[Boost Creep]

Originally Posted by kropscamaro16

lol i never even use 6th gear because the drone is so bad

I'll go for sixth at 50 mph if just cruising. I guess one advantage to the stock exhaust.

[DaveC113]

Originally Posted by Ryephile

Go drive an automatic transmission version of the engine you have. Observe the ratios selected for given engine loads and torque request. This gives you evidence of what the OEM deems acceptable engine operation. You will find that at low load the RPM is at low BSFC / high fuel economy, and at high load the RPM is at peak torque to the axle.


You won't find an OEM admitting exactly what "lugging" is, it's too vague a term and is mainly a catch-all term to give them an easy legal path for warranty denials. If the oil pressure is too low and causes metal-metal contact in the bearings, then the engineers failed to design the pump correctly. If there's LSPI, then the combustion chamber was incorrectly designed and ECU calibrators failed at their job.

Autos can cruise at lower rpm vs a manual but I agree it'll give you an idea, the LT1 can operate at really low rpms!

I disagree w/ the 2nd part though, if you have a manual it's your job to be in the correct gear and avoid lugging or overrevving. If you choose to go WOT at low rpms in 6th gear it's your car and your fault if damage is done imo.

[cbr1100xx]

That's one thing I liked about my '15 GT PP that comes with 3.73s. The shorter gearing means more shifting but 6th gear on the freeway was awesome. As long as you were going 65, you had power in 6th b/c it revved higher. Yes, gas mpg suffered on the hwy but I don't enjoy driving at 1600rpm on the hwy in a tall 6th gear anyway.

I didn't like that the GT manual transmission makes a burping like noise when you shifted the car going at reasonable speed but that's another story......

[Ryephile]

Originally Posted by Vtor_ZL1

Comparing automatic and manual for load is... not the same...

The ECU strategy disagrees with you. Load is load, and torque request is torque request.

Originally Posted by DaveC113

I disagree w/ the 2nd part though, if you have a manual it's your job to be in the correct gear and avoid lugging or overrevving. If you choose to go WOT at low rpms in 6th gear it's your car and your fault if damage is done imo.

Let's just go with your assertion. Exactly what damage is occurring, and at what RPM are you referring to? The ECU strategy meters out specific amounts of torque from idle to rev-limit, on top of the excellent knock strategy to account for varying fuels and carbon build-up over time.

If you're trying to go full-load at 400 RPM, then I'm afraid the calibration just isn't designed for that, though it will extrapolate from its plausibility calculations. By your assertion, the ECU calibrators have no control over how the engine operates within its designed RPM band. That's simply untrue. If this conversation was happening 25 years ago with the old LT1, certainly it would be less scientific, with poorer understanding of LSPI, knock, and poorer implementation of knock strategies, and essentially no control of load due to cable throttle.

Let's try to separate human-perceived NVH from measurable LSPI or knock. Just because the chassis is resonating does not necessarily indicate something inappropriate is happening within the engine.

[kjchristopher]

Originally Posted by Ryephile

You won't find an OEM admitting exactly what "lugging" is, it's too vague a term and is mainly a catch-all term to give them an easy legal path for warranty denials.

I've seen it defined (by Cummins? - going by memory so it may have been another manufacturer) as 100% torque demand when the rpms will not increase or are decreasing.

I've also seen direction from Cummins (in their ISL manual) to not request 100% torque below peak torque rpm.

[Nsxmatt]

These same engines are in 6000lb trucks towing 12,000lbs lugging up hills all day. People just like to overthink things. Just drive the car... even if it's 6th gear all day.

[Boost Creep]

Originally Posted by cbr1100xx

That's one thing I liked about my '15 GT PP that comes with 3.73s. The shorter gearing means more shifting but 6th gear on the freeway was awesome. As long as you were going 65, you had power in 6th b/c it revved higher. Yes, gas mpg suffered on the hwy but I don't enjoy driving at 1600rpm on the hwy in a tall 6th gear anyway.

I didn't like that the GT manual transmission makes a burping like noise when you shifted the car going at reasonable speed but that's another story......

SS has 3.73 gears.

[SSDan]

Originally Posted by Nsxmatt

People just like to overthink things. Just drive the car... even if it's 6th gear all day.

I agree. The car will tell you when its in too high of a gear for the rpm its at when you add throttle. It will lurch or buck a little - that is what I have always called lugging an engine. Just shift down a gear when you sense that and move on. I have never understood why people want to highway cruise at 65-70 mph in fifth gear. Why spin the engine at a higher rpm and waste fuel when the car cruises just fine in 6th at those speeds. Don't flame - I didn't buy the car to hyper mile it. When I want to have fun I let that LT1 eat and mpg be damned. Otherwise why not cruise in sixth gear.

[cbr1100xx]

Originally Posted by Boost Creep

SS has 3.73 gears.

True but different engines and the Camaro still has taller gearing compared to a Mustang GT PP w/3.73s. There's a very noticeable difference in rpms driving the 2. The GT has much shorter gearing overall.

[cbr1100xx]

Originally Posted by SSDan

. I have never understood why people want to highway cruise at 65-70 mph in fifth gear. Why spin the engine at a higher rpm and waste fuel when the car cruises just fine in 6th at those speeds.

Because the car feels dead at those speeds at 1600rpm or whatever. It's nice to tap the gas and feel "something".

[JamesNoBrakes]

Originally Posted by cbr1100xx

Because the car feels dead at those speeds at 1600rpm or whatever. It's nice to tap the gas and feel "something".

#YouShouldHaveBoughtAnAutomatic

[MATTY-1LE]

My semi rule of thumb is to get on the freeway in fifth, and leave it there til i find my lane and then shift to 6th. And to be honest at times i leave it in 5th if i am trying to get in and out of traffic. In either case i usually never go below about 1400, just doesnt feel right

[TJay74]

Originally Posted by Boost Creep

Lugging puts a lot of load on the bearings when you have the least oil pressure down near idle.

Really you don't want to do any kind of heavy acceleration under 1500-2000 or more. Light throttle is fine down low, but the more throttle you want, the more rpms the engine wants.

These engines put out around 30psi of oil at dang near idle, bearing will see no more load than they would normally. Engine doesnt care about high load from off idle to redline either, it is all about the gearing and load on the engine.

One of the issues with lugging the engine at low RPM's and high gearing is engine detonation. The higher the gearing and the lower the RPM you are at the higher the potential for detonation which can lead to engine damage.

[torqueaddict]

From the owner's manual:

. Do not let the engine labor.
Never lug the engine in high
gear at low speeds. With a
manual transmission, shift
to the next lower gear. This
rule applies at all times, not
just during the break-in
period.