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Discussion Starter #1 (Edited)
I decided to make my own intake because I wanted something that would never give me a CEL. I also wanted something straighter than what is currently out there. I relocated my battery so I have a straight shot right to the throttle body. All of the aftermarket CAIs have bends to go around the battery.

My CAI costs about the same as an aftermarket. The advantage that mine has is that it uses a stock MAF housing. It would be about $40 cheaper but I've only found one supplier for the 22 degree elbow and it's not cheap. You could also save $63 by cannibalizing your stock airbox top. I didn't want to do that so I bought a new one.

I've had this CAI on my car for 10,000 miles with no CELs. It also sounds great!

Here's how I made it and the parts I needed...

Mazdaspeed6 Air box top - onlinemazdaparts.com $63.02
3" dia 22deg elbow - Turbohoses.com $50.98
3” dia 45deg elbow -
Ebay $15.00
2.75 to 3” reducer -
Ebay $15.00
3" straight coupler -
Ebay $7
3" Liner hose clamps - globalindustrial.com $19.00 for a package of 10.
3" K&N Conical Air Filter - Summit Racing $42.46
5/16" K&N breather filter - Summit Racing $18.95
3" Hose Joiners - Racepart Solutions $5.95
Vacuum caps for VAD solenoid - Autozone $6.99
12AWG heatshrink ring terminals - hardware store $various (Check the bolt diameter before buying the terminals. I think I bought 1/4" ring terminals)

First, here's the almost finished product...




Click on the pics below to enlarge them.


I purchased a MazdaSpeed6 airbox top. I measure a friend's MS6 and found that the MAF housings are identical to ours. Before cutting...


I used an air saw to cut the MAF housing out of the air box. It doesn't have to be perfect at this point just get close...


I used a pair of flush wire cutters to trim off the excess material. I then took a sanding block with some fine grit paper to smooth everything down. Here's a pic before sanding...


To mount the VAD solenoid, I decided to cut off the stock rusty ground connector and mount it there. I re-terminated the four ground wires. I used two 12AWG heatshrink ring terminals. The heatshrink terminals are important because you don't want the grounds corroding over time. I bought a nut and lockwasher to mount the VAD. I think they were 6mm. I also used vacuum caps to cap the in and out of the VAD solenoid. Most auto parts stores sell variety packs with multiple sizes of vacuum caps for a few bucks. In this pic you can see the VAD mounting...


In this pic you can see the new ground wire mounting location. I slit some 5/8" heater hose and slipped it over the edge of the hole's opening. It made a decent grommet...


I cut off the stock tube that went from the valvecover to the intake bellows. Carefully slit the tube with an exacto knife to get it off of the valvecover connector. The K&N breather just clamps onto the stock valvecover connector...


I just have the 45 degree elbow resting on the edge of the fender hole. I didn't have the grommet installed or VAD mounted in this pic but you still get the idea...


When you go to piece all of the parts together, you will need joiners to slip inside of the silicone elbows and transitions. The link in the parts list has nice prefabricated aluminum joiners. You need three of them. Instead, I had a piece of 3" stainless exhaust tube laying around so I just cut off three 3" long pieces. One is used between the 2.75" to 3" transition and the 22 degree elbow, another is used between the 22 degree elbow and the 3" straight coupler, and the last piece is used between the 45 degree elbow and the air filter...


I also used liner clamps to hold everything together. Liner clamps are good because they don't dig into the silicone hoses when you tighten them down. They have a smooth piece that slides over the slots in the hose clamps...


When I originally mocked up the CAI, I just used cheap hardware store hose clamps, that's why you can see the hose through the slots in the clamps...



BP
 

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Discussion Starter #3
At this point, I don't think that it will. It's been 10,000 miles since I put it on and it's never thrown a CEL.

The only time that I had a problem is that I went through one of those high pressure car washes and left the car running. It ran like crap for a couple hours after that but once the MAF dried out, everything was back to normal. I did learn my lesson and now whenever I go through a car wash, I turn off the engine.
 

