"OLD" Newbie here
I have a 2012 Speed3. I'm planning a "cat'ed downtube" as my first "CASH" mod and am saving my pennies. I've heard of a couple of individuals who've removed large sections from the bottom of their stock airbox prior to or instead of an new intake. Anyone hear of that and or have any info on whether it was beneficial.

Welcome.

I know what you are talking about, but can't seem to recall the proper terms to describe the modification you are talking about. Essentially, the airbox has an extra portion that serves to help quiet intake noise. People remove that aspect of the box. It doesn't add much to a mz3, but for the speed series, I don't know. Breathing is more important for turbos, so I suspect you would get better, though slight, gains than I would.

I actually put a simota SRI into my MZ3 and it was still mostly just more intake noise and a little better throttle response.

Taking a shot in the dark here, but is it a resonator removal? Either way, I know nothing about it and associated performance changes.

Ha ha, welcome to cmzc. Home of epic meets and sound advice!

Removing large sections of airbox? A ghetto mod would be drilling holes in there, but that's nonsense. A catted downpipe would be a bad first mod. I'd wager to say removing the stock airbox/new intake should be mod #1.

I could save you all the steps involved in modding, and just suggest a 5.0 tho:D

sweet baby jesus DO NOT do the exhaust first. you will blow your motor.

Fuel pump internals, intake, accessport. those are the "standard" Gen2 starting mods.

Learjet45 wrote:Taking a shot in the dark here, but is it a resonator removal? Either way, I know nothing about it and associated performance changes.

Yes, it is a resonator removal. Apparently no performance gain, just a little intake noise. I believe aa did this before he got his cobb sri. Lots of guys on mazda 3 forums have done it as well apparently. I just went to an sri.

kingtut wrote:Ha ha, welcome to cmzc. Home of epic meets and sound advice!

Removing large sections of airbox? A ghetto mod would be drilling holes in there, but that's nonsense. A catted downpipe would be a bad first mod. I'd wager to say removing the stock airbox/new intake should be mod #1.

I could save you all the steps involved in modding, and just suggest a 5.0 tho:D

sounds like the redneck douchbag in fast and the furious 4--"Muscle beats import everytime."

Not really sure how helping a guy understand what part people remove from the airbox is bad advice either? Just what some people do. In fact, I was given the same advice from your buddy, though I ignored it. Though as I said, the MS3 is a different, more refined and finicky creature than its lowly step brother the mazda3.

Shadowden wrote:sounds like the redneck douchbag in fast and the furious 4--"Muscle beats import everytime."

Not really sure how helping a guy understand what part people remove from the airbox is bad advice either? Just what some people do. In fact, I was given the same advice from your buddy, though I ignored it. Though as I said, the MS3 is a different, more refined and finicky creature than its lowly step brother the mazda3.

Please forgive me Sir. My comments were in no way directed at you, or your comments. I was merely providing a bit of insight to the OP.

My 5.0 comment was made due to the 2 previous MS3 owners who modded, then ditched for a new 'Stang.

(Pens cologne-scented apology letter)

Look man if you are going to spend money on on a DP you really need to do your research. I am also a gen two owner(2010-present) and I did a ten min research and found out not to do any "redneck" mods! lol seriously get a short ram intake(SRI) and turbo inlet pipe(TIP). If your hard pressed on dough get this set up first.

http://www.corksport.com/corksport-power-series-short-ram-intake-2010-mazdaspeed-3.html

kingtut wrote:Please forgive me Sir. My comments were in no way directed at you, or your comments. I was merely providing a bit of insight to the OP.

My 5.0 comment was made due to the 2 previous MS3 owners who modded, then ditched for a new 'Stang.

(Pens cologne-scented apology letter)

Message received. Smells nice. Lunch next Friday:o:D

I wouldn't cut up the airbox. It's not going to provide as much benefit as a $100 intake (used) and if you do it wrong you could potentially allow dirt and debris to bypass the filter and get into your engine, which obviously would not be a good thing.

