Add DRLs to Toyota Previa? Or not?

[Alaric Darconville]

I'm not much enamored of DRLs because I'm a good-looking rebel who lives by his OWN rules!

So, '95 Previa -- high/low DRL or turn signal DRL? The turn-signal ones would have great side visibility and still really good front visibility, but the high/low version might have advantages of its own.

 

[cwol97401]

Re: Interesting headlight bulb test results

Because I'm a good-looking rebel who lives by his OWN rules!

So, '95 Previa -- high/low DRL or turn signal DRL? The turn-signal ones would have great side visibility and still really good front visibility, but the high/low version might have advantages of its own.

Why not both?

 

[-Virgil-]

Re: Interesting headlight bulb test results

Because I'm a good-looking rebel who lives by his OWN rules!

...and you know what you see with your eyes in the real world, so who cares about any whatever-photo-meter stupid lab dweeb geek says! Yeah! (right? ;-) )

So, '95 Previa -- high/low DRL or turn signal DRL?

That depends on how high on your bucket list it is for you to design, build, test, and debug a very complicated circuit from scratch, and how much time you have to do it, to wind up with a DRL system not discernibly or measurably more effective than you'd get by spending maybe half an hour putting in a turn signal DRL module. As you note, the front turn signals on the Previa are very well located and specified for DRL functionality.

("Both", that is headlamp DRLs and turn signal DRLs, would not be wise, helpful, or better. Pick one or the other.)

 

[Alaric Darconville]

Re: Interesting headlight bulb test results

...and you know what you see with your eyes in the real world, so who cares about any whatever-photo-meter stupid lab dweeb geek says! Yeah! (right? ;-) )

That's how we in the tun3r circuit ROLL!

That depends on how high on your bucket list it is for you to design, build, test, and debug a very complicated circuit from scratch, and how much time you have to do it, to wind up with a DRL system not discernibly or measurably more effective than you'd get by spending maybe half an hour putting in a turn signal DRL module.

I LOVE that sort of thing, usually, but that sounds like it could be just too much effort.

As you note, the front turn signals on the Previa are very well located and specified for DRL functionality.

I really love the design except for the part about not having a distinct side marker that could be set as a repeater. But they do have a good, wide range of visibility.

I'll admit I have what could be a Very Bad Idea: The high/low method could yield a sort of "campsite crawl" mode, or something, but probably the turn-signal DRL itself would be better for that anyway-- probably less deleterious to my night vision. (And by "crawl", I mean it-- letting engine idle pull me along. I'd install this otherwise.)

Why not both?

Because, "no".

 

[-Virgil-]

Re: Interesting headlight bulb test results

I LOVE that sort of thing, usually, but that sounds like it could be just too much effort.

Well, I don't mean to discourage you. Someone ought to tackle it sooner or later, just for mountain-climbing reasons ("Because it was there!").

I really love the design except for the part about not having a distinct side marker that could be set as a repeater.

Given the design age of the Previa, it wouldn't surprise me to learn there is a Japan-market version of the turn signal that incorporates a repeater.

I'll admit I have what could be a Very Bad Idea: The high/low method could yield a sort of "campsite crawl" mode

More glare than regular low beams, so it would kind of defeat the purpose of a campside mode. Turn signal DRLs or a reduced-voltage low beam feed (or a reduced-voltage fog lamp feed, even better) is what you'd be looking for there.

 

[Alaric Darconville]

Re: Interesting headlight bulb test results

Well, I don't mean to discourage you. Someone ought to tackle it sooner or later, just for mountain-climbing reasons ("Because it was there!").

Didn't Mallory die on Mount Everest?

More glare than regular low beams, so it would kind of defeat the purpose... Turn signal DRLs or a reduced-voltage low beam feed (or a reduced-voltage fog lamp feed, even better)

But front fog lamps are TOYS!

As far as "more glare", if the voltage is roughly half through each filament (on a per-lamp basis, right? The two lamps would be in series-parallel, not all four filaments in a great big ol' series?), then the rough (extremely rough!) number would mean that for a 60/55W H4 with 1650/1000lm output, the total output (ignoring the proximity of the filaments to each other keeping them heated a bit hotter than if in separate envelopes) would be about 251lm per lamp. That's a quarter of the standard low beam output. Per-lamp wattage would also be about 38W. The color temperature would plummet, too.

Doing all four filaments in series, well... Dim

Given the design age of the Previa, it wouldn't surprise me to learn there is a Japan-market version of the turn signal that incorporates a repeater.

MAD JDM, yo!

I've seen some UK versions with a repeater over the front wheel well, but that'd require extra work. It's probably not the hugest deal, anyway.

 

[-Virgil-]

Re: Interesting headlight bulb test results

On the glare issue, the above-horizontal intensity of the full-voltage low beam is less than the above-horizontal intensity of a half-voltage high beam.

I've seen some UK versions with a repeater over the front wheel well, but that'd require extra work.

No, that's not what I'm referring to. The Japanese vehicles at that time often had the repeater placed in a location comparable to the US front sidemarker, rather than the European location behind the front wheel. The Japanese-spec repeater is often built into front turn signals or front position lamp units that wrap around the front corners of the vehicle. The funny part is that many of these Japanese-type repeaters meet (and are homologated to) the European repeater requirements, but most European-spec versions of Japanese vehicles of that time used separate repeaters behind the front wheels. If you have access to a Toyota EPC, you might want to spend some time excavating to see what you can turn up.

