injected vs the air flow (MAF) based upon the feedback from the O2 sensor? What else is the O2 sensor adjusting (EGR or other stuff)? I'm interested to know if the O2 sensor doesn't do what I think it does as that would help my understanding of engine control systems.

CAIs attempt to reduce 'turbulence'. We are saying the same thing again. Pressure drop and turbulence are highly related. What turbulence bench testing would you do if you were designing a CAI from scratch (pressure drop rake)?


Anyways back to the topic at hand, none of the above explains the significant loss of efficiency. My guess is something is leaking / not sealed.

 

[Volley]

I have the exactly same setup...an Airade CAI and a Flowmaster exhaust. Which Flowmaster are you running? I have not had the same experience in fact I have had the opposite. I calculate my mpg and keep it logged. Here was my experience 16.4mpg average stock (although I was still in break in period), 2 tanks with CAI only 17.17 and 17.19, and finally 2 tanks with CAI and Flowmaster are 18.32 and 18.94. In the interest of disclosure I'm not a speed demon but not a granny either. I try to keep the cruise on 65-70mph on the highway and have an equal amount of in town/highway driving on my daily commute of 30 miles or so each way.

Anyway it definitely sounds like something is wrong on yours. I would go back to the install instructions for the CAI and go through everything from the beginning to make sure everything is right, also check your new exhaust for leaks, never know.

 

[tko125]

I have the exactly same setup...an Airade CAI and a Flowmaster exhaust. Which Flowmaster are you running? I have not had the same experience in fact I have had the opposite. I calculate my mpg and keep it logged. Here was my experience 16.4mpg average stock (although I was still in break in period), 2 tanks with CAI only 17.17 and 17.19, and finally 2 tanks with CAI and Flowmaster are 18.32 and 18.94. In the interest of disclosure I'm not a speed demon but not a granny either. I try to keep the cruise on 65-70mph on the highway and have an equal amount of in town/highway driving on my daily commute of 30 miles or so each way.

Anyway it definitely sounds like something is wrong on yours. I would go back to the install instructions for the CAI and go through everything from the beginning to make sure everything is right, also check your new exhaust for leaks, never know.

I have the Force II Series exhaust. After further deliberation, I decided to uninstall the whole system and re-install it to ensure that the problem was not my own doing. I've now seen an improvement and am back up to the 16.7/16.9 MPG range. This is still 2/10 MPG lower than my previous average (keep in mind it's winter and I run oversize tires (275/55/20). I've decided to monitor it a bit further before going to air-raid. We've had a cold winter up here in the NE and 0-20 degree temperatures don't do anyone any favors in terms of fuel efficiency in the engine (increased friction, oxygenated fuel, etc) . This week calls for day time temperatures in the high 40's to 50's. If I can get above 17MPG I'll be satisfied.