DIY cai?
 

Z1's installed


http://i39.photobucket.com/albums/e1...psc0afe538.jpg


All done. I ended up needing a 2 more couplings, 45* ones. If someone would have made 30* I think it'd be a little better. Because of the extra 15* I had to bend some tabs outs of the way where the bumper snaps to the support bar. I think you have to do this to the stillen anyways but its no big thing. The pipe isn't hitting anything and the couplings aren't kinked or will rub anything that will hurt them so I'm real happy with fitment. There is not much movement so no need for a bracket. Over all its a perfect fit, 2.5" pipe, lots of silicone so no heat soak! And even though I needed 2 more couplings, I didn't néed all the pipe so next time I could save money by not buying 36" of it.

http://i39.photobucket.com/albums/e1...ps35511e6a.jpg

http://i39.photobucket.com/albums/e1...psfb0c01f2.jpg


http://i39.photobucket.com/albums/e1...ps4349f062.jpg

http://i39.photobucket.com/albums/e1...psf204b683.jpg




So to update this I have all the parts needed but the filters. I ended up getting what you see in the pics. I'm going to cut my MAF sensors off the stock air boxes as its the same ID as the Stillen's. the couplings provide the bends needed and it will sit just like them.

Now doing this I've spent about $110 on the 6 couplings and clamps. I could save more if I bought a lot of each item and I was thinking about eliminating the 90* couplings as people on eBay sell pipe in a 90* bend. I'd just give them the length I needed since the filter end is shorter than the MAF section. The k&N filters that Stillen uses are $70 shipped from the cheapest place I could find online. So people out there doing drop in's for around $70, or whatever the drop in's cost, for $110 more you now have a Stillen setup! Its the same size pipe, same MAF, the only difference is the post MAF tubes. Z1's post MAF tubes run about $112 but this way you don't have to drop $500+ cash right away for Stillen. You can spend $180 first, get the cold air like the Stillen's, and then buy the post tubes and only have $292 invested!!

Parts needed

2- 2.5" straight couplings
2- 90* bent couplings
2- 45* bent couplings
2- 2.5" to 3" couplings
2- 2.5" long, 2.5" piece of pipe for in between the 90* and the 2.5" to 3" coupling
2- 2.5" long, 3" piece of pipe for the K&N filter to bite onto the end
2- K&N RU-2820 filters
16- hose clamps
1- 36" long 2.5" pipe
Then later if you want, post MAF tubes.

Pipe, couplings, clamps all put together kinda.

http://i39.photobucket.com/albums/e1...psca658e6d.jpg

More close up of everything.

http://i39.photobucket.com/albums/e1...ps713a5e05.jpg






Anyone make there own intake? The stock MAF tube is 2.5" OD and nice and straight. A simple cut and you'd be done. Now if you didn't care about heat you'd just install a 2.5 ID K&N filter and call it a day.

But for those that care about heat and want to run the filters behind the bumper it doesn't seem that hard to do. Looking at the stillen gen 3, right before the MAF housing is about a 45* bend in the pipe. A simple 2.5" silicone coupling in a 45* bend would do nice. Same goes for the 90* bend around the core support. So 4 couplings, 2 filters, and a foot or two of 2.5" aluminium pipe off eBay and it seems pretty easy. I'm guessing around $100 or so. If you want to do the whole system pick up the post MAF tubes from Z1 or else where for $108-125 and you got what I'd say is a pretty simple, cheap, CAI.

Anyone do it because I didn't see it in the DIY section?

Megan made a 3" one, its in his build thread. Only one I can think of right now.

That would definitely need a tune since the MAF would be messed with going up in inside diameter. Plus the cost of a MAF flange to weld onto a 3" pipe. Ill check it out though, thanks.

i thought about making my own post MAF tube once, but then i realized it would be easier to buy them

honestly unless you were doing LTI, id stick to the stock airbox with drop in filters and post MAF tubes

I just hate the clutter. I did pull the boxes. It does have a nice open almost ram air effect from behind the bumper stock. I do think a few more hp can be picked up though because of a completely round k&n filter vs a flat panel filter.

Update

You need to figure out a way to keep the tubes from moving around from engine vibrations.

The MAF sensors are incredibly sensitive to airflow tumble effects, resulting in misreads and power loss.

Should be simple enough to make a bracket that attaches to the bolt hole where the airboxes were and attach it to the pipe with a hose clamp. Bend a piece of metal into a L shape and strap the short end to the pipe with a hose clamp. Twist the other end in a vice, drill a hole in it and bolt it to the old airboxes mounting hole.

I like this simply for using all silicone tubing. It will absorb far less heat than the metal tubes of G3s.

Can someone take pics of the stock airbox, removed from the car, from the front? What is the inlet size? They are pretty well hidden up in the core support.

