KMiata vs. LSxMiata

Anybody wanna learn me? I guess I'm trying to figure out more of what is the point on the KMiata? With the price point seems like doing s LSx swap would make more sense but I'm not privy to the Miata world so maybe I'm missing something.

I'm intrigued, just not sure if it makes any sense. 2300lbs 250BHP track car wouldn't be the worst thing. How much does a LSx Miata typically weigh?

Just thinking out loud.

Boy, talk about engines with different personalities! As someone pointed out to me in another thread, by the time you pony up for the K conversion, you are in S2000 territory, so what's the point?

Seems to me that the third option sounds pretty good - A V6 Miata:

http://www.superfastmiatas.com/JV6%20Miata%20Kit.html

You get a lot more torque than the K motor, and don't have to deal with changing the transmission or rear end like you do with the LSX. My only hesitation would be that I was reading a build log where it wasn't all smooth running, so I'd want to do more diligence.

I'm considering both right now and it seems like if both swaps are fairly well done with good parts, an LS swap seems to cost a couple grand more. But that's a debatable...

I dislike Hondas with a passion. I lie squarely in the v8 camp.

mndsm wrote: I dislike Hondas with a passion. I lie squarely in the v8 camp.

I dislike V8s. I lie strongly in the 4-rotor camp.

Cactus wrote:

mndsm wrote: I dislike Hondas with a passion. I lie squarely in the v8 camp.

I dislike V8s. I lie strongly in the 4-rotor camp.

I think you and i can still be friends. Rotary miata ftw.

Kreb wrote: As someone pointed out to me in another thread, by the time you pony up for the K conversion, you are in S2000 territory, so what's the point?

Did not think of that....

The big thing with the LS swaps vs the I4 and V6 swaps is the strength of the drivetrain. The LS swaps replace everything with parts designed to stand up to teenagers in 4000 lb cars while retaining a factory warranty. The I4/V6 swaps are keeping the stock trans, rear end and halfshafts. This is a big reason for the cost difference, but it does mean that you're exploring the limits of the drivetrain. We already know from years of experience that 250 rwhp is about the limit of the stock trans in the car.

There hasn't been as much attention to detail on the Honda swaps yet, as far as I can tell. A number of cars are running around, but none are fully finished with AC, PS, everything functional. There's more DIY engineering involved at this state of their lifespan. That's good or bad depending on how you feel about it.

As for weight, that can be tricky when the primary source of the numbers is the guys who are selling the kits, and the Honda swappers are using "less weight" as one of their selling points. I think 2300 lbs is unlikely unless you're looking at a stripped car, in which case I'd expect a similarly stripped LS car to be around 2400 or so. I think that's where mine is. In street form with all mod cons, 2550 or so for an LS NB is about what you should expect. Expect the car to gain about 200-250 lbs from stock with all systems installed.

I'd also research into what's going on with the K swaps on track. IIRC 949Racing lost the engine in theirs, and Andy Hollis lost the engine in his K-powered One Lap Miata during testing. Both of those guys know how to prep a car. I don't know if it was two cases of bad luck or if there's something else going on.

And of course, the big difference is torks. I've got 400 lb-ft (or ft-lb, I always forget) to the wheels from 2800-6600 rpm. High revving power is fun, feeling like you just got hit in the back by a semi is also fun. Choose your poison.

If you're looking for affordable swapped power, the honda v6 swap looks interesting (because you get to keep one of the best parts of the car -- the transmission).

But for big power / fun... LS all the way

That all came across as more dismissive of the Honda engined cars than I meant, sorry. They're definitely interesting, but there are areas that are still a question to me so I mentioned them. I've been on track with a track prepped one that was being driven very aggressively (sometimes a little TOO aggressively, oopsie) and it was a quick little booger.

Apples to Oranges, but one could argue that a strong NA 4-cyl is more true to the nature of the Miata. I think a K24 in a Miata would be all the engine you would need, but it's also pretty damn expensive to still have a 4-cyl Miata. What about the 2.5 Mazda/Ford swap? It won't make the peak power that a K24 will, but it should have good "under the curve" power.

The 2.5 Duratec isn't an inspiring motor in any way, really. It's a logical swap for the NC because it's so easy, but that's the only real compelling argument for it.

I've taken Miatas about as far apart as you can take them (although not quite as far as Nohome has), and I've never found where the nature is installed.

Well, by that logic no automobile has any "nature" or "soul". Maybe I just mean that a K24 Miata is still like a Miata, just better. Whereas a V8 miata is just a completely different monster.

I'm just a Honda nerd that has never dissected a Miata though. So, take my opinion with a grain of salt. I do know K-series, and they are tons-o-fun to drive at the absolute limit.

(I do want to reiterate my point that the K Miata swap is too expensive)

Oh, I get the idea. I've had a Miata with a pretty hot naturally aspirated 4 cylinder, and it was a ton of fun. Faster than it should have been, too, although you had to work for it. No more or no less a Miata than the V8s or the turbo cars, it's a different flavor of the same dish. They all share the same friendly chassis and are all very much Miatas.

I have had exactly one drive in a 302 converted Miata, and while I really like the experience, I can tell you that a lot of people would live in some degree of fear from that combo. A LSx swapped Miata is going to require that you keep your brain involved in the game.

