Air Flow Meter After Turbo Right Before Throttle

[frozenwaffles]

Hi guys, I've heard good things about putting the afm right before the throttle body. Better idle, smoother acceleration and much less decel problems. Anyone confirm this? Also how much boost can the afm (z32) handle???

[89CAL]

Is this with atmo BOV cause the best place for AFM is where it is in stock position

Z32 handles up to 350rwkw I think

[frozenwaffles]

ok some things i forgot to mention:

Its a 100% track car - max, power, max speed, max hadling, max pollution

there are no emmisions systems on the car.

blow-by is vented to aomosphere.

BOV is vented to atmosphere.

this discussion has nothing to do with street compliance or anything like that al all

[paulr33]

if what you think is true nissan would have done it from factory

imho leave it where it is, its there for a reason and setup in that order

[frozenwaffles]

thats a very boring answer paul...

[Simon-S14]

prob not best to put it right before the TB however on mine it is on the cold side of cooler pipes on the pressure side. i did it mainly to eliminate the stalling you get with a AFM in front of a large turbo, and it works quite well

[XRATED]

As of yesterday I just completed installing a trust T67 kit into my 32 gts-t. I didn't want a 4" to 3" reducer infront of the turbo for the afm, not to mention the reverberation from the turbo would stall/distort the afm signal.

I relocated the Z32 afm post cooler.

Try and keep 200mm between the sensor and tb.

I havn't had the car tuned yet from the previous set up, but the car drives fine... no hesitations, stalling, off throttle disruptions.

For top mount turbo's with a 4" intake, I would recomend this mod.

J.

[Fat_Tony]

not to mention the reverberation from the turbo would stall/distort the afm signal.

Any evidence to show this happens? Maybe if you just stuck in on right in front, but most setups have a good 200mm between the AFM and turbo.

Any evidence to show 4" to 3" reducer causes a restriction?

[paulr33]

its just odd

4" intake and the 3" intercooler pipework

surely the restriction is the other way around

ie after pressurized compressor, not before?

[XRATED]

Any evidence to show this happens? Maybe if you just stuck in on right in front, but most setups have a good 200mm between the AFM and turbo.

Any evidence to show 4" to 3" reducer causes a restriction?

I have as many other people have had issues with solid intake pipes, large turbo's and isuues with stalling from boost to closed throttle... Back in the 90's there were little jap intercept modules that were designed to stop the irratic/stalling issues caused by 'dose'/reverb.

Are you serious... 'any evidence' hello- your putting a 'reducer' on it. daaaa. Ha ha ha.. Suck through a garden hose, then squash it by a 1/4- you'll still get the air you need, but you have to work harder to get it.

At the power levels I'll be running (still stock engine 25), very little would be lost buy restricting the intake down to 3"- there is a small gain in transitional responce and low end spool up.

J.

[zebra]

Do you still have the tiny standard thottle body? And I bet your ports are standard too. And have 200,000ks on the standard piston rings.

See where I'm going with this?

[XRATED]

Do you still have the tiny standard thottle body? And I bet your ports are standard too. And have 200,000ks on the standard piston rings.

See where I'm going with this?

VH45 tb, greddy manifold and port matched/cleaned up head. 90k km's

I bet you've got a tiny throttle body-

J.

PS. I'm planning to run around 1.5bar so I'll see if the Z32 case stays together. I have seen 4 or 5 cars that run over 20psi with the same afm location.

[zebra]

VH45 tb, greddy manifold and port matched/cleaned up head. 90k km's

I bet you've got a tiny throttle body-

J.

PS. I'm planning to run around 1.5bar so I'll see if the Z32 case stays together. I have seen 4 or 5 cars that run over 20psi with the same afm location.

cool

wasnt aiming it directly at you (my thottle body that is )

Just see it all the time on here, people trying to get every ounce of response out of a flawed engine.

I personally wouldnt trust a Plastic AFM with 20 odd psi of pressure and a hot engine bay.

[XRATED]

cool

wasnt aiming it directly at you (my thottle body that is )

Just see it all the time on here, people trying to get every ounce of response out of a flawed engine.

I personally wouldnt trust a Plastic AFM with 20 odd psi of pressure and a hot engine bay.

The afm is post cooler and sits outside the engine bay. I've seen plastic pipes pake explosive pressures of well over 600psi, so I'm not too conserned about the casing... it's just the lid that's siliconed in over the board that's I'll have to watch dosn't fly off. If it works well, I'll prolly re-shell the afm into ally pipe to cut down on the amount of clamps/joints.

J.

[rob82]

I wouldn't trust an AFM to stay in tune for any length of time with the airflow meter having to cope with the amount of oil that will be discharged from a turbo. Hope you guys are keeping a good eye on AFR's.

[STATUS]

works fine but keep it closer to the cold side of the cooler, as far from the TB as possible, generally with a PFC we actually cut the z32 in half and epoxy the sensor into the cooler pipe... this is needed as boost over 20psi generally blows the z32 circuit cover apart. If you drill a 20mm hole in the cooler pipe and epoxy it in place it can handle 30+psi no worries.

We also play with cooler pipe diameter to raise or lower the resolution of the sensor.

The PFC has a very user friendly afm voltage curve and it takes very little time to "write" a perfect curve to suit any pipe size and boost level. It is possible with nistune etc but its much more time consuming.

[DVS JEZ]

Does the sensor have to be in the correct orientation when near a bend?

[scotty nm35]

I don't think it will work well mounted on a bend, mine on the intake didn't, it was very erratic no matter which way I adjusted it.

[Simon-S14]

works fine but keep it closer to the cold side of the cooler, as far from the TB as possible, generally with a PFC we actually cut the z32 in half and epoxy the sensor into the cooler pipe... this is needed as boost over 20psi generally blows the z32 circuit cover apart. If you drill a 20mm hole in the cooler pipe and epoxy it in place it can handle 30+psi no worries.

We also play with cooler pipe diameter to raise or lower the resolution of the sensor.

The PFC has a very user friendly afm voltage curve and it takes very little time to "write" a perfect curve to suit any pipe size and boost level. It is possible with nistune etc but its much more time consuming.

thats interesting to hear. mines still mounted as an OEM afm, no chopped or anything.

so larger diameter then the ID of an AFM would give you more resolution? or is it the other way round?

[R31Nismoid]

Ye putting it in say, 4" piping will give more resolution as the AFM is measuring less air.

Hence Nismo and Z32 AFM's are close - but not identical in resolution.