Has anyone else noticed that the intake inlet is restricted? I purchased my 2001 ES in February of last year (just came out) and noticed it right away.

The inlet snorkel is just to the passenger side of the radiator, as I'm sure anyone that has had the hood open knows, and has no place to get air from. The hood seals to the radiator support and goes over the top of the inlet, so there is no way engine air can get in. But the grill support is completely solid (although thin) plastic right under where the inlet is. With the hood closed there is only about 1/8 of an inch between the grill and over the top of the headlights. I've worked on cars for a long time and have never seen a system that had almost no way to get air until this one!

What I did on mine was to get a drop in K&N filter first. I drove it stock, with the K&N and then with the mod I'm about to describe.

The upper part of the grill support is just a flat piece of plasic between some ribs for support. Immediately under the air inlet I used a dremel tool to cut out an area approximately 3 1/2 inches deep by approximately 9 inches wide being careful not to cut the stiffenening ribs but still removing all the flat area. This allows cool air coming in from the grill to be drawn up into the air intake. I'ts completely invisible from the outside of the car, and if done with the proper cutting bit, is extremely clean looking with the hood open.

I drove the car stock for a few months and then dropped in the K&N. I drove that for another month or so to see what it would do and was not really impressed. It felt like it made a little difference but not much. I then did the mod I described above. I disconnected the battery (erases the short term memory in the ECU) and left if until the next morning. I then reconnected it, fired it up and drove it around for a day to let the ECU 'learn' again.

The difference is amazing for such a no-buck mod. The engine now revs cleaner, harder and doesn't feel like it's choking off at 6000 rpm like it did before. It now pulls all the way to redline and my mileage went up by about 1.5 MPG. To say the least, I'm much happier with how it drives now. The neat thing is, it's just as quiet as stock, didn't involve much of an investment and really woke it up. The car now feels like there is some urgency when I decide to sport around in it.

 

sounds like a good mod, got pics?

 

Sorry. Don't have a digital camera or scanner. I'll see about taking some regular pics and getting them on CD or something.

 

Yes, that was something I noticed too. At first I thought the Protege 5 got cool air from the grille, so I left it. Soon I realized that when the hood is closed, the intake is completely sealed off, so I thought why would someone design a stock intake to be like this? First I removed the front piece of plastic, which restricts air very much due to the snaky passage of the air from there to the airbox and the numerous drops that allow for water to flow away, leaving the airbox part to take it air which gives me a minor performance increase. Afterwards, I put a Ractive Superflow Intake in, and boy was it a great mod. The engine feels much more responsive, the car accelerates much better at all revs, and the fuel economy has improved dramatically. Not trying to sound like a riceboy, all excited about his intake, but Ractive's products are not all bad. i don't understand why people attack them, maybe because people say its cheap due to it's price. Anyways, I encourage everyone to get one if they want to get a little more horsepower and much more fuel economy.
And the Protege 5 doesn't really have a restricted intake, I took a look at the MPV's and the intake tube is 1/2 inch behind the left headlight, what design! The only good stock intake is maybe the Miata's, but then its a sportscar.

 

I performed this mod this afternoon. I unplugged by negative terminal to let the car sit overnight. I will try 'er out tomorrow. The mod went well. However, I try to remove the entire front grill assembly. In doing so, I snapped the glossy black trip piece at the top in two. Fortunately you can't tell when I put it back because the two pieces butt up against eachother seamlessly. However, I'm still going to order a replacement. Any suggestions on where to do that. Do I have to order it through the dealer? They gouge prices!

 

You might want to try a search online for used mazda parts dealers. I found a couple the other night and like an idiot forgot to bookmark them. Which part did you remove? On the grill assembly at the top there is an area that is recessed slightly and runs from the grill to the radiator core support. This is the area that I modified and only removed a section that is about 1.5 inches wider than the opening of the intake inlet. This is the part of the grill assembly that you look down at when the hood is open immediately in front of the core support. NOT the 1st inch or so from the front that actually holds the upper trim in place. The section I removed was about 15-20 square inches directly over where the horn is mounted. Added bonus of this mod is now you can get to the horn! All the screws and push in fasteners will remain.

 

Never mind! I know what you did. I didn't understand that you tried to remove the grill. I did the mod with the grill attached to the car as I ascertained that removing it is a major pain in the ***. I used a long narrow router bit for the dremel that is generally used to cut thin plastic or sheetrock. It's 1/8" in diameter and leaves a very clean cut line. After it's done, all you have to do is take a very fine flat file to the edge and it will take off the slight plastic ridge that cutting leaves.

 

Anyone have any pics of this mod? I havent even looked at the intake yet, but it would be nice to see a pic so I can understand better .

Would this mod void the warranty, since you are physically altering the car itself, not adding or replacing something like in other mods?

 

My Miata gets it's engine air from the same place my P5 does - Namely the crack between the hood and the fender. The airflow through the engine bay is designed so that the air inlet is in a negative pressure area. The air intake receives "outside air" which is much cooler (and denser) than "underhood air." The very end of the "snoot" connected to the airbox on the Miata is the smallest diameter of any part of the engine air intake system, and I'm assuming it's "tuned" and designed as it is for good reason.

The flow of air through the engine bay on a modern car is much different than cars of old - More holes in the grille are not necessarily better, as allowing more air to come in through your modifications, is allowing less to come through some other place where the engineers thought it was more important. By ramming air in through some new opening, you're changing the high and low pressure areas under the hood.

