Question: If you want a Mazda Miata with more power than the stock four-cylinder engine can provide, what would you do? You could go with an LS and make an overabundance of power and torque, but need to beef up the driveline to handle the sheer output. You could turbocharge the stock four-cylinder engine, but even the best turbocharged applications still have lag, and a turbo engine that pulls hard up top typically compromises on low-end response due to compressor sizing. You could go with a Honda K-Series inline-four, and while that will rev to the moon and make good power, sometimes you just want more combustion pulses than a four-cylinder can offer.
Happily, there is another tantalizing off-the-shelf option. Rocketeer Cars has been building Mazda Miatas with Jaguar AJ-V6 engines for nearly a decade, and not only is the horsepower figure similar to what you’d get from a stock 5.3-liter or 4.8-liter LS-based truck motor, there’s a whole lot to love about this V6 beyond its output on paper.
While the donor engine can be found in the Jaguar S-Type, its lineage is actually more complicated than that. See, Ford didn’t have the capacity to work on an overhead cam six-cylinder engine for its front-wheel-drive cars, so it contracted Porsche to do some of the engineering work. From there, Ford used Cosworth’s sand-casting method to make the cylinder heads, and the Duratec V6 was born. Jaguar, then owned by Ford, saw this V6 and decided that with its own cylinder head design, direct-acting tappets, and variable valve timing, it could be good enough to use under a leaping cat hood ornament. Thus, the AJ-V6 was born.
In stock three-liter form, it pumps out a tidy 240 horsepower and 221 lb.-ft. of torque. Crucially, it’s oversquare so it loves to rev, it comes with a standard redline of 6,800 RPM, and it’s actually 11 pounds lighter than the 1.8-liter engine in later NA Miatas. An interesting candidate for swapping into a Miata, made a little more interesting by a few tweaks Rocketeer Cars has made.
See, Rocketeer has designed its own carbon fiber intake plenums to not just fit nicely under a stock Miata hood, but help bump the V6 up to 280 horsepower. That’s 143 percent of what a 1.6-liter Miata made when new, all in a car that weighs roughly the same. Translation: 7.9 pounds per horsepower, slightly better than a Porsche 718 Cayman GTS 4.0. Back in 2017, Evo had a go in a Rocketeer development car, and while the plenums and tune weren’t ironed out yet, the results sound spectacular. As per the magazine:
The V6 takes a moment to catch and in this pre-production phase it’s a little unhappy when cold or on very light throttle openings. But damn does it sound good, with a rich, throaty note.
Every slightest movement of the throttle pedal, once past the initial stutter, results in instant response. Tom says the plenums may dull this slightly, but the trade-off will be perfect manners at low revs and more power at the top end. Today’s limit is around 6000rpm but even that’s enough to give the growling MX-5 ample pace, with one of the best soundtracks I’ve heard from a car in years.
Admittedly, the swap is not a cheap kit, but it is comprehensive. For £5,995 or just under $8,000, you get a whole new subframe, new engine mounts, a throttle bracket, special accessory drive parts, an electric water pump, a full exhaust system including manifolds, a baffled oil pan, the adapter plate, clutch and lightweight flywheel needed to mate the V6 up to the Miata transmission, carbon fiber intake plenums, an oil filler tube, throttle bodies, basically everything needed except the engine itself and the electronics.
Should you wish to not piece the electrics together yourself, Rocketeer sells a kit with the full harness, brand new pre-tuned standalone ECU, all the necessary sensors, and idle air control valves for £1,995, or about $2,653, and they’ll even help you with an engine for additional cost. Oh, and if you want to do the driving but not the wrenching, turn-key conversions start at £16,662 (around $22,170 at current conversion rates), or you could go really nuts and have them build you a restomod, a ground-up refurbishment and personalization of a V6-powered Miata.
In essence, Rocketeer Cars can get you the parts to build a much quicker Miata, or build you something like a Singer-modified Porsche 911 or an Alfaholics GTV for far less cash than some of these ultimate mega-dollar restomods that have been gripping the car scene. It’s a properly fascinating endeavor, giving the best-ever copy of a British sports car a British dose of extra performance, all while keeping the Mazda DNA largely intact. After all, a variant of the three-liter Duratec V6 with variable cam timing was used in the Mazda 6.
