Hey guys, I've got a 2005 Mazda 6i 2.3L, 5-speed sedan. My motor wen't a couple months ago so I feel like if any time, now would be good to consider some upgrades. It was 4-cylinder engine, since I need a new one anyway, I'm wondering if someone could tell me if it's possible to upgrade to a 6-cylinder without any complications?

 

While I've never even looked at such a swap and don't know the specifics, my guess is that such a swap would be fraught with difficulties such as but not limited to the following:

• Mechanical hard points for the various linkages such as throttle and cruise control may well be very different
• Electrical interfaces for the engine, the computers, and the instrumentation are all most likely very different
• Fuel system upgrades may include the pump and filter, the tank, and the line routing
• The air intake plumbing is most likely very different
• The transmission may be a completely different unit and not have the same hard points for the half-shafts, shift linkage and/or the clutch linkage
• The exhaust system is most likely very different between the four and six cylinder models

Other differences which are most likely evident between the two models:

• Struts and spring rates
• Brakes
• Swaybars

Long story short, I'm thinking you'd be way-way ahead by putting in another 2.3 liter mill, and then if you want more juice, buy a turbocharger kit for your car.

 

Thanks Shipo. Definitely sticking with the 2.3L in this case then. And you actually answered my following question. Does it make sense to put a turbo/supercharger on a 4-cylinder? and if so, would you recommend a turbo or a supercharger?

I'm trying my best not to screw up this car so I'm taking others suggestions into consideration ha

 

First thing's first; if you want to keep the resale value of your car as high as possible, put a new motor in it and leave it alone.

The above said, if you're planning to keep it until it's just a pile of rust and other assorted parts, then there's no worries about resale and you can mod to your heart's delight. Regarding forced induction, supercharging and turbocharging both have benefits and drawbacks; for my part, I would never put a supercharger on a 4-Stoke automobile engine unless drag racing was my ONLY reason for driving the car. Why? Supercharging provides low-end grunt at the expense of direct engine drag. As an example, a recent supercharged 4-Cylinder engine I took a look at showed that the normally aspirated version of the engine produced about 150 hp, and with the blower mounted, the net output was right bang on 200 hp. On the surface that looks like a 33% increase or 50 additional horsepower; looks pretty good right? Wrong (in my book). Why? Because the engine was actually generating some 240 horsepower and the supercharger was consuming a whopping 40 horsepower at full tilt. Said another way, the engine was burning enough fuel to generate 240 hp and enduring the associated wear and tear of that much power, but only yielding a paltry 200.

On to turbocharging; these blowers essentially run off of the "free" energy contained in the exhaust system, and as such, you could have built the above referenced engine with either 200 hp (with less wear and tear and fuel consumption), or you could have built it with 240 (with the same wear and tear and fuel consumption, but 40 extra horsepower). The drawback of turbochargers is that that "free" energy doesn't really start coming online until the 1500-1800 RPM range, and that means that momentarily the engine will feel quite slow when accelerating from a standing stop.

 

yea i just bought this car 3-4 months ago, and plan on keeping it for a very long time. Resale is not in my concern hah.

I have heard the same issues regarding superchargers vs turbos. Frankly, it's only for personal pleasure and enjoyment of the car. Maybe minor racing on the freeway, so having the downfall of waiting till about 1500-1800 RPMs, I don't feel too worried about.

Now, I've heard of many different types of turbos. Going from water-cooled vs oil-cooled, internal vs external wastegates, ball vs journal bearing, etc. For my 5-speed Manual 2.3L Engine, what is your recommendation on a turbo and where can I get the kit?

 

The only turbos I would even consider have bearings which are both oil cooled and water cooled (there's no such a thing as a water cooled only bearing as oil is needed for lubrication). That said, I've never installed a turbocharger on a car that didn't come from the factory with one already in place, so I don't know if there are any kits out there which include the plumbing for the coolant to the bearing housing.

The good news here is that there are other folks on this board who have experience in this realm and can offer advice.

 

Thanks Shipo! I'll continue to ask around about that.

Now regarding other upgrades, my mazda doesn't have a front kit where i could mount a cold air intake. Is there any other way to construct a cold air intake that doesn't have to come through the wheel wells? I'm looking to get the maximum cold air force I can.

 

Keep in mind that cold air is the enemy of fuel economy. Yes, the colder the intake charge the greater the oxygen density in the intake charge, and with a rich enough mixture, the greater the specific power output at wide open throttle, however, for partial throttle lean operations (such as when tooling down the highway), you really want warmer air to aid in fuel atomization.

While I haven't had a look-see at the 2005 Mazda6, I suspect its intake does a masterful job of balancing the two extremes of a cold intake charge at full throttle, and a warm(ish) intake charge for low power operations. Personally I'd leave it alone unless and until you put in a turbocharger kit.

 

I'll definitely take that into consideration since i plan on upgrading to a turbocharger soon.

What are some other ways you would recommend upgrading my car for performance? I know those "Chips" they have are BS. I have dual magnaflow exhaust which i feel should be somewhat adequate for what I'm looking for. Maybe some headers, or something?

 

Unless and until you do the turbocharger upgrade, I'd leave the car alone. Why? Things like intakes and exhaust systems are typically "Borrow from Peter to pay Paul" scenarios. Simply put, the factory intake and exhaust systems are tuned to create mid RPM range "resonance" which aids in volumetric efficiency in mid RPM range operations (said another way, mid-range torque). If you start messing with those systems you may gain a couple of horsepower at redline at wide open throttle, however, you're almost certain to lose as much or more power in the mid range, right where you need it the most.

So, if you spend most of your time driving around with your engine turning well over 5,000 RPMs, then an intake and an exhaust may well help.