Do you seriously believe that Dremmeling out a few bits of plastic from the grille could give you both more horsepower, and better fuel economy and that you discovered this "miracle" while the engineers at Mazda missed the boat?? I can assure you Mazda would have spent serious $$$ for 5 more horspower, and 1.5 more miles to a gallon - If it was free they would have done it your way from day one.

Most "modifications" made to the complex computer controlled automobiles of today are just that - Mods, and not "upgrades."

Don

 

Makes great sense to me! Why in the hell would Mazda engineers miss this if it were wrong? The P5 is a damn good vehicle, which obviously many ours were put into it to design. Like I said in my previous post, you better hope that you dont have any problems with your car in the future, because service could easily tell you that your "custom hole" was the cause of the problem. By law, you dont have to replace or add only Mazda parts on your car to keep your warranty valid, but I think you may be asking for trouble if you actually modify a part of the car that wasnt intended on being that way. Correct me if im wrong....

 

well, call me crazy, but I think my "custom hole" has helped performance. The definitely pulls harder now. Perhaps it was engineered that way on purpose. However, I don't think having a little better access to incoming air is a bad thing.

 

I'm going to have to back up hawkeye on this one. Contrary to Don and Mnkyboy's logic, not everything the engineers designed into the car was done that way for performance or economy and in some extremely limited instances, removing or "modding" stock pieces can result in performance gain by sacrificing something else. For instance, the 2000-current Celica has a large "butterfly valve" in the intake box just prior to the filter. It stays closed at idle and lower RPM ranges allowing only a small amout of air through, then opens at higher revs. Its puropse? To make the engine quieter. Removing it allows greatly increased airflow, a MODEST performance & fuel economy gain, and vastly improved throttle response. As for the protege, anything's possible. I don't agree with the logic that "if there were more performance to me had, the manufacturer would've already done it". Perhaps if performance were the ultimate goal, that might be true, but protege's are not sports cars and the engineers had other concerns when designing it. My theory is that in this particular market segment, Manufacturers are well aware that there are those people who are after performance, and those people are willing and content to perform aftermarket modifications to that end. As such, why should they spend valuable R&D $'s to do what sonebody else is going to anyway?

 

To be honest, the idea that a smaller air inlet is somehow 'tuned' to work better is ludicrous. Why do you think that there are so many aftermarket fresh air systems out there? Because they get more air into the engine! The factory stuff is done for inlet noise considerations as well as ease of production. As for the piece I removed, it's just a piece of solid plastic that fills the area between the grill and the radiator support. Since this is cast as one piece, I'm sure that it would have been very hard to cast a space in it. There would have been almost no way to get it to release from the mold.

I've been working on cars (trained mechanic) for about 16 years now. I've seen a huge variety of factory and high performance stuff and read a huge amount of performance theory as well as put a lot of it into practice. The factory stuff is usually made with packaging and production in mind and not performance. Witness the Ford Thunderbird supercoupe with the 3.8 eaton SC v6. The stock engine is pretty potent, but there are some small mods you can make that add 60HP on a stock engine. They are things that the factory didn't do for a couple reasons. Packaging was one, insurance was the other.

As to the negative pressure at the grill, what you have is a positive pressure area directly in front of the car trying to move into the grill area as well as over and around the car. This is what cools the car, air moving through the radiator. The area of plastic I removed will only let as much air into the air inlet as the engine can take and I'm sure it won't affect cooling for that reason. There is still no where else for air to go as the hood is still sealed to the radiator support. There should be no difference or a marginal difference in the air pressure around the headlight area. This will only allow a source for cool fresh air to get to the motor. Ever see really high horsepower turbo cars with a headlight removed? That's to get cool air in. It has a ram air affect at higher speeds. Another area of positive pressure is at the base of the windshield. That's a great area to pick up air from for a cold air induction system as it can be a couple psi higher than outside air pressure at speeds over 70 and thus act as a natural forced induction.

 

Someone suggested that we could cut the rubber strip that is directly in front of the intake inlet (it's on the hood) and you should get air. The rubber strip should be cheaper to replace than the whole grill assembly shall it be required.

But I didn't do that. Here's what I did instead (similar to what leungwingkei did):

I removed the bulky plastic ducting that is on top of the radiator, leaving the factory airbox with the open hole. I went to Walmart and found some nice flexible hose. It was meant for sewers for RV, but hey, it's much better quality than those intake hoses sold in Autozone/Pepboys.

The best thing is that it's 1/3 the price of those intake hoses, and it can be stretched to 10' long! The diameter was perfect (i think it's like 3") and it fits the airbox really well. And I bought some big hose clamps from Pepboys and clamped the hose on (didn't really need them).

The most difficult part was to decide where to position the hose opening to get the coolest air AND has to allow the hose to fit through. I finally decided that the best location is at the bottom because hot air rises. I saw an air opening at the bottom of the car, which i guess it's used to cool the transmission. I positioned the hose right on top of that opening. It's now below the radiator fan, so even when the fan turns on, the hot air won't get sucked in.

I also added a K&N drop-in and now the throttle response is a bit smoother. Has a nice growl to the engine too!

So now i've got cooler air, less restricted flow.

 

That rubber strip on the hood goes across the top of the air inlet not in front of it. The fix you used was the other option that I was considering. The reason I didn't do it that way was simply because I wanted to maintain the factory silencing. Be careful where you put the inlet though. If you mount it too close to the the bottom of the radiator you can suck water in if you hit a puddle.