There seemes to be a bit more going on in this forum than in the n2o section so I thought I would ask here. My goal is to get have a larger diameter maf sensor than the 300z. I was wondering is the mafs' offered by Granatelli or the likes would work with our cars. The reason I ask this is cause I know of someone who uses one from a cobra on his 240 without a hitch.

Let me know your thoughts.

 

Sure it is possible, will require AFR tuning and maybe an AFC or JWT ECU to be done properly. Some domestics match a larger MAF with larger injectors, i guess their is a ratio, but you would need to know the specs on the MAF compared to stock. 300zxtt maf is just as big as the intake pipes on a VQ so why do you want bigger?

 

yeah I think people seem to get the misconception that the Z32 MAF swap is done for physical size increase when thats not even the purpose

 

The reason for the increase in diameter is to get more air into the engine without tc/sc, looking into custom intake manifold. Guys please set me straight here, but i think there is something to be said about the fact that when a stang or maro upgrades this sensor it allows the computer to accomodate for a more aggressive a/f mix and timing without loading up the voltage on the sensor. However i could be way off on this.
Matt...How does matching the larger injectors and maf corelate between the two? And how big is the opening of your intake manifold and what does it taper down to, if you know?

Thanks for your replies, keep em coming.

 

The Z maf can read more air than a maxima MAF. That is why people switch to the Z MAF.

And why make a 3 inch hole when the TB is 2 1/2? Know what I mean?

 

I know why people switch to the Z maf hence my reasoning for yet an even larger maf. Don't know if there is a corelation to a larger maf being able to "read" more flowing air?
Reference my post above,"looking into a custom intake manifold"..., for instance 80mm maf mated to an 80mm opening of the intake mani.

Also, what might your thoughts be for the argument of increased air velocity the closer the air would get to the smaller orifice at the beginning of the intake manifold?...you know, going from a large cai and maf down to the smaller tb?

 

the z maf is the same size as the maxima maf... the callibration is different.

 

OH Damn.....now i'm a bit confused. Could you please elaborate?

 

the maf sends different voltage signals to the ecu.. for a tuner like jwt the z maf give him a better scale to work with. you can hook up a z maf where the max maf is because it is the same body but be forewarned, the z maf will not behave well on the charged side if you are boosted.

 

Yeah, JWT recommends mounting the z maf before the blower inlet and to run a recirculation hose from your bov to somewhere in between the maf and the blower, that way you don't run excessively rich when the bov is open, such as at idle or at partial throttle cruising.

 

Sorry should have stated that they were the same size...

and on the custom intake manifold... I missed that

And on going from the CAI to the TB... I say get a bigger TB..

Or a turbo

 

The MAFs have a sensor that measures the amount of incoming air. The Maxima sensor has a range of say 0-300whp, however the 300Z sensor has a range of 0-500whp.

The purpose of changing from a Maxima to 300Z MAF is NOT to allow more air through, but to have a sensor that has the ability to MEASURE more air for 300-500whp.

300whp/500whp are just examples, however INORDER for the Maxima ECU to work with the 300Z MAF, JWT must modify the ECU to understand the larger range it provides.

 

The numbers quoted to me by JWT are 350 hp with a Maxima maf and 420 hp with a Z32 maf, assuming both are used with 370 cc/min injectors.

 

ok question if i put a z32 maf on my car before i get the ecu changed will the car still run?

 

I think the answer is no, but I'm not sure. I have a Z32 maf and when I measured the resistances of the two pins that take voltage, they both measured exactly what my Maxima maf measured. Maybe this weekend I'll swap in the z32 maf and see what happens. Or not. I'd hate to ruin it or my ecu.

 

I dunno....I wouldn't try it though. like I said in the other thread, a backwards connection can blow the ECU, IMO I wouldn't risk it at all! but what would be the point of running it on an un-modified ECU and stock injectors to begin with??

 

that would mean you have to change the plug connector to fit the z maf and change it back if it doesn't work.. i wouldn't risk our ecu's reaction to the out of spec voltage since it won't know what to do with it anyway. my .02

 

What kind of gains have people notices with the new ECU programmed fro the z32? Is it really worth it to have the maf read up to 420hp?

 

I've seen 13+whp/tq on a SR20DET with ECU, MAF, and 550 injectors, however most if not all of that was from the JWT ECU putting the A/F ratio perfect at 12.5:1.

I'd call JWT and ask at what point you NEED to go with the 300Z MAF.

 

Ok ill look into it once i turn up the boost.

 

They will tell you what they told me, which is once you get above 350 hp, then you need to go with the Z32 MAF.

If you assume a bsfc of .55 lb of fuel/hr/hp and an afr of 11.5 (which is what JWT tunes to), then 350 hp equates to about 490 cfm. To get 490 cfm at 6400 rpm would take about 10-11 psi of boost (if you assume a volumetric efficiency of .85, assuming a higher ve lowers the boost required for a given cfm).

So, a Maxima MAF along with a JWT upgraded ecu programmed for 370 cc/min injectors at 43 psi fuel pressure should be good for up to 10-11 psi of boost. More boost than that will require the z32 MAF if you want to stay with a MAF metered afr.

 

has anyone ever considered archiving/FAQing links to some of these threads like this I can find a few great posts in this forum with a lot of good info, something to think about

 

THANK YOU! VERY very nice info.

So, once you exceed 350Whp on the Maxima MAF, your MAF no longer meters additional air, so the ECU can't increase injector pulse-width for additional fuel.

Bascially, you are relying purely on the FMU and AFC for enrichment beyond 350whp with the Maxima MAF.