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I own and operate a Miata shop in the San Francisco area that specializes in high-end performance parts with a specific focus on road race cars. We have our own private label line of products (BBKs, turbo kits, small adapters/blocking plates, etc), but I also like to resell products from other shops/manufacturers that I've used and liked. This thread is about one of those products. KMiata is a small operation based in the Chicagoland area that has developed a complete kit to stuff any K20 or K24 engine into a Mazda Miata. I saw this swap kit in development about 3 years ago, made some brief suggestions to the guy doing the work, and mostly forgot about it until he released the kit. As much as I love turbos, I have a special place in my heart for well thought-out swaps that make sense, and this swap makes so much sense. So when my good friend from college decided that it was time to get out of the NASA PT game and liquidate his truck/trailer/K24-powered S2000, I threatened him with bodily injury until he agreed to build one and let me tinker with it.  The donor car is a 2002 Emerald Green, Tan interior, ~129k miles, full Sport package car with a 6-speed transmission. He's going whole-hog all at once, so in addition to the K24A2 from a 2006 TSX, it's getting 15x9 6ULs, Gen2 XIDAs, a Blackbird Fabworx rollbar, fresh interior carpeting and seats, overhauled suspension bushings/balljoints, and more stuff I can't even remember right now. The car before we started. All stock, very slow.  Goodbye, BP.  In order to remove the factory harness and install the Honda engine harness, it's worthwhile/required to remove the dash, so that comes out next, along with all the HVAC stuff.  Next step is prepping the longblock. This is a 100k mile K24A2 from a 2006 TSX. Using the K24A2 in complete form avoids the hassle of finding a K20A head, which makes things go much more smoothly. The K24 is a very tall motor, so getting it to fit into the car is a bit of a chore. The swap kit deletes the factory K24 oil pump and replaces it with the K20 unit and a custom rear case/pickup tube/oil pan setup which allows everything to clear the stock-location steering rack. Removing the stock oil pump here. The steering rack would interfere by 2" or so  New K20 pump, notched to clear the K24 block, with a new rear case that comes with the swap kit.  In addition to the fresh pump, we did a 50deg RSX VTC gear for mid-range power and a fresh tensioner for reliability. All buttoned up and ready to go:  The kit uses an adapter plate and custom flywheel which bolts up to the K24, and then any 1.8L Miata clutch and transmission will bolt up to the adapter plate/flywheel. The trans has to be notched slightly to clear the starter:  And an OEM flywheel shield is used to protect everything.  All connected up and ready to go! 
Savington fucked around with this message at 19:00 on May 4, 2016 |
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May 4, 2016 17:46
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I like the cut of your jib.
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May 4, 2016 17:55
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At first I thought this was about cramming KA24 in there. Good pictures, curious to see how this progresses.
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May 4, 2016 17:59
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Jared592 posted:At first I thought this was about cramming KA24 in there. Good pictures, curious to see how this progresses. I thought he was putting in a KKK K24 Turbocharger.
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May 4, 2016 18:00
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It's nice to see a Savington thread again. I had missed your dumb Miata escapades.
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May 4, 2016 18:17
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what's the height of the motor with the k20 pump and oil pan? i'm curious about swapping one of these into my e30 at some point instead of a x52 motor.
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May 4, 2016 18:32
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So what's the budget to do this?
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May 4, 2016 18:38
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This is a good thread. So have you driven a K24/K20 Miata yet? If not I'm eagerly awaiting your impressions when it's done. I wasn't keen on this swap when Phone first mentioned it awhile ago, but I have warmed up to it as making the most sense like you said. Especially if you prefer being N/A like myself, this really is the way to go. Also would like to see the cost tally once it's done.
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May 4, 2016 19:22
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Seat Safety Switch posted:It's nice to see a Savington thread again. I had missed your dumb Miata escapades. Thanks! I have another good project going right now that I'll do a separate thread for when I make enough progress on that car to post about. Right now it's a ~200whp EFR6258 setup on pump gas, but I have a world-class T5 trans, EFR6758, and a built VVT longblock in the shop waiting for installation. Final power goal is 425whp on E85. BraveUlysses posted:what's the height of the motor with the k20 pump and oil pan? i'm curious about swapping one of these into my e30 at some point instead of a x52 motor. I'll snag a quick measurement next time I'm working on the car. BlackMK4 posted:So what's the budget to do this? Expect to spend about $8k in parts to do the swap all-inclusive on an NB, another $750-1000 on an NA. We're hoping to build a few turnkey cars for customers, and it's about $4k in labor to complete the swap.
