Pushing a tank of gas to the limit.

[CBR600RR]

For an apples to oranges comparison:

My Honda CBR600RR has an 18 litre tank. I get about 220km before the fuel lite comes on. I fill up and put in about 14 litres. about 20% fule capacity left

for the FR-S gas light coming on and filling up with about 40 litres means it also comes on with about 20% fuel capacity left

[engsr]

Originally Posted by BLL

Aren't you using more fuel when you coast clutched in to keep the engine idling? As opposed to coasting down a hill in gear with your foot off the gas and using 0 fuel?

With no load on the motor, the ECU thinks that the engine is just idling and will use fuel. It's best to coast in gear as that keeps the injectors off.

Originally Posted by Khyron686

So do most of you assume the light comes on with 10L left? Ie, about 150km left? Seems high.

Low fuel light, according to the BRZ manual, comes on with approximately 7L left. Sounds about right since there was one time I filled up just as the light came on and I fill up about ~42L.

I'm averaging about 7.5L/100km so I would imagine that 700km a tank is easy to obtain. I actually switched to 91 Shell and the mileage seems to be better (compared to Ultra 94). Have to see by the end of the week. Oh, and the chirping is gone, too.

[synchromesh]

Originally Posted by Khyron686

So do most of you assume the light comes on with 10L left? Ie, about 150km left? Seems high.

When I fill up immediately after the light goes on, the gas pump always reads 40L so theres 10L left. Huge contrast to my 91 e30 I had years ago where I learned the hard way that empty really means empty!

[FBaxteR-S]

Originally Posted by BLL

Aren't you using more fuel when you coast clutched in to keep the engine idling? As opposed to coasting down a hill in gear with your foot off the gas and using 0 fuel?

I'm just utterly confused by your statement.

In order for the engine to remain running, it is using gas...

[engsr]

^ As Mythbusters would say - Warning: Science Content.

http://www.popularmechanics.com/cars...l-fuel-economy

[BLL]

Originally Posted by FBaxteR-S

I'm just utterly confused by your statement.

In order for the engine to remain running, it is using gas...

Maybe my wording was a little confusing.

When you clutch in and coast, the engine is using fuel to keep it idling.
When you coast in gear, the engine is not using any fuel because the wheels are keeping the engine running.

[ymboc]

Originally Posted by FBaxteR-S

I'm just utterly confused by your statement.

In order for the engine to remain running, it is using gas...

To Clarify Further... modern engines (since ~2000 & earlier in the case of toyota) have the ability to cut the fuel to the engine when coasting in gear. The whole thing is simply termed 'fuel cut' and was introduced to improve gas mileage.

Basically the ecu knows when you've removed your foot from the accelerator, that you're in gear and that the car is traveling at sufficient speed (& engine rpm) that the momentum of the car will keep the engine (& all its accessories) turning over without having to inject fuel to keep combustion going.

If the rpms drop enough (to the point where you'd otherwise stall), or you step on the accelerator or clutch, the engine instantaneously starts injecting fuel again, combustion resumes and everything works as it should.

If you pay close attention to the car you can often 'feel' when the fuel cuts out and when it kicks in again.

[FBaxteR-S]

Wow, thanks a lot for the info guys.

Apparently I haven't been keeping up with the times, lol.

[smbrm]

Best I have measured so far is 5.7L/100km which was 100% highway driving. I am sure that at least 5.6 should be possible, but you have to drive very carefully and ensure no heavy footedness and keep the speed lower: 80-100 kmph.

[Khyron686]

You guys have the wrong car. If I'm under 10L/100 I'm mad.

[cRazy604]

Great info I actually thought coasting in neutral was a good idea

[dnr]

any idea on how many liters left when the tank signal turn on ?

[Future]

Originally Posted by Khyron686

You guys have the wrong car.

qft... AND... I almost always fill up with over a quarter of tank left... Enough fuel in the tank cools down the fuel pump...

[thorlius]

Originally Posted by Khyron686

You guys have the wrong car. If I'm under 10L/100 I'm mad.

I was going to say. The guy with 7.5L/100km? I am averaging 9.1L in my 2010 Cobalt 4AT (2.2L NA base model piece of garbage). The fuelly average is 7.8 for that car and I think a lot of those are with the 260hp TC 2.0L engine. I will be happy if the FR-S is under 10.