Found good pics on e-bay. How about weights?

The stock air box is mounted on rubber and can move and the OEM accordion post tubes have a great deal of movement. The stillen also uses no bracket so I fail to see the issue. "If" and its a big one, if it causes issues the Z1 post tubes are stiff as **** and will make it just as hard and no different than the Stillen's.

Well from the 90* to the MAF will be aluminium. The bumper portion that's silicone with aluminium pipe inside to make the connection I don't see that getting to hot since its out of the engine bay. At least the MAF housing is staying plastic unlike the stillen that's metal. That might help things out a tad.

you could get halfway there and order an ebay SRI(K&N Typhoon knock off) with a proper size maf adapter(2.5in iirc) so all you would need are a way to connect the elbow pieces to the pipes and have the filters in the same location as stillen G3s

I did the exact same thing and found that the vibrations make a huge difference on the dyno.

The airboxes don't move around nearly as much as you think relative to having nothing clamping the intakes down.

Take it to the dyno and see for yourself... I've got no problem with being proven wrong...

On a related note: I have the MAF bases cut from the airbox (i.e., plastic tube with base) and would happily sell them to you if you don't want to cut your airbox up. PM me if you want them. I can provide pics if you want too.

That's going to increase price no? The stock MAF is free and the pipe I got was $23 shipped. Any links?

Well I agree with them not moving much because they don't move under wot. When the motor rocks back under load it stays there. The MAF should see no change. Now during a shift or let off, yes, there should be huge swing in the pipe because the motor relaxed. Unless you're seeing voltage changes on the street and messing things up, ill never know. I don't do dyno's. they are pointless to me and I hate them. I use road dyno software that can calculate the weight of the car, aero dynamics, wheel diameter size, tire size, looks at wot, speed, rpm, etc etc and can tell you a real, true hp and tq since it can calculate the time it took you to go from say 2000 rpm to 7500 rpm. Its actually accurate because you have real wind pushing against you, ambient temps and not 300 degree dyno rooms, and real world roads. Only thing you must do is get all the info right, wheels, weight, etc. also find a flat road and dyno in both directions and average runs for a correct hp and tq. Normally these run like or lower than a mustang but is proven with 1/4 times and trap speeds.

Thanks for the heads up though. We'll watch the volts.

well if you want an effective DIY intake, you will at least need post MAF Tubes to help with flow

with the intake, it costs about the same as HPS tubes with free shipping and including your extensions it will cost you around $150 give or take if you need new piping or not(i dont think you will but there is a chance you might)

plus it will lean things out mechanically so you might make as much as stillen G3s(its 2.75" piping with a 2.5" Maf adapter which is bigger than the stock tube)

Red Shortram Air Intake Kit Infiniti 08 13 G37 07 08 G35 Sedan RAM Cool Dual V6 | eBay


there are cheaper ones on ebay as well, i dont know the intake size but i have seen other knock off intakes go for $90

Use your brain elsewhere. Just buy the post maf tubes and kn drop ins.

Not worth it to me. :ugh2:

Yeah I'm not messing with larger pipe. $10 says tuning will be a must, that short MAF housings not enough. Plus, now takjak has turned me onto the silicone having less heat idea. The less metal the better. He'll if I could make silicone tubes I would! $100+ is a ******* joke for those tubes!! If I can buy 6 couplings and not go over $40, no way them post tubes should rape your *** like that.

could you explain why it would need to be tuned?

i believe they are knock offs of either the K&N SRI or the Takeda SRI(im leaning more towards the takeda because of the size and style)

i suggest looking up Modshack's SRI

he already messed with silicone tubes and compared them to post maf tubes, they are basicly the same iirc

With such a small width MAF section and so large before and after, I can promise the voltage will drop. A larger tube drops volts so the ecu will think the motors at a smaller flow rate and will add less fuel than whats needed, run lean, it blows up. Typically a MAF section needs to be at least 9" long and nice and straight.

it actually provides more velocity than a straight through pipe would

I'm not in aero so id have no idea unless i saw hard data but the ecu isn't going to be able to compensate that much MAF volts in a rise or fall. Once out of the parameters of the ecu good luck not blowing it up. The car isn't turbo'd so there'd be no reason to go any larger than 2.34" ID. Since I've seen some cars run mid 13's AFR I wouldn't F with that ****. Not unless you're at the tuner tuning at that time. If stillen thought it was a good idea they'd of done it! But since they use 2.34" ID from just after the filter all the way to the TB, I'd say they figured it out.

Dynos are not pointless. They provide a method for quanitifying engine output meaningfully. Poor interpretations of their readings abound, but they are far from pointless.

So long as they are clamped down, it should be fine.