I expect that the V6 would spread the experience over a broader range; in other words, you would have to work at it a bit to get into serious trouble mode. Having to rev a bit higher to reach the good stuff brings and auditory reward. The Miata is a pretty entertaining chassis to start with, and some people don't need the full Carolina Reaper level of spice-up to expand the envelope, maybe just a shot of Tabasco is good enough.

I like classic cars and if I am going to do a swap I want the swap to stand the same test of time that defines a classic. In 25 years, are you going to have a car that is still relevant? I bet 302 and LSx parts are still available off the shelf but are you going to find the maintenance parts for the Honda? If it took any fabricated or proprietary bits to mate the engine and gearbox, I tend to stay away for just this reason.

Kreb wrote: You get a lot more torque than the K motor, and don't have to deal with changing the transmission or rear end like you do with the LSX. My only hesitation would be that I was reading a build log where it wasn't all smooth running, so I'd want to do more diligence.

I would think that any swap that involves more torque going through the stock drivetrain would mean you get to deal with changing the transmission and differential on a regular basis.

Keith Tanner wrote: I've taken Miatas about as far apart as you can take them (although not quite as far as Nohome has), and I've never found where the nature is installed.

Nature is an emergent property.

While all these are good points for one or the other, for us cone hunters either swap puts the car into horrible classes.

All good points guys, I guess I'm kind of intrigued by the K swap but was disappointed with the sticker shock.

NOHOME wrote: I have had exactly one drive in a 302 converted Miata, and while I really like the experience, I can tell you that a lot of people would live in some degree of fear from that combo. A LSx swapped Miata is going to require that you keep your brain involved in the game.

I've not driven a 302 car for some time, but whenever I'm dealing with journalists they usually comment on how much less vicious the LS powered cars are. They handle better, they put down the power better and they don't exhibit killer tendencies. Other than the inherent speed potential of a high power/weight ratio, they're not evil. The performance is never a surprise to someone who drives one, the civility and controllability is. This is not necessarily the case with the 302 setups.

"Not as fast as a V8" is a funny marketing tactic. It's like saying "you can use the stock clutch with our supercharger!" - which was also a marketing tactic used in the Miata world years ago. I still think the real differentiator is the cost/reward ratio. It comes back to everything behind the clutch. You either build the complete drivetrain to deal with the extra power (with all of the extra cost and effort that entails) or you use the stock parts (lower cost, easier swap) and accept the risk and/or the power limitations.

As for sticker shock on the K - a good swap kit costs money, and a well-executed swap costs even more on top of the kit. It's on par with the costs to mount a V8 in the nose of the car (as you'd expect) plus the trans adapter and all of the supporting modifications.

Ive looked into both and Ive decided to go turbo instead. Cheaper and keeps its all mazda with parts being easy to obtain.

That being said the LS option is definetley the better choice IMO because everything gets replaced with stronger bits.

Keith said: I've not driven a 302 car for some time, but whenever I'm dealing with journalists they usually comment on how much less vicious the LS powered cars are. They handle better, they put down the power better and they don't exhibit killer tendencies. Other than the inherent speed potential of a high power/weight ratio, they're not evil. The performance is never a surprise to someone who drives one, the civility and controllability is. This is not necessarily the case with the 302 setups.

Interesting observation. I wonder if it might be partly due to the fact that most 302 swaps are done simultaneous to modifying the 302 to get more power out of the engine? Low vacuum, carb induction and a stiff clutch tying it all together does not make for a relaxed drive. The LS engines can be at the same level of performance with stock tunes and factory parts.

The one I drove had a 100% stock FI engine and it was as you describe: Tame until you ask otherwise. Full disclosure...I drive an FRS and do not pine for more power.

A better alternative is swapping an extremely light 2-stroke into one.

https://www.youtube.com/watch?v=jEoj5u9WGvY is "Balto", with a 20-year-old 595cc Polaris triple for LeMons racing.

Modern snowmobile powertrains are well under 150 lbs for engine and belt reduction.

NOHOME wrote:

Keith said: I've not driven a 302 car for some time, but whenever I'm dealing with journalists they usually comment on how much less vicious the LS powered cars are. They handle better, they put down the power better and they don't exhibit killer tendencies. Other than the inherent speed potential of a high power/weight ratio, they're not evil. The performance is never a surprise to someone who drives one, the civility and controllability is. This is not necessarily the case with the 302 setups.

Interesting observation. I wonder if it might be partly due to the fact that most 302 swaps are done simultaneous to modifying the 302 to get more power out of the engine? Low vacuum, carb induction and a stiff clutch tying it all together does not make for a relaxed drive. The LS engines can be at the same level of performance with stock tunes and factory parts. The one I drove had a 100% stock FI engine and it was as you describe: Tame until you ask otherwise. Full disclosure...I drive an FRS and do not pine for more power.

I think it also has to do with the typical suspension mods. The Monster setup uses front springs in the rear and something odd in the front. It's a clever reuse of parts, but possibly not ideal. It's also difficult/impossible to fit a front sway bar and the steering rack gets moved as well IIRC. I've also seen more 302 setups with oddball wheel/tire combos, usually tall tires in the back aiming for maximum contact patch.