I was wondering as I was driving home today from Sedona... Do any of you with Xenon lights use the day-time running lights? Do you worry they'll burn out quickly?

Also, any of you (but especially CDI owners) downshift your car to slow it down, thus using engine braking.. I found it was useful, and probably would save brakes, and brake dust accumulation. But I wonder if its harmful to the torque converter?

any thoughts?

 

I have Xenon headlights and I use daytime running lights. I think that the added advantage of being visible offset the cost of a very unlikely replacement. I have run headlights on for years on conventional bulbs and I still got over 7 years of life out of tungsten filaments. I expect that these Xenon ballasts will outlast the rest of the car.

But this is my opinion. On a side note, since I leave the lights on "automatic" I find it better for the lights to not constantly turn on and off anyway. Every time I start my car in the garage in the morning they turn on then they would turn off and so on. . . So by having them set as constant will actually be better for them (for the most part). I will also not be flashing people at dusk when the threshold of activation is intermittent.

I don't have a CDI (unfortunately because they don't come with 4-Matic) but I constantly downshift in the mountains. I have the 5-speed transmission and I know that the torque converter locks in 3rd, 4th and 5th gear. This means that even while downshifting there should be no slippage and extra heat accumulation. I drive for about 7 miles at 85 MPH in 3rd gear coming down the Eisenhower Tunnel. I have shot an infrared LASER thermometer at my transmission housing and cooler when I reach the bottom of the hill (in Dillon CO). The whole housing was barely at 80 degrees F! Also, the whole engine and radiator were quite cold (the temp gage lowering to 1/4). I guess this is because it usually between -10 and 30 degrees F outside when I drive over the mountains and the engine is just pumping ice-cold air through itself. Yet, even in the summer I have never smelled anything strange. The key to saving your torque converter while downshifting is not to shift constantly, select a good gear and keep it there. I can usually tell when the converter has locked since the RPMs change a bit on the gage.

Hope this helps,

Steve

 

Use the brakes. They're a lot cheaper to replace than your engine. I use my HIDs as driving lights in the Audi and the S2000. So far so good.

 

Trust Mercedes. Xenon lamps are more stable and less consuming of power.
If you have failure over warranty period, you can change to cornering xenon from Mbenznl....

It is better to use engine brake in the long down hillside...

 

Good opinions.. so it's basically as I have been doing..

Xenon's on all the time (in automatic) so the tail lights aren't on unnecessarily.

Downshift on long downhill to save brakes..

 

This is a very controversial and vague statement. I invite you to come out to I 70 and just use your brakes, but please tell me when you do get on the highway since I don't want to be anywhere near when you loose your brakes.

Downshifting is not a problem at all if it is done correctly. It is not even the same amount of wear on your engine since it is not burning any fuel. You are turning your engine into an air pump.

Steve

 

Steve -

I don't recall the original post mentioning anything about long downhills.

Just a question about whether or not to use engine braking via downshifting or not.

Compression braking is not free. There is extra wear on the engine from the increased RPMs. There is a slight amount of wear and tear involved with regards to the transmission with every downshift.

Of course it makes sense to use some engine braking if you routinely have some really long downhill stretches.

For day to day driving though (situations where you won't heat up your brakes by overuse) just use your brakes. That's what they are there for.

On track days and autocrosses I heel and toe mostly for the sake of smoothness. Wear (of brake pads or the engine/clutch) isn't really a concern at that time.

Normal street driving is another story.

p.s. I've never been a situation that has caused me to "loose" my brakes. One of my pet peeves is that lose vs. loose thing...

 

The original post did not really have that. But I was specific about when I DO have to downshift. I totally agree with what you said. In every day city driving you are much better off not accelerating too much and coasting while softly braking softly to the stop. I have 11,000 miles on my E and my brakes still look new.

Using the tiptronic downshifting for city driving would be a waste. Brakes are designed for that. However, there are still some people who drive in what I call "binary stile." The foot is either on the gas (1) or on the brake (0). There is nothing in between. It is these folks who I see with red-hot rotors on the side of the interstate. I also have never even come close to overusing my brakes.

I think that most of us on this board agree on this stuff after all,

Steve

 

I know a guy like that! What's worse he's a fellow pilot and taxies a 110,000lb Jet in the same manner. I've had many conversations about it with him to no avail.. he's abusive to brakes, and in the case of the Jet to ramp personal/equipment.