2nd Generation (GE 08-present)The New Fit... Generation specific talk and questions here.
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Where do you get the idea that this engine is designed to run specifically on low octane fuel?... The U.S is one of the few countries in the world that has fuel with such low levels And the owners manual warns against using any lower than 87 octane.... This is one of the primary reasons that the Fits sold in other countries are faster and get far better mileage than they do here..
Where do you get the idea that this engine is designed to run specifically on low octane fuel?... The U.S is one of the few countries in the world that has fuel with such low levels And the owners manual warns against using any lower than 87 octane.... This is one of the primary reasons that the Fits sold in other countries are faster and get far better mileage than they do here..
The owner's manual and the fact it's an economy car.
Where do you get the idea that Fits sold in other countries are faster?
edit: Australian 1.5 produces 88KW and 145NM. Converted to HP and lb ft this is 118/107. The US 1.5 produces 117/106 (within rounding errors).
UK and Aus recommend 91 RON. The US calculates octane using (RON + MON )/ 2 so it's difficult to compare, but 91 RON is equivalent to (maybe even a bit less than) 87 using the (R+M)/2 method
They might be faster due to lower weight the Aus 1.5 VTI Jazz comes in at 1070kg or 2358LBS. The US Base MT weighs in at 2489lbs and the Sport at a piggy 2520lbs...
mmmmm at the risk of being a spoilsport, I still don't believe higher octane fuel will produce more power in an engine designed for regular gasoline.
One observation I can make is that the L15A was not designed to run on lower octane fuel. It was designed and marketed exclusively for Japan for several years. Japan doesn't even have 87 octane fuel, so far as I know.
Quote:
Originally Posted by Steve244
Conversely, if you put low octane fuel in a high compression or boosted engine, modern engines sense knocking and retard the timing so fuel ignites later, avoiding knocking but dumping unburned fuel in the exhaust and losing power. The Fit is smarter than this.
The L15A has a 10.4:1 ratio, which is a bit higher than a lot of engines in US market cars. Not extreme, but not exactly "normal" either. Certainly it would not be unreasonable to expect it to perform slightly worse if fed low octane fuel.
Quote:
Originally Posted by Steve244
Someone needs to dyno test their manual transmission Fit on both regular and premium gas and show us the results. If this shows the Fit produces more power on premium, then it's dumping unburned fuel on regular gas causing shortened cat life. I don't think this is happening on a 1.5L well designed economy car. I do think you are doing a disservice suggesting people run premium gasoline in it though.
Really, I'm not sure power is affected much. I only notice the torque at low RPM and moderate/high load. Whether or not significant amounts of unburnt fuel are expelled from 87 octane fuel, I don't know.
I would very much like to see a dyno test with different fuels. But as for my suggestion, as far as I'm concerned, it's something others can try for themselves (or not) to see if they like/notice any difference. At any rate, perhaps someone who tries 93 from my suggestion might decide to do a dyno test.
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Best tank: 518.1 miles, 47 MPG -- Best commute: 50.3 in, 45 out
'07 NHBP Sport AT
Previous owner's mods: Tint front and back, Mugen visors
One observation I can make is that the L15A was not designed to run on lower octane fuel. It was designed and marketed exclusively for Japan for several years. Japan doesn't even have 87 octane fuel, so far as I know.
Japan's 'regular' was 91 RON, at least as of 30 years ago. That would be about 87 AKI (RON+MON/2) in the US.
EDIT: You edited before I replied with my snarky deadpan reply. Anyone on here in Japan that can confirm the current "regular" sold there? I could ask my brother-in-law, but I'm not sure if he has a car over there.
I feel very fortunate that my state is no longer requiring veterans rated 100% disabled to pay property taxes.... What that means to me is that I can now afford the Hodata reflash and at a later date an AEM F/IC and methanol water injection system To support my KWSC..... I realise that the majority of people on this forum are younger than I am and assume that because of the small engine displacement of the Fit it is strictly a fuel sipping economy car and nothing more because they have less experience building and tuning engines that weren't near as sophisticated in design that were able to produce power gains by teenagers tearing them down and rebuilding them under shade trees and sharing labor and ideas in order to go out and measure off a distance and test the performance gains with a stop watch..... That is what it is really all about.. Screw a dyno run, It is a tool that measures power gains that is useful when tuning and verifying bragging rights to show your buddies....I prefer to measure power output by looking at my speedometer at a certain point on a steep hill accelerating from another certain point in a gear that allows me to gauge the power in the RPM I am looking for an increase in.... It is a tried and true practice that yields real world results in verifying gains or losses in power and it is cheaper than a dyno run.
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