Fuel Economy after 20,000K
02-19-2004, 04:40 AM
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Fuel Economy after 20,000K
In another thread, Gomez reports on a discussion with the "Renesis Master Technician…who reported these cars are ECU programmed to run rich for the first 20,000k".
Got me thinking. I have some data which may support this or otherwise -- my boringly **** fuel log.
Well, I can report there is some evidence to support the claim, at least in terms of fuel consumption.
Average fuel consumption 0-20,000K: 12.2L/100K
Average fuel consumption 20,000K-22,000K: 11.8L/100K -- about a 3% improvement.
A couple of observations: obviously, the sample 0-20,000K is much larger, or rather the more recent sample is smaller, so there is less confidence it is representative.
However, I do the same drive every week, use cruise a lot, so there is not a major variation in driver-dependent factors.
Therefore, seems to support the statement
Timbo
PS: If anyone wants a copy of my data for regression analysis, PM me! :p
Got me thinking. I have some data which may support this or otherwise -- my boringly **** fuel log.
Well, I can report there is some evidence to support the claim, at least in terms of fuel consumption.
Average fuel consumption 0-20,000K: 12.2L/100K
Average fuel consumption 20,000K-22,000K: 11.8L/100K -- about a 3% improvement.
A couple of observations: obviously, the sample 0-20,000K is much larger, or rather the more recent sample is smaller, so there is less confidence it is representative.
However, I do the same drive every week, use cruise a lot, so there is not a major variation in driver-dependent factors.
Therefore, seems to support the statement
Timbo
PS: If anyone wants a copy of my data for regression analysis, PM me! :p
02-19-2004, 05:25 AM
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I sure hope it will use less fuel later on.
I've done 3 fills so far, and the figures are 14.2, 15.7, 16.5. Not looking good because they are going up. Possibly due to me progressively exploring the higher rev ranges.
Hope it is also just caused by all the gear changes during the first 1000km.
I've done 3 fills so far, and the figures are 14.2, 15.7, 16.5. Not looking good because they are going up. Possibly due to me progressively exploring the higher rev ranges.
Hope it is also just caused by all the gear changes during the first 1000km.
02-19-2004, 05:29 AM
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Timbo, the guy I spoke to was most helpful and had no reason to bullshit...I had made it clear he was speaking to the (recently wallet lightened) converted..!
(BTW, it actually says in the previously mentioned RX-8 salesperson manual that RX-8 buyers are extremely well researched, know the car well, and will not accept "Bullshit" from you when you give them the sales pitch!!!)
He went over the service costs, and explained why the 60K service knudges $1000.....They replace the Iridium/Unobtanium/Platinum plugs and the fuel filter....Have your tank below quarter full when you go in for this service, otherwise some apprentice is gonna cop a facefull of PULP!!
Those who have damaged the front thin plastic undertray may be interested to know that heaps of spares are lying about the dealers as they are removed from cars that have the front spoiler
fitted at delivery...
Yours Truly, Gomez
(BTW, it actually says in the previously mentioned RX-8 salesperson manual that RX-8 buyers are extremely well researched, know the car well, and will not accept "Bullshit" from you when you give them the sales pitch!!!)
He went over the service costs, and explained why the 60K service knudges $1000.....They replace the Iridium/Unobtanium/Platinum plugs and the fuel filter....Have your tank below quarter full when you go in for this service, otherwise some apprentice is gonna cop a facefull of PULP!!
Those who have damaged the front thin plastic undertray may be interested to know that heaps of spares are lying about the dealers as they are removed from cars that have the front spoiler
fitted at delivery...
Yours Truly, Gomez
02-19-2004, 05:36 AM
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Originally posted by emailists
Glad your milage is getting better- it's isn't it 20,000 miles that somome mentioned as the turnover point as opposed to kilometers?
Glad your milage is getting better- it's isn't it 20,000 miles that somome mentioned as the turnover point as opposed to kilometers?
Gomez
02-19-2004, 05:41 AM
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Timbo,
A plot over the 22k would be meaningful - it may have been heavy early and weighted the latter.
What sort of consumption were you getting 18k to 20k?
Kev.
A plot over the 22k would be meaningful - it may have been heavy early and weighted the latter.
What sort of consumption were you getting 18k to 20k?
Kev.
02-19-2004, 03:12 PM
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Ok, will do some more plots on this and post them either later today or over the weekend.
et381, welcome to the forum. Yep, if you explore the rev range and use those gears -- in fact use more than 3,250 rpm continuously, and your fuel consumption will rise dramatically. This is not an economy car. I track fuel economy simply because it is my 'work' car, and the data does allow us to explore some types of claims about the ecu.
et381, welcome to the forum. Yep, if you explore the rev range and use those gears -- in fact use more than 3,250 rpm continuously, and your fuel consumption will rise dramatically. This is not an economy car. I track fuel economy simply because it is my 'work' car, and the data does allow us to explore some types of claims about the ecu.
02-19-2004, 03:31 PM
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Funny, I recently posted that I got better than 10l/100K on a trip to Vic. (Both there and back) (Lots of Freeway and lots of Cruise)
Even I was surprised... but now I'm thinking .... I just passed the 20K mark as I left Sydney.
Interesting!!!
