I plan to do my best to document the swap as closely as I can, and take away as much uncertainty about what is good and what isn't about this swap as possible. The waters in terms of information about this swap are very muddy. Hoping to help clear it up.

I second that

I’m gonna be doing the same swap on my speed6 and speed3 and it’s great to see videos like this because they aren’t many so please Any info will be greatly appreciated I will definitely like the videos

Appreciate it, I'm hoping to go through some of the stuff that no one seems to cover, everyone says what is best, but no one explains why.

I definitely will be. Parts have been few and far between, between wait times on parts etc.

How's it held up?

Did you ever find help with these questions?

@@Dyl_Cam I got the Damond plate & a new OEM Mazda PCV valve, to use with a dual oil catch can system. I compared the 2.5 timing chain & sprockets to the 2.3 items and swapped everything to the 2.5 stuff.

Yep.

the crankshaft main journals are theoretically the same, according to the spec sheets. however you would need to look into using a Long Rod kit of some kind. Honestly, depending on what your goal is, I see no reason to change the crankshaft out for the 2.3 one, unless you plan to make silly power. I've been searching all over the internet, groups, forums, etc. and have yet to see anyone breaking the 2.5 cast crankshaft.

what did you end up doing?

Pistons and rods between the 2.3 and the 2.5 are NOT the same. The 2.3 has a 94mm stroke, with a 6" rod length. The 2.5 has a 100mm stroke, and a 5.75" rod length. Bore of the 2.3 is 87.5mm Bore of the 2.5 is 89mm. I will be using stock sized pistons and rods for the 2.5, but forged.

Yep! when I get parts in It will continue.

​@@WeeManWTF2 Oh, well that makes me feel a lot better that it takes me a month or two to get this stuff done these days. Im not 19 anymore lmao. Used to stay up till 4-5am working on my DSMs and RX7. Figured you were done already since you uploaded this video in February. Do you know if anyone makes Pistons with Direct Injection dishing that work with the Molnar rods in the 2.5 block? Doing the swap in my speed right now. Started pulling my engine 2 days ago. Have a 2.5 sitting in my shop. Going to be throwing a stock bottom end in there for now, but these things are so cheap I will probably pick up another one to put Molnar rods and some kind of stronger pistons in so I can max out my cst4.

@@EvlEgle Your best bet would be to try to order 2.3 DISI pistons and see if they will make/have any in the 2.5 bore (89mm) But the issue you'd run into there, is piston height.

@@EvlEgle If you do stock bottom end, MAKE SURE you regap your piston rings!

@@WeeManWTF2 Yeah was planning on gapping the rings to .020 // 024

In my personal opinion, if you're trying to hit that kind of power reliably, I would recommend considering building up the 2.3, just because of the Forged crank. Now, based on speculation and here-say, I've heard of the 2.5 blocks built up with Rods and Pistons to make anywhere from 4-500 hp. I have yet to hear of the crankshaft being the failure point in any duratec based build, Mazdaspeed or not. Again, I can't confirm or deny that 100%, just based on what I have seen on KZfaq, the 2.5 swap, and other Mazda Facebook groups. Couldn't hurt to cryo treat it I suppose.

Thanks, I appreciate, and value your opinion. I am looking forward to your next video. Think I am going to swap in the 2.5 to get my girl by, and see if the 2.3 crank can be ground. then build from there. I just wish she wasn't such a hammer footed mean driver. I have created a monster..lol

@@hlhoover2427 Shes a lucky girl! best of luck. hoping to make episode 2 soon, all of the big exciting parts are on backorder, so I have nothing noteworthy to make part 2 about yet.

​@@hlhoover2427 How did the swap go man?