Gy6.35 HIR 921 reverse light upgrade (vs high power LEDs)

My build goal is consistently the same, it should look and function like stock as if Toyota designed it that way, but perform drastically better, this reverse light upgrade is no different.

This mod results in a measured improvement pushing near 3.5+x reverse light output over stock.
It works for 2001-2018+ Tacomas using the 921 bulb for reverse.

NOTE: This thread was created with Philips 30w HIRs. A new higher performing 35w HIR has been released from Osram, see end of thread for update.

First the results pictured from the bed, low power 30w HIRs left vs stock right:



I was not the original one to come up with putting a gy6.35 12v bulb into the 921 reverse fitting, from what I can tell it came up deep in the reverse 886 thread. For my purpose I chose the top 2 reverse light contenders I could find based on my research for a comparison shoot out which, as usual, pits the best high powered halogens against the best high powered LEDs.

1000 lumen 921 Chinese FlashWolves LEDs vs 750 lumen German Philips gy6.35 HIRs

The spec breakdown:
Stock incandescent 18w 921 reverse lights: 264 lumens
FlashWolves 18w LEDs: 1000 lumens
Philips 30w gy6.35 HIRs: 750 lumens
UPDATE: Osram released new 35w gy6.35 HIRs: 860 lumens.
Info in this thread is on the old Philips 30w 750 lumen HIR.

Stock incandescent vs LED vs HIR


High powered 921 LEDs
When looking at lighting upgrades the objective for most is more lumen output. Many over the counter LEDs manufactures do not necessarily share this objective. While LEDs are more efficient, an 18w incandescent reverse light (stock) swapped out for a 3w LED is is just a transfer in lighting technology and light temperature at roughly the same output level, and not an upgrade in actual output. As such I searched for the highest power 921 LED upgrade I could find. Numerous threads on the this forum recommended the FlashWolves 1000 lumen 18w 921 LEDs as the highest performing full power LEDs, promoting a nearly 4x improvement over stock. Going LED at full wattage sounded promising, approaching near headlight lumen output.

Gy6.35 HIRs:
Incandescent bulbs are at the bottom of the lighting technology hierarchy in terms of performance, being the least efficient and lowest output. This is what is stock for reverse lights. Halogens are a significant improvement, and what most vehicles utilize for headlights. Halogen IR (HIR) bulbs are rare and the pinnacle of halogen performance technology vastly superior to standard halogens. HIR bulbs use a reflective coating on the bulb to reflect the generated IR energy back to the filament to overdrive it with significantly more power with out any more heat or current draw. HIR are almost comparable in lumen output with HIDs, at stock halogen wattage. Philips just released their new gy6.35 bulb in HIR which is plug and play to the reverse lights, with 750 lumens, about 3x improvement over stock.

For a little reference, if you are unfamiliar with HIRs (unfortunately not available in our headlight bulb size):
http://www.rallylights.com/vosla-9011-hir1-9005-65w-halogen-infrared-bulb.html

For those not familiar with the gy6.35 upgrade, this is a 12v landscape bulb that can be swapped into the 921 reverse light assembly. The bulb requires very minor bending on the prongs to widen them so the bulb stays secure, but is otherwise is plug and play. People run gy6.35 in 35w and 50w halogens, but the circuit is only designed for 18w so 50w is over 2x circuits intended use and not something I would recommend. Many people say "I'm not in reverse that long, so it is not a big deal", which normally may be true but I'd rather not stress about my reverse light circuit backing out of a very long tight spot on the trail. The Philips HIR gy6.35 produces 750 lumens and draws less than the 35w halogen version which produces 420 lumens, all while performing equivalent to the 50w halogen making it the clear winning choice.

Gy6.35 output:
35w halogen: 420 lumens
50w halogen: 750 lumens
30w HIR: 750 lumens
35w HIR: 860 lumens

Comparing measured output

Stock incandesent lux reading:


LED lux reading:


30w HIR lux reading:


The LEDs were rated so much brighter, what happened?

It is not uncommon for LEDs to be vastly overstated in lumen output based on theoretical chip output multiplied by the number of chips, when actual output is significantly less.