Top graphic credit: Rocketeer Cars
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I wish I had good experiences with this engine, but my experience working on them in the S-Type and Lincoln LS tells me they are not anywhere as reliable as the Duratec they descended from. I’m not going to discourage anyone dropping one into a Miata, but I’d never do it myself.
If you increase the torque excessively you overpower the transmission, driveshaft, differential, CV shafts, etc. I always thought the Mazda 2.5V6 would be a great engine.
Mazda engineers have been telling us this for years!
If you go too strong on the engine, you need an upgraded frame, transmission, brakes, and suspension. At that point you have a Corvette or a BMW, not a Miata experience.
The genius bit is getting someone to pay more for an engine kit than both donor cars.
“… and a turbo engine that pulls hard up top typically compromises on low-end response due to compressor sizing.”
If you’re trying to accelerate low down in the rev range you’re using your gearbox wrong.
Strictly speaking, that “Jaguar engine” is really just a variant of the Ford Duratec.
And what other vehicles have a naturally aspirated version of the RWD variant of that V6?
That would be the Lincoln LS, Ford Mustang and Ford F-series.
But speaking of the Mustang, I would think the 2.3L Ecoboost 4cyl out of a manual Mustang would also work well in a Miata.
I’ve seen a few 2.0/2.3 EB builds but it’s definitely the swap I would have figured would have taken off far more than it has by now. That said, I don’t know if it’s much cheaper than the LS swap for what you’re getting
Hmmm. Why the V6? As covered by Jason in an article last year, the V6 is the V8 with two cylinders blanked off and is the same physical size.
https://www.theautopian.com/i-cant-decide-if-this-jaguar-v6-made-from-blanking-off-two-cylinders-from-a-v8-is-genius-or-just-lazy/comment-page-1/
Different V6…
Ah yes, so it is. Still an AJ designation but different.
A Honda K series or Mazda rotary make perfect sense to me. If you are going to do a V6, and spend $10k, why not jump to an LS?
I for one, hate the sound of a V6. I’m probably in the minority but give me an inline 6 or a V8 any day.
Honda K Series is going to cost over 10K in most cases.
The V8 swap is incredibly invasive and requires a new transmission, rear diff, driveshaft, etc.
I am also in a minority, but I hate the sound of V8s. We do agree on inline 6s though.
I’m in that minority as well – I think part of my issue is practically every domestic V8 out there has loud pipes that remind you about their cylinder count way too frequently. I personally love the warble of the 5-cylinder (same 3 major frequencies of a V10). 6s in any configuration are always pleasing to me, particularly the Busso and Honda’s CBX.
My personal favorite is the VR6, but I love the sound of an I-5. I’ve owned both and still get the itch when I think of their tone.
I concur that my contempt for the sound of V8s largely has to do with their owners who seem to think that we all should appreciate the sound of their engine. I’ll lump Harley owners in there too.
Busso engine sounds good to me too. I sometimes scope out the classified ads to see if someone is scrapping out a 164 so I can drop the Busso in my GTV2000. CBX sounds awesome. I never really followed motorcycles, but if my chainsaw sounded like that, I probably would not wear hearing protection.
“I for one, hate the sound of a V6”
Even a Busso?
TBH, I don’t know if I’ve ever heard one. I have heard a Dino 246 which was not bad. However, I have heard hundreds of clapped out/riced up Nissan VGs with no mufflers and it has turned me off V6s for life.
I dunno if I’ve heard one live either. I only mention the Busso since it has a strong reputation for being a sweet sounding V6. The VW VR6 has its fans too.
Theres also the Toyota V6 in the Lotus Emira. I would imagine that sounds OK in a Lotus, maybe not so great in an Avalon.
Come to think of it the Accord V6 I test drove was nicely growly when stomped on.
As the owner of this engine in a jaaag, these engines are absolute trash. I can hear the knock still to this day. It was thirsty, unreliable, difficult to access/work on and had the cost cutting that we’ve all come to expect from Ford. These are not good engines.
I saw a Miata with a 3800 swap. And of course, that 3800 was available with a supercharger 😉
And it’s MUCH more reliable than anything coming from Ford, Jaguar, or Porsche LOL
Even the 2.0T from the Solstice/Sky or some other GM would be good.
And of course, the always the LS swap or even the Connect and Cruise package 😛
Jaguar V6 engine kit*
*Engine not included.
