Turbo piping set up? AFM location

[garyneedsz]

I have a stock 81zxt motor setup. the manifold and turbo are stock. i have it setup to where the turbo is connected straight to the AFM by a coupler, then to a air filter. i want to move the source of to a cooler area, which is not right next to the A/C bracket which is where it is right now. So my goal is to essentially run piping to a different location.

 

my question is, should i run piping after the turbo, and then the AFM?

 

or should i run AFM, and then the piping?

 

would the placement of the AFM affect the air reading significantly or does it not matter.

[Tony D]

The Stock Turbo AFM is calibrated to take the inlet airflow before the turbocharger.

Placing the AFM after the turbo, under pressure, is a radically different flow and usually only done when someone is converting an EFI system from N/A to Turbo. This allows the standard condition flow monitoring of the N/A AFM/ECU combination to be effective with the addition of larger injectors and possibly a variable rate Fuel Pressure Regulator. It's old tech, though many of the DSM/Mitsubishi people like this with the MAF setups.

 

The most convienient location in an S30 without the AFM bracket is to invert the stock Turbo AFM, just forward or behind the radiator mounting bulkhead, using the hole for the left underdash ventilation vent (remove the plastic connector from the inner fenderwell to the hole). You can then use standard N/A CAI kits to get your filter off the front of hte bulkhead.

 

Make sure you use 'hump' hoses for the connections between tubingruns, as the motor will move on the monunts, and some flexibility in the intake system is required. Really, the farther the AFM is from the turbo, the less chance a backfire when cold will cause a problem with the shutter slamming shut and sticking. When it's close to the turbo inlet this is a possibility. Also, having a relatively straight run (about 6-8" on the stock turbo) is conducive to the best flow into the turbocharger inlet. Industry standard is 6 to 12 pipe diameter runs before a turbine inlet, and after any elbows before/after a metering device. So mounting about where the stock AFM is on a later model S30 is about as close a compromise to ideal positioning of the AFM as you will get. Imagine that, the Nissan Engineers did know what they were doing!

 

To be clear, airflow should be like below:

 

Air Cleaner-Tubing-AFM-Tubing-Turbocharger-Tubing-(intercooler-tubing)Throttle Body-Intake Manifold

[garyneedsz]

just the answer i was looking for! thanks.

 

i was a little confused when i read the first part, but then i read my post and just realized i worded it wrong. haha

 

thanks for the clear up though

[Pyro]

I moved my afm in front of the radiator support. mounted up high near the hood.

 

Cut the afm wires and extended them about 18 inches.

 

ran 2-1/2" mandrel bent pipe to the afm from the turbo inlet and used a little k&N filter on the end of the afm.

 

works great.

 

Moving the afm out front makes more room to run IC piping in the engine compartment.

 

Then installed a Bar & Plate IC under the AFM.