The bulb is also not a great design for the housing since the LED light is directional. The majority of the 921 LED diodes emit to the sides, where the light is not well utilized in the reverse reflector, unlike the omni-directional incandescent/HIR bulbs. Very few of the LED diodes actually face front to back to project light where it is needed causing a catastrophic reduction in performance, because the housing is not designed for the directional LEDs.

So while the LEDs are rated at 4x the output over stock, they do not produce much more projected/useful light output than the stock bulbs other than an often misleading change in color temperature. You can see more examples of how the LED light optics are different in this headlight thread here.

Wall shots

HIR left, stock incandescent right:


HIR left, high powered LED right:


More ground shots, HIR left vs LED right:


One of the things that is concerning with upping the halogen wattage is temperature.

Stock temp, 88 degrees:


HIR temp, 138 degrees:


To test durability, I left the truck in reverse for 20 minutes with the parking brake on while I drank a beer with the neighbor and then checked again:


Something surprising was the light output to the sides of the truck with the HIRs compared to stock or LEDs. The HIRs significantly extended rear side visibility.

While really not very helpful, people always seem to like photos facing the lights.

LEDs on the left, HIRs on the right. While the LEDs appear whiter, the photo shows the output difference is superior with the HIRs:


To install
The install only takes a few minutes. Drop the tailgate, and remove the top and bottom 10mm bolt on the inside of the bed wall. Then simply firmly pull the taillight out. Be sure to unclip the factory wiring from the lower clip before removing reverse light bulb to have enough play in the wiring to fully remove the bulb. Or you could end up with the bulb falling off inside the tail light and trying to fish it out like I did... The gy6.35 prongs are too narrow to hold the bulb firmly in place, so using a pair of needle nose pliers, gently spread the bulb prongs a small amount so they press into the sides of bulb socket to hold the bulb in place. Then install.

Note my prongs are spread wider than the socket:


The Philips gy6.35 HIRs textured prong bulbs are far easier to hold in place than the Osram HIRs which have slick polished prongs and slide out like they are lubed in butter. The Philips actually grip the side of the 921 socket. I fought with the slick Osrams for a while and actually ended up breaking one of the prongs off of one of my two Osram bulbs.

Step back. Cool down.

Think.

What are the engineering factors that will hold the gy6.35 bulb in place in a 921 socket? Pressure. Friction. Surface area. Cannot do too much about pressure or friction, but why has no one manipulated surface area?!

Rather than bending the prongs in the standard V pattern that everyone does, which utilizes the surface area of just the outermost tips of the prong for friction against the 921 socket, I used 2 sets of needle nose pliers to bend mine in an arch shape which puts the majority of the prong body in contact with the 921 socket creating a significant increase in contact surface area. After performing this mod on the slick prongs of the Osram, it actually held in place very securely, better than the textured prongs of the Philips.


Recommend gy6.35 prong bending shape, far right
Left to right: Broken Osram, 30w Philips HIR with standard prong bend, 35w Osram HIR with modified curved prongs.


Installed.


Alternative method for securing the bulb in the 921 socket, credit to @IronPeak for sharing:



Where to purchase Philips 30w gy6.35 HIRs
While Philips has them listed on their North America site, I have not yet been able to find their new HIRs domestically. They are readily available in Europe, and I'm guessing will be here soon. I ordered my 30w HIRs off ebay out of the UK. Note that these are not the same as the 35w or 50w gy6.35 standard halogen bulbs readily available in the USA.

UPDATE 11/11/17:
Osram just released a new 35w gy6.35 HIR bulb coming in at an impressive 860 lumens per bulb, while consuming 5w more than the Philips 750 lumen bulb. Best of all, the bulb has been released in North America and is available on Amazon, unlike Philips. To put the 860 lumens in perspective, an H4 silverstar headlight is rated at 910 lumens.

