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Hey everyone, I have a 2012 skyactiv 3 Hatchback, and I have been pretty much running in circles trying to see if I can do anything to this car aside from a short ram intake, exhaust, or a tuning job from OV(Not opposed to these things but its all I've found). I have a manual option gearbox, and am curious as to why something like that cannot be turbocharged. Also curious as to whether it would be possible to do some sort of tie in with the manual option to an actual clutch so that turbocharging then becomes possible, and just not drive it automatic. Or am I insane?

I have nearly no actual garage experience so if any of this is just stupid I apologize
 

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If you are looking for more hp, it isn't happening without a tune. SRIs are basically cosmetic when used by themselves. They mostly make noise and suck in hot underhood air.:sad 1: Aftermarket headers that really make a difference don't exist and may not ever exist. So far it seems that the factory header design actually does an excellent job. An axle back exhaust does a bit, a few hp at best maybe. Mid pipes and resonator swaps can kill power as the OEM parts are tuned to promote maximum scavenging by the header. Change the mid pipe and you lose that, which results in detonation which in turn leads to timing pull and loss of torque.:frown2:
Adding a tune to a Skyactive motor with an SRI and axle back can get you 30 or more hp depending on the car.
Forced induction can be tricky as the engine has a relatively high compression ratio, making for a lot of work to get it right. Cost is quite prohibitive if you have somebody do it for you.
Some things you can do outside of power increases are suspension upgrades. Better springs and shocks, a larger rear sway bar, lighter rims and better tires go a long way towards making the car fun to drive.
 

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Demon Spawn
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If you are looking for more hp, it isn't happening without a tune. SRIs are basically cosmetic when used by themselves. They mostly make noise and suck in hot underhood air.:sad 1: Aftermarket headers that really make a difference don't exist and may not ever exist. So far it seems that the factory header design actually does an excellent job. An axle back exhaust does a bit, a few hp at best maybe. Mid pipes and resonator swaps can kill power as the OEM parts are tuned to promote maximum scavenging by the header. Change the mid pipe and you lose that, which results in detonation which in turn leads to timing pull and loss of torque.:frown2:
Adding a tune to a Skyactive motor with an SRI and axle back can get you 30 or more hp depending on the car.
Forced induction can be tricky as the engine has a relatively high compression ratio, making for a lot of work to get it right. Cost is quite prohibitive if you have somebody do it for you.
Some things you can do outside of power increases are suspension upgrades. Better springs and shocks, a larger rear sway bar, lighter rims and better tires go a long way towards making the car fun to drive.
Now mazda did figure out stock turbos on the skyactiv 2.5 in the new cx9 so it is possible and maybe not as tricky as we would think. someone with enough knowledge of force induction on high compression engines would more then likely be able to do it easily. but that's where your definition of high cost comes in is it worth 50hp to spend $4000? not really that's better spent on suspension and other items to make the car feel better, or better put again towards a faster car. but again I am not your old lady and not your financial institution so I cannot tell you what to do with your money. and opinions are a dime a dozen, or hell even cheaper now more like a penny for 6 dozen because everyone has one even if they know nothing of the subject they speak of (not speaking to or about anyone in this thread) and will not back down even when presented with facts stating they are incorrect. so it maybe cheaper then I say to get a turbo on your skyactiv but again may not be worth it, just depends what your definition of too expensive is. These cars are built for the long haul not the drag strip and doing too much to them will ruin the reliability as with any car.
 

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Now mazda did figure out stock turbos on the skyactiv 2.5 in the new cx9 so it is possible and maybe not as tricky as we would think. someone with enough knowledge of force induction on high compression engines would more then likely be able to do it easily.
If I understand it correctly Mazda figured out how to add a turbo the old fashioned way by reducing the compression ratio to 10.5:1. That is an expensive proposition for non FI cars.
 

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Demon Spawn
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If I understand it correctly Mazda figured out how to add a turbo the old fashioned way by reducing the compression ratio to 10.5:1. That is an expensive proposition for non FI cars.
hm, they did. surprising, it does have quite a bit of max boost(stock) though at 17.4 pounds, I think they will have to do combustion ignition instead of spark ignition to get a turbo on a compression ratio higher then that, but that's just a diesel, though some car makers are trying to get gas engines to do this as doing it with gas is more efficient and cleaner. and theyre still doing it all on 87 grade gas, I wonder if they have even tried 93 with a 12:1 or 14:1 like the normal skyactiv engines are and high octane gas with a turbo, I bet it still preignites and knocks though, as your asking it to do quite a bit by then.

here is a link to Mazda's spec page on the cx9: https://www.mazdausa.com/vehicles/cx-9/specs click engine and it does say 10:1 compression and 17.4 pounds of boost that's actually rather good power and fuel economy with it though unconventional to get a turbo 4 in a big ole suv like that, but with 250hp and 310 ft pounds of torque who really needs a v6 lol
 

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.

here is a link to Mazda's spec page on the cx9: https://www.mazdausa.com/vehicles/cx-9/specs click engine and it does say 10:1 compression and 17.4 pounds of boost that's actually rather good power and fuel economy with it though unconventional to get a turbo 4 in a big ole suv like that, but with 250hp and 310 ft pounds of torque who really needs a v6 lol
Ha, I bet it was cheaper to add FI to the SkyActiv than design a new motor from the ground up.
 