Even I was surprised... but now I'm thinking .... I just passed the 20K mark as I left Sydney.
Interesting!!!
02-19-2004, 07:47 PM
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Originally posted by rpm_pwr
Timbo, surely you've been using the AC a fair bit more lately too? They're excellent figures for a car with such short gearing.
-pete
Timbo, surely you've been using the AC a fair bit more lately too? They're excellent figures for a car with such short gearing.
-pete
Where is Brisvegas, anyway? Sort of South Bne/North GC, I suspect
Actually, I tend nearly always to use climate control and set the temperature, which I guess means the compressor is running most of the time. I have purposely done a couple of runs without a/c, one of which did give me my best recorded figure of 10.6L/100K.
Actually, I think weight may be more an issue. One of the worst runs I did was when I was accompanied by one of my programming team, both Cbr-Syd, and in urban driving around Sydney (but about the same as I usually do).
He's a big boy - 6'2" in the old money and 110Kg. That dropped my consumption to 13.5L/100K
Yes, the gearing is short. To quote from our esteemed moderator, Hymee, I do find myself reaching for 7th and 8th sometimes :p
Tim
02-19-2004, 07:49 PM
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timbo,
Have you noticed any change in performance since 20000km .
Would think that running less rich would translate into more get up and go?
Your thoughts.
George Thomas
velocity red cloth oz Rx8.
Have you noticed any change in performance since 20000km .
Would think that running less rich would translate into more get up and go?
Your thoughts.
George Thomas
velocity red cloth oz Rx8.
02-19-2004, 07:57 PM
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Hi George
Not really. It always feels great to me, and the old butt dyno is pretty insensitive!
All of this makes me ask: is there any documentation on the ECU, its learning capabilities, and the various purported 'switches'?
What happens if you do an ECU reset? I *guess* that might reset the 'learning' elements, but the odometer-related 'switches' would remain. But I am guessing.
As a software guy, it all makes me very curious to see the code.
Hey, let's start an Open ECU movement!! :p
BTW, great choice in ride -- same as mine
Not really. It always feels great to me, and the old butt dyno is pretty insensitive!
All of this makes me ask: is there any documentation on the ECU, its learning capabilities, and the various purported 'switches'?
What happens if you do an ECU reset? I *guess* that might reset the 'learning' elements, but the odometer-related 'switches' would remain. But I am guessing.
As a software guy, it all makes me very curious to see the code.
Hey, let's start an Open ECU movement!! :p
BTW, great choice in ride -- same as mine
02-19-2004, 08:37 PM
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Timbo, you sure it wasn't the "I'm on display" factor that affected your economy with a passenger? 
The OS platform the ECU runs on is essentially open source, it's just that I'd lay good money it's security coded in the chip. Of course, if anyone can get me the ROM file the dealers use, I've got the Hitachi de/compilers
The OS platform the ECU runs on is essentially open source, it's just that I'd lay good money it's security coded in the chip. Of course, if anyone can get me the ROM file the dealers use, I've got the Hitachi de/compilers
02-20-2004, 05:46 AM
#16
Lots of good comments in this thread. I'm glad someone remembered my little comment about 7th and 8th gears
The reason the 60,000 km services is so dear is indeed to do with the fuel filter. I posted on another thread some info about this. The WHOLE FUEL PUMP / FILTER / SENDER assembly gets replaced! It sits in the middle of the left-hand tank. There is really only one tank, but it has a high hump in it over the tunnel, so it is effectivly 2 tanks. There is a pump/siphon mechanism that distributes it around.
Cheers,
Hymee.
The reason the 60,000 km services is so dear is indeed to do with the fuel filter. I posted on another thread some info about this. The WHOLE FUEL PUMP / FILTER / SENDER assembly gets replaced! It sits in the middle of the left-hand tank. There is really only one tank, but it has a high hump in it over the tunnel, so it is effectivly 2 tanks. There is a pump/siphon mechanism that distributes it around.
Cheers,
Hymee.
Last edited by Hymee; 02-20-2004 at 12:41 PM.
02-27-2004, 06:02 AM
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OK, here it is , the definitive answer to the 20K "switch" issue...
Picked up my car today (more about that in the "dock" thread) and as promised, collared the Renesis guy and grilled him about the oil and 20K "switch" issues...
All current Mazdas, with the sole exception of the MX5, have this program built into the code for the ECU...Tributes were the first to get it, 2's, 3's, 6's...all got it....
No switch, just gets progressively better "approaching 20K"...
Mazda are apparently quite proprietorial about the software used, to the extent that even the factory trained guys aren't fully in the (closed!)loop....
He said we'll never know, exactly.....
Taka, City Mazda are now apparently using Rotary Oil....
Junior Detective Gomez.
Picked up my car today (more about that in the "dock" thread) and as promised, collared the Renesis guy and grilled him about the oil and 20K "switch" issues...
All current Mazdas, with the sole exception of the MX5, have this program built into the code for the ECU...Tributes were the first to get it, 2's, 3's, 6's...all got it....
No switch, just gets progressively better "approaching 20K"...
Mazda are apparently quite proprietorial about the software used, to the extent that even the factory trained guys aren't fully in the (closed!)loop....
He said we'll never know, exactly.....
Taka, City Mazda are now apparently using Rotary Oil....
Junior Detective Gomez.
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