Subi is switched. Real time is open loop but with a non wide band O2 it can only read and adjust down to like 11.2afr which is bad when you need to run richer. Maybe nissan is different being NA. Megan should know.

Im in the garage right now using my cell, i will make it short.
I think understand what you just explained but I wouldnt put a bigger maf tube (2.75 OD) than what your intake is. It would just transfer the bottleneck somewhere elese and causing some intake resonance because of the relatively big gap of your last bottom picture.

IMO, your maf tube should be flowing slightly better than your TB. And from your maf to your intake manifold should either be the same or bigger than the flowing capability of your MAF tube. which help with throttle reponse if its a bit bigger

I would think with the intake you would want to have the largest ID at the filter and the smallest at the TB. That way you can increase the velocity of the air flow into the manifold. If you have restricted sections (by the MAFs) you will be creating a vacuum that prevents the maximum amount of air from flowing.

So I would think you want something like 2.75" - 2.5" - 2.35".

Depend what your goal is . This is partialy true.
If your pre-throttle tube is smaller than the Tb itself and the Maf . You are killing the throttle respond which for an N/a setup isnt something you want.

But I totaly agree from the filter up to the entry of the maf tube. Should be bigger
this is what was done on my custom cai... starting from 3" down to 63.5mm.

But I don't have a choice. The MAF section and some small sections are only 2.35" ID and the bottle neck. The TB is now 2.48". I either replace them with 2.63" ID (2.75" pipe) or leave them alone. I can't make what you made. If I replace all 2.35" sections my cai would roughly be 2.5" with with a few 2.63" sections. As you said to N0SL3N this might be good since the cai will taper into the smallest spot (the TB again).

Ok I did a little research.

The TB lip is 2.81" at its largest. That tells me the Z1 post tube is around that size ID since it has to slip over it. Now its not hard to slip over but it's also not that easy. So I'm going to guess the several inches of the z1 post tube is around 2.7ish inch ID.

http://i39.photobucket.com/albums/e1...ps387aa232.jpg

Now the OEM MAF section is only 2.54" OD which is why you see a bulge. The post tube is being forced into a smaller size. The silver pipe is 2.5" OD with the same ID of the OEM MAF tube. So forget all pipe before that, I'm running about a foot of 2.35" ID pipe with the MAF sensor in it that then opens up into the post tube that's 2.7ish ID that then goes down into 2.6" (TB opening lip) then 2.48" (right at the butterfly plate and port matched into the manifold) of the TB.

http://i39.photobucket.com/albums/e1...ps578ca956.jpg

So if I at least replaced the foot of 2.35" ID silver pipe and OEM MAF section with 2.75" OD pipe, not only would it fit pretty well into the z1 post tube but it'd also lower the huge gap (2.35" to 2.7ish" now, to 2.63" to 2.7ish) I have right now.

Any updates?

you need custom 2.75" intakes asap, the MAF housing will be your big restriction.

Still looking for a tuner that doesn't charge an arm and a leg. I like a few but when I know a uprev license costs xxx and you tell you change double, it's not cool. I'd rather have you lie and tell me the tunes labor is more.

Where's a 2.75 OD MAF housing I can weld to 2.75" OD pipe? I know a place for subis up to like 4" OD pipe.

Do you KNOW the cost of an UpRev license?
I do, and I know it's retarded cheap... But you can't NOT pay the park up... So... Just gotta bite that pillow and bend over.

Yeah the IPS tuner I've known for 5 years and friends with. He charges $150 uprev, $100 to rent dyno from IPS because he doesn't 100% work there, just a stop by tuner, and $200 for him to dyno my car. If it takes a hour it's the same. If it takes 5 hours, it's the same. For me at least. All others he charges $250 to tune. Subis he doesn't have to charge for uprev!! I miss $350 tunes, or custom etunes for $80.

I do have one update. I haven't touched my mpg in a long time. Its normally 22-23. It's been a week or so since I put the parts on and I've been driving everywhere!! Work, 3hr trips, etc etc. I do 75-80 on the highway. I've got maybe 600 miles so far and this has happened...it's gone way up.

I know uprev sells the weld in MAF flange but not pre welded to a pipe. so you would have to find a local fabricator to make the intakes for you.

25, that's awesome!

That's sucks about your tuner good luck with it, I did see a few 2.75 slip in Maf housings but I don't remember any weld in tubes