Running uphill in 6th gear == bad for oil?

[Quattro Pete]

Originally Posted By: blackman777
Jetta.

Would it hurt you to provide engine type? You might consider putting that info in your sig so it's always there for everyone to see what the reference is.

 

[eljefino]

The way to do it would be to get a scangauge and hit the same hill under similar weather in different gears. Anything else is armchair engineering.

 

[sciphi]

You guys would crucify me. I routinely (like 3-4 days a week) go up a very large hill in 6th gear at ~1750 RPM/55 mph. There's no predetonation since the timing's steady instead of jumping all over, and the turbo's making about 7 PSI. I could shift to 5th at about 2200 RPM, but that's wasting fuel in this Ecotec 1.4T.

 

[volk06]

On the gallons per hour read out on the tractor, I burn less fuel (9gal/hr) with a load at WOT in a lower gear(6) than 3/4 throttle (11 gal/hr) with the same load in a higher gear (8).

 

[getnpsi]

realtime readout is the best way to see for sure. slowing down to 60mph vs 70 or 80 on a climb is going to be better in any gear. Older cars on flat ground tend to max out timing at 2400rpm so shoot for under that unless you need to go around traffic at moment's notice. I also break with logic and hit the gas hard before the crest of the hill to coast longer, it's all timing if you know the terrain like back of your hand. For example dropping from 24 to 18mpg at the peak is rewarded better if you can coast an extra half mile doing 70-100mpg rather than back to 30-40 downhill. If that is the the way to work or home it pays in the long run to get habits down like that.

Steady timing doesnt mean optimum, the ecu could have set it lower already. It just takes a knock count to take away several degrees, in split seconds. Lugging a turbo engine doesn't hurt it any different than any other, but factory fuel maps might be dumping more fuel. If it sees boost it's worse for the wallet for the most part.

 

[donnyj08]

From what the OP posted, i find it hard to believe the engine was lugging. If in fact the engine were lugging i find it hard to believe that it would accelerate from 65-80mph. if the car would not accelerate under heavy top gear throttle, it would be lugging.

Being able to pick up 15mph going uphill in 6th gear is far from a lug in my opinion.

 

[TomYoung]

You have a lot of answers here, and I think that the consensus is that you did nothing wrong. You were gaining speed, and the engine was turning at a good clip.

There is also a movement afoot to keep efficient by shifting low and slow (especially in diesel trucks with progressive shifting). My 87 Carrera has a much-ignored, highly irritating upshift light that instructs sub 2000 rpm shifts.

All that said, I would ask if staying in sixth gear "felt right," or if you had any sense that there would have been a lot less drama going to fifth.

My belief is that the car is happier in the long-term with gentle treatment, including the well-considered downshift. Let the flames fly!

 

[heynow]

Originally Posted By: Brenden


Hitting WOT and going uphill to gain speed (60-80) is waste of fuel, can't believe you guys are even asking how that's a waste.


It has already been said, but it's worth repeating. WOT is usually when the engine runs most efficiently. Most modern vehicles do not significantly enrich A/F ratios at WOT for emissions reasons.

And how is going 60-80 up a hill a "waste of fuel"? I suppose any driving could be considered a "waste of fuel". Maybe he should have stayed home or just pulled over when he got to the hill?

 

[SwampSurvivor]

Originally Posted By: TomYoung
You have a lot of answers here, and I think that the consensus is that you did nothing wrong. You were gaining speed, and the engine was turning at a good clip.

There is also a movement afoot to keep efficient by shifting low and slow (especially in diesel trucks with progressive shifting). My 87 Carrera has a much-ignored, highly irritating upshift light that instructs sub 2000 rpm shifts.

All that said, I would ask if staying in sixth gear "felt right," or if you had any sense that there would have been a lot less drama going to fifth.

My belief is that the car is happier in the long-term with gentle treatment, including the well-considered downshift. Let the flames fly!


and maybe not running it wide open up a hill unless you're doing an Italian Tuneup?

 

[Malo83]

Your clutch thanks you

 

[Eddie]

You did nothing wrong. WOT probably equates to best efficiency and you were not lugging.

 

[Clevy]

Originally Posted By: blackman777
Originally Posted By: Brenden
CarNoobie is that you?


HA! No but I guess I am a newb. I thought wide-open throttle was the engine's most efficient state (like a diesel: no pumping losses).

In general I try to avoid shifting so I don't wear-out the clutch and have an expensive $1000 clutch replacement later on
.

Rev match. Don't need the clutch.

 

[Boatowner]

Originally Posted By: supton
Sure, it's a waste. But what burns more fuel: WOT in a high gear, or half-throttle in a lower gear / higher rpm, with same acceleration rate?


If you have a pyrometer and mpg calculater you can see as you drive how you are doing. That WOT hard running up the hill is running your exhaust gasses at around 1,000 degrees. If you downshift you will see your mpgs go up slightly, or at worst not change while going easier on your engine.

There is no way shifting wears out a clutch prematurely.

 

[cutter]

If I do anything wrong in 6th gear, my car will audibly let me know it's bad.

 

[wolfc70]

I would drop to 5th. Shifting gears if done properly, does not wear the clutch. At the 2000-3000 rpm range the engine is designed to operate efficiently at lighter loads. Running WOT at those rpm's does drop the pumping losses, but the engine is still out of its optimum volumetric efficiency range, so it is not making full power efficiently. Spark ignition engines are most efficient at WOT and in the power band, usually between the torque peak and the HP peak. Spinning an engine does not hurt it. If it was my car, I would drop a gear or two.

