The general consensus with the 2UR-GSE intake is to keep the stock airbox and use a drop-in air filter. Frequently, the aFe dry filter and Tom's Racing filter are recommended.

When I had my IS-F, I purchased both of these air filters. I didn't feel any difference between them and the stock air filter. I almost felt a slight loss in power, but I didn't have any data to it back up. I swapped back to the stock air filter and was happy.

I now have a GS-F and using OBD Fusion to gather some actual data. I recently changed the stock air filter (<500 miles ago), so figured this was a good time to test it against the drop-in filters I have. Both my aFe dry and Tom's Racing filters have less than 250 miles each on them.

Intake Mods:

• RR Racing carbon heat shield
• HPS silicone intake tube (post-MAF so shouldn’t affect the readings)

Test Conditions for all filters:

• Hood open
• Inside garage with door opened to the rear (no fans or outside airflow to the intake)
• Coolant and oil temps at full operating temp
• “Normal” drive mode selected

OBD Fusion:

• Comparing the Mass Air Flow Rate (lb/min) at various RPM's
• Idle reading, holding RPMs at 2,000, then 3,000
• Using OBD Fusion "log" graph feature to measure readings

Results:
All MAF rates below are measured in lb/min

Stock air filter
Idle: 0.690
2,000 RPM: 1.500
3,000 RPM: 2.660

aFe dry filter
Idle: 0.695
2,000 RPM: 1.580
3,000 RPM: 2.700

Tom's Racing filter
Idle: 0.650
2,000 RPM: 1.500
3,000 RPM: 2.580

Since the Tom's Racing filter seems to be the forum favorite, I ran the exact test 3 times in a row with the same results.

Conclusion:
The aFe dry filter does seem to show a slight improvement in airflow compared to the stock paper filter. This makes sense due to the larger pleats.

Unfortunately, it appears the foam design of the Tom's filter has a slight airflow disadvantage compared to the pleated stock and aFe filters.

I've decided to stick with the stock air filter. To me, it's easier to just drop in a brand new filter than continually clean the aFe dry.

These results should apply to all 2UR-GSE vehicles, including the IS-F and RC-F. Hopefully this data is helpful to you as it was to me in my air filter decision.

 

Though, since the aFe did come out on top, maybe I should give it another try. I just know the intake on this vehicle is so finicky it makes me paranoid changing much. Interested to hear the input of others.

 

Some other things to consider -

The Tom's Racing filter could flow better at higher RPM's / redline. I didn't test beyond 3k RPM's.

The foam design of the Tom's filter could flow better as the filter gets dirty, as opposed to the pleated design.

 

This test would mean nothing more than idle flow to 3k rpm. The problems are many, starting with a car standing still as opposed to moving air going thru the intake inlet. Think about holding your hand out the window in the wind, or a bag going 20 - 70mph. Also be aware that up in the 4k - 7krpm range the filters stretch and reshape with a air vacuum rushing by. K&N Engineering did some lab testing and data some time ago to show the filtration contaminates trapped in their filters some time ago. It showed that by the 2 different materials design, when air volumes rush by and the materials stretch together they actually filter and trap more, by design.

There was also data testing about filtration and flow that showed the K&N did flow more air. But when the K&N got very dirty the stock air filter they tested against, slightly out flowed the K&N. From years of reviewing lots of drop in high flow filter test, I would not run anything but the K&N drop in if, but only the Wet Oiled Filter only. They trap so much more fine particles. The foam filters were actually the worst IMO at flow and dirt both. Likely the reason I have never seen a stock factory foam filter in a car. Dry filters let way too much fine contaminates into the engine. After all most don't realize that your Air Filter is actually your Best oil filter. lol!

The drop high flows do provide a bit of some increase if the engine is performing up to standard. The other wrong thing I see some do sometimes is do back to back testing of filters and intakes. Without re-Tuning, it would take the cars ECU map to relearn completely in 50-100 miles of actually driving.

It's nice that you are least doing something, but a real time driving air CFM measures would be what's needed to tell what flows what for the purpose.

CL member here did a deeper dive on this a while back on the 3.6 V6. He actually did a similar build to his IS350 3.5 that I have done. He pulled off a 4.3sec 0-60. He played around with the drop filter, stock Air Box, and Intake factory pipe change.

https://www.clublexus.com/forums/per...n-results.html

 

Anyone have any experience with the GruppeM intake system?