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May 4, 2016 19:26
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Goddamn, 8k? Oh well, still a cool project so i'm bookmarking this for sure.
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May 4, 2016 21:18
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BraveUlysses posted:Goddamn, 8k? Oh well, still a cool project so i'm bookmarking this for sure. Things cost money. A VVT swap is $3-4K after you tally everything up. A decent turbo kit that won't leave you with a 1000kg rolling paperweight is about $5K. As soon as you crack open a BP to do something a bit high strung, whether it's NA or turbocharging, you're in for at minimum a few grand. It's relatively cheap to make a reliable 130-150whp in a Miata, but once you start setting your sights on 160whp+, poo poo gets real. Fast.
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May 4, 2016 21:33
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Not my choice of swap, but drat neat. Any chance of scaling the K and the BP? I'm interested in what those turn out at, in a "bench racing my swap before I do it" sense.
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May 4, 2016 21:35
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Scaling? A K20/24 will make 250whp+ with mild headwork and minor sorcery. Emilio blew 10k on a BP and couldn't break 200whp. e: oh, a BP weighs more than a Gen 4 GM motor. Fully dressed about 300lbs. The K series is lighter. Phone fucked around with this message at 22:06 on May 4, 2016 |
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May 4, 2016 21:42
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Engine weight. I know what a peripheral port 13B weighs, I don't know what a K24 or a BP weighs.
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May 4, 2016 21:44
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The swap kit itself is $3700 (subframe/mounts, oil pan/pickup/pump adapter, flywheel, trans adapter, wiring harness). You'll spend $1200 for a good K24A2 motor and then another $500 for the RSX VTC gear, K20 oil pump, and OEM tensioner. You need an uprated clutch ($400) to put behind the new motor as well. Once it's in the car, it's $1300 for the intake manifold/TB/header. To make it all run, you need a $300 OEM wiring harness and $450 for KTuner. Add in coolant hoses, a new radiator, miscellaneous hose clamps and electrical connectors and zipties and heat wrap and fuel hose, and $8k is a solid estimate. That figure does include all the easy go-fast bolt-ons (intake manifold, RSX gear, KTuner, etc) so you end up with about 50hp more than the stock motor made, but yes, engine swaps are never cheap to do correctly. We're using all new parts, a new OEM oil pump, a new clutch, a brand new OEM wiring harness, etc. so there's no corner-cutting going on here. He wants to daily drive this car and do track days, and he and I both know you can't cut corners if you want to do that. We did get a fairly accurate weight during assembly. Fully dressed VVT motor with the following items 468lbs:
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May 4, 2016 23:26
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Hm, cool, thanks. Always hard to find *good* weights of these things; you know how everyone doing engine swaps has their own axe to grind.
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May 4, 2016 23:47
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Are you using the kmiata headers, or doing something custom yourself? I always thought their solution was a little strange, but I guess the miata flow direction is opposite the K series when oriented for RWD. For my money though I think the coolest k-swap is the toyota MR-S. They're in the ballpark of miata curb weight, but aren't as expensive to swap. And bonus mid-engine so you can snap oversteer into a tree.
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May 5, 2016 00:22
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I have looked at that k miata website too many times now. What sort of redline are you looking at on the finished product? I know they lose ~1k to the k20 since the displacement gain is all in the stroke, but it's crazy how much NA power these K24s can make. An 8k redline with 220+whp in a miata would so fun.
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May 5, 2016 00:42
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Savington posted:I own and operate a Miata shop in the San Francisco area VL Motorsports?
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May 5, 2016 01:44
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Crustashio posted:Are you using the kmiata headers, or doing something custom yourself? I always thought their solution was a little strange, but I guess the miata flow direction is opposite the K series when oriented for RWD. We're using KMiata's new Street header. The Miata doesn't have room to run a 3" exhaust (or anything, really) down the passenger side, and the only place to cross under the drivetrain is at the oil pan, so while it looks a little odd, it's the right solution. The Race header looks really wild since they have to fit the entire 4-2-1 collector setup above the oil pan. moloo posted:I have looked at that k miata website too many times now. ~8000rpm is the goal. It's all stock valvetrain/cams for now. My friend had a very similar steup on his S2000 - K24A2 from a TSX, Golden Eagle IM, 3" exhaust. That car used an AEM Infinity and ended up at 224whp/180wtq SAE Dynojet. This manifold is supposed to be slightly better, and we're pretty sure the header is better as well. Since there are tenative plans to add cams to the motor at some point, he's not too worried with the initial power numbers. 240-250whp is the final goal with a streetable set of cams. charliemonster42 posted:VL Motorsports? Trackspeed Engineering. We started in San Luis Obispo in 2009 and moved to Sunnyvale in 2012. I haven't been to VL yet (they're only about a year old) but they seem to be a jack-of-all-trades shop (240sx, Miata, etc). We only do 90-05 Miatas, and I like to think that lets us do those particular cars very well.
