Discussion
How many (road) miles do you get from a tank of fuel? I filled up to the brim and having made a few short journeys over the week, mostly to demonstrate the effectiveness of the car to get from A to B without there being any time lapse at all 
, I reckon I'm looking at about 250 miles from a tank.
I haven't had a V8 before so I was a little taken aback.
, I reckon I'm looking at about 250 miles from a tank. I haven't had a V8 before so I was a little taken aback.
Edited by mars on Monday 15th January 09:31
) it may stretch to 250 miles?Thats probably about right. I get about 220 to a tank in a mixture of motorway and London traffic. Have seen almost 300 miles to a tank on the way to LM at a steady 80-100mph.
I'm curious, do any of the people who have had re-maps or Emerald ECUs seen an improvment in fuel consumption? I recall when Evo installed an Emerald ECU on their 340R they went from 20 to 27mpg with the same driving style.
I'm curious, do any of the people who have had re-maps or Emerald ECUs seen an improvment in fuel consumption? I recall when Evo installed an Emerald ECU on their 340R they went from 20 to 27mpg with the same driving style.
simonsparrow said:
Thats probably about right. I get about 220 to a tank in a mixture of motorway and London traffic. Have seen almost 300 miles to a tank on the way to LM at a steady 80-100mph.
I'm curious, do any of the people who have had re-maps or Emerald ECUs seen an improvment in fuel consumption? I recall when Evo installed an Emerald ECU on their 340R they went from 20 to 27mpg with the same driving style.
I'm curious, do any of the people who have had re-maps or Emerald ECUs seen an improvment in fuel consumption? I recall when Evo installed an Emerald ECU on their 340R they went from 20 to 27mpg with the same driving style.
I've seen vast improvements from having mine mapped etc, i'm getting up to 300 miles to the tank, on the other hand i've seen 5 mpg when pushing it
Mapping does help, since the standard 4.5 mapping is quite rich. I definitely noticed an improvement in fuel consumption post mapping, but it's not exactly a strong point of the Cerb anyway. I just tend to fill her up at 1/4 left on the gauge. I get 18-20 mpg most of the time, more over decent distances, less when booting it.
Steve.
Steve.
The Emerald certainly improved the economy of my Se7en - quite noticeably, however the real gains were made after the mapping session. Whilst it's true that the mapping gave me lots more power and definitely better economy, I bought a wideband lambda and started to log the AFR against the speed and load sites, and made a few small changes to the map from there. That gave me even better economy. I went from about 180 miles to a tank (much smaller tank than the Cerb) to about 220 miles.
And of course, you're right that I was "entertaining" my passengers on relatively short runs which would definitely drink more thirstily but I think my surprise was going from 220 miles for a 25 quid tank to about 250 miles for (about) a 60 quid tank.
Not complaining. Just curious. It's only money. You can always make more but you can't get more "life".
And of course, you're right that I was "entertaining" my passengers on relatively short runs which would definitely drink more thirstily but I think my surprise was going from 220 miles for a 25 quid tank to about 250 miles for (about) a 60 quid tank.
Not complaining. Just curious. It's only money. You can always make more but you can't get more "life".
Steve_T said:
I just tend to fill her up at 1/4 left on the gauge.
Top Tip.
I try and never let her get below 1/4 tank following a recent "oh sh*t, I've run out of petrol" incident. The guage isn't that reliable! In fact I now carry a full can of Tesco 99 in the boot.
Steve_T said:
I get 18-20 mpg most of the time, more over decent distances, less when booting it.
Similar for me. 14 mpg most of the time and 17 mpg for a longer runs involving motorways.
Ought to have said, my gauge does seem to be reliable (it moves in a predictable manner - unusual from what I hear), but if it wasn't I'd go for the mileage approach too. I have a second rule, which is to fill to the brim before 5pm on trips in France, to avoid being stranded. I've done the running on fumes looking for a hotel at 1am thing and I don't recommend that!
Steve.
Steve.
I reckon that i get 120/130 miles tops from a full tank.
That's just driving to and from work everyday, most of which is around 30mph.
On a long run i see much better economy at normal speeds 60/70mph.
This drops to a pathetic level when cruising at 120 for long periods.
I've got an Emerald ECU and the car is putting out about 391bhp at the fly.....
That's just driving to and from work everyday, most of which is around 30mph.
On a long run i see much better economy at normal speeds 60/70mph.
This drops to a pathetic level when cruising at 120 for long periods.
I've got an Emerald ECU and the car is putting out about 391bhp at the fly.....
