I have a 5 speed xA and noticed actually from the day I bought it that when I am in 5th gear driving down the road at 60 MPH that I'm running at 3K RPMs or even a little bit higher than that sometimes, at about 3,500 RPMs... I called my local Scion dealer and they told me that its just a balance between having a smaller engine and being at that speed. I would think otherwise, tho... I mean, 3K RPMs is still ridiculous even with a car that only has 108 HP. I feel that I am not really getting the best gas mileage that I should be getting right now, cause I often find myself filling up more now than when I had a car that was running almost twice the HP.

Has anyone else noticed this or thought that they too are losing mileage?

 

The EPA estimates are based on the engine running this tranny at those RPMs. You're just thinking about it too much. You can't base your mileage on tank to tank vs another car unlessthe tanks are the same size, etc. You need to write down your mileage at each fill-up and do the math based on the amount of gas you use each time.

 

It's true I should write down my mileage and do my math, but how many stock cars have you seen run 3 to mid 3K RPMs when in 5th gear at a steady 60 MPH pace? Even at 55 MPH I am running at 3K... That seems like too much engine work. At the most any other car (4 cylinder) would be running a little over 2K at 60 MPH. Also, there is a big difference from having a 20 MPG car to a supposively 43 MPG car... Even in the city, 30+ MPG.. On a 12.5 gallon tank, thats 125 more miles that I should be getting while driving in city, maybe take away 25 for being a standard, but hell, I aint a novice with the stick, so if I lose any its not much.

Thinking about it too much or not thinking about it too much, it still doesn't feel like the car is saving me the amount of miles its supposed to.

 

Get used to the fact that it just revs high. It's made to do it and it won't hurt it. You won't really shouldn't notice any gas mileage issues until you start getting into the 70's. That's when wind resistance and the higher RPM's will start to affect you noticably. Also, as it breaks in the mileage will increase. (Synthetic will also net you a couple extra MPG's).

It too me a bit by surpise as well, but I ride a Hayabusa so I'm used to high reving engines and that is real typical on some motors.

It would have been nice if they would have put a dog overdrive gear in for 5th, but alas they didn't.

If it really is a problem, you'll probably want to test driver your cars more thoroughly next time at high speed before you buy. You should always road test down a stretch of highway before buying.

ojhncal

 

My tC only runs 5mph faster than your xA at 3000rpm.

 

I drove my xA at speeds higher than 4000RPM for over 8 hours, and still got great gas mileage.

High Revs - Few moving parts - low weight of moving parts - light vehicle load = good mileage regardless.

 

on the way to denver i averaged in excess of 80 miles the whole way. over 4000 the whole way. got about 35 mpg. not too bad. this was an 8 hour drive with only one stop. held up awesome. dont worry though, i thought the same thing. its just the way these little japanese motors are meant to run.

just think of it this way, they wouldnt sell them in the US with 75 mph speedlimits if they couldnt do it safely.

scott

 

it's supposed to be like that. you find that out from a test drive.

 

Well, I test drove an automatic before I bought it, but I guess I didn't notice it really.. Guess this being my first import gas-saver, I'm not used to the differences between it and a GM vehicle, but I do appreciate everyone's knowledge with the xA. Maybe I just really need to break in the engine more, who knows?

UPDATE: Was talking to someone at the moment and realized the most obvious thing in the world.. My last car was a 4 speed automatic.. Not a 5 speed manual.. Of course I am going to be running 2K RPMs at 55-60 MPH, I'm at a lower gear... Duh.

I do apologize for my stupiity... I didn't even notice what the hell I was talking about there for a minute. Glad everyone helped me understand the situation better, even though there is no situation...

 

The auto is also geared lower. I think they geared the stick like that for the feeling of peppiness.

 

i think you are exactly right, it makes the car actually fun to drive rather than being a dog. personally, i would have really liked a sixth gear. the gearing 1-5 seems great, specially being on the highway going 70+ with only 95whp and being able to throw you back a decent amount. i cant imagine the auto is very peppy, on account of its 1 less gear and lower gearing overall.

jon

 

Don't put words in my mouth. The auto gets it just fine. There's a second difference in the 1/4 mile, that's like 1 car length. It's not a peppy/dog situation. The yellow paper in my wallet says "80+ in a 65" and it was up a pretty steep grade. Don't let the smooth taste fool ya...

There's also the difference in shift points that would be imteresting to test, head to head...

 

I'm not auto-bashing, as I have absolute NOTHING against autos, but you should know that 1 sec does not equal 1 car length. At 80+ MPH, 1 sec is a LARGE distance. Just count out a full second at that speed and see how far you go.

 

Just wanted to add here that after I installed my 17" wheels with 215/45/15 tires on my xA I noticed a reduction in RPMs at speed on the freeway.

I realize I lost a little bit of acceleration due to the increased weight/inertia thing, but since I freeway drive mostly I figure the RPM reduction saved me some MPG (the most I've gotten is 35 MPG and that was after the wheel/tire install).

 

Dont forget that VVT-I plays a role in MPG..............

 

15" tires on 17" wheels????? Keep in mind that if your RPMS relative to your speed have changed, you have incorrectly matched your tires to your wheels, and thus your speedometer will be off, as well as your final drive. In the end, the change to your gearing may help or hurt power output, as well as your MPG. But this is soley based on the tires relative to the wheel, regardless of the wheel size (unless you have 20" rims or something )

On the inertia thing. . . if you have the correct tires on your car, larger is always more inefficient. Lighter is always better, as well as a smaller radius. . . for both acceleration and fuel efficiency. However, a WIDER tire means both more weight, and more rolling friction (a 215 width is greater than a 185 width). I doubt you are running 15" tires on your 17" rim, so the number is probably off, thus I can't check if your overall wheel diameter is off. But I can't imagine anykind of tire that will yield better MPG with that large of a diameter change, along with the increased weight of the rim, unless you are running some kind of space aged light weight wheel.

 

I think you are mistaken on a few points. If you put on larger diameter tires, your observed RPMs will be the same at the same speed--only speedometer calibration will change this. With larger diameter tires, your actual speed will increase, but the speedo will still think it's the stock tires, so you won't see the difference, except in the speeding ticket you may get.

Larger diameter tires are usually more efficient. The taller gearing (especially on the xA and xB) will yield better gas mileage. It would take a big increase in rolling resistance (like race tires) to negate the taller gearing.

 

Ah yes, touche on the constant RPM and speed sensor readings, but the speedo will be off if the diameter has been increased.

Taller gearing (from a larger radius) will probably help MPG, but you also have to consider that larger diameter tires usually (if not always) come with wider widths. The percentage increase in rolling resistance, calculated by the percentage change in width must be calculated to the net gains/losses in effeciency. Secondly, you have to consider the change in rotational inertia associated with the bigger wheel rim and tire. All in all, you have to find the true size of the tire, as I doubt skawt01 is really running 215/45/15 on 17" rims.

 

Reposting some information from several other topics:

https://www.scionlife.com/forums/vie...=881022#881022

If I am correct, the xA and xB have the same ratios...

 

Sorry for the typo guys, I meant 215/45/17 tires on 17" wheels.

I had calculated a 3.76% increase in diameter w/the new wheel/tire combo, so the change in RPM is very slight, but I'm certain I've noticed a reduction in RPM at speed.

There will be MPG savings over time as freeway miles pile up, though not enough to offset the price of a wheel/tire purchase. This may be a suprise to you guys, but I actually recorded my highest MPG after I put the wheel/tire set on the car. Go figure.