Any interest in buying my MAF tubes so as not to have to hack up your airboxes? I can provide pictures later if you might be interested. They are exactly what you will have to create on your own...

EDIT: I have better pictures somewhere on my computer, but here's an example of one of them (don't think I have the filters anymore)

http://www.the370z.com/attachments/i...take-proj4.jpg

Its the exact same pieces you will have to cut from your own airboxes. These are already cut and sanded. Make me an offer and they're yours.

I was kind of hoping to buy some but only to have extras incase maybe I could put kits together for other people. That way they'd be cheaper since I'd buy so many couplings and length of pipe. But I'm sure I'd have to pay for a vender license here and that probably wouldn't be worth it because that and I've seen one guy ask $200 for his in boxes. At that price I'd never get my hands on enough.

All done

Pics?

First post.

i might do something like this in the near future if i decide to go with LTI

good write up

Thanks

Decided to change out my cai system that uses the OEM MAF section. It's only 2.35" ID which matched the throttle body. Now that my TB is 2.48", I need to have the piping bigger. From the way I understand it, your intake should taper down in size and not up. Tapering down would increase air flow like air going through a compressor on a turbo. I'm going with 2.75" OD pipe or about 2.63" ID. That should have the system bigger than the TB and really help. I bought new MAF housings and they showed up today. Only $40 on ebay. I'm still waiting on the pipe. I'll post pics soon.

http://i39.photobucket.com/albums/e1...ps893593c6.jpg

I could be mistaken, but I think narrower inlets are better to maintain part throttle velocity (or the incorporation of a butterfly of some sort), whereas gradual stepping up to wider diameter as you move towards the intake manifold would be ideal for optimal cylinder filling at WOT...

I could be wrong though... worth doing a little additional research on this, but I'm pretty sure that IM and EM runner designs almost always step UP in diameter from flow entry to exit, not down.

If it's unclear, I'd keep the diameter the same, and maybe incorporate velocity stacks at the intake inlets before the MAF's.

Anyway, be prepared to do a lot of rescaling the MAF voltage tables.

Good luck!

Stepping up when the TB is the choke point won't do anything I don't think. No need to have a bunch of air stuck in a dam and can't get through. The stillen uses a 3" filter, tapers to 2.5" OD all the way to the TB. You wouldn't want a 2" filter and step up. Nothing will get through a 2" because it's far away from the TB and it will choke out. A velocity stack can be small but that'd be attached to the runner so no pipe equals no choke. It'd suck all the air it could. Like a turbo compressor you want to have a bigger size going to a smaller size to speed up the velocity but ending at the smallest size. The taper rate depends on the length of pipe and the diameter from start to finish. I believe Megan's cai does this. You also wouldn't want to go to small then back up at the TB size. This or just run the smallest part of the system the whole way, again like stillen. But I can't do this because aluminium pipe doesn't come in a 2.48" ID size. So better to run 2.63" all the way through till it's forced down into the 2.48" TB. It's still going to act like a dam because the taper will happen in 2.5 inches but better than nothing. All I know is I don't want the MAF section I have now because it's the smallest part at only 2.35" ID.

Ok all done.

Instead of running the CAI like the Stillen I had before, I decided to change it up a bit. Since my piping is now bigger I also want it to flow faster and better. So I took out the 90* bend the pipe took to sit behind the bumper and kept my 45* coupling and ran the filter down into the wheel well. Bigger, better, faster, more power!!!!

http://i39.photobucket.com/albums/e1...ps67250005.jpg

http://i39.photobucket.com/albums/e1...ps7a02e025.jpg

Since I won't be able to drive to the tuner with the new MAF housing I modded the system so I could drive there with the OEM MAF housing and right on the dyno I can swap it out to the new MAF housing. August 8th can't come soon enough!

http://i39.photobucket.com/albums/e1...psf50506a1.jpg

http://i39.photobucket.com/albums/e1...ps67dc8ef9.jpg


Here's everything I took out. I even re-ran the AOS lines which saved some weight haha

http://i39.photobucket.com/albums/e1...psfc5649b4.jpg

i just stumbled on this thread. how did your dyno tune go?

fine. i guess the tuner had some issues with the 13 ecu not wanting to play well with UPrev but the timing, AFR etc are all ok. we dynoed with everything on the car but the new CAI, then installed the bigger MAF tubes, then tuned everything with a rescale of the MAF etc. picked up like 15/15 which is normal i think for a NA tune.

any close pics of the bend going to the wheel well

Funny wish I saw this before, Great write up, I made my own also Z1 tubes but I kept the stock boxes and attached piping to the rad support that feeds the stock box. been running it for a few weeks now and have a dyno I HOPE for this Saturday

I can try when I wake up. It's just a 45* bend. Nothing special.