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Discussion Starter · #1 ·
I've added a AFE Stage 2 Si Cold Air Intake to my '03 LB7 and have had slow throttle response ever since. I can go back to my stock air box and response returns. AFE guys have been great but cannot explain why this is occuring to my truck. I have tried cleaning the Mass-Air Flow sensor with CRC MAF cleaner, check all intake ducts and piping for leaks, and changed MAF's. The MAF is correctly positioned in the air stream so I'm at a loss.

Other Mods to truck are as follows:
Banks Six-Gun with speed loader
Air Dog 165 set at 10 PSI running
4" stainless exhaust
Big Head Wastegate set at just 22 psi

I have also disconnected the batteries for 20 mins after the change over to the AFE, per their tech support.
No codes and all scan data per a Tech-2 is normal.

Can this be a situation where the stock MAF cannot calculate the difference in airflow fast enough? Also, there are 7 small hole on the underside of the MAF that are not covered in the stock box, but are covered by a seal provided by AFE to mount the MAF into their system. You can see that they go into the MAF body, as metal in visible with a flashlight.

Please HELP!
 

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Hmm that's weird. I can see that u have a banks big head set at 22 psi? That is less than stock or right at stock. You can run 28-30 psi safely w/ a stock turbo. When was the last time you changed your fuel filter? I have the afe intake and have had no problems with my truck being sluggish except when I am at stock power levels.

BTW :welcome to the forum!
 

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Discussion Starter · #3 ·
New primary filter, plus the Air Dog filters. Power is there just have to get into the turbo to use it. Feels like a gas engine with 10 degs of timing pulled out.

Yeah 22 PSI is pretty much stock. With 318,000 miles, I didn't want to tempt fate with anything more. I occasionally run it at a local 1/8 mile track where its been 8.49 with a1.80 60ft time. It's actually my tow vehicle for my other truck to I race every weekend.
 

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Discussion Starter · #4 ·
BTW. Banks system has stock feel unless your into the turbo then it comes alive. I also have a Preditor (Granitelli) and when using that tuner set at any level, it makes the sluggishness feel less noticable as that particular tuner gives you increased throttle response at all throttle positions.
 

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Discussion Starter · #5 ·
This is an update to my original post back on 9/1/10.

The AFE Stage II si intake that I originally bought was causing the "Slow Throttle Response" issue. The "si" version or "Closed Box" uses a different air induction tube to the turbo, that repositions the MAF approx 4" further up the air stream than the factory box or the AFE Stage II "Open Box" base air intake system. The positioning of the MAF in the Sage II si intake changed, or altered the flow of the incoming air just enough to cause my "tip-in" throttle response issues. AFE sent me the base "Open Box" intake which has the MAF located, as with the stock intake, at the start of the intake induction tube and the issues I was experiencing went away. I have also turned up my boost to 28 - 29 PSI and am looking forward to running it as the truck feels quite a bit quicker than before..

I hope this helps others that might have similer issues.
 
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