I've got a 1970 Nova with the old chevy truck 292 inline 6. That thing will pull tree stumps. She's built to run full load all the time as they used to put those in trucks as big as 1.5 ton stake body trucks with dual rear wheels. I've got a manual 5 speed Tremec. Sometimes when I'm lazy I'll go from gear 3 to gear 5. She'll lug but keep on going. No spark knock.
What RPM do you consider lugging at WOT?
- Thread starter Avery4
- Start date
On a manual transmission car you get away with using low revs because the dual mass flywheel is smoothing out the torque pulses but you are giving the dual mass flywheel a hard time and they are not cheap to replace.
Pretty much nothing in 6th at 20mph. It may just slow to a stall if there is an incline, but once the management system is putting the correct amount of fuel to match the air, it just putts along. A bit noisier than under less load, but not lugging.
Pretty sure the Mazda 2.0 skyactiv with MT doesn’t have a dual mass flywheel. That’s reserved for fancy euro cars
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Wow! That just seems like it can't be good for the engine. Now I'm showing my age. Truth be told I currently drive a stick from the 1980's, and the newest stick I drove was a 2003 Civic in 2003. I didn't lug it.
I was curious about this when I bought my first throttle by wire car: a 2006 Toyota Matrix.
I gently got it rolling on flat ground in 3rd gear at idle speed (~700 rpm).
Then I floored the go pedal.
It smoothly picked up speed. No bucking. No excess vibration.
I suspect the computer simply limits how wide the butterfly opens at low rpm.
My previous 1988 Accord, fuel injected but with a throttle cable.
I found it would do classic lugging behavior, thanks to the time one of my cousins drove it with me as a passenger.
Thanks, now you have me I wishing I could drive one and see for myself. LOL
Yea the focus doesn't like anything under 800 rpms - it'll shake like the engine mounts are broken. The Evo was a little bit more forgiving, allowing a few hundred RPMs lower but that didn't leave much between shake n' bake and stalling.
Low compression + turbo + 4 cyl + A/C on + traffic = a lot of unexpected lugging.
A 4 cylinder rotating at 1200 rpm is producing 40 power strokes per second so these is no lugging per se.
Double that for a V8 to 80/sec. This will be true of an engine designed for low speed operation under 2500 rpm.
The modern day, current issue is that in the search for more power requires torque to be produced at a higher RPM.
so there is the intake resonance tuning to consider. A single mode air path may have little real torque at low rpm, where a dual runner system with tumble butterflies may have the ability to produce good torque at low rpm.
As far as throttling is concerned, there will be no substantial difference between 1/3 throttle and WOT at low RPM because there will be effectively NO throttling of the air at 1/3 throttle due to low air volume requirements
Other concerns are engine static compression and fuel antiknock tendency.
You don't want to load an engine with insufficient AKI at low rpm with hot air.
You have to learn you engine's torque curve and roll into the throttle when the engine is "on the pipe"
where that "pipe" is the Intake resonance tuning and the exhaust tuning combined.
To answer a question asked, when ever you load and engine it will produce more wear than at lighter loadings -
such as stead state at moderately high rpms. There fore it can be advantageous to run the engine at a somewhat higher RPM further onto the torque hump with more throttling than full load (effective WOT) the motor at a less advantageous and lower RPM.
HTH
- Ken
Double that for a V8 to 80/sec. This will be true of an engine designed for low speed operation under 2500 rpm.
The modern day, current issue is that in the search for more power requires torque to be produced at a higher RPM.
so there is the intake resonance tuning to consider. A single mode air path may have little real torque at low rpm, where a dual runner system with tumble butterflies may have the ability to produce good torque at low rpm.
As far as throttling is concerned, there will be no substantial difference between 1/3 throttle and WOT at low RPM because there will be effectively NO throttling of the air at 1/3 throttle due to low air volume requirements
Other concerns are engine static compression and fuel antiknock tendency.
You don't want to load an engine with insufficient AKI at low rpm with hot air.
You have to learn you engine's torque curve and roll into the throttle when the engine is "on the pipe"
where that "pipe" is the Intake resonance tuning and the exhaust tuning combined.
To answer a question asked, when ever you load and engine it will produce more wear than at lighter loadings -
such as stead state at moderately high rpms. There fore it can be advantageous to run the engine at a somewhat higher RPM further onto the torque hump with more throttling than full load (effective WOT) the motor at a less advantageous and lower RPM.
HTH
- Ken
ls1mike
$50 Site Donor 2024
I had the WS6 out yesterday. I was at 1300 RPM going down the highway at 62mph in 6th gear. When you put the go pedal on the floor it has no issues. Certainly no lugging. I think it has been mentioned before but drivetrain really plays into when a car will lug.
Pretty sure the Mazda 2.0 skyactiv with MT doesn’t have a dual mass flywheel. That’s reserved for fancy euro cars
You might be right but I was under the impression that all manual transmission cars now have a dual mass flywheel.
You press down on the clutch again, move from 6th to 2nd (which aren't near each other), release clutch and continue on your way
Thanks to everyone who responded, great information! My car (an 05 Civic with the 1.7 VTEC engine and 5 speed trans) runs pretty smoothly under load at about 2K RPM or higher, below that it isn't happy. It'll shake like crazy and rattle everything if loaded heavily at too low of an RPM. It doesn't have a dual mass flywheel or electronic throttle, so there isn't anything to prevent the engine from running rough when lugged. I imagine more modern cars would tolerate lugging a bit better, but it doesn't really matter to me since I don't lug it.
So would it be safe to say as a general rule of thumb that an engine isn't being lugged to the point of damage or excessive wear as long as it is running smoothly with no odd vibrations or sounds?
So would it be safe to say as a general rule of thumb that an engine isn't being lugged to the point of damage or excessive wear as long as it is running smoothly with no odd vibrations or sounds?