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Reading some of the chat in other places, if the tubing where the MAF is mounted stays the same as stock, a CEL is pretty rare. Changing that tubing seems to be the big cause of problems.
 

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great BP, this similar to what i was going to do to my 6, minus the breather filter. it will be about the same as a cheap ebay cai. i wanted to go with the AEM cai, no oiling req'd!
 

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Reading some of the chat in other places, if the tubing where the MAF is mounted stays the same as stock, a CEL is pretty rare. Changing that tubing seems to be the big cause of problems.
This is exactly the case. What happens being that the factory tune for airflow is cal'd to reference the stock diameter MAF housing when you increase that piping size you ultimately increase airflow. Moreso unmetered airflow that is un accounted for. So once the o2 sensors read that there is more oxygen it relays that abck to the ecu.

Now the factory tune does have a buffer of about 12-15% of variance allowed before it begins with a pending code and then illuminates as an active once past that. It trips a lean code. But in reality the car is not lean because it corrects for the variance and remains at stoich.

the buffer does allow slight increases to piping diameter without tripping a code. IIRC 2.75" is about the limit before it would constantly trip the code for being to far past the buffer.
 

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what about the pcv hose? where would you connect it?
you can cap the IM and install a breather after devalving the pcv, if you can stand the smell of your engine's farts lol
 

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Ok, so I plan to do this today. I will post results later.

A few questions first:

If I understand correctly with what you did, you just capped off the VAD, ground it off, then reconnected it?

Also, a buddy of mine has an SRT-4 and he's put a short RAM on his. He told me that the short RAM has better throttle response time, and that most CAI aren't worth the lag in throttle response because of the longer distance the air has to travel...So would that mean short RAM's are better or is it just a matter of opinion, or is he wrong?
 

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Discussion Starter #14
If I understand correctly with what you did, you just capped off the VAD, ground it off, then reconnected it?
You cap the VAD, keep it connected like normal, then mount it somewhere. I used a convenient hole that was already open. Check the pictures to see which one.

I didn't ground any of the VAD wires. I did re-do the stock Mazda ground block. It was all rusted and had to go. As you can see in the pics, I used some 12AWG heatshrink-type ring terminals. I combined a couple of the wires, crimped them together, then heated it up with a heatgun which heatshrunk and weatherproofed everything.

Also, a buddy of mine has an SRT-4 and he's put a short RAM on his. He told me that the short RAM has better throttle response time, and that most CAI aren't worth the lag in throttle response because of the longer distance the air has to travel...So would that mean short RAM's are better or is it just a matter of opinion, or is he wrong?
In my opinion, he is wrong. A short ram intake will always pull in hotter air hurting performance. A properly designed CAI won't hurt throttle response. A CAI with a 90 degree elbow right before or after the MAF or the throttle body will hurt performance. You want the largest, straightest piping that you can get.

BP
 

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You cap the VAD, keep it connected like normal, then mount it somewhere. I used a convenient hole that was already open. Check the pictures to see which one.

I didn't ground any of the VAD wires. I did re-do the stock Mazda ground block. It was all rusted and had to go. As you can see in the pics, I used some 12AWG heatshrink-type ring terminals. I combined a couple of the wires, crimped them together, then heated it up with a heatgun which heatshrunk and weatherproofed everything.



In my opinion, he is wrong. A short ram intake will always pull in hotter air hurting performance. A properly designed CAI won't hurt throttle response. A CAI with a 90 degree elbow right before or after the MAF or the throttle body will hurt performance. You want the largest, straightest piping that you can get.

BP
sorry, but the SRT guy is correct. the longer the distance the air has to travel to get into the cumbustion chamber, the more lag it induces. This includes running too large a diameter piping, extra piping and less than optimimum bends.

hot air reduces the volume of O2 molcules within the charge being induced. It does not HURT performance, but does not yeild as much power as a Colder Denser charge. Neither induction system produces actual power, but rather reduces the amount of power restricting components.