Scrooloose said:
I reckon that i get 120/130 miles tops from a full tank.
That's just driving to and from work everyday, most of which is around 30mph.
On a long run i see much better economy at normal speeds 60/70mph.
This drops to a pathetic level when cruising at 120 for long periods.
I've got an Emerald ECU and the car is putting out about 391bhp at the fly.....
That's just driving to and from work everyday, most of which is around 30mph.
On a long run i see much better economy at normal speeds 60/70mph.
This drops to a pathetic level when cruising at 120 for long periods.
I've got an Emerald ECU and the car is putting out about 391bhp at the fly.....
Must confess that I don't do much town only driving in the Cerb, but that does seem really low fuel economy. Have you got lambda plumbed in to the Emerald, it might help your economy. (I believe this has been supported for a while, but don't know if this is part of the current Cerb implementation)
Steve.
Edited by Steve_T on Monday 15th January 14:27
The Emerald will run a normal narrowband lambda but these devices only work around stoic values, plus or minus a very small percentage, and their influence on the map is simply to say "too rich" or "too lean" but not to say how far rich or lean it is.
For max power, the engine will be mapped marginally rich, too rich for the narrowband lambda's preference, so it will always try to pull you towards stioc, effectively leaning-off your map. This is why (I think) the Emerald will probably not be running in closed loop. If it were, then you would never be running on the values in the map that were input at the mapping session.
If you hook up a wideband lambda (they are cheap now - and I can put you in touch with a guy who can source them even cheaper than most others), and attach that to the Emerald's AUX input, you can accurately measure your AFR. This way you can determine whether you are close to your *required* AFR and not simply either side of stoic. Once you have tuned the map so that at each speed & load site you are achieving your chosen AFR, you will be achieving the best economy for the map.
Sounds complex, but it's really simple.
The next gen Emeralds will do self-mapping according to your chosen AFR values. Not sure when this will be applied to the AJP version of the Emerald though. It's a little different to the "conventional" Emerald owing to the unusual angle of the AJP "V". It might be that the software/firmware is universal. I haven't contacted Emerald yet to ask. I haven't had any tweaking time with the new car yet... and I don't know what the target AFRs should be for this engine. I suppose I would start by measuring what AFRs are being output today because the engine runs well and as it's been mapped already by trackcar it's bound to be right.
I'm not sure how you'd get on mapping with 2 wideband lambdas. It's almost unecessary to have 2 lambdas other than to check you are getting consistent results from both (as you have mentioned above). For mapping, you cannot make the ECU delivery different fuelling to each bank so as long as you can run a few tests against the consistency of your two banks, you only really need map with one wideband.
For max power, the engine will be mapped marginally rich, too rich for the narrowband lambda's preference, so it will always try to pull you towards stioc, effectively leaning-off your map. This is why (I think) the Emerald will probably not be running in closed loop. If it were, then you would never be running on the values in the map that were input at the mapping session.
If you hook up a wideband lambda (they are cheap now - and I can put you in touch with a guy who can source them even cheaper than most others), and attach that to the Emerald's AUX input, you can accurately measure your AFR. This way you can determine whether you are close to your *required* AFR and not simply either side of stoic. Once you have tuned the map so that at each speed & load site you are achieving your chosen AFR, you will be achieving the best economy for the map.
Sounds complex, but it's really simple.
The next gen Emeralds will do self-mapping according to your chosen AFR values. Not sure when this will be applied to the AJP version of the Emerald though. It's a little different to the "conventional" Emerald owing to the unusual angle of the AJP "V". It might be that the software/firmware is universal. I haven't contacted Emerald yet to ask. I haven't had any tweaking time with the new car yet... and I don't know what the target AFRs should be for this engine. I suppose I would start by measuring what AFRs are being output today because the engine runs well and as it's been mapped already by trackcar it's bound to be right.
I'm not sure how you'd get on mapping with 2 wideband lambdas. It's almost unecessary to have 2 lambdas other than to check you are getting consistent results from both (as you have mentioned above). For mapping, you cannot make the ECU delivery different fuelling to each bank so as long as you can run a few tests against the consistency of your two banks, you only really need map with one wideband.
mars said:
The next gen Emeralds will do self-mapping according to your chosen AFR values. Not sure when this will be applied to the AJP version of the Emerald though.
When I spoke to Jools recently I got the impression that this is possible - in fact has was busy plumbing a wideband sensor in at the time. It will need a firware upgrade for older Emeralds (like mine).
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