To be fair the Jags in question are worth basically nothing at the moment. £995 gets you a lot of car. I’m sure scruffier ones are cheaper, but this was literally the first one I clicked on.
https://ebay.us/m/WpD4uF
It looks like they are trying to sell the plate number and throwing the car for free.
Not sure how the plate system works in UK.
Personalised plates can be transferred online for £80, so this looks more like someone trying to get rid of an old Jag by forcing whoever buys the plate to take the car as well.
(Looking at the MoT history, it sounds a bit dubious to me. It had a CEL and an ABS warning, but passed the retest on the same day? I’m guessing the fix was ‘clear all the codes and try it again with your fingers crossed’)
That could have been a coil pack and a sensor, which is no big problem to replace.
The one stipulation for selling a plate in the UK is that the car has a current MoT test (it’s an annual inspection) – so since this car has a very recent one it’s a bit strange they’d try to sell the car as well as the plate – the car itself would still be worth money without it.
This is a pretty cool swap! And out of all the Ford (based) motors that are from the 90’s, the Duratecs were pretty solid! I worked on a fuckload of duratec tauruseses, contours, Escapes, and some cougars and the amount of major failures was very small compared to most other Ford motors at the time.
I’d almost put it up there with 4.6 2v reliability, almost. The V6 that followed is a different story.
Supercharger is the answer in this case if engine sway is off the table. Good gains without the turbo lag.
If I was going for a miata v6 swap, I feel like a J35 out of an odyssey or similar Pentastar/High Feature would be the move compared to a Jag motor.
There are plenty of J30, 32, and probably 35 Miatas out there, the problem I’ve seen with them is that it’s a very tall engine and as a result the oil pan is like 3 inches off the ground if you’re on stock suspension. Anything lowered and you’re in trouble.
Good knowledge to have! Apparently the 2024 move to DOHC took about an inch and a half off the height, so that might be nice for wrenchers in 10 years.
I’m not sure that the 35 fits at all. The only ones I’ve seen have been 30 or 32s, that extra half liter is significant
***and the mini-tech kit mounts the engine using a plate between the engine and transmission which doesn’t seem like the best solution.
I think the Pentastar has some potential as an engine swap candidate. I’ve always thought it would’ve been a great motor to swap into the Prowler: lighter, more powerful, and I betcha its smaller than the 3.5 too!
It’d be an odd sight in a Miata, but still likely a ton of fun!
So I think AutoAlex on Youtube had one of the first kits back when he was with Car Throtle. His little V6 miata is interesting.
I knew this all sounded familiar! I remember when he finished that project and being very interested in trying it myself. Gave up when I added up the numbers as a college student
Phil!
“143% of (the NA’s power)” should probably be “143% more than” amiright? Or 243%?
Lol! Thank you! I thought I was the only crazy one. I read this and my mental math told me it had 50 hp more.
I’ve been asking myself the same question. US 1.6 litre engines (a 1992 for this exercise) had 116 HP. That’s a 141% increase if you use the 280 HP number. The euro engines likely had a few more horses originally.
Kits for the GM V6 used in late model Camaros are available and have been for some time. I’ve seen them with AC and instrumentation working.
I think the GM V6 might be easier to find here in the US.
Thank you. That part made stop and think for bit. Then I got distracte…
This is either crazy or genius (and maybe a little of both as the line between the two is often quite fine).
This is intriguing and tempting, but the odds of me personally shelling out $10,600.+ for the necessary kit bits, in addition to the price of a Jaguar V6 engine and a whole donor Miata too, are slim.
Jag V6s do make some truly lovely noises though. Whenever I’m next to an F-Type at a stoplight, I roll down my windows just so I can hear it pull away at the green. 🙂
That’s a different engine – it’s a 90* V8 with two cylinders left empty, as opposed to the Duratech V6 which is a 60* V6 with all its cylinders intact. Strangely, Jag calls them both AJ series engines.
https://www.theautopian.com/i-cant-decide-if-this-jaguar-v6-made-from-blanking-off-two-cylinders-from-a-v8-is-genius-or-just-lazy/
Had to laugh a bit at this one. I have never seen an F-type in real life and I live 135 miles from a stoplight. While I would likely enjoy the sound, I’ll take not sitting a traffic light any day over that aural experience
Mr. Canoehead is probably right and it was a V8 I liked the sound of (there are lots of recordings of it online) but the V6 sounds decent too (not as meaty/throaty as the eight). At least judging by various vids on Youtube.
