If this kit where going on a street build for occasional track use, would there be a different gear set or final drive for a higher top speed? Love this swap!
Great question! We've been trying to work this out, and recently became aware of a GM diff swap that can support much lower final drives. We'll have more information on this option soon. We're currently working on a video update that should be out in the next month or so. It's been a busy season of testing and development, but it's almost time to share it with the world!
The front Fenders are fiber glass, but aside from that, we haven't really considered other composite body panels. We are, however, releasing a wild version of this build that's even more shocking on the scales. Keep your eyes peeled for an update in the next few weeks! ua-cam.com/video/91SjN5Vcrug/v-deo.html
How would the transmission and clutch handle engine upgrades? What kind of work would have to be done for forced induction or big engine rebuild like carpenter racing 250+ na hp?
Short answer is, it would handle upgrades as well as it would in the bike, so long as the top speed is kept at a reasonable level. The kinetic energy of a Hayabusa going 185mph is roughly the same as a 1600lb Miata going 125mph. After accounting for the difference in drag, 120mph is a pretty reasonable top speed. The 3.9 diff gets you to almost exactly 120mph, which is plenty fast. In fact, we recently did a 59 second lap at Lime Rock. We've done 10 track days so far with nothing other than oil changes. As far as big power adders go, there's tons of aftermarket support. Unfortunately, it's doubtful any of the currently available turbo kits will work due to packaging constraints. We'll develop our own turbo kit if people are interested, but I don't actually think that's the way to go with this build. For this, I think a stroker kit would be really neat. 1500cc stroker kits are generally cheaper than turbo kits, more reliable, less complex, and don't add any weight (unlike turbo kits which can add considerable weight to the front end). As far as the work involved, I'm not sure yet. We're planning a stroker build during the off season.
We run an NB1 in 24hrs of lemons and I have been looking for something along these lines. Is there a detailed video or log on how this was done available?
There will be a build journal of some persuasion on the website, which I'm currently working on. This would be a fantastic endurance racer i think. The light weight would keep the tires and brakes happy, and the switchable horsepower modes of the gen 2 hayabusa will make classing easier (i believe the lowest power mode is 150hp).
Damn. I'm just about to go test drive a mk1 mx5 I'm most likely going to end up with, I thought they're so little with a seemingly dull stock engine I should look into a swap like this and here it is. How much of a pain was the electronics to get working, if this is road legal? Do you have reverse?
The electronics are incredibly simple! Pretty much just plop the engine in the engine bay with the stock Hayabusa wiring harness completely intact, you barely have to unhook anything. Then I just installed a fuse box I bought off Amazon in the glove box to run things like gauges and lights. The only thing I had to splice was the fuel pump and level sender harness, which was really simple. As for reverse, it will be an optional add on. A lot of people will probably want to use this setup for auto-x or track only. The Torsen diff with 4.3 final drive will probably be the hot auto-x setup. A top speed of just over 100mph, but absolutely violent acceleration. We're testing with a reverse gear box that will take the place of the carrier bearing if you decide to go that route. The neat thing is that you'll have 6 forward gears and 6 reverse gears. It should have the same top speed in reverse as forwards. Useless, but kinda cool haha
Obviously you don’t build a car like this for economy, but I am curious what it achieves town and highway. I’d love a second gen miata-busa build. Does it happen to mate with any tremic 6 speed manual gearbox?
This build is definitely track focused, but it could be driven on the street by someone who is pretty hard core (which I'm guessing most interested parties would be haha). Neither this car nor the Exocet we built for testing were registered or street legal, so it's hard to collect street driven data. Seeing as people are interested in this data, we'll figure out a way to do some street testing next season. We've done a good bit of track testing with the Exocet (Pineview, Watkins Glen, New Jersey Motorsports Park Thunderbolt) and it's relatively fuel efficient. At 1,200 lbs with a 3.6 diff, our burn rate was approximately 1 gallon every 7 minutes. I believe the Miata may be an even lower burn rate due to the fact that the Exocet has so much drag. For comparisons sake, both of our spec Miatas burn roughly 1 gal every 9-10 minutes in race conditions, and our stock Evo X was 1 gal every 3 minutes of track time. As for gearboxes, this swap uses the factory hayabusa gearbox. The gen 2 gearbox works fantastic, we haven't had any issues with it at roughly stock power (just an off-the-shelf tune). The gen 1 gearbox has issues with the second gear dogs, but replacement transmissions with dog undercutting are relatively cheap (about 700 bucks). Moto IQ tried to develop a Hayabusa Miata swap kit a number of years ago, but they removed the stock Hayabusa transmission and ran the output shaft to a Miata gear box. We believe this defeats a lot of the purpose of this swap which is really to be as light as possible. The Hayabusa engine AND transmission weigh a combined 194lbs. Running that through a Miata transmission adds weight, no sequential/paddle shifters, and increases complexity.