 

[cwol97401]

Just curious about the hi/low DRL... Could an of the shelf reduced voltage module be used with a couple 5 pin relays to drive both beams in parallel? And or (not taking into consideration the severely diminished output) two relays used at each lamp module to do some polarity swapping so achieve the hi/low affect? This later may not be desirable, but could it work?

 

[Alaric Darconville]

Re: Interesting headlight bulb test results

On the glare issue, the above-horizontal intensity of the full-voltage low beam is less than the above-horizontal intensity of a half-voltage high beam.

Bizarre. You'd think a 1650lm filament going down to 156lm would greatly reduce glare, since there's only 10% of the original light, if that ((Actual Voltage/Design Voltage)^3.4)*(Design Lumens) formula works out. I guess it must be true-- high beam DRLs do look pretty glaring to me... Bizarre.

If you have access to a Toyota EPC, you might want to spend some time excavating to see what you can turn up.

I'll have to look into that. I just bought a new turn signal, so I'm not super excited by the prospect of re-buying it, but on the other hand, I love lights!

 

[cwol97401]

Just curious about the hi/low DRL... Could an of the shelf reduced voltage module be used with a couple 5 pin relays to drive both beams in parallel? And or (not taking into consideration the severely diminished output) two relays used at each lamp module to do some polarity swapping so achieve the hi/low affect? This later may not be desirable, but could it work?

Never mind, I just answered my first question, a relay driven by the DRL module would still power the headlamp at full power :-( . The second question still stands though.

 

[-Virgil-]

Re: Interesting headlight bulb test results

Bizarre. You'd think a 1650lm filament going down to 156lm would greatly reduce glare, since there's only 10% of the original light.

Stop thinking in lumens (off the bulb), start thinking in candela (out the headlamp). The minimum allowable axial intensity for an HB2 high beam at 12.8v is 40,000cd, and the shape of a US high beam means you've got roughly that intensity for a degree or two up, down, left, and right from HV. Ten percent of that: 4,000cd. The glare control points just above H for the low beam cap out at between 500 and 1,200cd, depending on which point we're looking at.

 

[Alaric Darconville]

Re: Interesting headlight bulb test results

Stop thinking in lumens (off the bulb), start thinking in candela (out the headlamp). The minimum allowable axial intensity for an HB2 high beam at 12.8v is 40,000cd, and the shape of a US high beam means you've got roughly that intensity for a degree or two up, down, left, and right from HV. Ten percent of that: 4,000cd. The glare control points just above H for the low beam cap out at between 500 and 1,200cd, depending on which point we're looking at.

While I didn't know all the numbers, I was inching toward that in my head. An R30 light bulb in the ceiling that's 10% the filament lumens as a bare A19 bulb can still be an excellent task lamp thanks to the reflector. It's not lighting the whole room-- it's got the reflector to aim it. I think I grok it.

 

[fyrstormer]

Re: Interesting headlight bulb test results

I thought it was illegal to modify the operation of safety-critical vehicle lamps? Maybe you should buy a new car instead, to be sure it's kosher.

 

[Alaric Darconville]

Re: Interesting headlight bulb test results

I thought it was illegal to modify the operation of safety-critical vehicle lamps? Maybe you should buy a new car instead, to be sure it's kosher.

Every modification discussed is legal under FMVSS 108.

 

[-Virgil-]

Re: Interesting headlight bulb test results

I thought it was illegal to modify the operation of safety-critical vehicle lamps?

That is not the case. It's illegal to modify them in such a way that required lamps are absent, prohibited lamps are present, or lamps operate in an illegal manner. It's unsafe to modify them in such a way that required lamps are absent or lamps operate in an unsafe manner. That still leaves a lot of room for vehicle lighting modifications that are both safe and legal.

 

[Alaric Darconville]

Re: Interesting headlight bulb test results

If you have access to a Toyota EPC, you might want to spend some time excavating to see what you can turn up.

Some internet scouring (and some timely assistance from a friend) has revealed the 81510-95D01 and 81520-95D01 part numbers. Now, if genuineserviceparts.com has them (and not some "supersedes previous edition" update that deletes features), I may be in business. They also have those glass-lensed ECE-but-still-RHT headlamps I so lust for...

 

[-Virgil-]

Re: Interesting headlight bulb test results

Well, hot diggity! Remember if you do this to wire up the repeaters so they serve both as sidemarkers (steady burning) and as repeaters (flashing), and you'll have to add a separate side reflex reflector because that probably won't be present, not being required in Japan. That's easy, though.

 

[Alaric Darconville]

Re: Interesting headlight bulb test results

Well, hot diggity!

Void where budget prohibited, though
I do plan on keeping this vehicle for some time, but along with the upgrades I want, there are just the repairs and upkeep.

Remember if you do this to wire up the repeaters so they serve both as sidemarkers (steady burning) and as repeaters (flashing)

Per #4 in this thread, that was my reason for wanting the Estima/Lucida lamps-- so I could do the "markerflash" mod.

and you'll have to add a separate side reflex reflector because that probably won't be present, not being required in Japan.

Quite easy. Probably not as "pretty" as one would like (it'd be obvious it was a sticker or reflex reflector affixed to the body panel), but still very simple.