Here’s a conversation that happens roughly once a week:
Someone buys an NC MX5. Falls in love with it. Decides they want more power. Starts researching turbo kits. Gets excited about manifolds and downpipes and wastegates. Orders parts. Then opens the bonnet with a tape measure and realizes they’ve made a terrible mistake.
The alternator is in the way. Properly in the way. Like, “your turbo manifold is going to have to route around it like it’s playing snake on a Nokia 3310” in the way.
Welcome to one of Mazda’s less celebrated design decisions with the NC.
Why Mazda Put The Alternator Where They Did
To be fair to Mazda, the alternator placement makes perfect sense if you’re designing a naturally aspirated roadster that’s never going to see a turbo in its entire life. Stick it on the exhaust side, belt it up to the crank, job done. Works fine. No issues.
The problem is that Mazda didn’t account for the fact that a lightweight, rear wheel drive roadster with a bulletproof engine and perfect weight distribution is basically begging to be turbocharged.
So now you’ve got this alternator sitting exactly where every turbo manifold wants to be. And suddenly your “simple” turbo build becomes a game of 3D Tetris where nothing quite fits and every solution involves compromise.
The Actual Problem (With Pictures You Can Probably Imagine)
Let’s say you want to run a proper turbo setup on your NC. Nothing crazy, just a decent GTX3071R Gen2, something that’ll make good power without exploding.
You need:
A turbo manifold that routes from the exhaust ports to the turbo without melting itself or everything around it.
A downpipe that’s large enough to actually flow, ideally 3 inches if you’re making proper power.
Space for all of this to exist without requiring a hammer and creative language to install.
And here’s where the alternator ruins your day. It’s sitting right there on the exhaust side, taking up prime real estate. Your manifold has to route around it. Your downpipe can’t take the direct path it wants. Everything becomes a packaging nightmare.
You end up with manifolds that have weird bends they shouldn’t need. Downpipes that compromise on diameter or routing because “it won’t physically fit otherwise.” Heat management issues because everything’s crammed together tighter than a London tube at rush hour.
It’s not impossible to work around. People do it. But it’s always a compromise. Always a bodge. Always “well, it fits if you do this weird thing.”
What Happens If You Just Ignore It
Some people try to build turbo NCs without relocating the alternator.
Here’s how that usually goes:
Option A: Compromise on the manifold design. Get something with extra bends and longer runners than ideal because it has to route around the alternator. It works, but you’re leaving performance on the table and adding complexity where you don’t need it.
Option B: Compromise on the downpipe. Run a smaller diameter pipe, or one with more bends, or route it in a way that’s not optimal. Again, it works. But you’ve just spent money on a turbo setup and immediately kneecapped it with restrictive plumbing.
Option C: Get creative with heat management. Wrap everything in heat wrap, add shields, pray to the gods of thermodynamics. Your engine bay becomes a sauna. Your under bonnet temps skyrocket. Components that don’t like heat start complaining.
Option D: Just accept it and bodge something together. This is the “I’ll figure it out when I get there” approach. Spoiler: you don’t figure it out, you just make it work badly and then live with it.
None of these are great options. They’re just “less bad” options that people settle for because they didn’t know there was a better way.
The Proper Solution: Move The Damn Thing
Relocate the alternator from the exhaust side to the inlet side. Suddenly all your problems disappear.
Your turbo manifold can route properly. Your downpipe can be the right size and take the path it wants. Everything fits without requiring percussive maintenance or creative metalwork. Your engine bay temperatures stay sensible because you’re not cooking the alternator with turbo heat.
Here’s the clever bit: we use an alternator that was originally designed for the inlet side of the engine, Which means it’s already designed to live in that space. We’re not bodging something to fit where it shouldn’t; we’re using a part that Mazda engineered for that exact location.
It’s not revolutionary. It’s just… sensible. The kind of thing Mazda might’ve done if they’d been thinking about forced induction from the start.
What Our Kit Actually Does
We’ve put together everything you need to relocate the alternator to the inlet side of the engine bay. This isn’t just a bracket, it’s a complete kit with all the hardware, belts, and tensioner required to make the swap properly.
