Cruising regularly at 4000 rpm

[G-awesome]

4k rpm sounds better if you have a TRD exhaust...just sayin' ...but you'll probably use more gas if you driving around everywhere around 4k rpm consistently

[Jordanwolf]

Originally Posted by Hades

I don't know why everybody is assuming you're in 6th gear. I cruise in 5th at 4k+ quite a lot.

In any case, I don't think 4k RPM is enough to cause excessive wear to anything.

Really dislike this part about the MY17 final drive.

[PandaSPUR]

I don't think I'm ever below 4k when cruising.

Although, I did switch to a quieter exhaust (from Injen to HKS) because of this. Got tired of sounding like a douche at every light and every pass.

[Jordanwolf]

Originally Posted by PandaSPUR

I don't think I'm ever below 4k when cruising.

Although, I did switch to a quieter exhaust (from Injen to HKS) because of this. Got tired of sounding like a douche at every light and every pass.

In any gear? In a '15(this is what your description says)? I'm always cruising at 2.8k when I can if not slightly lower. I have a stock 17 and feel like it's working harder than it should when above 3.5k, not in 6th gear, and cruising, based on the sound it produces.

[spike021]

Originally Posted by Jordanwolf

In any gear? In a '15(this is what your description says)? I'm always cruising at 2.8k when I can if not slightly lower. I have a stock 17 and feel like it's working harder than it should when above 3.5k, not in 6th gear, and cruising, based on the sound it produces.

How would you describe "feel like it's working harder than it should when above 3.5k, not in 6th gear, and cruising"?

When that's the case for me it obviously sounds different, but that's because the revs are higher, which is.. normal? Revs will sound different at different amounts. Not sure how that would mean the engine is working harder than it should?

[StraightOuttaCanadaEh]

Originally Posted by Jordanwolf

. I have a stock 17 and feel like it's working harder than it should when above 3.5k, not in 6th gear, and cruising, based on the sound it produces.

that's exactly what I feel like lol

I mean I know cruising at a higher rpm will naturally cause more wear and tear on two identical cars. If you cracked open an engine of a car that was driven with a 3K rpm ceiling, common sense suggests that it'll be less worn out than an identical car regularly driven at a 4K rpm ceiling. What I want to know is the extent of the wear. Is it no big deal? Is it incremental? Exponential? Cause obviously it is avoidable. I can slow down. However my knowledge of factors contributing to long term engine wear is nil, so I thought I'd ask. If it's nothing to worry about, I'll keep on going. Later when I put the Edelbrock on it, that'll probably add a bit more wear, no? Cause it's like a monkey on its back.

[Clipdat]

Source?

Originally Posted by StraightOuttaCanadaEh

I mean I know cruising at a higher rpm will naturally cause more wear and tear on two identical cars.

[Jordanwolf]

Originally Posted by spike021

How would you describe "feel like it's working harder than it should when above 3.5k, not in 6th gear, and cruising"?

When that's the case for me it obviously sounds different, but that's because the revs are higher, which is.. normal? Revs will sound different at different amounts. Not sure how that would mean the engine is working harder than it should?

I don't find it abnormal in anyway, just don't feel like it's the optimal cruising RPM if that makes sense.

Plus, would RPM not directly relate to how hard an engine is working, besides lugging the engine and some other small things that can happen at strange RPM's? 0.7k idle vs 2.5k idle?

Edit: Maybe I should rephrase "working harder than it should" to 'working harder than it needs to'

[Tokay444]

Originally Posted by venturaII

I don't think that's the concern of OP. He's thinking total accumulated wear over time. And yes, cruising around at 4000 rpm WILL wear your motor out faster than at 2000 or whatever. It's simply piston feet travelled/vehicle distance.

Far too many variables at play to make such a blanket statement.

[strat61caster]

Originally Posted by venturaII

4000 rpm? That's barely 80mph, which is par for the course on most interstates. And load is certainly a factor with wear, but in this case there's not going to be a significant difference, if he's just maintaining cruise speed. Towing, accelerating, etc are a different story.

4k rpm in 6th gear is near enough 90 mph, not 80, with either F/D. OP's in Toronto, not flying acrossing the middle of bumfuck nowhere.

My statement about load was about comparing wear rates and different rpms, not OP's scenario, he'll be fine doing whatever the hell he's doing, this thread is just for the trolls now.

[Tokay444]

Originally Posted by PetrolioBenzina

I don't understand why people would assume 4k is unsafe or causes abnormal wear. OP, if you are worried about drag-racing, "you bought the wrong car".

Call it ignorance.

[Capt Spaulding]

Just to make sure we're on the same page, how fast are you going and what gear are you in. As many have pointed out, 4k in 6th is around 90mph. Where in Canada are you able to do that?

As to the wear question, I don't think you can model it as a direct relationship between rpm and wear either linear or curvilinear. It will depend on a number of other variables. (e.g. oil quality and viscosity, temp, oci) Years ago some friends and I campaigned a Honda CB750F in a series of endurance races. After 2 seasons and about 10 races, we pulled the engine down. The bores were within .001" of their original (measured) diameter. Main and rod bearings where in good shape - plastigaged out well within spec. And the transmission looked like new. And this was on an air cooled engine, in Texas, in summer, running at 10,000+ rpm WFO for between 4 and 12 hours at a time. I lightly hatched the cylinders, put new rings (just cause), rode it for a couple of years on the street and it ran like new when I sold it.

I wouldn't worry, but I'm still curious about your driving specifics. I've run my BRZ at 3500 (85mph)+ for extended times and distances, but I live in Texas. Everything is a 300 mile drive. We have 85mph toll roads.

[Overdrive]

How you maintian the engine is likely to have more of an effect than your cruising rpm habits will. If you're good about that and you don't do 20,000 mile oil and air filter changes with a track day every other day and jaunts down dusty country roads on the off days, I think you're going to be fine for a long time. As long as your driveway isn't the on-ramp to the highway and your fluids have time to heat up a little before you start your 4k cruising, truly don't sweat it. There's another 3500 rpms available to the engine, and you're looking at likely several years and tons of miles before you can even lightly perceive any sort of effect on your engine due to wear. I mean, are you cruising/commuting for 4 hours or something crazy like that?

You're less likely to have problems doing your daily cruising and good regular maintenance than the person who only drives it for a few hundred sunny-day-only miles in the summer, barely lets it stretch a leg, and packs it away the rest of the year like it's a $20 million Ferrari GTO.

The only thing that'll really be hurting from sustained 4k compared to sustained 3k is fuel economy. Just the price to be paid for quicker acceleration. If you have to cruise at higher speeds to avoid being a hazard on the road going 20mph slower than everyone else, so be it.

[StraightOuttaCanadaEh]

Originally Posted by Capt Spaulding

Just to make sure we're on the same page, how fast are you going and what gear are you in. As many have pointed out, 4k in 6th is around 90mph. Where in Canada are you able to do that?

I'd rather not say how fast I'm going, but I will add this is pretty much the staple left lane speed around these parts. But I am in 6th gear when I am at 4K. Thanks for your post and the technical details, it looks like there isn't much to worry about.