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Discussion Starter #1
So, before I begin, I'd like to just clear up that I am very new when it comes to doing anything to a car aside from driving it, changing the oil/tires etc.

Recently put an exhaust on my MZ3 (2012 Skyactiv sedan) and it's kind of opened my eyes. I really want to do a lot more.

I'm finding it difficult to do much with the Sky engine though. I'm considering swapping it for either an MS3 Engine or a 2.5L.

I know some are going to say I should get an MS3, but honestly I dislike the hatchback look and much prefer the sedan.

I want to try to get this to 300-350HP (that's the goal for now.)

Any advice to someone new?

(I feel like this has come up before but I couldn't find it. Might have looked in the wrong places or might just not know how to use the search effectively, so I'd like to apologize if this has been something on here already.)
 

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Demon Spawn
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yeah, right now with skyactiv tech still being so new there are not much aftermarket performance parts for them, I have the 2.5L (hatchback, I love hatchbacks) and the 2.5L engine, though it gets bad mpg for a small car and a 4 cylinder, is quite peppy and fun to drive. no it does not have a ton of power like the ms3 engine but it also gets better mpg then the ms3 so, there is that. the one thing many people do not realize is the 2.0,2.3 and 2.5L engines in these cars from 04-13 (the non skyactiv ones) are basically the exact same motor the only difference is the bore and stroke size (to make the 2.0 into a 2.3 they gave it a longer stroke and to make the 2.3 into a 2.5 they bored it slightly and also extended its stroke slightly) and they are what is called the mazda L series engines. the 2.3 turbo out of the speed 3 was on wards 10 best list in 2008 and the 2.5 was on wards 10 best in 2011, whats also funny is the new focus rs uses the same 2.3L motor as the speed 3 and 04-09 3 hatch and s trims only big differences are ford intake and exhaust, ford ecu and a bigger turbo setup then the speed 3 but the internal parts and block and cylinder head are the same exact thing. The odd thing with the 2.3 turbo out of the speed 3 is they used counterweights on the crankshaft to help it last longer, but the regular 2.3 did not get them (I don't know why, maybe because it only had 156hp and could easily take more, obviously) but the 2.5 has the same counterweights and molybdenum coated crank like the speed 3 motor did and also uses more robust internals like forged valves and rods like the speed 3 so the 2.5 is ready and happy to take a ton more strain then it does at stock power. from my research the turbo setup off a speed 3 will bolt onto any of the L series engines (swap intake and exhaust manifolds to speed 3 ones for the inlet and outlet ports on the turbo setup) but the rest supposedly bolts right up without needing anything but an ecu reflash so it knows the turbo. honestly I would try to find a speed 3 engine and put it in the sedan, you may have to move and modify the intercooler setup some as the factory sedan hood will not be tall enough to allow the top mount intercooler. (the speed 3 hatches from 07-09 have a taller hump in the middle just for this and the 10-13s have a taller hood and hood scoop to get cool air over it.) read this wikepedia page It makes for a good read and has a lot of info on the L series motor that you may want and may need to know if your planning the swap https://en.wikipedia.org/wiki/Mazda_L_engine
 

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Discussion Starter #3
Okay to make sure I am understanding, you're saying to look for an L 2011 2.5 Engine, then swap the intake and exhaust system for what is on the MS3. This setup should fit but the top mounted intercooler wouldn't, would an MS3 hood swap onto this or would it better to look for a front mounted intercooler?

Currently I have a stock automatic tranny. I'm not opposed to either automatic or manual to be honest, I know manual has its benefits, but I don't know how much I'm going to need it, in either case what do you think as far as transmission goes?
 

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Demon Spawn
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Okay to make sure I am understanding, you're saying to look for an L 2011 2.5 Engine, then swap the intake and exhaust system for what is on the MS3. This setup should fit but the top mounted intercooler wouldn't, would an MS3 hood swap onto this or would it better to look for a front mounted intercooler?

Currently I have a stock automatic tranny. I'm not opposed to either automatic or manual to be honest, I know manual has its benefits, but I don't know how much I'm going to need it, in either case what do you think as far as transmission goes?
your current transmission will not or at last should not mate up to any L series engine as it was designed after these where and designed for the skyactiv engines so more than likely has different bell housing, input and output shafts and other connections so if you go the engine swap route your looking at needing a transmission as well. I would advise against a stock auto with an ms3 engine as the auto already kinda sucks with the L series engines and burns the fluid at stock power kinda fast so adding 118hp and 120 ft pounds of torque more on it will kill it quick(over a stock 2.5l L series with an auto tranny), the manual will be your better option as it is built stronger and can handle the ms3 power output much easier your skyactiv auto is a much more robust and better designed transmission then the older designed ones on the L series engines. your starting to get into dangerous territory here price wise you maybe could get a decent junkyard setup with all you need for $2-400 but you need wiring ecu and everything if you where to do this and these cars are not really worth that much to invest 6k+ into engine and tranny swaps just to get more power, your better investment would probably be to save the cash and put it towards a proper sports car, but that's just my .02 cents, its your car and your cash so that makes it your decision.

