The underhood vent also mates up almost perfectly with the top of the stock resonator lid on top of the stock airbox. I've been working on opening up the stock lid (which is off my car at this time due to my modded airbox) to almost seal with the vent (or at least come close to it). Winter has slowed my efforts, but as soon as I get any more progress I'll update my DIY intake thread in the engine mod forum.

 

BUMP FROM THE GRAVE FOR THE NOOBIES! This mod started me on the righteous path to n2o and later turbo. Maybe it will do the same for someone else.

 

I did this before and it's evolved a bit since then...



This was how it started...had a section of a PVC pipe between the coupler and the filter, but it was so long the front of the cone had to rub under the Master Cylinder bracket.

made a heatshield a few months ago, and switched the Lowe's pipe couplers and bought a 3" to 2" Spectre adapter, and put it in inside the smallest insert for the filter and tightened down the clamp. Shortened up the length by about 1 and a half inches, and made it sit perfect.



Only problem? It's still louder than my exhaust... LOL.

 

Excellent, I like it. Slipping the coupler itself directly in the filter is a good way to shorten up the length.

 

The heatshield helps give it a nice sucking sound too. Too bad my stereo is always so loud I can't hear it.

 

So I'm thinking about doing this to my new Fit, and I have a couple questions that haven't been clearly answered in this thread.

Firstly, you (Lyons) mentioned needing an oil catch in place of the breather filter due to oil mist from the pcv. What exactly is the pcv? I assume it isn't coming from inside the filter itself, since that other guy said he hasn't seen any issues with his breather filter. Is my best bet to try and set it up like he did with a white filter so I can tell when it's dirty?

With the issue concerning the velocity stack, how exactly were you able to preserve it? I'm assuming the velocity stack is the flanging part at the end of the MAF tubing.

Does the use of heat shield show any noticeable gains? Specifically for the original design with the main filter being perpendicular to motion as done by kurisux. If so, how did you (kurisux) make it?

 

It's not noticeable in outside temperatures above 70 degrees. Which is just about all of Arkansas summer. But in the winter and early Spring, when we had like 50 degree weather, I could definitely feel a kick, even though now, it feels like my new retry at this intake feels about the same as it was in the winter. I think I had a leak somewhere. But as long as the heatshield properly blocks off the filter from the engine side, and has some protection from the transmission underneath, it should do well. I found a template somewhere, measured the angles and read the measurements of the sides and just bent it all to fit, made some angled pieces of sheet metal, and pop riveted it all together, then used a 3" hole saw on a drill press to drill the hole for the filter.

And as for the PCV, all that is is a breather for the blow-by and excess oil fumes from the crankcase to be drawn back into the intake to burn off inside the combustion chamber. Some people say it's necessary to have an oil catch can, but I've had this intake for probably about 5000 miles and haven't noticed any oil on my filter or seen any of it misting around the engine and getting things mucky. In my honest opinion, the idea of an oil catch can seems like something that would work in a controlled lab environment, but on the street, it's really impractical. I have noticed any loss of power or idle problems due to a loss of vacuum, and like I said I see no oil so it must be doing fine. And if you use the Spectre filters like both I and Lyon used, there is no need for a velocity stack; it's made into the end of the filter.

 

Whenever I get a chance, I'll get a tool to read the IAT with it running and the hood closed and see what temperature it is.

 

My IATs were always ambient w/o a heatshield, unless standing still for a long time. It'd probably be useful for stop and go.

 

My the metal part of the filter is always cold when I touch it after driving, if that says anything. Without the heatshield, it would be cooler than the rest of the engine but still lukewarm.

 

Thanks for the replies! Just picked up some of the parts from Autozone today. I should have it set up within the week.

Is it preferable to use metal piping, or is PVC okay?

Edit: Never mind. I ordered a 3" dia extension, and I'm going to do something similar to kurisux if it isn't long enough.

 

So I've been reading in the performance forum, and apparently the ECU adjusts for increases in airflow, thereby reducing the gains. How true is this of this mod?

 

This is a popular myth. The simple reality is the stock airbox is pretty well designed and you arent going to get any amazing gains from an intake. Just a nice sound. There's nothing the ecu can do to 'rob' power gains. Except pull timing. But the ecu's timing has nothing to do with airflow.

The way I believe this myth came up is that some members spent ~$600 on an intake and exhaust (axle back or mid pipe, any part but the cat delete, cat delete is only ihe part that seems to increase power noticably) and didnt get any gains. The companies they bought these parts from advertise gains, so they blame it on the ecu instead of the mods themselves, not realizing that neither cat back or intake is going to get you any realistic gains.

If somebody would offer up an explaination on what mechanism within the ecu is causing the 'power robbing' I might believe it. But after vast experimentation I'm not buying it. Adding more fuel proportional to increased airflow doesn't rob power. It adds power... and I wouldn't begin to believe that it richens the afr to the point of losing power, thats extremely unlikely. So unlikely I would need a log to believe it. I promise you its not touching timing.

 

I am wanting to turbo like you did, are you going to do an extensive write up of parts? its hard to find specific parts in Aus,

 

You hit the nail on the head with that one...

I think it started from some ECUs having a torque learn-down feature from the factory on cars with factory forced induction (this GM site even talks about it). But even after overriding the feature on those cars the more level-headed enthusiasts agree that besides a pleasing exhaust note and throaty intake growl there's no perceivable gains short of bolting on a bigger blower. The CAI makers probably latched onto this to explain their products' failure to perform as advertised.

 

From previous experience with various cars, I'm gonna keep my stock box. The FIT needs all the low and mid range power it can get. The reservoir isn't there just to quiet things down. The top end gain can't be justified in my case.

 

All the important parts came in today, so I finished it up! This was done on a 2011 Fit Base.







All in all, it cost me:
Main filter - $27
Breather filter - $10
Small 3" tube - $2 (Amazon.com: Spectre 8808 Air Intake Tube Extension: Automotive)
Screw collar - $4? I ended up only using the rubber fitting
Old bicycle tube - Free
OEM MAF housing - Free
OEM 2.5" to 2.5" coupler - Free
OEM screw collar - Free

I used the short 3" tube to stick it inside the 3" to 2.5" reducer, giving it the support it needed to be able to stick the whole thing in the filter, thereby reducing the length like kurisux did.

I used the rubber from the screw collar I bought and cut it down to be able to use it as a step-up rubber for the MAF housing to reducer connection. I also used the coupler that was in the original airbox as well as the original screw collar.

I did run into a problem in the beginning where I couldn't take off the screw collar with a phillips as described in the original thread. The metal on the screw was way to soft, and the screwdriver ate it up. I spent about half an hour (or more) trying to file in a new screwdriver guide (regular flat), and ended up realizing (all too late) that it was also a hexagonal bolt. A ratchet wrench would have done the job much better and faster.

For some reason, when I tried to put the new intake in, the original collar was too big. I used old bicycle tubes to wrap the coupler and provide the needed thickness.

All in all, it was a fun project, and I ended up with a ~$50 version of what has been sold for much much more. I look forward to more DIYs!

 

I like it! It makes me happy every time I see somebody complete one of these! It gives me hope in our platform.

 

which of theseswould this work? sorry about the dumb question im new at this stuff.


this first one has a lower max working temp (140)
Shop AMERICAN VALVE Flexible Coupling 3" X 2" at Lowes.com

while this one has a higher (180) but doesnt have the fasteners
http://www.lowes.com/pd_22807-58421-...ing&facetInfo=

 

Between those two, I'd go with the higher rated one to play it safe. Screw hose clamps aren't that expensive.