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May 5, 2016 03:28
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Savington posted:Trackspeed Engineering. We started in San Luis Obispo in 2009 and moved to Sunnyvale in 2012. I haven't been to VL yet (they're only about a year old) but they seem to be a jack-of-all-trades shop (240sx, Miata, etc). We only do 90-05 Miatas, and I like to think that lets us do those particular cars very well. Ah okay. My little brother used to work for VL until they let him go for what initially seemed to be justifiable reasons, but later turned out to be slightly less-so. He still has a good relationship with them, so I'm not going to trash them on here. They're definitely more spread out than you guys seem to be; near as I can tell they're primarily miatas but they'll work on anything. Had them install my rear suspension bushings on my e30 because I was too lazy to do them myself.
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May 6, 2016 00:50
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OK, into the car we go. Having the transmission attached to the engine does not make the process of putting a K24 into a Miata substantially more difficult, so it's far easier to attach the trans to the engine while it's sitting on the ground, vs. trying to benchpress or deadlift it into place once the engine is bolted up. The K24 locates the starter on the opposite side of the engine, which means cutting a small notch in the bellhousing of the transmission. Pretty much every swap uses the same subframe. They're built by V8Roadsters, but KMiata's version has K-specific mounts (ours for the K24, obviously). It's a tubular part with NB-style mounts for the steering rack and the updated lower control arm geometry for improved bumpsteer. I didn't weigh the subframe by itself, but Internet Folklore and Rumor (TM) has it at ~10lbs lighter than stock.  On the way in. The motor mounts get left off until the engine is all the way in, because the oil pan nestles around the steering rack and the motor mounts will interfere with that if installed too soon.  It just looks right in the engine bay. Not out of place, not stuffed in. Just looks like it belongs there. 
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May 6, 2016 21:07
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I have the biggest erection edit: Can you cram an s2000 cluster in that thing?
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May 6, 2016 21:09
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doogle posted:I have the biggest erection Possible, but it would basically be the same as converting a f20c speedo to a k20 car (since he's using a k20 harness) plus, at the very least, converting the signal from the miata trans speed sensor to s2000 speedo. Kmiata has a $300 conversion harness that let's you use the factory miata gauge cluster including all the lights and stuff. moloo fucked around with this message at 22:39 on May 6, 2016 |
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May 6, 2016 22:37
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Once the bare longblock is in, it's time for accessories. Let's start up front. In every factory application, the throttle body exits on the other side of the intake manifold compared to what you would want in a Miata. We want the throttle body aimed forward, which means getting crafty with the alternator and belt setup. K Miata sells a 4-pulley setup that doesn't use a tensioner, but the belt and pulleys are sized so that you don't need one. As the belt wears, you can shim the alternator outwards if necessary, but it's a big 7-rib belt and it won't move much.  We're using Skunk2's new Ultra Street intake manifold, which is sized for lower power applications like a stock K24A2. This IM also has a plenum which just so happens to be reversible, which allows the TB to aim forward. Since the K24 throttle body would be upside down, and the K24 TPS is an unmitigated piece of poo poo anyway, K Miata makes an adapter plate which allows you bolt on a 70mm B18 throttle body and orient it right-side up as well. A small bracket adapts the factory throttle cable to the B18 throttle body, and the TB adapter has a port for the factory MAP sensor. Easy.   The header is another K Miata piece. This is their new low-cost Street Header. Not quite as much power as the crazy bag-of-snakes Race header, but it's half the cost and makes good power. The owner is leaning towards upgrading when cams are added later on.   I make a crazy 76mm twin-core triple-pass radiator for Spec Miatas and turbocharged cars, but the K24 doesn't need anything that big, so Koyo's new Hypercore radiator drops into place and fits perfectly.  Next up is wiring.
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May 6, 2016 23:15
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That's a thing of beauty. I love how elegantly simple that belt setup is.
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May 6, 2016 23:49
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That's right, I forgot you made rads... uhm... semi-off-topic, but how impossible would it be to get one with the bottom outlet on the passenger side? Just wondering at this point.
