miata aftermarket headlights

NA Miata LED Bulbs in H4 Housings *Review*

That was a long title... almost as long as the amount of time I spent trying to find information and reviews of other people who have tried using LED H4 style Bulbs in their NA Miata. My H4 halogens were starting to die and proper lighting is very important to me. When you're in a car as small as a Miata, it's vital for other cars to know of your presence. And when you and your pals are tearing up a twisty mountain road while delivering tofu for your dad's tofu shop, you need to see what's ahead of you without blinding other drivers. With limited information about other Miata driver's experiences with LED headlight bulbs, I decided to try them out first hand.

Purchasing the Headlights

Not all LED headlight bulbs are created equally. They come in many different brightness levels, LED patterns, with or without a cooling fan, etc. It's worth noting that most LED headlights are near the 6000k color range, which produces a very white light.

I chose these Atshark LED headlight bulbs because they were rated at 3600 Lumens/bulb (7200 Lumens combined). Also the LED chips are positioned so they let light out evenly around the bulb, which is similar to a halogen bulb. I opted for a bulb that came with cooling fans. Some LED bulbs come with only heat sinks, and some reviews complained about the rear portion of the bulb getting very warm.

This bulb was also rated highly and had great customer reviews. Although this product did not have the highest amount of stars, it received detailed reviews with evidence and insight, which I took into consideration when choosing this bulb.

*Notes on Fitment*

  • Make sure you have H4 headlight housings before purchasing LED bulbs for your Miata.
  • Ensure the bulbs you are purchasing are H4 style bulbs.
  • Every H4 housing will be a little different from brand to brand. The housings used in this review are Hella's 7" Diameter E Code housings.


*This is meant to serve as a write up on my installation experience. Every LED Headlight bulb is somewhat different. Attempt at your own risk.*

Installation is exactly replacing bulbs with regular halogen bulbs, but with a few extra (but simple) steps. If you know how to use a screw driver and are able to plug and unplug something from an electric socket, you are capable of changing headlight bulbs in a Miata. There are many DIY threads on how to replace NA Miata headlight bulbs so I won't cover that; I will go through the extra steps that have to be taken when installing LED bulbs.

The LED bulbs I chose came with a big fan assembly to cool the back of the bulb. The H4 bulb retaining clips will fit around the fan.

1) The LED bulbs also came with its own wiring harness and a module built into the wiring harness. First plug the wiring harness from the new bulbs into the OEM headlight harness. I thoroughly wrapped the three connections on my headlights with electrical tape. This was done to prevent excessive water from going on the connections and corroding them.

I ended up tightly wrapping the three connections in electrical tape afterwards. 

2) Since new bulbs add length to the wiring harness, you can fish the excessive wiring back into the engine bay. Leave some slack in the wire because you have to keep in mind that the headlights need to open and close.

3) I didn't want the new headlight's wiring module to be flopping around, so luckily there's a pre-existing hole in the module that allowed me to bolt it to a pre-drilled hole in the headlight frame.

Wiring module is bolted to the side of the headlight assembly using a pre-existing hole and an M6 bolt and nut.

4) Plug everything else back in and clean up the lengthy wiring harness. I know this isn't a 240sx, but I used zip ties to neatly tuck and secure the wiring off to the side. Remember to keep enough slack so the headlights can open and close without snagging the wires.


testing out the new lights

Right off the bat, the LED bulbs are much brighter. Before driving, I aimed the headlights downward to prevent blinding oncoming drivers. I ended up aiming them back up and had lots of people flashing their high beams at me as a complaint of my super bright lights. I don't blame them; the LED's were even illuminating the trees over the road!

After aiming them back down again, I went for a casual drive on a local twisty road. This twisty road was my baseline because I vividly remember driving this road on a regular basis with my halogen bulbs. My biggest complaint I had of my halogen bulbs in H4 housings was that the side vision wasn't the greatest. The LED bulbs provided much better side vision and it was easier to see farther around each corner. I should add that I only adjusted the up and down aim of the lights, not the side to side aim.

Sides of the road are better illuminated with the new LED bulbs.

The lights provided better side aim probably due to the fact that the light scatters in different directions in a greater amount compared to halogen bulbs. This fact remains true with the light that shines directly in front of your car. The LED light does scatter and doesn't aim well. Like I said earlier, with the lights aimed too high up I was blinding people and illuminating the trees above the road. I brought the headlights back down to compensate but then I couldn't see as far down the road as before. 

Driving down a road with low beams. (Note how far the light aims after bringing them to a less blinding height.)

Same headlight adjustment with high beams. Don't focus on the yellow sign, the car was moving very slow between both pictures.

final thoughts

The LED's definitely perform better than the old halogen bulbs. My only complaint is that finding the right aim setting is like a balancing act just because the lights are so much brighter and more prone to blinding oncoming drivers. I was able to find a happy median adjustment where I could see down the road without blinding oncoming drivers. Although if you plan on getting LED headlight bulbs for your H4 housings, I would recommend doing a projector retrofit or purchasing housings with real projectors already built in. With projectors, you'll have an easier time aiming the bulbs and get the most performance out of your LED headlights. This is due to the fact that good quality projectors have a much better cut off compared to conventional halogen housings. 

Yes they are that bright.