What you get:
All mounting hardware every bolt, spacer, and fitting you need to mount the alternator in its new home. ~
Belt and tensioner the correct length belt and tensioner setup for the new routing, because working out belt lengths at midnight when you’re halfway through an install is nobody’s idea of fun.
What you need to know:
This kit is for non-AC cars only. If you’ve got air conditioning, the compressor is in the way and you’ll need significant modification to make this work. At that point you’re on your own, sorry.
You’ll also need the correct alternator for the inlet side. We don’t reuse your old exhaust-side alternator, we use the one that was designed to live where the AC compressor sits.
You’ll need the 3-pin type from either a Mazda 3 (A3TJ1091, 110A) or Mazda 6 (A3TG1391A, 90A).
Both slot straight into the MX5 NC like they were meant to be there, because they basically were. Cheap and easy to find at breakers or online.
For LHD owners: You might need to trim a tiny bit of metal off the alternator to clear the steering arm. We’re talking about a minor haircut, not reconstructive surgery. Five minutes with a grinder, job done.
When You Actually Need This
Do it now if:
You’re planning a turbo build and want to do things properly from the start. Seriously, do this early. It’s exponentially easier to relocate the alternator when your engine bay is still relatively stock than when you’re neck-deep in a turbo install and realizing this should’ve been step one.
You’re already running boost and fighting packaging issues. If your manifold looks like modern art or your downpipe has more bends than a politician’s promise, this is probably why.
You’re building a high-power NA setup with custom exhaust manifolds. Less common, but if you’re going down this route you’ll appreciate the extra space.
Don’t bother if:
You’re staying completely stock forever. Save your money for trackdays or better tyres. You don’t need this.
You’re building a mild turbo setup with a kit that’s designed around the stock alternator position. Some kits account for this. Check with your kit manufacturer before assuming you need to relocate.
You’ve got air conditioning and aren’t willing to do major modification work. This kit isn’t for you.
The Bit Where We’re Brutally Honest
Relocating your alternator isn’t going to make your car faster. It won’t add power. It won’t improve throttle response. Your mates won’t notice unless they’re the kind of people who spend time staring at other people’s engine bays (and if they are, they’re proper nerds and you should keep them).
What it will do is make your turbo build possible without compromise. It’ll let you use the manifold you actually want. The downpipe that actually flows. The heat management that actually works.
It’s not the sexy mod. It’s not the one you post on Instagram with fire emojis. But it’s the mod that makes everything else work properly instead of being a constant source of compromise and regret.
If you’re building an NC for proper power, this is foundation work. The kind of thing you do once, do right, and then build everything else on top of without having to fight packaging issues at every step.
The Install Reality Check
This isn’t a 30-minute bolt-on job. It’s also not a week-long nightmare. Figure on a few hours if you’re reasonably handy with tools and have done similar work before. Longer if you’re learning as you go, which is fine, everyone starts somewhere.
You’ll need to:
Remove the old alternator. Fit your replacement alternator, it bolts straight to the engine block, no custom brackets needed. Re-route the OEM wiring to the inlet side (it’s long enough, you just need to pull it across). Sort out the belt routing with the tensioner and hardware from the kit. Check everything clears and tighten it all down properly.
The alternator mounting is straightforward because it uses the existing engine block mounting points. The wiring is already there and long enough, you’re just routing it to a different side of the engine bay. Take your time and you’ll be fine.
If you can change your own alternator (which you should be able to on an NC), you can fit this kit. It’s not harder, just
What You Get For Your Money
A properly engineered solution to a packaging problem that Mazda left you with. The ability to build your turbo NC without compromise. An engine bay that makes sense instead of looking like you tried to solve a Rubik’s cube in the dark.
You also get the satisfaction of knowing you did it right instead of bodging it. Which doesn’t sound like much until you’re three trackdays deep on a properly sorted turbo NC and everything’s still working perfectly because you didn’t cut corners on the fundamentals.
Ready to give your turbo build some proper breathing room?
Get the Alternator Relocation Kit here
(NON AC CARS ONLY)