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MatthewLTL

macrumors 68000
Jan 22, 2015
1,684
18
Rochester, MN
Can anyone of you tell me how to tell the Watt vs Lumen conversion for Automotive lighting? For instance a standard non-headlight/fog light bulb on a car is around 25Watts. A 40 watt bulb would be 380-460 Lumens.
I want to get some Switchback LEDs for my front turn signals/ DRLs. The LED Bulbs are 40-50 Lumans. Can anyone tell me how bright this is exactly?
 

bunnspecial

macrumors G3
May 3, 2014
8,352
6,495
Kentucky
Lumens are lumens.

There's no conversion for wattage to lumens unless you know the efficiency. This is pretty well know for tungsten incandescent bulbs since they've been made for 100 years and are fairly consistent. It's different for tungsten-halogens, but still well known. LEDs are much more efficient.

Even so, lumens are a measure of light output, so if you want equivalent light output you need to match this value.
 

MatthewLTL

macrumors 68000
Jan 22, 2015
1,684
18
Rochester, MN
Lumens are lumens.

There's no conversion for wattage to lumens unless you know the efficiency. This is pretty well know for tungsten incandescent bulbs since they've been made for 100 years and are fairly consistent. It's different for tungsten-halogens, but still well known. LEDs are much more efficient.

Even so, lumens are a measure of light output, so if you want equivalent light output you need to match this value.
So how bright would a 7W LED be vs a 25W incandescent?
 

bunnspecial

macrumors G3
May 3, 2014
8,352
6,495
Kentucky
LED technology is evolving, and I think the output is also somewhat color temperature dependent.

Check the specs on the exact parts you are examining for the real answer-that's the only way you're going to get an accurate answer.
 

MatthewLTL

macrumors 68000
Jan 22, 2015
1,684
18
Rochester, MN
LED technology is evolving, and I think the output is also somewhat color temperature dependent.

Check the specs on the exact parts you are examining for the real answer-that's the only way you're going to get an accurate answer.
The SBLEDs are 6000K white and 3000K Amber. 40LM (I Assume Amber) and 50LM (I Assume White)
 

XrayTed

macrumors regular
Oct 14, 2014
116
288
Haven't had my 68 Firebird on the road for a few years, was hoping this would be the year but it looks like next year.
Got alot of stuff done, purrs like a tiger.
FullSizeRenffder.jpg
 

senseless

macrumors 68000
Apr 23, 2008
1,887
257
Pennsylvania, USA
I was really set on the BMW 135i until I realized they all have low profile tires mounted on expensive rims. I'm concerned about Pennsylvania potholes destroying the wheels and tires.
 

Suture

macrumors 65816
Feb 22, 2007
1,003
213
I was really set on the BMW 135i until I realized they all have low profile tires mounted on expensive rims. I'm concerned about Pennsylvania potholes destroying the wheels and tires.

Do they still use run flats?
 

A.Goldberg

macrumors 68030
Jan 31, 2015
2,549
9,715
Boston
Got the interior LEDs today (two days ahead of schedule): View attachment 570228 View attachment 570229 View attachment 570230
INSTALLED! View attachment 570231
DOME LIGHT COVER BACK ON View attachment 570232 INSTALLED IN TRUNK!

Discovered the reason an LED wouldn't work in the 3rd brake light. Daewoo switched the polarity of where the socket plugs into the wiring harness of the car.
View attachment 570234 View attachment 570235
Snipped the wires and flipped them. View attachment 570237 SUCCESS! Now I have a LED in the CHMSP.

Those are some fine photographs.

You need to put some butt splice connectors on those wires.

They're fantastic. So much detail!

I'm sorry this belongs in the Car Mod Thread.
 

2298754

Cancelled
Jun 21, 2010
4,890
941
Then he'd have to reduce wheel diameter and it might hit the brake caliper. Then there's the it'd look pretty dumb part.
Not necessarily. Depends on the stock wheels that came with the BMW that the other poster wants to buy. I swapped the RFTs on my X5 for high-end all seasons and the ride changed dramatically. I didn't even change the tire size at all.
 

2298754

Cancelled
Jun 21, 2010
4,890
941
I was really set on the BMW 135i until I realized they all have low profile tires mounted on expensive rims. I'm concerned about Pennsylvania potholes destroying the wheels and tires.
While these issues are valid, I do think they're overblown. Our roads are even worse up here in Boston and my BMW's wheels have been fine... especially after swapping the RFTs for regular tires.

The days of low-profiles being expensive or high maintenance are gone IMO. Most cars these days have "thin" tires.
 
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Reactions: D.T.

D.T.

macrumors G4
Original poster
Sep 15, 2011
11,050
12,467
Vilano Beach, FL
I was really set on the BMW 135i until I realized they all have low profile tires mounted on expensive rims. I'm concerned about Pennsylvania potholes destroying the wheels and tires.

Having driven around PA (Pittsburgh/McMurray), yeah, there's some abusive roads :) Always glad we [usually] have our T4R when we're up there, especially in the winter.

It's a consideration, but just about _any_ performance type vehicle is going to have low[er] profile tires. That's part of the formula. I know folks that during the winter in those areas switch over to their "beater" wheels (with appropriate winter tires), or even just garage their fun car and bust out the winter truck :D

I actually cracked a wheel on my Lexus, hit a pot-TRENCH, knew it was a hard hit, but didn't think much about it, was coming home late - the next morning, the tire was flat, leaked through the crack. That was an expensive wheel, though not fully forged either.

I say go for it anyway. The 135 is awesome.

Haven't had my 68 Firebird on the road for a few years, was hoping this would be the year but it looks like next year.
Got alot of stuff done, purrs like a tiger. View attachment 570616

Beautiful. I'm sure just about everyone in this thread would like to hear more about it and/or see more photos!
 

A.Goldberg

macrumors 68030
Jan 31, 2015
2,549
9,715
Boston
Already is
Than its probably unnecessary to post essentially the same thing in both places at the same time. It seems both threads have the same people in them.

Hey guys could a 40W LED work on a circuit meant for a 25W Incondescent bulb or would I blow a fuse?

Also is 1400LM too bights for tail lights?
I think you should keep this in the car mod thread.
 

senseless

macrumors 68000
Apr 23, 2008
1,887
257
Pennsylvania, USA
While these issues are valid, I do think they're overblown. Our roads are even worse up here in Boston and my BMW's wheels have been fine... especially after swapping the RFTs for regular tires.

The days of low-profiles being expensive or high maintenance are gone IMO. Most cars these days have "thin" tires.

Yes, the regular tires don't have the stiff sidewalls like Run Flat Tires.
But swapping RFTs for regular tires is a risky option in a car without room for a jack and donut spare. Slime won't fix sidewall damage. I had this happen this year and last. Run flats would have gotten me home, I'm guessing.
 
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