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-   -   AEM CAI:LTFT and IAT Mystery Solved (

SeeeeeYa 10-11-2012 11:21 AM

AEM CAI:LTFT and IAT Mystery Solved
This is a thread on IWSTI that I think has info that may concern people here.

While the LGT platform doesn't have the problems I've encountered with my 11 (08+) STi, body-wise, the AEM CAI installation is fundamentally the same. People who have this CAI, and others with similar ones, may want to explore the facts in this thread.

Spec B 10-11-2012 11:50 AM


GTTuner 10-11-2012 02:16 PM

Very interesting indeed. So he insulated the MAF from the metal intake tube, then grounded the tube?

Spec B 10-11-2012 02:23 PM

Pretty much.

I suspect that the knock sensor noise (Knock Sum increments) at low load and RPM is also an electrical issue - I just do not know enough to be able to confirm my suspicions.

scoobydoobie 10-12-2012 04:31 PM


Originally Posted by Infamous1 (Post 4110696)

Have you or other tuners noticed inconsistencies while tuning with the AEM CAI? Would say, the KSTech intake (stock size MAF), be a more stable choice?

bugblatterbeast 10-22-2012 06:03 PM

I had a chance to try insulating the maf sensor this weekend. I used a slightly different method which might be of interest (as it is less work).

I placed small squares of 1mil Kapton tape over each screw hole on the intake. Then I inserted the maf sensor. With the sensor as a guide I poked a small hole in the middle of the tape. Next I installed nylon bolts through the tape. The size is M4x0.8.

I haven't had a chance to make to make precise measurements yet. What I've noticed though is 1) the hickup I used to have when the rad fans cycle is gone (I had previously assumed it was just the blast of air upsetting the maf) 2) the car stays in lean burn more frequently (I'm mapped to run leaner than stoich under cruise conditions) 3) the engine runs smoother. number 3 is very apparent at a few RPMS as I'm using a single mass flywheel + hardened tranny mounts.

it is too early to tell (only 40km), but fuel economy seems to have improved. after I've driven a couple thousand with this modification I will know for sure.

SeeeeeYa 10-23-2012 05:53 AM


Originally Posted by Infamous1 (Post 4112567)
No it's not an issue with the LGT.

I wouldn't be so certain. The "issue" isn't in the realm of "tuners," because tuners don't work to the level of resolution this issue addresses.

Time, and more people investigating the possibility, will tell. Those satisfied by tunes with +-5% fuel trims could care less. Those who don't know what you're talking about when the conversation turns from power to polished throttle, won't care. Those with automatic transmissions... the bulk of LGTs... likely won't care. Those who accept "studder" and other engine anomalies as normal, who think any oil on the stick is fine, or who have others do their dirty work, won't care.

But people with manual transmissions, like those for whom the original thread was directed, will have more reason to question the status quo. Those who pursue impossible perfection, who log and adjust tunes as an inseparable part of ownership, will wonder what-if. Some will take a look. I'm betting some will find a penny heads-up.


For example:


I've installed the IAT to the charge pipe to help with speed density fueling with the MAF still located in a short ram intake. The idle with that setup was inconsistent at best. After reading this thread, I grounded the two pipes to the intake. After tuning, that returned the Five-O 1400's to manufacturer's latencies. Big improvement in driveability.

SeeeeeYa 11-17-2012 07:43 AM

First post here updated.

See "stumble" and "hesitation."

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