860 lumen 35w Osram gy6.35 HIR:
https://www.amazon.com/Sylvania-588...&qid=1510363962&sr=8-4&keywords=GY6.35+12V+ir

The new 860 lumen HIR


35w HIR lux reading:


Starved
With the 35w Osram HIR and the 30w Philips HIR installed at the same time, the max lux reading was 460 from the 35w Osram HIR, which was less than the 486 I had previously measured the 30w Philips HIRs at. The Osram should come in about 15% higher than the Philips based on the specs. Something was off. I initially used a newer professional grade light meter for the updated comparison reading, but went back to my hobbiest light meter to eliminate the variable with no better results. After thinking it through I realized the lights are choking on overloading the small gauge reverse wiring. Removing the 30w Philips bulb the 35w Osram shot up to 529 lux, a 15% improvement. This places measured readings of the Osrams about 10% brighter than Philips, which is approximately inline with the specs.

If you've read my other lighting threads about installing a standalone harness, this is proof of the benefit. Stock wiring hinders performance when turning up the wattage by restricting power. In this case a 860 lumen bulb is failing to provide performance of even a 750 lumen bulb due to inadequate wiring. A relayed standalone harness for the reverse lights would provide at least 15% benefit and likely more by going to a heavy gauge wire. This would also alleviate the load on the tow circuit while providing even brighter reverse lights. Note for future mod.

How do HIR temps compare? After 30 minutes in reverse at 48 degrees outside:
Philips 30w HIRs:


Osram 35w HIRs:


HIR output pic, Osram 35w HIR left, Philips 30w HIR right:
I might add, it very dark outside in this photo. The combined light output of the HIRs lights the exceptionally well.



I am confident in saying there is no brighter reverse light bulb available for the stock housing than the gy6.35 35w Osram HIR.

7440 bulbs
I get many messages from non-Tacoma owners about reverse light upgrades. If you have a common 7440 reverse light, you may be able to use a 7440 to 921 base adapter to still run this mod,

$15 PA LED 2x T10 168 194 to T20 (7440) Bulb Base Converter

like this one.


If you found this interesting, you might be interested in my other lighting threads:

Fog light upgrades:
The LED SAE J583 Fog Pod & Fog Light Review

Other lighting upgrades:
3rd Gen HID vs LED vs Halogen H11 projector headlights
The ultimate headlight upgrade H4 (not LED or HID)
The 921 LED Reverse Light Bulb Study

Rock Lights:
The Rock Light Showdown

More information on automotive lighting:
Automotive Lighting 101
Why LEDs should not be run in Halogen reflectors

Home lighting upgrades:
High quality efficient home lighting using LEDs, HIRs and Halogens

I'm always happy to help people on their truck projects, if you have any questions don't hesitate to PM me or reply to this thread.

 

Informative analysis and great write-up, as always.

Any concerns bumping current draw from ~1.5A to ~2.5A on stock wiring? What about the operating temp increase?

 

Very well written and tested. The differences in temperatures is pretty scary, but if you have your truck in reverse long enough to cause significant damage then I'm pretty sure that's the leadt of the worries

 

The circuit is rated at 10A, so I took it from consuming 3A (both bulbs) to 5A. I believe the circuit is used for trailer reverse lights as well. Many people are running the 35w halogen version of the gy6.35 upgrade without any issues. One of the reasons I really wanted the HIRs was to have the lower current draw compared to the 35w halogens, along with more output, as I am not a fan of over taxing a circuits engineered use.

As to the operating temp increase, 138 degrees isn't terrible. Even leaving the truck in reverse for 20 minutes to really test it got the temp up to 153 degrees, placing my hand on the lens was just warm to the touch, not hot. Guys running the 35w or even the 55w halogen gy6.35s have not had issues and those would be hotter, though I would not recommend running the 50w halogens.

 

A friend gave me a cheap set of LED's and the only positive is they make it easier to see in the backup camera but they suck! How do Sylvania 921 ST SilverStar's compare?

 

I wouldn't worry about the lens as much as the plugs and wiring.

 

Another well written and informative post with lots of down to earth information and well reasoned recommendations. Keep up the good work!

Personally, I gave up on finding a 921 bulb that gave me as much additional lighting as I was looking for. So I went with the best out of 5 sets of 921 LED replacement bulbs I tried to reduce the current draw on the Reverse Light circuit. I then added a set of 30 watt (six 5 watt LED) add on lights bolted to existing holed underneath my rear bumper which are wired into the same circuit. Problem solved.