As for the intake, using all that 3 and 4 ply coupling is never recommended. Under load they have a nasty habit of flexing which is why you see people run piping in IC setups instead of just the coupling(as these don't retain heat like piping do... but they do flex). good to see enginuity, but the methology needs to be refined. Couple of short runs of aluminum tubing will make that thing 100% better. Plastic, fiberglass, or CF would be even better it will not retain heat like metal will.
 

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Discussion Starter #16
I've gotta disagree...

No human being is going to notice the difference in lag between a 2' vs a 3' piece of pipe. Now if you are using a bunch of sharp bends and transitions you are going to disrupt flow, hurting performance.

You are contradicting yourself. Hotter air hurts performance. Not only does the less dense air allow less power production, the PCM pulls timing because of the increases intake air temperature. So a short ram intake pulling in hot air WILL reduce power.

Using multi-ply silicone bends is fine as long as the plumbing is supported properly. Of course, if it is allowed to kink, you are going to hurt performance. Having a blanket statement that all silicone bends are bad is ridiculous. Yes, an intake made of all mandrel bends that is perfectly smooth and insulated on the outside would be perfect. I'd be absolutely amazed if there was a 1% improvement in power or torque in my design over one with, "Couple of short runs of aluminum tubing...".

BP
 

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I've gotta disagree...

No human being is going to notice the difference in lag between a 2' vs a 3' piece of pipe. Now if you are using a bunch of sharp bends and transitions you are going to disrupt flow, hurting performance.

You are contradicting yourself. Hotter air hurts performance. Not only does the less dense air allow less power production, the PCM pulls timing because of the increases intake air temperature. So a short ram intake pulling in hot air WILL reduce power.

Using multi-ply silicone bends is fine as long as the plumbing is supported properly. Of course, if it is allowed to kink, you are going to hurt performance. Having a blanket statement that all silicone bends are bad is ridiculous. Yes, an intake made of all mandrel bends that is perfectly smooth and insulated on the outside would be perfect. I'd be absolutely amazed if there was a 1% improvement in power or torque in my design over one with, "Couple of short runs of aluminum tubing...".

BP
1st, I said it wasn't recommended, not that you couldn't do it. I have done it in both turbo and NA setups and though it works, it isn't optimimum was my point.

2nd, the SRT4 is boosted and that does infact make a HUGE difference(which is why you are incorrect and he is right) in performance. It will not be nearly as noticeable without boost, but there is still a signifcant difference.

Intakes do not MAKE power at all. they reduce restriction of the stock restrictive intake. SRIs do not "reduce power" they simple do not make "as much" power as CAI, which is all but negated by the speed the air passes into the TB.

I'm currently running a SURE SRI on my V6 and before that had over 110k on my AEM CAI. the HP difference is minimal at best and the Throttle response is very notiably improved....
 

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Discussion Starter #20
1st, I said it wasn't recommended, not that you couldn't do it. I have done it in both turbo and NA setups and though it works, it isn't optimimum was my point.

2nd, the SRT4 is boosted and that does infact make a HUGE difference(which is why you are incorrect and he is right) in performance. It will not be nearly as noticeable without boost, but there is still a signifcant difference.

Intakes do not MAKE power at all. they reduce restriction of the stock restrictive intake. SRIs do not "reduce power" they simple do not make "as much" power as CAI, which is all but negated by the speed the air passes into the TB.

I'm currently running a SURE SRI on my V6 and before that had over 110k on my AEM CAI. the HP difference is minimal at best and the Throttle response is very notiably improved....
FI is a whole different animal. Everything that I'm talking about is for a naturally aspirated setup.

Ugh. Yes, an intake doesn't make power on it's own but an intake will cause the engine to make more power. The resonators and bellows on a stock intake restrict air movement which reduces the engine's power output and slows throttle response. An ICE is just an air pump. The easier that it is to get air in an out, the more power that it will make.

Also, a SRI drawing in hot underhood air will cause the PCM to pull timing reducing power. A CAI equipped engine will always make more power than with a SRI.

I like a good debate. ;)

BP
 
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