 

[Lead Shoes]

Originally Posted By: Christopher Hussey
Originally Posted By: Brenden


Hitting WOT and going uphill to gain speed (60-80) is waste of fuel, can't believe you guys are even asking how that's a waste.


It has already been said, but it's worth repeating. WOT is usually when the engine runs most efficiently. Most modern vehicles do not significantly enrich A/F ratios at WOT for emissions reasons.

And how is going 60-80 up a hill a "waste of fuel"? I suppose any driving could be considered a "waste of fuel". Maybe he should have stayed home or just pulled over when he got to the hill?



People splitting hairs, changing how your post was meant to be interpreted and starting petty arguments is why I don't get caught up in these long threads.

I'm only going to say it one more time.

Staying at 60mph or at least dropping down a gear to go from 60-80 on a large incline would yield better MPG than trying to accelerate from 60 to 80 at all or doing it in top gear, PERIOD.

For the naysayers, get a Scangauge II and test it yourself like I have. I use mine a gather a lot of data on driving techniques, and I can assure you dropping down a gear to 4th and using 50% throttle to get up the hill is better than staying in 5th and using 100% throttle in all of the vehicles I have DD'd with my Scangauge.

 

[blackman777]

I've heard that turbos can "rev too high" if you push them too hard (while below 2000) but maybe that's just a flaw with VW's TDI engines? Peak fuel economy/efficiency is 1600-2400 for my non-turbo engine.
Originally Posted By: Brenden
Staying at 60mph or at least dropping down a gear to go from 60-80 on a large incline would yield better MPG than trying to accelerate from 60 to 80 at all or doing it in top gear, PERIOD.
I wasn't trying to accelerate. I was simply trying to maintain speed, but the engine slowly crept from 65 to 66 to 67 to 68 while I was distracted (watching the other cars). Today I climbed the same mountain, but in the opposite direction. The steeper slope made the 6th gear slowly drop from 70 to 69 to 68 to 67 and then I hit the peak, and it crept back up again.

ANYWAY I doubt I'm harming the engine as long as it's spinning >2500 rpm. Oh and the instant MPG Gauge showed 20 MPG. That's better than a lower gear has given me in the past.
Thanks everyone.

 

[bionictony]

is this the 241 toll road? going southbound uphill in 6th gear i can maintain speed of 65mph at about half throttle. If i WOT it does nothing. if i shift up to 5th gear it will rev up to 4k rpm. going northbound the hill is steeper. i have to go up this hill in 5th gear. if i use 6th, my speed will decrease very slowly while going uphill. i'm driving a toyota matrix xrs with 2zz-ge engine.

 

[ueberooo]

this is close to right but not true, you want to be a little bit to moderately below WOT:
Originally Posted By: Eddie
WOT probably equates to best efficiency and you were not lugging.



Originally Posted By: eljefino
It would have been better to drop to 5th and run 80% throttle.
[....]
The definition of lugging is if your cam and valves can't use more air to make more power even if you open the throttle more. I don't think you were "there."

I'm going to stick this BSFC map in. I can only begin to explain it.

Basically it's a map of engine efficiency for input vs output, your scenario puts you in or near the "red blob" assuming your engine is cammed/ valved/ set up like a Saturn 1.9 16V. This sort of applies for many econo box normally aspirated smog american motors.,


Hey, great info and chart eljefino. You can see this 4-cyl engine peaks in torque around 3000 rpm, and the sweet rpm spot for specific fuel consumption sits below that torque point by a thousand rpm or so, at around 2000 rpm. This darker reddish circular area (call it the "sweet spot") also sits higher to on the vertical axis--but not at the very top most part, meaning that the engine is running at peak efficiencies near wide open throttle (near WOT); it is actually less efficient at WOT (as the fuel has a harder time finding o2, and the computer actually allows for a richer mix of fuel:air where there isn't possibly enough air for all of the fuel).

The wider yellow area is still a very efficient area of operation; the RPM range this area spans is roughly 600 rpm to 3250 rpm. Thus, if you want to drive economically, don't take your rpm a way over the peak torque rate (like, say, over 4000).

The most inefficient (bsfc-wise) area of operation would be when you are near idle-throttle (bottom part areas) and that's when the pumping losses come in (your engine is working as a large vaccuum pump). However, running at, for example, half throttle is not at all very close to that area we want to avoid.

( I actually think the OP did okay, running it where he did. Maybe the only thing he could've done better is laid off the pedal just a bit. I do that sometimes, loose speed up the hill, and drop below 55 (or 50) and put it from 5th to 4th (or even 3rd). )

 

[Gotch]

Lugging can occur at higher rpm. There is a lot of misconception out there that it only occurs at low rpm. The definition that I was taught (College - Motive Power course) and we tested on our in-house dyno, is that lugging is when the throttle is at 100% and you lose rpm. The highest stress occurs at the engine's torque peak (where it is most efficient). When lugging takes place at the torque peak the BMEP is also at its highest. This is where the most wear and stress occurs. Higher rpm lugging is not as hard on the engine due to it being less efficient and more oil pressure is available (typically).

Long and short of it is that if you are losing rpm and increasing throttle doesn't help, drop a gear (or two) and your engine will thank you. If you can gain rpm, you are not lugging.