I'm assuming that one needs to take the same care in not touching the glass capsule on an HIR bulb as one does on Halogens?

 

Any pics?

 

The 921 ST Silverstars advertise "up to" 30% brighter than stock. But realistically, the coating on the bulb will reduce output though make it appear whiter. By comparison the HIR is spec'd at about 300% brighter.

At about 150 degrees, I'm not overly concerned with the plastic plugs, the HIRs run cooler and have lower draw than people running the 35w halogen gy6.35.

Thanks. I thought about adding aux rear lights, or flush mount bumper LEDs, but I really wanted something factory looking.

Yes, good point, I should have mentioned that, I wore gloves for the install to protect the bulb. Often times I would just be careful, but there isn't a good base to hold on the bulbs for the install and it good a couple attempts to bend the prongs just right to fit snugly into the base.

 

I'll try to post something up as soon as the weather clears. It's pouring rain right now and supposed to turn to snow later tonight.

 

Very good info.
Ever thought of stuffing more bulb in the 921 socket? T20 perhaps..

 

I had not thought of using a T20, I haven't heard of anyone doing that one either. Interesting idea though, I'd be curious if the base fit the 921 socket as it would have better output over the stock 921s. The 21w T20 looks to be about 460 lumens, an improvement over the stock 264 lumens but not up to par with the gy6.35 HIRs at 750 lumens.

 

Working on a solution now

 

Found some gy6.35 HIRs domestically on eBay for cheap here. They are the previous version from Philips, but have the same specs, 30w 750 lumens.

 

As always Crash you are the lighting master. And this was the one problem left in lighting for us that follow your upgrades.


I have tried almost every LED on the market. Though better and produce more light it doesn't seem to help in the backup camera. It's weird how my super LED's make it harder to see through the camera than the stock bulbs. It looks brighter when you turn your head to see but who does that anymore...ha
So can't wait to do this. Bulbs ordered and awaiting arrival.


Thanks again !!!!

P.S. Not afraid of the heat at all. Like was said, they are never on long enough to worry about it. Especially if you tested at 20 minuets and had no problems. Even backing out a tight trail I have never had them on for that long.

 

Now if we could find em in the states and not on flea bay...

 

Wonder how the 90w H11's would do in the reverse bucket .
For now, my trittons light it up pretty darn good.

 

Backing out of my driveway at 5am this morning, I can say the difference is extreme and improves rear vision significantly. I did the torture test for 20 min because I knew it would be something people would question, and I wanted to prove that it wouldn't overheat. It was a little weird to look at my truck in reverse and not be in it.

The previous version of the bulb, Philips 30w gy6.35 EcoVantage, were readily available at Home Depot and others before being recently discontinued. I suspect the new version will roll out domestically soon. With a 4000hr life span, I didn't mind paying a little more to get them from overseas rather than wait.

 

I have not tested "FlashWolves 1000 lumen 18w 921 LEDs" but from my experience most data published by LED bulb sellers are simply marketing BS. Here how it works: Seller calculates the max power the bulb can output by multiplying number of LED chips and Absolute Maximum Power from the LED chip catalog. You have 45 LED chips, each one have max absolute power of 0.4W and you have 18W, 1000lm. reality is that you can't run LED at max absolute power in such bulb (too much heat) so in order to have the bulb not burn in first 10 seconds they run it at much less power (not disclosed). If it is 3W (that is 0.25A) the bulb will produce marginal output compared to what they publish. I tested many different "ebay" and "Amazon" bulbs and the result was always the same.

There are very few exceptions to this "marketing BS" rule. Well known companies like Osram, Philips, will either not publish any data, or give true value. Also if you buy a bulb from well known company like superbrightleds.com for example, you can trust the data they publish. 99% stuff on Amazon or Ebay is just "too good to be true".

Your lumen measurements of LED bulb are 100% in line with my experience.

 

Just got mine in!!!!! Going to try and do tonight after work. I'll let you guys know how awesome this is (because every lighting mod Crash does is awesome!!!)


P.S. I like how that site C&B-80 posted sells in lots of 3. cheap enough to not care about the extra and now i will have an extra if one blows out.