I also second the people saying don't get a downpipe first. That's something you get after you already have a few mods like an intake and an AP for starters, and I have read the gen2 fuel pumps are even pickier than the gen1's, so upgrading that should be high on your priority list too, especially if you're planning on going as far as stage 2 (downpipe).

Well, ok then.
First, I appreciate everybodies responses.
Please excuse my poor techinical reference r/t removing large portions of my airbox.
In fact i believe it to be the "resonator removal". I did not think that doing that would allow debris into the intake. I believed that to be just a factory means of quieting the intake. I thought of the mod as just smoothing the air flow possibly requiring less vacume to deliver fuel and thats all.
This is my thought process. Research data i received was based on information retrieved from two other MS3 forums. I only recently found this local site.
Their first three recommended mods based on performance and longevity were, a set of Engine Mounts, a DP, and then an Air Intake.
I believe i dont drive vigorously enough to warrent a set of motor mounts first.
The DP was reported to deliver a net gain of 40 horsepower due to the awkward exit from the turbo on the stock exhaust. Theoretically, this should only benefit the engine as you can not put more in then can come out.
I dont the understand the reference that doing the DP first will "Blow The Engine".
Of course i am not a mechanic or a tuner and thats is the reason i ask. The worst scenerio i could forsee would be a cel if the DP did not have a properly located O2 sensor, but most it seems locate them appropriately.
AND, though i appreciate the recommendation for a Mustang,... i had a GT and dont want another rear wheel drive vehicle in CO. Then i had an STI, which i got out of hand on and added an intake, complete head back exhaust, CAI, bigger turbo, huge intercooler and piggy back. It would smoke GT's and Roush's but that was then.
I was just looking for a nice little, economical, compact,.. reasonable in the snow, which i could get 300hp from and had a certain level of longevity.
I think i made a good choice.

One problem with a downpipe as a first mod is that your boost will increase because of the reduced backpressure. This sounds like a good thing as it increases power, but it also means you'll be running into all sorts of cuts as the ECU will not like the higher boost. So you'll put your foot down and be all happy for about 1 second until your face hits the steering wheel because the ECU saw boost above its acceptable levels and stopped your fun.

I don't agree that a downpipe alone will blow the engine, but you probably won't be able to use the extra power because the ECU will be fighting you the whole way. You need an AP to be able to correct this and raise the thresholds for the cuts, as well as properly tune for having a downpipe. Plus, if you're modding at all, you should really have a way to monitor your car's vitals, which an AP can do for you.

Especially with the picky fuel pumps in the Speeds, you need to keep an eye on your fuel pressure. Adding a significant amount of power (40hp is over 15% increase) can cause the HPFPs to fail and drop fuel pressure while at WOT. At the very least you should be monitoring it, but most likely you will also need to upgrade the pump or at least the internals inside the pump at some point. Better to do these things up front than to wait until something fails and potentially damages the engine.

And yea, older GTs and Roushes are slow. 2011+ is another story though. But you're right, when it snows, the Mustang stays in the garage. That's when I take my Miata out, lol.

Oh and 40hp from the downpipe alone seems a bit high. I had intake, turbo inlet, upgraded top mount intercooler, catless downpipe, and an AP with pro-tune and I gained about 50hp over stock with all of that. With that setup I was around 250hp at the wheels uncorrected. Stock dyno was right at 200hp uncorrected at altitude. And you may not need full engine mounts, but just the rear one will make a huge difference. It cuts down on a lot of wheel hop and makes the shifting much less sloppy, all without adding too much NVH. I had all 3 mounts because I wanted to get rid of all wheel hop, and it did just that, but it also added a ton of noise and vibration.

Ok, that sounds resonable, thanks.
Definately going to monitor vital signs and download
good maps as appropriate.
I didnt here that the pumps were that touchy.
You know anyone with reliable internals?

Others will have to chime in on the internals. I bought a full replacement pump from PTP and had no issues with it but lately they have been kind of shady as a business and others have reported problems with their pumps.