@@spec13motorsports well first I greatly appreciate the response. I seen that other kit you were referring too, they use some sort of primary reduction gear at the crankshaft with a 1.6:1 ratio to ensure the rpms don’t exceed the transmissions capabilities. I did not know you were using the stock hayabusa transmission in this build, that is exceptionally light. Thank you for taking the time to respond, would love to see more of your testing and progress.
@@county_bear9509 that reduction gear is actually a stock component in the hayabusa drive train. It's essentially a torque multiplication device. We're currently working on a video update that should be out around the first of the year, and a website with pricing and kit details following shortly after. We'll share those to our Instagram and Facebook profiles and of course upload them to UA-cam.
Yes, we are in the process of developing a swap kit! We just completed two more test days at New Jersey Motorsports Park. Keep your eyes peeled for an update in the next few weeks!
That's kind of the beauty of this swap. The Hayabusa engine, transmission, and all accessories weigh 194lbs, a huge weight savings over the factory Miata power plant, transmission, and accessories. Also this particular car happens to be gutted with a 6pt roll bar, making it 1,575lbs.
Great question! Reverse will be an option, but yes. Right now, we're working with a company in England that makes 1:1 reverse only gear boxes for bike engine powered cars. It's kinda neat because you'll have 6 reverse gears. This company holds the world record for speed in reverse. But we're also working on our own low cost solution in house that uses an electric motor. It won't be setting any speed records in reverse though haha
@@dgh6g33gf @Alex yes, we spent last season testing, and we're currently working on finalizing the for production design. We expect to be taking orders "this summer." ua-cam.com/video/91SjN5Vcrug/v-deo.html
@@DiscoMiata actually, given current gas prices, this is definitely something we will log as testing continues. We're still developing the production kit, but we'll have info on fuel economy before the kit is available. Probably some time this fall.
For this build we are testing with the stock Hayabusa gear box. In the interest of reliability, the car's top speed is mechanically limited to 125mph. A vehicle this light traveling 125mph is roughly the same kinetic energy as a Hayabusa motorcycle traveling 185mph; a modest speed as far as the Hayabusa is concerned. Therfore the transmission should not be severely over loaded.
@@TheAdventureLog it's actually pretty slick! We made a custom front drive shaft with a carrier bearing and slip yoke. Mount the carrier bearing to the tub (you'll have to drill two holes in the tub), then you just slide your stock NA/NB drive shaft into the supplied slip yoke and you're off to the races, so to speak! It's a simple and cost effective solution.
@loddy210 so sorry, I didn't see this reply. No steering shaft clearance issues for left hand drive, but right hand drive inherently has clearance issues. We have a solution for this, but it will be a slight additional cost for rhd.
Teaser video out now!
ua-cam.com/video/91SjN5Vcrug/v-deo.html
If this kit where going on a street build for occasional track use, would there be a different gear set or final drive for a higher top speed? Love this swap!
Great question! We've been trying to work this out, and recently became aware of a GM diff swap that can support much lower final drives. We'll have more information on this option soon. We're currently working on a video update that should be out in the next month or so. It's been a busy season of testing and development, but it's almost time to share it with the world!
1600 lb is a lot of weight saving!! But do you guys concerned about replacing body panel with something lighter like fiberglass?
The front Fenders are fiber glass, but aside from that, we haven't really considered other composite body panels. We are, however, releasing a wild version of this build that's even more shocking on the scales. Keep your eyes peeled for an update in the next few weeks!
ua-cam.com/video/91SjN5Vcrug/v-deo.html
@@spec13motorsports thanks for reply, can't wait to see your big project!! Btw is it possible for nd miata to achieve the same 1600 lb weight?
