K doesn't spin backwards :)
t know the K swap has a lot of people all excited. It may be the magic ticket for track cars, or it may take out transmissions. We'll see how it goes. I know there are a couple of pretty high end installs taking place that will really sort it out. Not the same performance level as the LS swaps, but less money too.
Don't know if it has been mentioned, but if by using a Miata gearbox and a Honda K series engine, I can get a lightweight V6 in an MGB, I might look in to this.
Are there K series 6s? I thought they were all 4s?
K's are I4. J's are V6.
Don't really see how the K series is any better than the options out there though because it still uses the stock transmission. it's about the same weight as the LFX motor according to the info I've seen.
Good that all of these swap options are coming out though. It will be interesting to see where they all kind of fall out.
I have thought about a Honda K series engine in an MX-5 before. My thought process always ends up coming back to this. Buying an S2000 is a much lower effort way to get a roadster with a high-winding, high-output Honda engine.
Type Q wrote: I have thought about a Honda K series engine in an MX-5 before. My thought process always ends up coming back to this. Buying an S2000 is a much lower effort way to get a roadster with a high-winding, high-output Honda engine.
Much lower effort, yes.... for a heavier car with less aftermarket for the motor.
Swank Force One wrote:666csi wrote: Swank force one: I was under the impression you'd be lucky to get 115whp out of an early 1.8L BP N/A and a turbo would demand more than a perfect cooling setup for reliable track use judging by what's being said on this thread. Also, I'm pretty sick of turbos in general for now...a personal problem I guess.There's 200whp n/a BPs out there. Cost-effective? No. But 150whp doesn't have to be hard or hugely expensive to do. I know of a 172whp stock bottom end BP. What I would do if I were starting with an old tired early BP. Throw the old motor away. Or at least the head. Stick VVT 10:1 pistons in the bottom end. Grab a BP4W head, cut it 0.060". Intake, header, exhaust, and megasquirt. Won't cost as much as any of the swaps, won't be as much work, and you won't have to worry about keeping some bizarre swap car running.
Not to argue since I'm mostly a lurker here, but I've done a lot of research on NA power in miatas, and if you have an early car (90-93), then what emilio describes in this famous post is not as cost effective as people often describe it, especially if you live in CA or have any other issues with emissions compliance, or even if you're just looking for something a little more stock-ish. Intakes are kind of a wash on early cars, the selection is limited due to the wiring harness and they don't add much power. You're probably better off with a Randall and a K&N filter, combo of roughly $200. RB or JR header is $450, decent exhaust is $3-400, MSPNP is $800. That's $1800 and yes, you should be buying this stuff used, but even with savings on used parts, look at the time it's all going to take: now you've added parts hunting, learning the ECU, and tuning to the effort that's already involved in just getting the parts on the car. Plus, a good ECU tune, which you'll want in order to maximize the tiny power gains you can achieve on your 1.6 (or if you're like me and you swapped in a fresh 1.8 with FM's handy kit, your 1.8,) - that's going to require dyno time and a tuner. Now you're looking at what, $1500 minimum plus a lot of work, running hopefully 150whp. Realistically with all the doodads and thingamajobbies that come up when you do projects like this, closer to 2k. (You'll get sick of hunting a particular part, you'll break down and buy it new. We've all done this.) So now you're $2k into a project to add 40whp to your 1.8 miata or let's say $2500 for your 1.6 miata since you need an engine too, which hey, that's not bad, and I'm partially down that road myself. But if I could have skipped all this and bought a $2k USD kit to put a $500 ecotec in my car to achieve 200whp and 200lb/ft, then you can bet that's what I would have chosen. The Honda J kit is an interesting idea but the whole look of their outfit and kit is not very positive, plus by the end of the day it's going to cost you, what, $3500 for their kit plus a J motor? At that point I'm getting a martin's v8 kit and starting to scour CL for Ford 302s, which almost grow on trees and are one of the best sounding motors for any miata swap. What is all comes back to is that modifying the BP, whether its a 1.6, early 1.8, or even a later 1.8, is basically the least cost effective way to go faster in the car in a straight line, IF you're not a fan of forced induction. And some of us would really prefer a naturally aspirated driving experience. I know I'm not alone, or this thread wouldn't be 12+ pages long.
It must be said that the GM LE5 is not putting out 200hp in stock form... http://en.wikipedia.org/wiki/GM_Ecotec_engine#LE5
Not sure what the ECU setup for these guys is to get the dyno chart they're showing on https://www.facebook.com/MTMotorsport.ca
Probably HP Tuners. And lots of bolt ons.
They likely had to do just as much work to the LE5 after install as it takes to get an NB motor to 150whp.
Sometimes it's about which is easier. I've had few turbo Miatas.
I probably just sold one. Emilio's formula is easy. I can do it in weekend. 
And BP Miatas have far more legal classes. If you want 200whp n/a, the BP is a terrible choice. 150whp? Totally different ballpark. I'm bored of power, personally. 
Swank Force One wrote: Sometimes it's about which is easier. I've had few turbo Miatas. I probably just sold one. Emilio's formula is easy. I can do it in weekend.
For people with less experience, who are not likely going to be racing, Emilio's formula is a bit more daunting, but there's a learning curve for everything I suppose. My main point there is if you're not an expert, it's neither as cheap or as easy as it's often made out to be. No such thing as a free lunch and so on. I definitely agree that power gets boring. I haven't owned powerful cars, but I've had a few literbikes and coming from that, most cars feel slow. Might as well get one that's fun to drive so there's my 90 miata. Anyways, not to pull this thread off topic - I'm curious to see if any miata guys are actually going to go with the J motor. As far as the ecotec, that's also these guys: http://www.alphafabindustries.com who seem to have a number of kits set up to put the motor in dune buggies. Interesting stuff.
