Myxalplyx

Do not attempt this modification. I'm just documenting for my own purpose. Do at your own risk!

I purchased a 2014 1.8ltr Honda Civic LX CVT air cleaner housing to do this mod here --> 2014 Civic Air Box Housing



I used a hacksaw to cut out the maf sensor housing and took measurements of it vs the stock 2015 Honda Fit maf sensor housing. Here is what I came up with.

Stock 2015 Honda Fit Maf Sensor Housing:
Inlet diameter: 2.04" (56.82mm)
Outlet diameter: 2.17" (55.12mm)

Stock 2014 Honda Civic Maf Sensor Housing:
Inlet diameter: 2.24" (56.90)
Outlet diameter: 2.63" (66.80mm)


Here are a couple of pictures of the maf sensor housings side-by-side.



I don't even need to tell you which is which because the difference in size is obvious. But if you can't tell, the 1.8ltr Civic maf housing is on the right side and the top of the pictures.

I removed the maf sensor from my stock housing and inserted it into the 1.8ltr Civic maf sensor housing. Then I started the car up. No check engine light and it revs just fine. No engine stutter!

I found a bullshit generic filter I could use for testing thankfully so I'll be driving around tonight to see if everything is ok. I'll toss this filter out for an S&B filter tomorrow if all goes well.

Gawd, I hope this works. I'll be keeping my other maf sensor housing with me in case I need to change them out on the side of the road. :rotfl:

Again, I'm not recommending this to anyone. Just sharing my experience! If this works, next up is getting my stock maf sensor bored out by Maxbore. I'll send it out tomorrow if this is successful tonight. **Fingers crossed**

Short video clip --> Had to cut it short since the Misses was calling me for dinner. :-)

claymore

Dam you do some good experimenting. Looks like you will be the GK guru with REAL work and drag strip results for proof.

Myxalplyx

Just trying to have fun Claymore.


The larger maf sensor worked fine at part throttle conditions. Could drive around all day. Wide Open Throttle (WOT) showed 17.0:1 air/fuel ratios and the engine ecu detected knock. I put in 92 octane after it went empty and tested again. No knock detected but still 17.0:1 air/fuel ratio and I lost 15hp (Per Android Pro Torque software).

So, I am purchasing the item(s) below for the maf sensor to read correctly. Maybe the the wider diameter on the maf sensor outlet will give me some performance.





The insert portion is all I need so the maf reads correctly. The back half of the civic maf is signifcantly larger than stock and should compliment the throttle body being bored. Everything will be open right up to the back of the maf sensor itself and everything in front of the maf sensor (The intake itself) is opened up. Splendid!

I ordered the part and am expecting it to arrive next week before heading back to the track. Awesome! This just might work! Don't see why it won't.

claymore

You are also letting in more air with the larger inlet and that is probably causing the leaning out. I made a system for a suzuki samari type vehicle out of 3 " PVC pipe and it drove the ECU nuts leaning it out. I solved it by gradually blocking off the intake with duct tape until it got just the right amount of air the ECU could cope with.

Octane increases always give increased power by allowing more ignition lead. Your fuel choice is not making the detonation that is coming from being TOO LEAN.

Myxalplyx

Will keep an eye on things Claymore. Thanks for the heads up!

Here's a minor update -->

**Update**

The Spectre maf airflow sensor kit came in. Had a nice cool Spectre bag with it, with all the reducer pieces inside as well as maf sensor connectors for a 3" pipe they provided. The kit is very nice and I'm sure if could be really useful for someone using a 3" intake. However, this is where I made my mistake.

The maf adapters are all for a 3" pipe. They are supposed to reduce the piping size as follows:
3" to 2.75"
3" to 2.5"
3" to 2.25"

What I needed to do is reduce my maf sensor inlet from 2.25" to 2". Specter doesn't sell a 2.25" adapter reducer (Or even a 2.5" one that I could find). So I was stuck in a dilemma.

So out came the knife and hacksaw. I cut up the 2.5" and 2.25" several ways. I took a fair amount of pics but I'm too tired (lazy) to put them up now. Very ghetto looking.


What I ended up doing is sliding the cut up 2.25" into the 2.5". Then sliding both of those into the Civic Maf sensor to reduce the inside diameter down. Both pieces were slid into the inlet side of the maf sensor, with both pieces allowing the maf sensor to be inserted through the top. Here is what is looks like inside.

I need to work on making the inlet air transition into the maf sensor smooth. Right now, it's an abrupt/harsh transition. Any suggestion on what I can apply to make this transition from the silicone hose to maf smooth? Some type of liquid/paste that hardens that wont' get sucked into the intake. I'll be stopping by Home Depot tomorrow to find something to smooth this out inside.