How would the transmission and clutch handle engine upgrades? What kind of work would have to be done for forced induction or big engine rebuild like carpenter racing 250+ na hp?
Short answer is, it would handle upgrades as well as it would in the bike, so long as the top speed is kept at a reasonable level. The kinetic energy of a Hayabusa going 185mph is roughly the same as a 1600lb Miata going 125mph. After accounting for the difference in drag, 120mph is a pretty reasonable top speed. The 3.9 diff gets you to almost exactly 120mph, which is plenty fast. In fact, we recently did a 59 second lap at Lime Rock. We've done 10 track days so far with nothing other than oil changes.
As far as big power adders go, there's tons of aftermarket support. Unfortunately, it's doubtful any of the currently available turbo kits will work due to packaging constraints. We'll develop our own turbo kit if people are interested, but I don't actually think that's the way to go with this build. For this, I think a stroker kit would be really neat. 1500cc stroker kits are generally cheaper than turbo kits, more reliable, less complex, and don't add any weight (unlike turbo kits which can add considerable weight to the front end). As far as the work involved, I'm not sure yet. We're planning a stroker build during the off season.
We run an NB1 in 24hrs of lemons and I have been looking for something along these lines. Is there a detailed video or log on how this was done available?
There will be a build journal of some persuasion on the website, which I'm currently working on. This would be a fantastic endurance racer i think. The light weight would keep the tires and brakes happy, and the switchable horsepower modes of the gen 2 hayabusa will make classing easier (i believe the lowest power mode is 150hp).
Loddy210, reach out to us on our Facebook page for further discussion:
facebook.com/Spec13Motorsports?mibextid=ZbWKwL
Damn. I'm just about to go test drive a mk1 mx5 I'm most likely going to end up with, I thought they're so little with a seemingly dull stock engine I should look into a swap like this and here it is. How much of a pain was the electronics to get working, if this is road legal? Do you have reverse?
The electronics are incredibly simple! Pretty much just plop the engine in the engine bay with the stock Hayabusa wiring harness completely intact, you barely have to unhook anything. Then I just installed a fuse box I bought off Amazon in the glove box to run things like gauges and lights. The only thing I had to splice was the fuel pump and level sender harness, which was really simple. As for reverse, it will be an optional add on. A lot of people will probably want to use this setup for auto-x or track only. The Torsen diff with 4.3 final drive will probably be the hot auto-x setup. A top speed of just over 100mph, but absolutely violent acceleration. We're testing with a reverse gear box that will take the place of the carrier bearing if you decide to go that route. The neat thing is that you'll have 6 forward gears and 6 reverse gears. It should have the same top speed in reverse as forwards. Useless, but kinda cool haha
Obviously you don’t build a car like this for economy, but I am curious what it achieves town and highway. I’d love a second gen miata-busa build. Does it happen to mate with any tremic 6 speed manual gearbox?
This build is definitely track focused, but it could be driven on the street by someone who is pretty hard core (which I'm guessing most interested parties would be haha). Neither this car nor the Exocet we built for testing were registered or street legal, so it's hard to collect street driven data. Seeing as people are interested in this data, we'll figure out a way to do some street testing next season. We've done a good bit of track testing with the Exocet (Pineview, Watkins Glen, New Jersey Motorsports Park Thunderbolt) and it's relatively fuel efficient. At 1,200 lbs with a 3.6 diff, our burn rate was approximately 1 gallon every 7 minutes. I believe the Miata may be an even lower burn rate due to the fact that the Exocet has so much drag. For comparisons sake, both of our spec Miatas burn roughly 1 gal every 9-10 minutes in race conditions, and our stock Evo X was 1 gal every 3 minutes of track time.
As for gearboxes, this swap uses the factory hayabusa gearbox. The gen 2 gearbox works fantastic, we haven't had any issues with it at roughly stock power (just an off-the-shelf tune). The gen 1 gearbox has issues with the second gear dogs, but replacement transmissions with dog undercutting are relatively cheap (about 700 bucks). Moto IQ tried to develop a Hayabusa Miata swap kit a number of years ago, but they removed the stock Hayabusa transmission and ran the output shaft to a Miata gear box. We believe this defeats a lot of the purpose of this swap which is really to be as light as possible. The Hayabusa engine AND transmission weigh a combined 194lbs. Running that through a Miata transmission adds weight, no sequential/paddle shifters, and increases complexity.