ProDarwin wrote: Probably HP Tuners. And lots of bolt ons. They likely had to do just as much work to the LE5 after install as it takes to get an NB motor to 150whp.
You might be right, and I'm very interested in seeing the details on their kit for precisely that reason.
Sure, i'm not trying to say it's on the same level as an oil change, but it's certainly easier than a motor swap no matter how you slice it.
ProDarwin wrote: Probably HP Tuners. And lots of bolt ons. They likely had to do just as much work to the LE5 after install as it takes to get an NB motor to 150whp.
Intake, header, exhaust and a tune. Anybody that knows these (and other current gm) motors knows what kind of power is in a tune., and Matt knows how to tune.
The attraction, as I understand it, is the easy, inexpensive and extremely reliable 200 lb/ft of torque with OEM - like drivability.
Zomby Woof wrote:ProDarwin wrote: Probably HP Tuners. And lots of bolt ons. They likely had to do just as much work to the LE5 after install as it takes to get an NB motor to 150whp.Intake, header, exhaust and a tune. Anybody that knows these (and other current gm) motors knows what kind of power is in a tune., and Matt knows how to tune.
Yeah. And that's what it takes to get 150 from an NB motor.
It's funny that people are talking about swapping Honda engines into Mazdas, when people are swapping Duratecs into E30s for less nose weight/more power. Why not Duratec into Miata? Heck, I'm 90% certain that it would just be wiring and motor mount fabrication, there's probably a transmission/driveshaft/PPF combo that makes the engine bolt up to the rearend.
I thought there was concern about how tall the Duratec was - or am I making things up again?
I don't see it as being taller than the Honda K engines.
Reality check: The Duratec fits in the same place a CVH (Focus) fits. The CVH was about the same height as a BP engine when both were in the Escort. From another angle: The Duratec fits in the same slot as the 2.3 SOHC (Ranger), which was also used in the Fox Mustangs, which also fit 5.0 EFI engines, which are known to fit under the hood of an NA.
Should be fine.
Also, I want one of these now:
Because Duratecs are way way waaaay cheaper than S14s dollar-per-horsepower.
I don't think there's enough gain to be had with a Duratec/MZR. It's also not a very inspiring engine in stock form. Just bland. Although the 2.5 variants might make it worthwhile.
Very few engines are inspiring in stock form. However, it is on par with the K-series as far as ultimate power capability is concerned. Big big big ports and there's a decent and growing aftermarket for it.
The thing is and maybe Kmiata is being honest and the others are not really bringing it up as Keith has said a number of times there is a lot more to it than a swap kit with mounts a trans adapter plate and an engine. But Kmiata lists the swap price as being in the 8k-9k
"A competent, DIY enthusiast should be able to do the complete conversion for $8000-$9000. This is only an estimate, as the builder’s choice of K series engine and power goals will determine the final cost. 220-230whp is realistic with most stock engines with a good tune, and much more power can be made with an upgraded valvetrain and/or a built engine."
That's a lot of money for that much power
And living in California is another reason the Jackson Racing rotrex kits may simply be the easiest option because CARB stickers.
As Liquiddog was eluding to, I think the semi emilio recipe built 1.8 is still going to run you a couple grand or so
Knurled wrote: Very few engines are inspiring in stock form. However, it is on par with the K-series as far as ultimate power capability is concerned. Big big big ports and there's a decent and growing aftermarket for it.
Ironically, the BP is fairly fun in stock form.
I'm a bit skeptical about some of the recipes out there for BP power and how easy it is. Emilio has put up some good numbers, but I know he doesn't share everything. Either our dyno reads low in the sub-200 range (there's some evidence of that, actually) or there's some real fudging out there.
Keith Tanner wrote:Knurled wrote: Very few engines are inspiring in stock form. However, it is on par with the K-series as far as ultimate power capability is concerned. Big big big ports and there's a decent and growing aftermarket for it.Ironically, the BP is fairly fun in stock form. I'm a bit skeptical about some of the recipes out there for BP power and how easy it is. Emilio has put up some good numbers, but I know he doesn't share everything. Either our dyno reads low in the sub-200 range (there's some evidence of that, actually) or there's some real fudging out there.
Couldn't agree more, Keith. I feel like hopping up the BP is sort of a vestigial tail for the miata community, at least in terms of N/A power. It's not that useful anymore, there are better ways to build a more powerful miata, and no one really thinks about it too much. People just sort of say "yeah go for the I/H/E/tune and you'll get 150whp from a 1.8" but really, it's the absolute least economical way to go in the long run, if you ever want more than 150whp, and even that 150 is suspect. I think if some of these new swaps pan out, then we have a real alternative to a well made turbo or supercharger kit. That, at least, is my hope. In the meantime, I find the stock BP to be lots of fun, especially when you're running 4.30 gears in a bare bones car with zero options, NB sport brakes, and a rollbar. I'll be saving my power funds for a bit to see which way the wind blows with the new swaps, though I suspect we'll get a new well sorted JR blower kit with CARB compliance before that happens. J engine swappers, prove me wrong...
Liquidog wrote: Couldn't agree more, Keith. I feel like hopping up the BP is sort of a vestigial tail for the miata community, at least in terms of N/A power. It's not that useful anymore, there are better ways to build a more powerful miata, and no one really thinks about it too much. People just sort of say "yeah go for the I/H/E/tune and you'll get 150whp from a 1.8" but really, it's the absolute least economical way to go in the long run, if you ever want more than 150whp, and even that 150 is suspect.
I would bet that a good portion building for NA power are doing so because of classing. The 150whp builds align nicely with CSP allowances. There are a LOT of Miatas running CSP.
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