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May 7, 2016 01:26
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mekilljoydammit posted:That's right, I forgot you made rads... uhm... semi-off-topic, but how impossible would it be to get one with the bottom outlet on the passenger side? Just wondering at this point. Very doable, just costs about $50 more than the standard radiator. It also becomes a dual-pass at that point. Shoot me an email at info@trackspeedengineering.com for more info.
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May 7, 2016 01:43
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Between this and Crossthreaded, I now want a K-series Exocet.
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May 7, 2016 07:15
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The K-series is a returnless setup, same as the Miata, so we just rerouted the factory feed line and built a new nylon line to connect from the Miata feed line to the OEM K24A2 rail. I did slide a little heat shielding over the fuel line for safety, since the header is now on this side of the car. A DW100 replaces the factory fuel pump in the tank for a little extra capacity without overpowering the OEM 60psi FPR.  For the NB, we started by pulling the dashboard and all the HVAC equipment. We then removed the entire OEM engine harness, which unplugs at a big blue connector under the dash. This blue connector provides power and signals to the ECU, and then runs signals from the ECU to the dash and the rest of the car, so every single wire you need to splice into is available at that connector. (ignore the single wire spliced in at the fuel pump connector, we changed that later)  We’re using an OEM Honda ECU and a new OEM Honda engine harness. The OEM harness we’re using is from a Honda Element. The Element also came with a K24, so things like the crank sensor and knock sensor are wired correctly for a K24 application (the K20 is wired a little differently). The harness actually comes in two parts – one engine harness and one “charge harness”, which includes the plugs for the alternator, starter, and knock sensor. These harnesses are inexpensive enough that it wasn’t worth the hassle of trying to procure them from a junkyard in good, uncut condition – we just bought brand new parts from a Honda dealer.  The harness has a few large plastic guards, which all need to come off in order to allow the harness to be packed into the Miata engine bay.   On the other side of the harness, we have the ECU connectors and a larger grey connector that normally attaches to the Element’s dash/body harness. The two ECU connectors go to the ECU, and the grey connector will plug into the KMiata adapter harness.  Here’s the ECU and patch harness setup. This is a fully tuneable KTuner ECU. The OEM Element harness plugs into connectors A and B, and the KMiata patch harness plugs into connector E and the grey dash/body connector. There are also a few extra wires for constant +12v, switched +12v, fuel pump, and fan control, as well as wires for the tachometer, CEL, and OEM coolant temp gauge. The KMiata patch harness includes a trio of relays for main relay function, oxygen sensor wideband function, and a fuel pump relay to trigger the OEM 1.6L Miata relay. For this NB application, we bypassed the KMiata fuel pump relay and ran the ECU’s fuel pump output directly to the OEM Miata relay. Everything will get mounted behind the glovebox and tied up/tucked behind the dash.  On the engine bay side, it’s an OEM harness, so everything plugs in really nicely. The only things worth mentioning are the hookups for the starter +12v and starter solenoid. The OEM Honda charge harness includes the positive terminal for the battery, so we cut that off and crimped it to the OEM Miata harness. On the left are the two wires that normally fasten to the Miata starter, and on the right is the OEM Honda charge harness with the battery terminal cut off.  We used a big, screw-type connector and a huge piece of heat shrink over the top afterwards.  The OEM Honda starter solenoid wire is actually routed through the engine harness and pinned to the grey body/dash connector. KMiata’s patch harness then provides a flying lead which gets routed back into the engine bay and attached to the factory Miata starter solenoid wire. With that, the engine starts and idles. We still have a bunch of small things to get done – we’re going to add a remote idle valve and we still need to build coolant and heater hoses, but the heavy lifting is done. We’re also working on a whole ton of other chassis work – XIDAs, a poly/SAE863 bushing setup, 6ULs, Blackbird Fabworx GT3 rollbar, Elise seats, full stereo system, and the list goes on and on.
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May 25, 2016 18:09
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Great write up so far, keep the updates coming.
