I'm planning to run 8-10psi for a goal of around 250hp. From from my research on the MZR, that's completely & realistically within its durability limit for stock internals. My tuner claims 300whp capable, but I don't need that in this vehicle, and I value durability over performance for this application, so I'm not going to go that far. For the engine, the rods are weak and don't like high-torque-low-rpm situations. This will be addressed in tuning, and also was part of the reason I chose the GT2871R over the K04. (the K04 provides much more power earlier and lower in the powerband.)
On the 5speed manual transmissions, 3rd gear was the weak link in the drivetrain. There's little to no info on the 6-speeds - I will be the guinea pig. If I have transmission issues, I am perfectly OK with being the guinea pig for fitting an ms3 trans to the 2.5L MZR (can't find anyone who's done that yet either.)
The ms3 mani is susceptible to cracking, but so is every turbo manifold. If you listen to the ms3 "snobs", the only manifolds worth using are the $900 Full-Race or CP-E, personally I don't buy that. Stock ms3 manifolds cost under $50 (mine was $40). Certainly the Full-Race and CP-E appear to be good items, but if you search enough, you will find that people have had issues with them as well. If you say, “Well I’ve heard a hundred stories of cracked stock manifold, but I’ve only ever heard about one or two issues with a Full-Race unit!” keep in mind that there are probably 1000 stock units in operation for every Full-Race unit out in the field. If the OEM manifold does crack in a couple years, then I’ll be out another $40, plus maybe six hours of my time – but I’ll still be nearly a thousand bucks ahead.
Going to a T25 flange then necessitates the use of the standard Garrett turbine housing, which in turn requires the use of the Garrett outlet flange, which means custom downpipe. It definitely opens up the world to easy custom manifolds and exhaust, but I specifically didn’t want custom for this build, I wanted off-the-shelf.
When it came down to the eBay cast log style manifolds (godspeed) vs. the ms3 OEM unit: I work at an OEM and have respect for the level of design, testing, and QC that an OEM part endures, and I know for a fact the aftermarket (eBay or boutique) pieces aren't getting anything near that, so was an easy decision. There are people making 400+hp on the stock manifold, it won't be a performance bottleneck.
I researched the ms3 swap extensively, and my conclusion was the same – it’s not as easy as it looks. Everybody’s knee-jerk reaction is, “Hurr-durr, just drop in a DISI engine!” but like you said, the basic architecture of the rest of the two vehicles is completely different. Only two have ever been attempted: the Car&Driver Bosswagon, and Autobahn One Lap of America car. The Bosswagon never ran right, and the One Lap car didn’t run without the Instrument cluster duct-taped into the dash, because the DISI wouldn’t run without the ms3 gauge cluster – and that was with Mazda technicians working with Mazda Japan engineering support (I read the full build thread). Combine that with the price that ms3’s still command at auction, and it was a poor option.
Regarding the concept of a Franken-motor: I didn’t read the article, but there are several companies that make MZR engine internals. If you need a stronger MZR it’s not a big deal to buy some new rods and build a bottom end that can make big hp numbers. But again, I’m not interested in big hp numbers, just enough to where you can’t use the word “gutless” to describe the vehicle and how it accelerates. Keep in mind that the DISI has its own issues, namely fueling with the HPFP. With a built MZR, you just need a big pump and big injectors - a totally conventional method and no issues getting enough fuel for big hp numbers. The DISI engine and HPFP reaches its limit quickly and is not so simple to upgrade.
On the 5speed manual transmissions, 3rd gear was the weak link in the drivetrain. There's little to no info on the 6-speeds - I will be the guinea pig. If I have transmission issues, I am perfectly OK with being the guinea pig for fitting an ms3 trans to the 2.5L MZR (can't find anyone who's done that yet either.)
The ms3 mani is susceptible to cracking, but so is every turbo manifold. If you listen to the ms3 "snobs", the only manifolds worth using are the $900 Full-Race or CP-E, personally I don't buy that. Stock ms3 manifolds cost under $50 (mine was $40). Certainly the Full-Race and CP-E appear to be good items, but if you search enough, you will find that people have had issues with them as well. If you say, “Well I’ve heard a hundred stories of cracked stock manifold, but I’ve only ever heard about one or two issues with a Full-Race unit!” keep in mind that there are probably 1000 stock units in operation for every Full-Race unit out in the field. If the OEM manifold does crack in a couple years, then I’ll be out another $40, plus maybe six hours of my time – but I’ll still be nearly a thousand bucks ahead.
Going to a T25 flange then necessitates the use of the standard Garrett turbine housing, which in turn requires the use of the Garrett outlet flange, which means custom downpipe. It definitely opens up the world to easy custom manifolds and exhaust, but I specifically didn’t want custom for this build, I wanted off-the-shelf.
When it came down to the eBay cast log style manifolds (godspeed) vs. the ms3 OEM unit: I work at an OEM and have respect for the level of design, testing, and QC that an OEM part endures, and I know for a fact the aftermarket (eBay or boutique) pieces aren't getting anything near that, so was an easy decision. There are people making 400+hp on the stock manifold, it won't be a performance bottleneck.
I researched the ms3 swap extensively, and my conclusion was the same – it’s not as easy as it looks. Everybody’s knee-jerk reaction is, “Hurr-durr, just drop in a DISI engine!” but like you said, the basic architecture of the rest of the two vehicles is completely different. Only two have ever been attempted: the Car&Driver Bosswagon, and Autobahn One Lap of America car. The Bosswagon never ran right, and the One Lap car didn’t run without the Instrument cluster duct-taped into the dash, because the DISI wouldn’t run without the ms3 gauge cluster – and that was with Mazda technicians working with Mazda Japan engineering support (I read the full build thread). Combine that with the price that ms3’s still command at auction, and it was a poor option.
Regarding the concept of a Franken-motor: I didn’t read the article, but there are several companies that make MZR engine internals. If you need a stronger MZR it’s not a big deal to buy some new rods and build a bottom end that can make big hp numbers. But again, I’m not interested in big hp numbers, just enough to where you can’t use the word “gutless” to describe the vehicle and how it accelerates. Keep in mind that the DISI has its own issues, namely fueling with the HPFP. With a built MZR, you just need a big pump and big injectors - a totally conventional method and no issues getting enough fuel for big hp numbers. The DISI engine and HPFP reaches its limit quickly and is not so simple to upgrade.
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