chai

Hey there everyone, i have a question and hope u guys have an answer for me. Heres tha question y is that when i'm going down the highway at 55-60 mph my rpm read close to 2500 rpm and i tought that it should be around 1500-2000 rpm. Can any one tell whats wrong my this problem cuz i talk to some techs and they cant tell me y its up around that rpm on highway speed, plus my tc is an auto too and tha only upgrade i did was add an exhaust on it, so if any one can help me PLEASE!!!!

makaveli510

i think its just the way the tc's drivetrain is built, but i have a 5 spd im at 3000 when im doin 65 its just the way it is i know it sucks

draxcaliber

dude, seriously...there is nothing wrong with your car. the tc has short gear ratios for better acceleration. that is it. it can change if you put larger wheels and tires on your car, or change the gear ratios in the tranny.

so calm down.

SquallLHeart

nothing is wrong with your car... it's NORMAL.... hmm.. you should see how high the rpms get in a manual at highway speeds.

CuRiOuSfIsH

learn to live w/ the noise at highway cruises. 2500 aint bad. The 5 speed is like 2800RPM at 60MPH.
But yeah, normal cars w/ a 4 speed tranny would probably have a lower engine speed for highway cruising but the tC is different, in a good and bad way.

scionteecee

u guys stress 2 much over nothin n0 offense

Killface

OK, I think some gearing 101 is in order. The tC automatic has the following gearing:

1st: 3.943: 1
2nd: 2.197: 1
3rd: 1.413: 1
4th: 1.020: 1
Reverse: 3.145: 1
Final Drive: 2.740: 1

This leads to an overall ratio of 2.79: 1. At 65 MPH (with factory tires) the car turns over approximatelty 2479 RPM (By my calculations). Anyway, this is perfectly normal for a four cylinder engine. Most actually turn more RPMs than that. For instance, my first car turned 2585 RPM @ 65 MPH (89 Lebaron 2.5L-4 auto). In general, larger engines are geared taller due to having more torque (and therefore less need to multiply torque through gearing). Taller gearing can also help mileage, unless it is so steep as to cause excess strain on the engine. Anyway, the designers of the tC decided on the best compromise of economy and performance when they chose it's gearing.

I hope you didn't fall asleep after all that, as its pretty involved. Also, I barely hear my engine on the highway, I hear mostly wind and road noise.

chai

hey thanks for all ur responds cause now i dont have to worryie about the rpm any more and just cruise on the road like i use to so thanks everyone of u guys who answer...

bigwillystyle23

i had a old toyota truck jacked up with 33x12.50 inch mud tires and that thing cruised really high on the interstate! it was like 3500 rpm at 75. it wasnt near as fast as my TC though.

RollTide

Yeah certainly nothing to worry about there. Any drive train problem that modified your rpms (like slipping problems) would show up during acceleration, but not just cruising. Remember, rpms are mechanically preset in most cars (new fancy transmissions are getting stupid though). In other words, the engineers at Toyota calculated exactly what rpm they wanted the car to run at on the hwy long before a transmission was ever built. KillFace just gave you a quick example of that.

Generally speaking, drivetrain problems will appear as one of a few things:
1) serious vibration problems in the steering wheel in FWD (shows a rotating part problem. Could be axles, drive shafts, wheels, tires, even a bad hub)

2) Erratic rpm jumps during acceleration (usually means slipping of clutch/flywheel contact or automatic equivalent)

3) Just plain horrific noises (differential or transmission problems). Usually this is a big problem.

You're fine