CAI, IAT & MPG acronyms abound
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Joined: Jun 2010
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2002 C32 AMG
CAI, IAT & MPG acronyms abound
So my mpg and butt dyno said something wasn't right. My custom cai was full of sand and the filters clogged. As an experiment i removed the cone filter housings and stuck big spectre filters just behind the grill horns but they are still kinda on top of the valve covers. My mpg dropped to like 17 around town and 22 highway (from 20 & 25).
I should have measured my iat with the cai on but i didn't. With the open filters sitting in the front of the engine bay my iat after a few min on the freeway are between 105 -115. ( measured by obdii puck and torque app) the iat is 85 - 95 around town before i get on the highway. Is this way out of whack for what my ecu is expecting? Or is it just more air volume than my ecu is expecting?
other than my dip in mpg, engine does not run as smooth at idle. Time for a tune to set timing or back to inline cai?
I should have measured my iat with the cai on but i didn't. With the open filters sitting in the front of the engine bay my iat after a few min on the freeway are between 105 -115. ( measured by obdii puck and torque app) the iat is 85 - 95 around town before i get on the highway. Is this way out of whack for what my ecu is expecting? Or is it just more air volume than my ecu is expecting?
other than my dip in mpg, engine does not run as smooth at idle. Time for a tune to set timing or back to inline cai?
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Joined: Jan 2011
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From: Scottsdale, AZ
C32, E93 M3
iat around town should be higher than on the highway where there is more airflow.
Terrible idea to have open filter sucking air from the hot engine bay.
I'd love to see a picture of your setup
Terrible idea to have open filter sucking air from the hot engine bay.
I'd love to see a picture of your setup
Thread Starter
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Joined: Jun 2010
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2002 C32 AMG
I'll snap one tomorrow, pics of my cai intake are on the diy intake thread.
So if iat is higher on the freeway either my obdii isn't getting the right reading or the filters are sucking air directly affected by engine temp at higher rpm and not by airflow?
Or is it that the faster moving air being sucked in at a higher rpm raises the iat?
So if iat is higher on the freeway either my obdii isn't getting the right reading or the filters are sucking air directly affected by engine temp at higher rpm and not by airflow?
Or is it that the faster moving air being sucked in at a higher rpm raises the iat?
Thread Starter
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Joined: Jun 2010
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2002 C32 AMG
So I added some extra tubing and put two cone filters right up front. My iat went down 10 degrees across the board! When I'm on the throttle iat peaks at 104, all normal driving is 96-98. Car runs great again and I'll do some long distance mpg runs on the way to work this week.
I know the hodge podge tubing in my engine bay is practically sacrilege but I'm just experimenting. The surface area of the two cone filters that i have fitted are 32" each, that's only 75% of the surface area of the stock filters! If i can't find bigger filters that fit i may just go back to the stock air boxes. Srr, having problems uploading photos from my Android, Will post soon.
Obviously colder is better but what is the lowest iat anyone has achieved? What is a reasonable goal? Should i stop fussing around and just buy a tune and a pulley?
I know the hodge podge tubing in my engine bay is practically sacrilege but I'm just experimenting. The surface area of the two cone filters that i have fitted are 32" each, that's only 75% of the surface area of the stock filters! If i can't find bigger filters that fit i may just go back to the stock air boxes. Srr, having problems uploading photos from my Android, Will post soon.
Obviously colder is better but what is the lowest iat anyone has achieved? What is a reasonable goal? Should i stop fussing around and just buy a tune and a pulley?
