AEM ETI intiake

AEM ETI Technology Enhances Cold Air Intake Performance

By Mike Kojima

If you have been in the game of modifying cars for 10 years or so and got your start modding compact cars, you probably remember the good old days when adding a cold air intake was probably the first or second engine mod you did to your car.  In those days a really well designed intake could add as much as 10 or more whp to your car's output and even the most basic poorly designed ebay intake usually added at least a few dyno verifiable horsepower.  A cold air intake was considered to be a good bang for the buck modification and thousands were sold.  Even the most mechanically inept were usually able to install an intake with a few simple hand tools.

aem eti intake test
SR Motorcars was nice enough to let us borrow their Dynojet chassis dyno.  They are only a few blocks away from our office so this works out pretty well.  Our test car was a brand new Lexus IS350, a car that is notorious for hating intake systems.

Fast forward to now.  Today's modern cars have much more sophisticated engine management systems than those of just a few years ago.  The OBDII DTS code trip range has been narrowed and the detection of out of range sensor parameters has been made more sensitive.  Engine control systems also have more command authority and can actively change timing and fueling to a higher degree than ever before.  Also the window of an engine's operation under closed loop control has been greatly expanded.  Some cars only have 10% of their operating range under open loop.

AEM ETI Intake test
AEM ETI intake test

The engines hardware has also been refined with better computer modeling and simulation allowing engineers to do a better job at design optimization.  Simply put, there is not much horsepower sitting around at the bolt on level anymore. Engines are more optimized and most of the low hanging fruit on the power tree has already been picked.

With the engine's big brother ECU system monitoring everything and with better engine design, the old days of easy bolt on power are largely gone.  Simply bolting on a cold air intake that’s been optimized for more power can trip the OBDII system causing smog check failing DTC error codes to be stored by the ECU and check engine lights to be triggered.  The savvier intake manufacturers have stepped up their game.  They carefully place their mass air flow meter (or MAF) elements in the intake, tune the diameter of the MAF sample tube and the length of the tube, not only for more power but also to keep the ECU happy.

AEM ETI intake test
The AEM ETI intake is pretty straightforward, straight bigger diameter tubing with integral MAF sample tube, the OEM spec filtration dryflow filter element, heat shield and all hardware.  The MAF signal converter box is what makes it all happen.

Better manufacturers tune their intakes on the dyno and also log MAF voltage and tune the MAF placement.  Then they do extended monitoring of the ECU's long and short term fuel trims to make sure nothing is getting out of range where the intake may cause skewed fuel trims, check engine lights and error codes.  The result is usually an intake that improves power but with gains that are much less than the old days.  The power tuning of the intake is compromised to keep the ECU happy.

AEM ETI intake test
AEM's MAF signal converter uses the stock connectors for clean and easy plug and play no cut installation.


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Wednesday, August 18, 2010 12:14 AM
If only the IS350 came with a 6spd manual, it'd be a better car. It looks like an even better car still w/all the engine covers removed.

Anyway, please correct me if I'm wrong... but the converter box lets the ECU see the actual amount of air flow, and thus, is able to account for it properly? Is there ever a case where the stock sensor gets close to or reaches its limit of detecting air flow in stock condition?
Mike Kojima
Mike Kojimalink
Wednesday, August 18, 2010 12:27 AM
Yes you are correct, The stock MAF almost never maxes out on a NA car. On turbo cars it could be a problem with mods.
Wednesday, August 18, 2010 2:43 AM
It's impressive that the gains are across the entire powerband. Now I know why AEM has been hiring electrical engineers like crazy...
Wednesday, August 18, 2010 3:35 AM
Thats actually quite impressive, I cant wait to see the 370z tested and see what the boys at AEM can find lying around HP wise.
Wednesday, August 18, 2010 4:32 AM
AEM is putting those new engineers to work huh?
Dusty Duster
Dusty Dusterlink
Friday, August 20, 2010 5:12 AM
That's a really cool piece of engineering, but it would almost certainly give you warranty troubles, since you're screwing with a sensor input.

I'm curious as to how, exactly, that little black box works. Is it convincing the computer that less air is really flowing in, thus leaning out the mixture?

This is also a reason I like tuning some domestic motors better--they're equipped with a MAP (Manifold Absolute Pressure) sensor instead of a MAF (Mass AirFlow). I suppose, though, that depending on how the computer is set up, it might still cause the loss of performance gain over a period of time.
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