Driving Hard?

brianpavlovic · May 11, 2005

Just curious about driving hard....

I drive mostly highway miles everyday to and from work, would highway driving be considered "Hard Driving"? The car never gets past 70 mph?

moribundman · May 11, 2005

If you are talking about smooth highway cruising, then no, this would not constitute driving hard. However, maybe you bust out of your driveway and race up the on-ramp, then weave in and out of traffic in second gear at 70 for the next 45 minutes...

brianpavlovic · May 11, 2005

No, in fact my 05 GLI 1.8T never sees engine rpms over 3000! I actually stay at a constant 68 mph. I am just concerned because I have never owned a turbo motor and I want this car to last. I am now using GC and I am thinking about using Voll Synthese 5W-40 by Lubro Moly. There is NO moly in it and from what I have been reading, it is pretty good stuff. Any thoughts?

Patman · May 11, 2005

"Driving hard" means you're going full throttle at least 4 or 5 times (or more) a day, IMO.

moribundman · May 11, 2005

quote:

my 05 GLI 1.8T never sees engine rpms over 3000!

Well, you should run the engine up to the redline at least on occasion. This engine was made to be driven in a sporty manner. I would also avoid cruising for prolonged time on cruise control. Vary the speed (RPM) at least a little on occasion. If you have never run the RPM up to the redline you may one day be unpleasantly surprised if you eventually do redline the motor.

Not that LM is bad or anything, but you can do at least as well with some other, easier to find oil. I'd use a full synthetic VW502.00 rated oil. GC is a fine choice. Why switch?

Quattro Pete · May 11, 2005

quote:

Originally posted by brianpavlovic:
No, in fact my 05 GLI 1.8T never sees engine rpms over 3000!

Wow! You should have bought a diesel.

This engine is fun ABOVE 3K rpm, not below. Like Mori said, I would make sure to let it stretch its legs at least a few times a week.

As far as "driving hard" in regards to turbo, it's not what rpms you reach, but how fast you get there. Your turbo already kicks in at around 2K rpm, so if you floor it from 2 to 3K rpm, you're making the turbo run pretty hard - you're in full boost. That in itself is not a problem, just don't shut off the engine right after doing that, and never do it on a cold engine.

Cruising at a steady 70 mph is not considered "driving hard" by any means, unless you're going up a 15% slope all the way.

[ May 12, 2005, 08:24 AM: Message edited by: Quattro Pete ]

drive it forever · May 11, 2005

Freeway driving are the easiest miles for a modern engine in a car that has an overdrive tranny.

VaderSS · May 11, 2005

quote:

Originally posted by Patman:
"Driving hard" means you're going full throttle at least 4 or 5 times (or more) a day, IMO.

In the Impala, that's about right. Any more than that and the tires don't make it to 28k...

For the Festiva, it spends a good portion of it's life at WOT. Amazing the abuse it can take. Interstate is IMO, harder on it than city, and that's reflected in the fuel economy I experience, low 30s. 'course, if I slow down to the speed limit, it does feel like it's loafing and the fuel economy can get as high as 41. Top speed for it, in OD, is about 95, and I tend to run 80-85... Those speeds are loafing in the Impala though.

ruking77 · May 11, 2005

Oh gosh NO! From your description you have the "easiest" of miles. This is easiest on the engine and transmission and brake systems. You can go the longest between OCI's! Life is good!

The only thing you should probably think about are the proper procedures for turbo longevity. One of my cars is a VW Jetta TDI (turbo diesel). So in fact, I am walking the walk. There are subtle differences between the turbos on a gasser and diesel, but there are a lot of similarities.

At some intervals, you will want to go 3000-3500 rpms(you can go to redline, but this will do well also) to fully boost the turbo. Also physically you are fully opening the vanes so they do not get stuck and operate poorly. Also with todays turbos you really don't have to idle it "separately" at shut off. So for example, at freeway RPMS of 2800-3000, as I come off the RPM's to take a freeway exit, I will do a 1 to 2 min time hack. So by the time 1 to 2 min passes, you are usually at your destination and ready to shut down. So in the above case if you are hitting a rest stop at shorter intervals of 1-2 mins then just idle long enough to commplete one to two mins. While just idling does not hurt anything, you are passing gas and in the long term, this is a lot of gas at idle, with "no work accomplished".