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Demon Spawn
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Ha, I bet it was cheaper to add FI to the SkyActiv than design a new motor from the ground up.
they already have a 3.0l and 3.7l design for v6, but they are dated and out of production, so fuel economy and power would need to be improved to make a marketable suv like the cx9, so a turbo 4 set for mid range power like you said was probably cheaper.
 

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Demon Spawn
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it is very difficult to turbo charge the skyactiv motor due to its very high compression ratio its over what many naturally aspirated gas spark ignition cars run your average spark ignition gasoline powered car has a compression ratio of about 8.5-10.1:1 outside atmosphere pressure upper limits for turboing in this setup are about 10:1 with 9:1 being preferred for longer engine life. the skyactiv motor in naturally aspirated form has 12-14.5:1 compression ratio which is much higher then normal spark ignition ranges and makes preignition(knock) very likely if something goes wrong diesel engines are not spark combustion as the gasoline counter parts are but rather compression ignition so they just basically force the air/fuel mix to combust as it compresses which is why diesels sound the way they do when idling, and somewhat the skyactiv motor sounds like a diesel at idle too (from outside the car and not that loud) and diesel motors have something like 20:1 compression ratios to accomplish this, many also use what is known as a glow plug in each cylinder, these go in similar spots to spark plugs but instead of jumping an ark to get resistance and spark to create fire to ignite the mixture all the glow plug does is get hot and help ignition efficiency when the diesel enbgine is cold and some newer ones like the vw tdi use them in high load situations to improve mpg and throttle response, but its just a metal piece that sticks into the cylinder and has a connector to electrical system that allows it to get really hot to aid in heating the cylinder and mixture within. your gasoline motor does not and cannot do this because they are a different design, gasoline motors use spark plugs to light the air/fuel mix on fire as it combusts this then causes the mixture to put downward pressure on your piston and create the power.

Now that you see how a basic spark combustion and compression combustion work we will go into why it is difficult nay impossible to turbo your skyactiv motor. your car has a 12:1 compression ratio meaning at peak piston upward motion right before ignition the mixture is 12x as compressed as it was when it entered the cylinder at the bottom of the piston stroke. ok and your asking 87 octane gas to do this which in older style engines would have a hard time above 9.5ish:1 without igniting before the spark(example the NC Miata (06-14) had a 10.1:1 compression ratio and required premium to prevent knock) and creating knock which can and will damage an engine if left uncheck for much time at all. as gasoline actually has more ignitability and energy potential then diesel, but that means less compression can happen before it ignites. if you have your fuel/air mix igniting before the car puts the spark out it causes the piston to slam back down too early and messes up the rhythm of the engine, it can also burn the cylinder lining, heads, and piston as well as cause compression leaks if run like this too long due to the extra strain the engine was not designed for, this also raises internal temps very quickly and at an unchecked rate which adds even more strain.

Ok then you add a turbo to this engine already at 12:1 ratio and force more air and fuel into the piston as you get on the gas, well 87 octane even 89,91,93,95 (basically any retail sold gas at a gas station) can only take so much compression before knocking occurs and 93 wont even go above 12:1 very well without special timing and engine management systems like mazda has designed, the skyactiv motor retards the timing a lot more then normal engines to compensate for this and its by design, you add a turbo and the system will have no way to compensate for the added forced in air and fuel and will start knocking at very low rpm and load due to unknown (to it) added air and fuel volumes. and the timing can only be retarded or advanced so much to compensate for things changing. from wikidepia (easy source to back me up):"Setting the correct ignition timing is crucial in the performance of an engine. Sparks occurring too soon or too late in the engine cycle are often responsible for excessive vibrations and even engine damage. The ignition timing affects many variables including engine longevity, fuel economy, and engine power. Modern engines that are controlled in real time by an engine control unit use a computer to control the timing throughout the engine's RPM and load range" so forcing more volume of mixture into your engine and then having it at an already high compression ratio and only so much ability to actually advance or retard the timing is a dangerous mixture for your engine and its life.
 

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Also curious as to whether it would be possible to do some sort of tie in with the manual option to an actual clutch so that turbocharging then becomes possible, and just not drive it automatic. Or am I insane?

I have nearly no actual garage experience so if any of this is just stupid I apologize

By manual option I take it you have an automatic?
No you can't use a clutch with an auto. Automatic transmissions don't work that way.
 

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