YM13

I have a 5spd on the yota and I get mad at watching all of the other cars pass me on the highway because I cannot bring myself to let the RPM's go over 2,500 for a long period of time. At 2,600 RPM i'm riding at around 70 MPH...I guess my question is is it ok to go at lets say 3,000 RPM and how much damage/wear would that cause on my engine (if any). It just seems if I ride at 3,000 RPM for 2 or 3 hours, then i'm taking away a good bit of life from my engine...is this speculation correct or am I just worrying too much? (I guess I have the low gears on my yota?)

02SE

I have the same drivetrain in my '97 4Runner. It's had no problems at all in nearly 10 years of ownership. In fact, I think it drives just like the day I bought it.

Just perform the routine maintenance, (oil changes, etc.) and it will be just fine.

Yes, IMO you are worrying needlessly.

89macrunner

My 89 4runner ran 3k rpms in 5th gear going 70.

Just add some bigger tires and calculate the speedo difference.. thats what I did.. haha

CoedNaked

Yeah you honestly got nothing to worry about. Superior gearing comes at a price and that is slightly higher RPM's at highway speeds, but if you keep it maintained you won't have any issues what so ever. If you're concerned about wear, look into synthetic oil.

Consider that your 4runner probably has 4.10 or 4.30 gears.

My 93 Truck which has the exact same transmission as you (with afew modificatins to fit the 3.4 engine - a variant of the R150F I have behind my 3.0) has 4.56 gears and with 31" stock tires which I have, I am turning about 2950-3000 RPM's while going about 70 MPH. I usually try and keep 'er at about 2750 RPM's though and cruise about 60-63ish MPH in most cases. And the engine holds up beautifully.

Also consider that while the engine is revving a bit more on the highway, that it isn't working as hard with your rear end gear ratio because it amplifies the engines torque that much better making the engines job easier. So yeah she's revving a bit more than you'd like, but she's not working as hard at those rev's with the 4.10 or 4.30 gears you probably have. (I'm guessing 4.10's).

I personally wouldn't worry about it.

Remember though that someone did say about highway driving that as soon as you go above 55 MPH - wind resistance starts to increase dramatically which causes excess drag. So you could also slow down slightly to say 65 MPH or so and it'll be the best of both worlds.

SteveO

Read this thread, then perform the calculations for your rig, and put yourself at ease.

https://www.yotatech.com/forums/f31/rpms-36s-4-88s-vs-5-29s-113649/

pat161

I wouldn't worry about it at all. My 00 w/ the 2.7 5 speed and 4.56 ran over 3,000 anything 70 and over, never missed a beat in 100k, it would still be going strong had I not wrecked it.

RustBucket

iTrader: (1)

These smooth, OHC, japanese engines can cruise at 3k all day!

rdharper

If you previously owned a big american V8 (probably a gas-guzzler), I can see how you'd feel that way.

As others have said don't worry about it.

First time I was exposed to this was in a 1964 Porsche S90 Cabriolet. Specific instructions in the manual stated you should keep the rpm's *above* 3k rpm's during break-in.

And note that F1 cars are limited at 19K rpm's not because of inability to handle higher rpm's, but as a cap on power. They don't break either.

Happy motoring!

crolison

Yeah i havea 97 4runner 2.7 5speed with 4.556. I cruise at 70 at around 2700ish, and at about 2950 i hit 75.

Pest

Actually, it is much healthier for a motor to be running at high RPM, even 4k or higher for for extended periods of time at a constant speed as opposed to the constant up down up down from city driving.

It helps both the motor and the transmission. It's the same principal behind driving the highway up into the mountains. You're better off leaving it in 4th or 3rd at high RPM going a little slower than trying to be the pace car and constantly jumping between gears to maintain speed.

You can also look at racecars. I'm no expert, but I'd be willing to bet that NASCAR's (the ones that just drive in a big circle) endure less engine problems/maintenance than the Indie or Rally cars do (the ones that are much more entertaining to watch with actual driver skill...lots of turning, speed variation, etc.).

pruney81

My fifth gear went out in my 86 4Runner a few years ago and I ran it at 4k RPM's at 70 miles per hour for an entire summer and it handled it fine.

CoedNaked

Plus - the higher RPM's put the engine towards it's torque peak which is a more efficient "state," plus it's good to run a nice extended cruise at reasonable RPM's to help blow some carbon out of your engine.

Before Toyota puts a new engine in a vehicle, they will run it at 5000 RPM's for I think it's 3 or 5 minutes straight.

YM13

Thanks guys, wonderful information...this has turned my opinion somewhat but I am still wondering if it will take away some time away from my engine because of the extra wear...because the piston is moving faster doesn't that mean that the engine is wearing away faster? or is it insignificant? Thanks again

Elton

mines right around there

CoedNaked

If your piston is going through more strokes in a given time speed i.e. you are revving your engine higher, it means there is more heat being generated. But because your water pump runs on the serpentine belt, it is also cycling the coolant through to compensate for the increased heat from the added cycles so as long as your cooling system is healthy you're fine.

