Can anyone tell me the difference between a stage I and a stage II air intake system besides the fact that the stage II is almost twice as much? What do you think is the best intake out there? Looking at AFE mostly but like feedback. Anyone notice a increase in gas mileage?

 

I have a stage 2 AFE with the progaurd 7 filter... 6" flange vs 4.5" IIRC. I loose about 1~1.25 mpg compared to the stock airbox. the performance difference is night & day... motor revs up much easier, turbo spools quicker, egt's are lower and on cool down, it is about 30~40% quicker with the big filter on there (compared to the stock airbox). I generally target 300 deg F for it to shut down (TST takes care of the monitoring & shutdown for me ... way cool).

hope this helps...

 

Why does more air flow with the after market intake cause you to loose mpg I would think it would help out?Whats the advantage of stage I compared to stage II?

 

more air means more fuel which helps your turbo spools faster. I've concluded that the faster your turbo spools, the more your mileage will go down. keep your foot out of it and it's not so bad. with the stage 1 you get a smaller filter setup. this slows the spoolup down IMO (no experience with the smaller filters other than stock vs stg 2) compared to the stg 2 filter. stg 2 will get you more top end, but loose bottom end for every day driving. wot you may have a boost in low end torque because you've spooled the turbo and have good boost built up.

you have to decide what it is you want out of your truck...