Safe Cruise rev??

[NismoDan]

Ok, so I drive from LA to San Francisco a lot nowadays and was wondering what you guys thought was an ok RPM to let my KA cruise at.
All I have on it is an AEM short ram intake, and the engine has always seemed pretty stout.

For reference, I was in my friend's Explorer when we drove from LA to SF recently, and he was going between 85-90 mph while pretty much having his tach sit right at 3k. Now, at the same time, his engine redlines at 5.5k or 6k.
So I figured, if he can go to 3k out of a possible 6k before redline, should I be able to sit at 4k rpm and not have my engine explode?

Thanks!
:2f2f:

(What was kind of sad was that because of my reluctance to rev my KA any higher than 3.5k...my friend in the Explorer beat me from LA to SF! :duh: )

[silviasichigo]

:tweak: just wondering what is your reasoning behind this question besides the engine blowing up thing? Have you ever actually made that particular drive? and during this drive did the thought occur to you to look at your Tach? I am just wonderingin any event in 5th gear at 80MPH 3500-4000 should be a normal crusing rpm, But since I am in Japan I can't really actually cruise at that speed for very long. that is just my edjumacated guess.

[aznpoopy]

i usually drive a bit over 3k around 75-80mph. naturally if u want to baby the engine keep the revs lower.

[NismoDan]

:tweak: just wondering what is your reasoning behind this question besides the engine blowing up thing? Have you ever actually made that particular drive? and during this drive did the thought occur to you to look at your Tach? I am just wonderingin any event in 5th gear at 80MPH 3500-4000 should be a normal crusing rpm, But since I am in Japan I can't really actually cruise at that speed for very long. that is just my edjumacated guess.


Umm...yes...I make the drive quite often, actually.
My home is LA, but im in SF for college.
The reason for asking is that I'd rather not force my trips to be any longer than they have to. That is, I'd like to know how high you guys think would be OK to keep my KA at on the freeway. I don't like going only 80. 80 on the 5 North gets you passed hardcore.

[crioten]

highway driving is a LOT easier on your engine than say driving from stoplight to stoplight...

that is only if everything is working pretty good... the engine is designed to be run anywhere on the rev range, and actually will run better at any rpm that is around highway crusing speeds

think about it, its always seeing a constant amount of higher oil pressure that keeps things lubed. its also not being revved to redline (liek when pulling out onto a street, etc.)... you get the idea :)

[orion::S14]

You are NOT going to wear out a KA just by running high revs on the highway...

I've run +90 for HOURS with never and issue...

This is in my S14, in many different configurations:

Stock, automatic trans.

I/E, auto tranny.

I/H/E, 5-speed.

I/H/E, ECU, underdrive pulley, blah, blah, blah...

An now with turbo...I drive an hour (one way) at least one day of the week for work, and run 80-90 the whole time, passing under full boost (12psi), etc...I'm hard on the car, it's why I have it. Stock KA, it does fine...has for 115,000 miles so far!

Don't worry....run 110mph the whole way if you want...just use good oil (Mobil 1), and make sure the engine temp is fine (unless you have a cooling system problem, it will be fine).

- Brian

[twitchy]

yep, engines are designed to rev

in fact thats pretty much all they do

so dont worry about it.. The KA is a lovely highway engine and you shouldnt worry about it

[NismoDan]

Sweet!
Thanks for all the help, guys.

My cooling system's doing fine (I keep my eye on the temp gauge all day) so I should be good.
I might throw an oil cooler on in the near future just for some added peace of mind. :D

[sciamop]

Ok, so I drive from LA to San Francisco a lot nowadays and was wondering what you guys thought was an ok RPM to let my KA cruise at.

Bouncing off the rev limiter, of course. Is there any other way to drive?

Todd
93 Coupe
91 SER w/ bent frame

[kandyflip445]

If your engine temp is fine then you shouldn't need an oil cooler, unless you're pulling something. I've gone ~3 hours going 110 on I-40 REALLY late at night. No issue with the engine. I run Redline oil, so I dunno if that helps it any. Just keep the maintanence up.

[citizen]

the only thing that slows me down on that drive is the speed limiter. I wouldnt worry about your engine being hurt from weak stuff like that

[theicecreamdan]

I did 90-110 from Arizona to San Diego, in the middle of august, in my s14 with no trouble, other than my soaked #1 combustion chamber but it had been like that from the day I left San Diego to drive up to Boise.

KA is a wonderful engine that will take a lot of beating and still work hard.

[Pepperoni]

You should be okay revving it higher while cruising... just dont be redlining the whole way if you know what i mean.

(not to jack your thread, but i figure it's on the same topic) What is the optimal cruising speed if you want to save gas (for an SR)? Im guessing around 65 mph or ~3000rpm

[XxJaPxOxNeEs23xX]

i dunno i was wondering the same thing. i try to cruse at around 2200 or 2000 rpm without the engine bogging or struggleing i mean