plus you said your novice at working on cars which is not a bad thing, knowing your car and its parts is good,but taking on an engine swap is a BIG step from changing oil, it involves many tools, detailed step by step procedures, marking where and how things are supposed to line up and fit together and much more, so more then likely you wont have the tools, space to work on it, or know how to properly accomplish it. as engine and tranny swaps take time, space, know how and money to do. so you would more then likely be adding labor onto this to have a skilled mechanic do the swaps and that can easily add $3-6000 in costs on top of the engine and transmission with all the wiring, sensors and everything and then your looking at putting $8-12000 into a car that's worth maybe $10000 to begin with, plus doing a non factory engine and transmission swap will lower the resale value as your vin and placard info will no longer match what is on the car and this will be a turn off to many potential buyers should you ever decide to sell.

Plus remember man its a mazda 3 not a Porsche, they are fun little cars but not firebreathers by any means, and wont be worth much in 5-7 years as they get a ton of miles on them and wear out as all mechanical things eventually do/ your money may well be better spent putting it towards skyactiv engine mods or a proper sports car. that's why I am not modding my 3. 1 its an auto so I don't think it can handle much more then stock, and its an auto so its less fun for me then a manual (I prefer manuals, more control and more fun, plus manual transmissions weigh less) that and I am saving my mod money for a proper sports car to do this to instead of a commuter car that's peppy and fun with lots of features, but not a sports car. Every time I see an expensive mod and I want it, I put aside some money into the faster car fund and force myself to quit looking at the mods because I want them but just don't feel this car is worth expensive mods when I use it to commute to work and drive from site to site at work. I need it reliable not fast.

Yes an ms3 hood swap will allow a top mount intercooler but front mount is not bad, because your grill is already forcing cooler outside air in as you drive. and yes the turbo setup minus intercooler should go directly from a 2.3 onto a 2.5 with a 2.3's intake and exhaust manis on it and a few other changes, you would need to verify this though as I have never actually done the work to do it, just done the research as I was interested but as you read above that's why I have not done it.
 

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Discussion Starter #5
All understandable and I've been playing with this idea for a while, it's still not set in stone, but I'd figure I would come here to weigh my options. I've also consulted a few of my buddies that have way more experience than me.

I am not terribly worried about experience or tools, I have access to a place that has pretty much any tool available (to include lifts) and I would only need to pay for the bay while I work. The place is also staffed with a lot of mechanics that advise and teach but the place is otherwise a DIY.

Not many mods out there I've found for the Skyactiv, otherwise I would. I recently installed a cork sport exhaust onto it, I know I could do an intake, but not sure what else to do after that.
 

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OK, so to put it in more simple terms and in a format that is actually readable, 300 hp isn't about to happen anytime soon. If you have not had any experience beyond a simple exhaust swap, installing a different powertrain from an earlier car is not the place to start your career in mechanical work. Nothing is compatible. Transmission, electronics, engine management, nothing at all. You will have to strip everything from both cars, transfer the powertrain and the entire wiring harness and all needed accessories to yours. That is a huge job, made even more complicated if you want a MS3 motor with its turbocharger and all that goes with it. Bottom line is if you want big power, you are going to need to do one of two things- pay somebody many thousands to do a powertrain conversion and hope it stays together or get rid of your car and find something that is already capable of 300+ hp.
 

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Demon Spawn
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OK, so to put it in more simple terms and in a format that is actually readable, 300 hp isn't about to happen anytime soon. If you have not had any experience beyond a simple exhaust swap, installing a different powertrain from an earlier car is not the place to start your career in mechanical work. Nothing is compatible. Transmission, electronics, engine management, nothing at all. You will have to strip everything from both cars, transfer the powertrain and the entire wiring harness and all needed accessories to yours. That is a huge job, made even more complicated if you want a MS3 motor with its turbocharger and all that goes with it. Bottom line is if you want big power, you are going to need to do one of two things- pay somebody many thousands to do a powertrain conversion and hope it stays together or get rid of your car and find something that is already capable of 300+ hp.
Thanks for summing my thoughts up nice and neat. I am bad with doing that. always have been. and I apologize if I ramble on or get unreadable sometimes.
 
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