[ May 12, 2005, 11:04 AM: Message edited by: ruking77 ]

Geoff · May 11, 2005

You have bought a car engineered to run near its redline for extended periods. The Germans won't buy a car the size of the Golf unless it can sustain 100+ mph. A 1.8L is a big (read: performance) engine in Europe.

At 68mph you might require 40-50 hp. This and the constant throttle make for an easy life for the engine.

VaderSS · May 11, 2005

The amount of power it takes to go a certain speed depends on many factors, including driveline losses, rolling resistance, coefficient of drag, frontal area...

At any rate, my 63HP Festiva, which has a poor cD, but small frontal area, will do about 105 in 4th gear, near the HP peak. Roughly 63 HP to do 105. Again, small car, poor cD, YMMV...

Does that mean it takes 31.5 HP to do 57.5 MPH? No, drag increases exponentially, not linearly. It probably takes less than 12 HP to push 60 in the Festiva. That's why the fuel economy goes to pot so quick. I'm not feeling very "mathy" today, so I'm not going to dig up the formulas...

Mitch Alsup · May 12, 2005

quote:

Does that mean it takes 31.5 HP to do 57.5 MPH? No, drag increases exponentially, not linearly. It probably takes less than 12 HP to push 60 in the Festiva. That's why the fuel economy goes to pot so quick. I'm not feeling very "mathy" today, so I'm not going to dig up the formulas... [/QB]

Not quite: aerodrag measured in HP increases with the cube of speed (s**3) and when measured in TQ increases with the square of speed (s**2). Exponential is reserved for things that increase a lot faster than squared or cubed..

XS650 · May 12, 2005

quote:

Originally posted by VaderSS:

Does that mean it takes 31.5 HP to do 57.5 MPH? No, drag increases exponentially, not linearly. It probably takes less than 12 HP to push 60 in the Festiva. That's why the fuel economy goes to pot so quick. I'm not feeling very "mathy" today, so I'm not going to dig up the formulas...

Assuming the 105mph is actual top speed and not speedometer top speed....

About 15 hp for 60 and 19.5 hp for 68.

Power required is proportional to speed ^2.7 as a good approximation that included rolling resistnce and aero drag.

[ May 12, 2005, 02:13 PM: Message edited by: XS650 ]

VaderSS · May 12, 2005

Did not know that exponential did not apply to squared and cubed. LSNED

The 105 is drag limited and based on the tach. Speedo goes to 85.

XS650 · May 12, 2005

quote:

Originally posted by VaderSS:
Did not know that exponential did not apply to squared and cubed. LSNED

They qualify as exponential functions, so unlearn what you just learned

burnout · May 12, 2005

Why'd you buy the 1.8T if you don't want to drive fast anyways?

Or is your under 3000rpm rule only for break-in?

Driving fast and going full throttle won't harm the engine as much as you think, as long as you keep up maintenance. I drive my saturn vue like a race car, but I properly warm it up, change the oil very frequently, and use the best filters/oil.

Mitch Alsup · May 12, 2005

quote:

Originally posted by XS650:

quote:

Originally posted by VaderSS:
Did not know that exponential did not apply to squared and cubed. LSNED

Click to expand...

They qualify as exponential functions, so unlearn what you just learned

No, no, no, no!

Exponential is e**x :where e is 2.71....
Squared is x**2
Cubed is x**3

While squared and cubed have exponents, those exponents are constant; while in exponential function it is the variable that is in the exponent. This makes all the difference in the world when x gets usefully large. Indeed, it takes an infinite series of terms with exponents to model an exponential function of a single term!

JMK3rd · May 12, 2005

quote:

While squared and cubed have exponents, those exponents are constant; while in exponential function it is the variable that is in the exponent. This makes all the difference in the world when x gets usefully large. Indeed, it takes an infinite series of terms with exponents to model an exponential function of a single term! [/QB]

I was just about to say the same thing!

brianpavlovic · May 12, 2005

Well, I just bought the car in March and I want to break her in easy. I will say this, this is my first german car / 1.8T, but I love it!!!!! Once the break in time is complete, I will probably drive it like it was supposed to! The car has 1500 miles!

Mitch Alsup · May 12, 2005

quote:

At 68mph you might require 40-50 hp. This and the constant throttle make for an easy life for the engine.

I bet at 68 MPH he needs closer to 4 or 5 HP to overcome aerodynamic friction and rolling drag.

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