@@spec13motorsports well first I greatly appreciate the response. I seen that other kit you were referring too, they use some sort of primary reduction gear at the crankshaft with a 1.6:1 ratio to ensure the rpms don’t exceed the transmissions capabilities.
I did not know you were using the stock hayabusa transmission in this build, that is exceptionally light. Thank you for taking the time to respond, would love to see more of your testing and progress.
@@county_bear9509 that reduction gear is actually a stock component in the hayabusa drive train. It's essentially a torque multiplication device.
We're currently working on a video update that should be out around the first of the year, and a website with pricing and kit details following shortly after. We'll share those to our Instagram and Facebook profiles and of course upload them to UA-cam.
@@spec13motorsports ahh, I did not know that. Looking forward to it man!
What kind of clutch does it run?
It uses the stock clutch with spring spacers to increase clamping force slightly.
Are you guys producing a swap kit? I am coming in to possession of a clean NA that I would love to do something like this to!
Yes, we are in the process of developing a swap kit! We just completed two more test days at New Jersey Motorsports Park. Keep your eyes peeled for an update in the next few weeks!
@Spec13 Motorsports looking for that update😊
how did you get the car to 1600lbs?
That's kind of the beauty of this swap. The Hayabusa engine, transmission, and all accessories weigh 194lbs, a huge weight savings over the factory Miata power plant, transmission, and accessories. Also this particular car happens to be gutted with a 6pt roll bar, making it 1,575lbs.
@@spec13motorsports ever thought about an exocet swap?
@@JNatellaare offering an Exocet swap kit. It's 100lbs lighter than the atom, and about 100lbs heavier than the Radical sr3
ua-cam.com/video/gzWIVzAwKk8/v-deo.htmlsi=Eg6yuqcVgfIixCOh
But can it reverse thought?
Great question! Reverse will be an option, but yes. Right now, we're working with a company in England that makes 1:1 reverse only gear boxes for bike engine powered cars. It's kinda neat because you'll have 6 reverse gears. This company holds the world record for speed in reverse. But we're also working on our own low cost solution in house that uses an electric motor. It won't be setting any speed records in reverse though haha
@@spec13motorsports So you guys are gonna be selling the full swap kit? Do you have an estimated release date?
@@dgh6g33gf @Alex yes, we spent last season testing, and we're currently working on finalizing the for production design. We expect to be taking orders "this summer."
ua-cam.com/video/91SjN5Vcrug/v-deo.html
What kind of fuel mileage does it get?
I would like to know as well
That's a great question! Are we talking on-track fuel economy, or street fuel economy? That's something we will log as testing continues.
@@spec13motorsports preferably street.
@@shawnmatthews5118 you will never know
@@DiscoMiata actually, given current gas prices, this is definitely something we will log as testing continues. We're still developing the production kit, but we'll have info on fuel economy before the kit is available. Probably some time this fall.
What gearbox have
For this build we are testing with the stock Hayabusa gear box. In the interest of reliability, the car's top speed is mechanically limited to 125mph. A vehicle this light traveling 125mph is roughly the same kinetic energy as a Hayabusa motorcycle traveling 185mph; a modest speed as far as the Hayabusa is concerned. Therfore the transmission should not be severely over loaded.
@@spec13motorsports Id be interested to see how you're mating it to the rearend.
@@TheAdventureLog it's actually pretty slick! We made a custom front drive shaft with a carrier bearing and slip yoke. Mount the carrier bearing to the tub (you'll have to drill two holes in the tub), then you just slide your stock NA/NB drive shaft into the supplied slip yoke and you're off to the races, so to speak! It's a simple and cost effective solution.
@Spec13 Motorsports any steering shaft clearance issues?
@loddy210 so sorry, I didn't see this reply. No steering shaft clearance issues for left hand drive, but right hand drive inherently has clearance issues. We have a solution for this, but it will be a slight additional cost for rhd.