What is a safe rpm range to cruise at?

Hey guys, I read some other threads on this but got some mixed answers. I have a 3.4l 02 Tacoma and I just made a 2 hour trip to the beach and it was all highway drive I am running 35’s and I was a little scared to go over 70mph because of the rpm’s, they were sitting at about 2500-2600 and I didn’t know how healthy it would be for it to go any higher. Felt a little annoyed considering I had to tell the person I was following to slow down a little for me.

But anyways to the point, would I be okay to set cruise control at 3k rpm’s and just coast, or am I going to be shortening my engine life?

Ps: I just broke 200k miles as well

 

flat it should cruise at 2200-2500, but you shouldnt be scared of the engine going to 3500 if you need it to get to speed limit. My engine revs up to 4500 when getting on the hwy.

 

I’m not scared to rev it when speeding up because I know I’m just going to shift out of the high rpm’s anyways. It’s more of just a cruising range I’m wondering but I couldn’t do 2200 on the freeway I would be going just over 60 and I already get blown by going 70.

 

well what gears do you have? 4.10’s im assuming. If they are I would imagine the rpms to be lower and you really need to keep it in the pedal to power those 35’s. 3000 is pretty high for cruising unless your going up a hill. Mines usually at 2200-2600

 

I believe I might be at 4.56 gears. I did not put the lift and tires on the owner prior had done that. But with the power I have compared to other tacomas it’s pretty similar so I came to the assumption they are 4.56.

 

you can cruise at 3k but the trans is working too hard and youre waistinf more gas. Unless youre on a lil steep grade going up i dont think cruising is normal at 3k unless you are regeared but u have 35s so the rpms shouldve settled

 

Only thing I would be worrying about would be gas being close to $7 a gallon.

Higher RPM and low MPG go hand in hand.

 

I try to not go over 2500-2600 RPM with the 3.4l after MPG drops off big time. I run 33’s with 4:30 gears and get about 18-19 MPG if I keep the RPM’s in that range ~ 70 MPH

 

You're not hurting anything by cruising at higher RPM other than your wallet from the lower MPG. on the highway going 75-80 I probably cruise right at 3k - 3200 RPM.

Redline is what, 5600 or so? Still well below that

 

3000 rpm will not hurt your engine as long as your keeping after the maintenance .

With fuel prices I avoid the interstates I have no need to drive to keep up with traffic at 80 mph traffic.

 

It's a misconception that high rpm (sub redline) damages anything. If you drive in 4th gear your engine rotates the same number of times per mile whether you go 20 MPH or 100 MPH. The only thing that will suffer is fuel economy. As long as you have circulating oil and coolant that are in good condition and at the correct level, you can drive at whatever RPM you like.

 

My 02 3.4 5 speed runs about 2800rpm when running 70 on the interstate. I had the same concern but I figure as long as my MPG and maintenance are up to date, I should be fine. I averaged around 21mpg on my trip running exclusively interstate.

 

With 5.29s and 35s I try and keep it under 3400 RPM on the highway

 

Sub-redline RPMs are fine. I remember crossing North Dakota while the driver kept the cruise control at 100mph. 1997, 5spM, V6, 2WD. +2 tires. Engine still fine. Give it what it needs and the engine does what you need.

 

???

You know the cruise control sets the speed (not RPMs), right? lol

But as others have said, you have absolutely nothing to worry about running much higher RPMs. Assuming you don't have oil pressure issues or other problems (that would cause issues no matter what RPM you run), you have zero to worry about except your fuel mileage.

 

FYI for anyone new to nerding out over gears and tire sizes... the transmission is also a big part of that puzzle. The manual and auto have substantially different overdrive ratios. In other words, an auto with 5.29 gears isn't comparable to a manual with 5.29s--a manual with 4.56 is a closer comparison.



Lots of gear ratio and tire size math to be done here for anyone sufficiently curious: http://www.grimmjeeper.com/gears.html

 

I wish I knew what gears I have but my 5 speed I cruise with 30x9.5 around 70-75 mph and it's a touch over 2500rpms

 

as long as it's under redline, you're fine

 

I have a 2nd gen with 4.56s and 35s. I've been constantly cruising on the hwy at around 2800-2900rpm daily for the last several years. Besides wasting a lot of gas, 11pmgs, I have not noticed any ill affects.

 

Easy.

Count the times a rear wheel goes around for one driveshaft turn.

For example, if its 3 1/2 it’s a 3.50:1