Engine Question about MAF sensors and pipe diameter...

Question about MAF sensors and pipe diameter...

When I get my piping done for my turbo, I'll be installing the MAF sensor into larger diameter piping to match the Celica intake throttlebody. My question is:

Is the MAF tuned to the diameter of the pipe or is it the ECU's fuel map? Since I'm using a pipe the same size as the Celica's intake, can I simply use the Celica's MAF sensor or even a 2003-04 Corolla's MAF with my cars?

the MAF senses air temp due to velocity, correct?

so a larger tube = "slower" velocity, meaning you'll run "lean" correct?

I'll subscribe to that logic, if thats how the MAF works...

taken from http://www.cobbtuning.com/tech/airflow/

so if you have a larger pipe, the less air is going to flow through, using less energy to heat up the wire, making the ECU think that it isnt sucking as much air, therefore balances out by using less fuel, and yea, lean

Vamp, I have used different sized piping for intakes with MAFs before (2ZZGE) and I had no problems at all. Since you're going to be tuning the car anyway, you'll tune it to whatever airflow you are reading compared against the wideband, so you can adjust it any way you like.

-Doc

you can also create a valve deflector that directs air to the MAF seperate from the main flow and get diverted back to the right. pretty much all it does it measure air density.

MAF measure the "weight" of air coming - hence the terminology MASS AIR FLOW. Like Tamago mentioned - most measure the current needed to keep a control wire or film at a certain temperature. Info is then relayed to ECM to be compared to preset maps to determine correct ignition and fuel. The MAF is generally keyed to both size of the intake piping and distance from intake valves in the head.

Lots of time when you add an aftermarket intake that hasn't be properly designed - at higher RPMs, resonance of certain frequencies can crop up when the air traveling through the intake plenum actually bounce back toward the intake opening and confuse the MAF. Usually the result is a read "lean" condition due to misread quantity of air. But if your going to have a separate A/F computer - doesn't really matter. But will entail more tuning on your part.

what he said ^

Hey, let's at least quote the right person! just buggin ya.

Alright. Just want to make sure about everything. I'm having issues with my MAF at the moment, but I think it's because this generic intake has the sensor right before the filter, which doesn't give it a smooth enough air flow and causes irregular lean idling. When the car's moving, it's fine though.

My bad! I started my reply and was interrupted. Got hung up in a meeting and finally finished it when I got free. In thoses 23 minutes that passed - all you guys wrote in.

Good find with that link - good link to direct someone to instead of trying to explain all of that info.