Am I correct in that all these pretty F-Type Jags have automatic transmissions? If so, that is sad.
Yeah, OK great (it actually is pretty cool), but what about those Campagnolo (style?) wheels on the copper one?! I’ve been wondering why there aren’t repros of at least some of their styles for years. In fact, that was one of the exact styles I had in mind for my GR86.
They might be Rota BM8s.
They’re fake versions of the Hayashi Street.
https://jdm-car-parts.com/cdn/shop/files/HayashiRacing1.jpg?v=1728348387
Dammit, well there goes my hope someone was making repros of old Campys.
Check out Auto Ricambi. They make some reps of old Italian wheels for vintage Fiats and things. You’d obviously need to do something with your hubs as these are all 4-lug, but I’ve seen a 4×114 conversion done to an FRS before, so it is possible:
https://autoricambi.us/1966-1985-fiat-124-spider/wheels-lug-bolts-and-center-caps/
Interesting coincidence. The license plate on the orange car is JTR. JTR is also an acronym for “Jags That Run”, a 40+ year old company that got its start by selling kits to swap a small-block Chevy into 70s-80s Jaguar sedans and coupes.
They’re still around, and still offering engine swap kits for Jag, Datsun, Volvo, and Chevy S-10.
https://jagsthatrun.com/
So – A British-inspired roadster from a Japanese company that was formerly connected with American Ford, with a Ford-sourced engine that’s British-engineered and tuned by a former British subsidiary of Ford.
Makes perfect sense!
How does the rest of the Miata Driveline hold up to the jump in power? I went and looked at their kit to see what’s included and it’s pretty complete; so I’m assuming it’s re-using the Miata Trans, driveshaft and Rear end…. I have no idea what kind of power NA Miata parts are capable of managing.
It does use the stock transmission and rear end. I’ve read that both are capable of around just under 300hp.
Impressive!
If that’s the case, then why not just get a more widely available and cheaper 3.3, 3.5 or 3.7 out of an F150, Mustang or Transit?
They don’t like to rev.
AJV6’s aren’t incredibly expensive either.
“They don’t like to rev.”
That’s not true at all… even the 3.3 in the F150 hits peak power at 6500rpm (just 300rpm lower than 3.0 AJ-V6) and will rev to something like 7000rpm
And the updated ‘Cyclone’ versions of the Duratec (which the 3.3 is a member of) make more power than the old AJV6.
Even the the older 3.7 had variants that had horsepower that peaked at nearly 6800rpm (in the Radical RXC V6)
Because those are neither more widely available or cheaper.
“Because those are neither more widely available or cheaper.”
Not true. A quick check on car-part.com showed 11 pages worth of engines for just the 3.3L from Ford F150s.
And it can be had for under $1500… or for not much more than a used AJV6 that will be a decade or more older
And in terms of availability, my search on car-part.com indicates that there are at least 10X more 3.3L Cyclone-Duratec V6 engines out there compared to the AJV6.
The real issue, as @Thatmiataguy indicated, is how tall the engine is.
Which is to say that to fit in the Miata, the intake on a truck-sourced 3.3L may be too tall.
But I bet a 3.7 out of a 5th or 6th gen Mustang would fit as well as the AJV6
Modern Ford engines are tall, too tall to fit under the hood of a Miata without either cutting a hole in the hood or dragging the oil pan. The reason why LS swaps work at all is because they’re a lot shorter than an equivalent DOHC engine from Ford.
Look at Flying Miata for info as they do alot with LS swaps in Miatas and will be able to tell you the HP loads for the different variations of transmissions.
Unfortunately they got out of the LS swap business a few years ago. They didn’t want to get caught up in all the emissions drama that started happening, so they pulled all their programmable ECUs, turbo kits, everything, and decided to make everything they sell CARB compliant. They’re releasing a turbo kit for the NC in a few weeks.
I think they passed the LS swap torch to some guy on the east coast, gave him their blessing to do it instead.
V8 Roadsters took over the LS swap business. Monster Miatas also dabbles in LS’s, though the original 5.0 is their bread and butter.