The stock maf sensor Inlet diameter is 2.04" (51.82mm).
Now the Civic maf sensor with the two Specter pieces inside has an inlet diameter of 2.07" (52.99mm). Close enough! Not exact but I'm gonna test it out anyways.

The piece is all ready for me to swap out with the stock piece while testing at the track. Don't worry, I won't be installing them the way you see them. The stock maf is on the left side and the Civic maf housing is on the right (It's upside down though but you get the point).


I am waiting for my throttle body to be bored out by Maxbore and sent back to me. I'll be testing that throttle body with the stock piece on the left with a few drag runs. Swap to the Civic maf housing, do some more dragstrip runs. Then may swap again back and forth a couple of times just to remove any beliefs that cooler air temps are making one setup seem favorable to the other.

How will it turn out? Who knows! Who cares! It's all good fun and I like testing things like this out. This is all for now.

claymore

Awesome I really like what you are doing. But keep an eye out on your A/F we don't want you to grenade your nice new engine.

Myxalplyx

Thanks Claymore! I'll try to be careful.

*Update 10/8/14*

Stopped by Home Depot to try to find something to smooth out the transition of air on the inside of the Civic maf sensor piping. This is the where the air just enters the maf sensor, going through the two Spectre piping inserts. It's really rough and can cause problems with the maf sensor reading (From what I read) and so it should be as smooth as possible.




^^So I found this material called 'Water weld' that once applied it hardens up (cures) within 20 minutes to fully cured in an hour. That is the white material you see inside the inlet of the silicone hose, where it meets the maf sensor piping. It's not perfect but it is what I was looking for. I did not apply this on the discharge side of the maf sensor (Where the Spectre piping ends an the internal maf diameter continues). It's rough there but the air will not hit it directly as it would going into the maf sensor. The HPS piping is like this on the discharge side as well. No need to smooth it out there.

Again, I have no idea what to expect. This is all experimentation but fun. I'll be testing it out on the road, than the track tomorrow night if my Maxbored out throttle body arrives.

Myxalplyx

I did 8 runs tonight. The first three I was testing a Maxbore Throttle body. Then I tested the Civic Maf sensor with the 2.5" and 2.25" inserts inside 2X. Then I removed the 2.25" insert to bring up my air/fuel ratios (Bad move) and did two more runs. Here were the results.

16.007@87.16mph (Maxbore Throttle Body)
15.853@88.99mph (Maxbore Throttle Body)
15.917@87.40mph (Maxbore Throttle Body)

16.038@88.23mph (Maxbore Throttle Body/Civic Maf Sensor Housing with 2.25" & 2.5" inserts to reduce diameter)
15.959@88.54mph (Maxbore Throttle Body/Civic Maf Sensor Housing with 2.25" & 2.5" inserts to reduce diameter

16.331@85.80mph(Maxbore Throttle Body/Civic Maf Sensor Housing with 2.5" insert only)
16.323@87.22mph (Maxbore Throttle Body/Civic Maf Sensor Housing with 2.5" insert only.

The first five runs were ok. The Civic maf housing with 2.25"/2.5" seems to have an average mph higher than using the stock maf sensor although the stock one had one nice run that was faster and quicker than both the Civic runs.

The last two runs got nasty. Ignition timing dropped down to the single digits (6-7). It was running in between 10-13 on the previous runs. Something happened during run #6 around 3000rpm. It died mid run, the ignition advance dropped (Detonation?) and it sucked all runs after that. Power was lost in the upper rpm range and air fuel ratio was 14.0:1 vs 12.0-12.3:1 in my previous runs.

So...what does all this mean. The Civic maf sensor has an inlet opening similar to the stock maf sensor housing but the outlet is larger. This outlet being larger may have a slight advantage at wide open throttle. However, off idle acceleration was slightly slower with the Civic maf (2.25/2.5").

NEVER use this maf sensor if you can help it. If you plan on experimenting, please use high octane gas to protect your engine. This is tricky stuff and I'm no tuner. I'm using 92 octane from now on. No further tests with this maf since gains weren't signifcant (Losses were). That's all for now.

claymore

With a larger opening you are loosing velocity that is why you move the power band up and lose low end power.

Your detonation problems are from leaning everything out with now too much air without adding more fuel.

Myxalplyx

I may run some more tests now that I am using 92 octane. Timing is held right at 15.5 all the time during wide open throttle.

ejoes

I am new to the room. I have a 92 civic with a 98 engine. I started my repairs when half the locals overcharged me plenty and the other half
new less about the car than me.
I like the crock pot...you can have "sloppy joes" while under the hood, lols.
Your posts so far have helped me plenty. Thanks...ejoes!