Is 3900 rpms at 70 mph bad? this really worries me when i am goin 70. I dont want to overheat the engine.

is there anything i can do to lower it?

 

your cool dont worry, they are all like that, i asked the same question six months ago, and the response i recieved was along the lines of the transmision being geared to be "peppy" rather than sluggish , but everyone i knows is like that, @80mpf mine cruises around 4000

brent

 

Yeah, once you're in 5th gear it's about 50rpm for every 1mph (3k @ 60mph, 5k @ 100mph, etc...)

 

i can't stand driving slow..
i beat the crap out of the car and never over heated.

i managed to go from la jolla to city of industry in about 1hour and 15 mins.

I would go on a range from 85-110 back and forth depending on traffic and turns.
RPMS STAY HIGH ___.. at first im worried but now i just got used to it..
what can u do?

 

You won't overheat it at cruise. Now, if you are climbing a steep hill in summer it might more likely.

In order to make the heavier car feel "quick" Toyota put a very high (numerically speaking) final drive ratio on the Scions. The penalty is high cruise RPM and probably reduced longevity. It was a lot cheaper to do this than to replace the transmission gearsets or (gasp) offer a 6-speed.

The solution isn't all that cheap. The Echo final drive might fit and would lower engine RPM by about 25%. A partial solution is to fit larger diameter tires, which would lower engine RPM by about 10% max.

George

 

I guess this is a manul tranny issue (70@3.9k rpm)? At 70MPH, mine (auto-tranny) is at 3K. Then again, I drive slowly to 70MPH on a flat freeway.

 

no its not a manual issue...
i have a manual and at 4,000rpm im doing exactly 80mph.....

figure it this way 1mph = 50rpm in 5th gear.... so 4000rpm divided by 50 = 80mph

 

if your really going 3900rpm at 70mph you might have a problem...clutch slipping maybe...
did you change your tires....if so what size...if u went to a smaller diameter tire this would cause that.....
if you have a automatic tranny....your torque converter could have a problem and is not locking anymore

 

i have 17's on mine. but they are pretty close to stock size wheels with tires. so i dunno... it worries me, but if there isnt anything i can do, oh well. :?

 

With stock rubber and wheels, my auto does 3500 @ 80MPH consistently...

 

Damn kids messing around near my PC. Sorry for the double post

 

and he said 3900 at 70mph....thats way high for stick or auto....go to your local dealer and ask a tech in service about it....

 

I spent ALL DAY at texas world speedway between 5 and 6krpms at full throttle and the engine never even got warm.

Its a tiny, modern engine, 4krpms isn't bothering it at all.

 

for what it's worth. I've had an xA standard for a few weeks. stock 15" tires. 60 mph = 3000 rpm. 70 mph = 3500 rpm.

 

I can cruise at 80mph at just over 3k rpm.

KiL

 

doesn't matter what wheels/tires you have

an INDICATED 70mph will always be at 3,500rpms

 

yes it does matter

if you have an oversize wheel then the rpm will be alot lower
ive had 19s on my benz stock size was 14s and my rpm is wayyy low

 

The speedometer is based on how many times the wheels turn around.

when you get tires with a different sized diameter, the speedometer will be wrong.

So yes, if you got huge tires, the rpm when you are *actually* going 70mph will be lower.

but the rpm when your speedo *indicates* you are going 70 will be the same.

unless your car uses GPS or an optical sensor under the car to gauge its speed (And it doesnt)

 

I checked it this morning on the way home from work. At 70mph on a flat stretch I was steady @ 3500rpm. I have stock wheels and tires on the box.

 

Nope, still 3K@70mph as before. How about tire pressure? Recommended on stock steelies/tire is 29/30psi as per manual. I'll check my cold air pressure early tomorrow morning.