I totally agree with you in the sense that it doesn't make sense, but I know several people within my region that have made the swap. All have picked up noticable power gains all the way through. I was highly skeptical when I was first told about it, for the very same reasons you mentioned. The cost was nominal so I gave it a shot, and frankly I am glad I did. I was pulling around 270-273 consistently prior to the install (281-283 after the maf, intake tube, and retune for the larger maf). The car was tuned via about 20 pulls and extensive tuning with the 70mm (stock) maf, and it was tapped out in terms of power production. The latter tune was done off another cars basemap on the 3" maf and another 3 pulls (thats all) to get the 281-283.

I have seen many posts on my350 where Uprev states the ecu issues were limited to just the early 03 sedans (not coupes).

My car also stops making power around 6300 and dies off (but not as drastically as I have seen on others).

 

Here is the dyno chart:


Peak power happened at aprox. 6300rpm and stayed flat till redline ( or near anyways, I let off 100rpms before redline ).

I don't think shifting my powerband any higher would be a good idea as the loss in low end torque will probably affect me more than the small gain I will likely see up top.

I agree with what you say about the maf...making the maf housing larger will lean out the car and advance timing assuming no additional tuning is done ( this is due to the car thinking it has less load due to decreased airflow in the sensor ), but this is not the case since additional tuning was done. I do not see the size of the housing it's self being a restriction as it's pretty large for the power we put down.

 

You are right about the housing. The car basically not run without proper tuning. I installed mine after getting on the dyno. Swapping to a rev-up plenum is a silly suggestion (that should be ignored). In terms of power you are fine. Keeping in mind that it is auto, which inherently has a larger loss through the drivetrain. That's most likely a low 240's (perhaps even a bit higher) whp through a 6sp.

 

on the mass air flow unit, I would say yes and no. from what I have seen looking at a/f ratio from 5800 and up most stock tune tend to run too rich. Which btw most manufactures do for that safety net).That being said the introduction of a larger volume of air (3"maf) would lean it up thus gains to be made. Of course you prabably could accomplish the same thing by getting the a/f very close to 13:1.On my vet the stock maf would support 500 before it maxs out , which iirc was 3"inch.My question would be losing velocity with the larger maf which would mean losing bottom end grunt. Someone would have to confirm what the stock maf can support as far as airflow/hp.maybe some input from the turbo guys can shed some light if the swap is required.

 

The a/f was the same on the 70mm maf and 80mm maf. It had nothing to do with leaning out the air mixture (in terms of power gains). My car is 13:1 until 6k when it teeters to 12:8 at redline. Without tuning the car runs like dog crap with the larger maf. I will post pics of the before and after where nothing changes but the maf, intake tube, and quick retune. Give me an hour to get back home and I'll post em up.

 

now this is getting interesting!!!! Some guys in the c5/z28 world actually removed the maf altogether(speed density tuning) because of maf maxxing out and pickied up considerable hp and response.btw going to the larger maf did you notice any lack of throttle response???Afterthought....anyone ever ported their throttle body? 8/14 hp to gain on an ls1/ls6/ls7!!I could go on and on as far as ecm tuning that I have'nt seen mentioned here.This prabably should be posted somewhere else but for the at guys there should be programming to be done to make it shift harder,on time and change shift points.Once again this is being done for vets and z28. ecm i'm almost sure controls these areas.Any tuners want to jump in here???

 

First, I assume the the latter of your post is relating to auto guys (I should mention I am 6 sp). I did not notice any change in throttle response, and if anything it increased slightly.

Here are my before and after dyno's. Keep in mind that these are on a load bearing dynodynamics that reads ~10% under a dynojet (from my expereice it is more like 8-9% SAE).

Before:



After:Swap to samco intake tube, 80mm z1 maf, cleaned maf sensor, and quick retune.
Yes.....my car made 254ft of tq (its a crazy car). Can't find the one with af, but its about 12:9 or so. Let off at 6300 (hence the rapid drop off)



Here is a link to an early Moderator on my350 who made the swap (who also ported the tb).
http://my350z.com/forum/intake-exhau...stalled-5.html

*Note my final tune is a bit less aggressive and pulled 260.7, but I couldn't find the graph.

Generally the people who have ported the TB's on bolt-on VQ's have seen no gains, but I could certainly forsee some gain with the larger maf in conjunction. It wouldn't make sense though unless you ported the TB opening on the upper plenum to match the increased tb size.

Cheers, hope this helps.

 

If you are curious, the lines on the second graphs are: Lowest) Stock graph on file (03 Z) Middle) My car with bolt-ons (same as the 246 w/o tune) Highest) Close to current .

 

Interesting...I might have to look into this...need to find out what the inner diameter of the Injen cold air intake is too.

 

I would have to assume its ID is greater than 3". I think I remember someone posting before that it was 3.25", but I'm not certain.

 

So i just pulled out my MAF housing as well as my Ztube on my g35coupe and the measurements are 2 17/18" and 3", respectively. So is this Z1auto upgraded MAF just 1/18th larger in diameter?

 

Were you measureing OD? Stock is 72 inlet 70 exit.
Z1 is 80 inlet 78 exit.
I am not endorsing this as the all-mighty NA mod. Just posting my experience. Both dyno's are uncorrected. Ambient temp was 72 on 1st dyno and 71 on second. IAT temps were within ~2C.
I have know of 4 guys with z's that have made this swap. Thus far my gains are higher than the others (perhaps some attributed to cleaning the maf sensor itself). The lowest I saw was 6whp gain all the way through (using utec).

 

I was measuring the ID only on the exit. I'm not doubting you at all, I was about to order the housing and was thinking of ordering the Samco tube as well, but wanted to see if it is any different from my Ztube (is the samco 3" ID). Since I was at it I measured the MAF and got confused with the numbers. Let me take some pics.

 

Yes, the samco is 3" ID. I primarily got it because it was cheap and retained the factory look.

 

So just measured the MAF housing again. Looks like the Z and G have different numbers.

In: 72mm
Out: 74mm

I see so the Z1 is not really a 3", it's actually larger and different from one side to the other. Little confusing the way they list it.