It was partially emissions, but mostly it was the business case. Having an engineer working on development for four cylinder parts lets us service a lot more people than building V8 parts. Same with the programmable ECUs – they sucked up 25% of our customer support resources for 4% of our sales. They were discontinued long before the V8s were.
The NA/NB turbo kits have been CARB compliant for years. The NC kit starts shipping on Tuesday the 13th.
The ND LS conversions went to Sarasota Super Sport performance using the same hardware we developed. V8 Roadsters offers parts for the earlier cars, but not the ND.
Source: I’m one of the owners
Oh shit, it’s Keith! The man, the myth, the legend!
I bought one of your last Hydra ECUs when they were on closeout in late 2016. It’s too bad you don’t do that kind of stuff anymore, but it makes sense that the business case wasn’t really there anymore.
I’d be really interested to see how these kits hold up long term. 5 speeds are pretty fragile in turbo NA6s/NA8s that push much over 200 hp, 6 speeds hold up a little better. It’s the torque that does the damage, though, and perhaps the V6 isn’t so punishing.
The turbos may also be more abrupt in their torque jump once boost kicks in, whereas the 6 will be linear and almost gentle on the trans by comparison. I can imagine transmission gears don’t enjoy jarring changes in torque.
From what I remember back when I was deep into the Miata mod scene, 5-speeds were preferred for better shift feel and were good to about 250 hp. 6-speeds didn’t shift quite as nicely, but were good for close to 350 hp; apparently they were quite overbuilt and could handle more power than the 1.8 could on stock internals.
Mazda went the opposite direction on the ND transmissions and they are considered a weak point in the car. As a matter of fact, Flyin Miata sells kits to swap NC transmissions into an ND because the NC transmissions are stouter.
This is one of the few reasons that the “Fiata” is superior to the ND1. They had NC transmissions. Correct me if I am wrong, but the ND2 fixed the transmission issues.
IIRC, the NA Miata was designed with the purpose of a latter, possible V6 engine. Hence why the Monster Miata 5.0L conversions exist.
The V6 engine is very possible. Check out the M2-1006. It was a factory V6 Miata
Lincoln LS are fairly cheap I’ve seen people harvest those 3.0 for a Miata. I think it’s a little less power then the jag version.
Plus, I gather the Ford Duratec six has a good rep reliability wise. Nobody ever says that about any Jag. 😉
One of my cousins was a Ford engineer that bought a jag of that era his theory being it’s basically a Ford. I think he got the employee price and everything. Didn’t work out for him either. The jag-ness has a way of overcoming anything. His dad who had been a Ford engineer laughed at him from the git go because he knew it would bite him in the ass. You still hear people say the ls is basically a jag but they are definitely more reliable. You see them get neglected for years and still keep going.
Oh nice, basically a domestic Jaguar AJ-V6.
Yes very similar not sure about the cams ? I think the jag had some strange set up that gave them about 30 extra hp? The 3.8 was more favorable in the ls so the 3.0 have been cheap for a long time.
From TFA:
Right, and then Ford adopted the Jaguar version, made some minor tweaks and called it a Duratec V6, which went into the Lincoln LS.
So the big advantage here over the old Monster Miata is weight? Seems like a cool conversion and doubles the price of a Miata.
Other than weight, this swap has a better chance of being emissions compliant as the engines will likely be newer than the chassis (and this kit includes cat converters, etc.). The old 5.0 used in Monster Miatas were made until 1994?
Also, this kit uses the stock drivetrain, which is a lot less invasive than the Monster kits that require souring a T5 and a Ford rear end.
Sounds like your talking about California emissions. If so, I’m sure there are many people that would pay for a fully legal swap.
This might be CA legal, but I am referring to states like AZ. The rules are that you need to have the same year or newer engine swapped in, plus all of the OE emissions equipment.
I thought Rocketeer were building KLZE swap kits? Guess I have them confused with someone else. The AJ V6 is a potent little engine, I’d advise anyone who does swap to replace all coolant pieces with metal ones ASAP.
This is my end goal for my 1994 Miata. Seems less annoying than a K Swap (the NVH and poor exhaust note) and less expensive and invasive than a V8 swap.
The exhaust note on a modded K series ranges from junk to out right bad under most driving scenarios, but then you go WOT in the upper RPMs and its glorious! I have no comment about swapping the Miata.