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Thread: 2.5 I4 Swap?

  1. #1
    1,000 rpm - releasing the clutch
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    2.5 I4 Swap?

    First off, I'd dearly love to have a V8 Roadster, but unless I win the lotto, it ain't gonna happen! I remember a while back, on another forum maybe, there was a guy down in Texas somewhere that was doing 2.5 upgrades for Miatas, and I thought it was a pretty reasonable price. But tragically, I lost that information and can't seem to find it.

    Has anyone here heard/seen anything like that? I did some looking around here, but all I could find was V8 & V6 conversions.

    (And before anyone says, "Use your Google!", I already did, and could not find what I was looking for. Here is what it turned up

    Thanks! I really do think there is a 2.5 upgrade in my future. Not this year, and maybe not even next year, but the year after... maybe.

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    tsingson (05-06-2017)

  3. #2
    5,000 rpm - there be torque here! MiataQuest's Avatar
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    You have an NC, correct? If so...

    According to this old "for sale" ad the engine is a drop in. BTW I just love that car!
    Link: http://clubroadster.net/vb_forum/28-...-must-see.html

    In the ad it says he used Moto East for the engine installation.
    Link: http://www.moto-east.com/main/service/

    My son has a Mazda 3 with the 2.5
    It runs real strong.
    Definitely worth the swap. Maybe inquire what a NEW engine costs.

    I will be having a NEW GM EcoTec 2.4 installed into my NA in June.
    That will maximize the power withstand of the Miata drivetrain, give me torque, and clean up the engine bay getting rid of all the turbo plumbing while lowering weight. It should be more reliable than a stressed out turbo 1.6 with more useable power.
    Last edited by MiataQuest; 05-06-2017 at 09:35 AM.

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  5. #3
    1,000 rpm - releasing the clutch
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    Correct, got the NC. The Mazda 6 that my wife uses as her DD has the same 2.5 as would be going into mine. Also, the Ford Escape has the 2.5 in it too, and both those cars pull pretty hard for four-bangers. I'd love to have one in the Miata. All that torque and half the weight of those other cars! It ought to be a hoot to drive!

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    Admin / Pit Boss / Miataholic Phatmiata's Avatar
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    V8roadsters has that motor in one of their NA miatas. They test all their suspension products on it at the track.

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  9. #5
    Admin / Pit Boss / Miataholic Phatmiata's Avatar
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    Admin / Pit Boss / Miataholic Phatmiata's Avatar
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    here it is a year later after they built it, its a track duty car for testing parts

    http://mazdaroadster.net/showthread....om-V8Roadsters

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  12. #7
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    Ah ha! Found it. Brian Goodwin, I think was the first one doing these conversions.



    And then Joe at Dynotronics was doing them too. If I recall correctly, one could pre-arrange an install, drive there and hole up in a hotel room for a few days while they do the swap, write a check, drive it home. Easy! It kind of sounds like a pretty easy plug & play swap so now I'm wondering if this is something I could do at home... (Will have to rent an engine hoist tho)

    Clearly, more research is needed. But time is on my side, since I don't *need* to do anything yet. Most of the guys that do these swaps blow up their motors and are forced into doing something to get back on the road.

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    Ah just realized that you have an NC, probably a much easier swap carry on carry on.

    I still want the engine out of my speed3 in my NA.

  15. #9
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    I was doing some of the numbers on the NC 2.5l swap, very interesting. I see a few NC miatas with bad engines for cheap on occasion. The 2.5 engine can be had for very cheap with low miles.

    Our sponsor, Goodwin Racing, has some really nice products that make this a really enticing project. Check it out!

    http://www.good-win-racing.com/Mazda...t/61-1506.html

    200hp naturally aspirated in this car would be stellar!


    For example, I found an '07 Grand Touring near me with a bad engine for about $3500 (!!), a low mileage 2.5 was about 700-900. I reckoned with the GWR tuner, header and exhaust, I would have an NC that could run with or beat an s2k for about $6-7k altogether. That's very tempting.

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  17. #10
    5,000 rpm - there be torque here! MiataQuest's Avatar
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    Road trip opportunity!

    Get a round trip airline ticket from San Diego to Nebraska and back.
    Drive the car to Goodwin Racing and drop it off. Fly back home.
    After the conversion is completed fly back out to Goodwin racing.
    Drive up and down the coast for a few days to break in the new engine with mixed driving.
    Return to Goodwin racing. Get an oil change and inspection.
    Drive back to Nebraska.

    Sell this to the wife as it's a vacation for her!
    Last edited by MiataQuest; 07-05-2017 at 03:18 PM.

  18. #11
    Ninja Messiah kung fu jesus's Avatar
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    San Diego is terrific. If I was offered to move back to SOCAL and it was in San Diego, I'd do it. The Miata people there are second to none and extremely friendly. The beaches are the best, too.

  19. #12
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    All your NC hopes and dreams realized.

    http://www.motorauthority.com/news/1...-74-in-a-miata

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  21. #13
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    Even better one. He puts the heat on a GT3.


  22. #14
    4,000 rpm - entering the fun zone Hyper's Avatar
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    That dude Joe at Dynotronics takes forever to do a swap, my friend's NC was in the shop for years and he did a really bad job on the build. rod knock missing parts etc. I do not trust his job at all. The 2.5 has been documented enough for a the average dude to rent a lift and do the swap himself. It doesn't involve too much brainstorming, is a simple swap of engine parts and some porting of the intake manifold.

    EDIT:

    I just acquired an NC PRHT Grand Touring with a 6speed LSD and sport suspension. The car was a dealer trade of one of my customers of which I got at an amazing price. I have not created a build thread yet because I am in the process of finalizing my NB build but the moment I am done with that build I am going to do the engine swap, most likely a full built 2.5 with Cosworth supercharger.

    Here is the picture of my Bone Stock Copper Red NC PRHT Grand Touring.


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    Love me a good 2.5, the perfect around town NC with lots of 'pull away from stoplight' torque.

    Planning to do another 2.5 conversion.....soon.

    Head mechanic Rocky is doing these for customers here every month. Customers have shipped us cars for 2.5 conversions from just about every state in the land....including both Hawaii and Alaska.

    Starting to hunt Craigslist for a blown motor NC1 thinking we do another shop project 2.5 build soon. If somebody spots a busted motor NC for sale, let me know. Thanks,
    Last edited by GoodWin Racing; 04-15-2018 at 11:23 AM.

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