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May 26, 2016 04:55
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Got all the suspension back into the car. The control arms get Energy Suspension bushings, SAE863 sleeve bearings, and 1144 steel sleeves. The ES bushings normally have a lot of stiction, so a smart Miata guy in Washington devised this setup last year. It uses an SAE863 iron-reinforced sleeve bearing in between the polyurethane and a downsized steel sleeve, so the suspension rotates on the sleeve bearing and not the polyurethane. The result is about a 90% reduction in stiction over a standard polyurethane setup without any of the NVH associated with delrin or sphericals. These should also last a lot longer. The washers on the end are for the alignment bolt positions, which have longer slots that would leave the sleeve bearings exposed to the elements.   Bauer Extended LBJs for added camber at sensible ride heights. These add about 2 degrees of camber over a standard lower ball joint, so you can get ~3 degrees at ~4.5" pinch weld height without needing to max out the adjusters. Before these, we would have been limited to the 2.2-2.5* range.   In situ with Gen2 XIDAs and fresh Trackspeed brake lines. The car will run the OEM Sport brakes for now, but I suspect a Trackspeed 11.75” BBK will find its way in at some point. A Racing Beat tubular FSB, stock RSB, and Supermiata endlinks will round out the suspension setup.   With all the coolant hoses built, we bled out the cooling system by lifting the nose into the air and using a magic funnel. It drank another half-gallon of coolant after the thermostat cycled, so everything did its job.  Header starting to color up nicely.   Once it’s on its own four feet again, we will start to put the interior together. New tan carpet from Moss Motors will go with the tan Elise Probax seats that currently live in my ‘02SE, christened “Acamas” (son of Theseus). Acamas will get a set of black Probax leather seats to match the black interior in that car. The Blackbird Fabworx GT3 bar has made several appearances in photos already, and a Robbins canvas softtop will complete the interior transformation.
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May 31, 2016 05:54
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Wow, I can't believe I haven't seen this thread until now. My best friend's aunt and uncle own a miata of the same color and generation as the swap car. Its existence has been the physical manifestation of the greed that alienated them from the rest of the family for over a decade. The aunt (the eldest daughter) was named the executor of the will, which, according to her meant that mom wanted her to have all the money. So, in a family with 8 siblings, and at least 30 grand kids, every dime went to the mazda dealership for the "British racing green" miata. Anyways, years pass and I see the miata every summer because they have a cottage that you drive past on the way to my friend's family cottage. Last August at my friend's wedding the uncle overheard I was into "car stuff" and asked me to change the timing belt. I told him that the job is easier with special tools i didn't have and that it's generally a good idea to replace all the pulleys at the same time. He didn't want to spend more than $150 so I declined the job, and didn't think of it till last weekend when I saw the miata sitting behind a bunch of crap half-covered by a tarp. I inquired, and apparently it broke down in the fall near the cottage, it was towed back and hasn't moved since. What should I offer them for a NB with a busted timing belt?
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May 31, 2016 18:29
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Since they're dicks, I'd offer less than $2000 depending on what it comes with. You can get all new gaskets, pulleys, and a timing belt for ~$300 and spend about half a day making the car run under it's own power. That said, if they're cheap enough morons to let the timing belt go, there's probably a bunch more of deferred maintenance waiting to be done as well (coolant, trans + diff oil, radiator probably resembles a UPS uniform, etc).
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May 31, 2016 18:39
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500 dollars with unknown history maybe less if there's significant rusting, they're not expensive cars, they're just fun cheap cars to mess around with. You don't need special tools and you don't need to replace the pulleys (and generally you shouldn't unless you want to start spending stupid money for high quality replacements) for a timing belt. NA/NB timing belts are one of the easiest timing belt jobs.
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May 31, 2016 18:40
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I think it should be your goal in life to buy the stolen family miata for $300. You should then drive it past the bad family members as often as possible.
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May 31, 2016 19:26
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Okay, I don't want to hijack this thread. Savington, are you going to corner balance the car? I'm really curious to see if there's a change in weight distribution with the aftermarket subframe+swap.
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May 31, 2016 19:39
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We can derail between his miata porn pics.
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May 31, 2016 20:24
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TWSS posted:Okay, I don't want to hijack this thread. Savington, are you going to corner balance the car? I'm really curious to see if there's a change in weight distribution with the aftermarket subframe+swap. We will, yes. The entire setup is 20lbs lighter than the BP that it replaced, but we also added a rollbar, swapped the seats, added frame rails, etc. The distribution will shift rearwards by a few tenths of a percent, but it won't be a dramatic difference. In CA, reasonably nice NB2s start at about $5k for 100-120k mile cars with a few imperfections and go up to around $9k for sub-50k perfect examples. With a busted timing belt, it's worth $3500-4k as long as you know the rest of the history. A non-running NB2 with no history isn't worth more than $2500 to me, because that's what it's worth in parts.
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May 31, 2016 21:51
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Are you planning on getting this air board certified?
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Jun 1, 2016 00:20
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