Also consider that if your engine runs slightly hotter, say a few degrees hotter, it will thin your oil out a bit. But this isn't neccessarily a bad thing. First off slightly thinner oil flows better, which goes hand in hand with heat expanding thing/tightening clearances, whcih means it can fit into tighter spaces and lubricate well. But also remember that you do have an engine oil cooler where your oil is cooled by coolant so assuming again everything is in reasonable shape you shouldn't have any issues.

Also remember that when you are cruising your engine isn't working as hard because it only has to maintain the speed of the vehicle it doesn't have to change speeds. That is why someone who has driven a vehicle on the highway a lot with more K probably has a vehicle that is in better shape than one that is started and stopped all day and goes through the rigours of constant accelerations in the city where the engine has to work harder.

rdharper

No question a lower rpm engine will wear less... period.

However, as you suggest, the engine lifespan is not likely to be determined by the higher wear rate due to the higher average rpms. There are a bunch of tradeoffs.. power/efficiency etc.

If you were looking for literally a million miles on the same engine... get a big caddy v8 and take care of it. Its been done.

If you are looking for 300k with good maintenance... you have a good chance with a Toyota.

Remember the F1 case? They want the engine to reliably run one race at least. But power/efficiency is maximized at very high rpm... limited at 19krpm currently... for the expected lifespan.

Tradeoffs.

Lastly consider a case I know well. I have a hydro system running 24/7.. now going on 32 years. Main bearings in the big generator have never been replaced.... nor even lubiricated. The system puts out 3hp in 120AC 3 phase power. How is that possible?

Well the generator is rated at 5KW, we run it at 2.1KW (determined by the water head available which is a pretty steady 140lbs).

Also... most generators run at 60hz (3600rpm). This system (an old WWII design) runs at 1200pm and uses huge sealed timken roller bearings.

This generator is huge, heavy and built to last.

Tradeoffs.

Mark in MD

Comma, I started a thread about a week or two ago, asking opinions on gear selection and engine wear on a cold engine climbing a steep hill. The conclusion was higher RPMs would wear less in this instance, since the oil pump is pumping more oil, and the combustion chamber pressure would be less at higher RPMs.

In response to the first post, when I run to the beach every August, I get off I-95 and onto I-40, headed East towards Wilmington, NC. The interstate is straight and under-used, and doing 90 mph is easy. My old 3.0 would be steady at 4,000 rpms at that speed for about an hour or so. With A/C.

No problemo.

P.S. Watch out for radar around mile marker 410.

rdharper

Of course my comments were with reference to the life of the engine.

As to the specific case you mention... no question that 90% of wear occurs in the first 3 minutes after starting the engine.

My recommendation... if you live near an uphill load, or near a freeway... consider a 5w 30 or 40 oil, and let the engine warmup before you move it... on a cold day. Or even on any day, before leaving your driveway.

Once the engine is warm.. anything above 2k is fine.. high or low.... doesn't matter. (imo)

Mark in MD

Thanks. Yes, I already use 5w-30, per the manual.

I agree in general that "warming" the engine before driving it is a good idea. But I'm a little unsure about it because of the other argument that says starting an engine and letting it warm up too long is bad for the engine. And in three minutes while parked in the morning, I'm not sure if I see any movement in the engine temp meter.

Also, in this new truck, the gear selection recommendations are in incredibly low RPMs, which is unlike any vehicle I've ever driven. It's got me shifting from below 2,000 into 800 to 1,000 rpms. I've never seen anything like this, and tried to get some comments on it, but not many people had anything to say.

Here was my thread:

https://www.yotatech.com/forums/show...highlight=gear

Thanks again

rdharper

Read a bit of your other thread.. I understand your question/concern.

Letting the engine warmup for 1-2 minutes is fine with a 5w oil. The idea is to make sure you have oil pressure up... and circulating.

As to Toyotas low rpm recommendation... That is a 4 liter V8? or V6. That is a fairly big engine. I believe what they are saying is take it easy on the rpm's during break-in. Generally good advice, although lots of people will tell you that modern engine tolerances makes this old advice unnecessary. I suspect that Toyotas caution is probably correct. At least observe there upper shift point during break-in.

I'd say 2.5-3K is a good range for your hill. If you have a full load, let it warm up a bit longer, increase the rpms a bit.

All things considered... I suspect you are in good shape.

Btw, one more thing.. you might consider synthetic 5w-30. Mobil or Shell both make good synthetics. That buys you a better shot at the oil performance remaining constant between changes. And probably means a real 5w at startup.