reallly quick question about RPM on highway

[Socalheatz]

is it normal for the tC when hitting 70ish to be at around 3K rpms? my dad's camry (same engine i was told) at the same speed only needs like 2K rpm... which im guessin saves some gas at hi-speeds. please clarify thanks

[athletefeet66]

yes it is normal. dont worry you are still getting good gas mileage. and there is pretty much nothing you can do to change it....

[ack154]

Depending on which Camry, it's just geared differently. And the tC should be at 3k around 65mph (for a manual anyway). But that's normal. They're two different cars.

[Socalheatz]

gotcha, and its the 2004 4cyl camry

[equinox2355]

Socalheatz wrote: gotcha, and its the 2004 4cyl camry

they could have the same exact motor (which they aren't 100%) and still it'd be like that. From the flywheel back they are totally different. The gearing is what makes the difference. For me I like it, I don't have to downshift to pass people.

[silverstreaktc]

^^^but gas mileage would be sooo much better

[paulky_2000]

silverstreaktc wrote: ^^^but gas mileage would be sooo much better

But which would you rather DRIVE???? :clap:

[a_german_named_hans]

we already get pretty good highway gas mileage.

Just curious. could u take a Camry tranny and bolt it to the tc?

[silverstreaktc]

no i mean mileage would be so much better with a 6th gear paulky. don't be talkin down to me just cause im a little kid





just kidding. you're cool.

[LRomero]

I'm at roughly 3500 RPM going 80mph on highway. My tests have averaged out at 300-350 miles on a single tank (15 gallons) of 87 reg (a road trip I usually take every few months).

[senseiturtle]

Actually, gas mileage isn't based solely on RPM. I had a long discussion with my friends over at my university's engineering group.

Engines are actually most efficient at energy conversion from fuel to power when they're running unhindered... I.E... at full throttle. Now, that's the best for producing sheer power, which is not what we want when just going down the highway.

Contrast- Engines are least efficient at producing power at idle... they're producing practically zero, yet sucking gasoline. Though... while maintaining a constant speed, you'd want to idle, since that's the "best fuel sipping state".

There's all sorts of factors complicating this... but, to make it short... our motors turning at 3500rpm have just as many "sparks" (combustion events) as a V8 at 1750 RPM... which, is roughly what a typical v8 does on the highway... and why corvettes actually get about 27+mpg highway.

Acceleration is your enemy. Weight is your enemy. That's about as far as we can go, outside of basic maintenance. A 6th gear might lower our RPMs, but it's very probable that it would move us to a much less efficient zone of the powerband, nullifying our gas mileage increase from reduced RPMs.

[pinoyFMtC]

^Cool, good info.

[tcboi513]

what about for auto's is 2.5-3k normal ? I have a injen short ram and trd exhaust ?

[drjohnson36]

senseiturtle pretty much said it all in a nutshell... But I've got a couple things to add :)

Lowering RPMs will reduce fuel consumption, no matter what. That issue with the power band will only really matter if you try to accelerate to pass someone... it typically doesn't take even 30% of the engines maximum horsepower to overcome highway wind resistance. Chrysler's new Hemi engines have a system on them that shuts down half the cylinders... and they toss this engine in a 6000 pound truck and they run just fine on the highway.

But retro-fitting a camry transmission to the tC would probably only net you a gain of MAYBE 3 mpg... Lets do the math and say your tC will last you 150,000 miles. If ALL of those miles are highway, you'll only save 500 gallons of gas in the entire service lifetime if you slap the tranny on THE DAY YOU BUY IT... that adds up to what... 2000 bucks? The camry transaxle alone costs 2800 bucks. Not much else to be said really...