Testing an MPG idea
26 October 2015, 09:50 AM
#1
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Testing an MPG idea
Further to actual MPG discussion on this thread I have filled up last night and switched to other map.
This wont be just a long drive, I will just use the car as normally do over the next week or two and when I fill up again I'll share my results.
At least one other person was interested in the results, not just me
I've already commented on my ECU,
But if anyone has any questions about my car or driving, just ask
Of course I realise this is just one man, one car and one tank of fuel, so it wont be the worlds most conclusive experiment, but it might bring an interesting observation.
At least one other person was interested in the results, not just me
I've already commented on my ECU,
When I next fill up I'll switch map and keep a record.
I can’t recall the ECU, might be Syvecs, might be Alcatek, I’m pretty sure it's not ESL. Duncan @ Racedynamix did the mapping and as I said it is just a simple duel map; the only discernible difference to the end user (IE me) is low boost pressure or high boost pressure. I can’t even recall the pressure figures, it was done a couple of years ago and I normally just leave it on higher boost
I can’t recall the ECU, might be Syvecs, might be Alcatek, I’m pretty sure it's not ESL. Duncan @ Racedynamix did the mapping and as I said it is just a simple duel map; the only discernible difference to the end user (IE me) is low boost pressure or high boost pressure. I can’t even recall the pressure figures, it was done a couple of years ago and I normally just leave it on higher boost
Of course I realise this is just one man, one car and one tank of fuel, so it wont be the worlds most conclusive experiment, but it might bring an interesting observation.
Last edited by Lunchmoney; 26 October 2015 at 09:54 AM.
26 October 2015, 11:09 AM
#2
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Hi mate
It was me who was interested in the result
I've been thinking about duel maps for a while as I travel down to London a few times a year plus a fair few other motorway journeys. I am interested to see if this setup could save fuel on a 500 mile trip. It takes about a tank and half(ish) at the moment to get to London and back.
It was me who was interested in the result
I've been thinking about duel maps for a while as I travel down to London a few times a year plus a fair few other motorway journeys. I am interested to see if this setup could save fuel on a 500 mile trip. It takes about a tank and half(ish) at the moment to get to London and back.
26 October 2015, 01:17 PM
#5
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26 October 2015, 01:41 PM
#7
A decent mapper will adjust the whole map(the proper way) So if it's done correctly you should see an MPG difference with the low boost map.
The closed loop leaner tune will defiantly see an improvement
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26 October 2015, 02:52 PM
#8
I know some mappers just lower the boost target and leave fuel and ignition maps the same on both high and low boost.
A decent mapper will adjust the whole map(the proper way) So if it's done correctly you should see an MPG difference with the low boost map.
The closed loop leaner tune will defiantly see an improvement
A decent mapper will adjust the whole map(the proper way) So if it's done correctly you should see an MPG difference with the low boost map.
The closed loop leaner tune will defiantly see an improvement
26 October 2015, 04:07 PM
#9
When you start going for big power like you jay then MPG is the last thing on your mind I suppose.
Plenty of lazy mappers out there,but plenty of real good professional mappers too,just making sure you find one of the good ones
@lunchmoney,,are you going for a map on the rollers or a road map?
See if the mapper will show you the difference between the high and low boost maps,even get a pic or two of the boost,fuel,ignition,maf scale,injector scale,tables ect...
And see if he will let you have a peek at the datalog files too
Plenty of lazy mappers out there,but plenty of real good professional mappers too,just making sure you find one of the good ones
@lunchmoney,,are you going for a map on the rollers or a road map?
See if the mapper will show you the difference between the high and low boost maps,even get a pic or two of the boost,fuel,ignition,maf scale,injector scale,tables ect...
And see if he will let you have a peek at the datalog files too
27 October 2015, 09:17 AM
#11
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@lunchmoney,,are you going for a map on the rollers or a road map?
See if the mapper will show you the difference between the high and low boost maps,even get a pic or two of the boost,fuel,ignition,maf scale,injector scale,tables ect...
And see if he will let you have a peek at the datalog files too
See if the mapper will show you the difference between the high and low boost maps,even get a pic or two of the boost,fuel,ignition,maf scale,injector scale,tables ect...
And see if he will let you have a peek at the datalog files too
27 October 2015, 11:24 AM
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Wheels also DO make a difference. Big wide wheels with sticky semi slick tyres have alot of rolling resistance. I woukd expect to see a marked improvment with standard 17s on road tyres on a 500mile journey
27 October 2015, 02:56 PM
#15
In theory it shouldn't make a difference! mapped right to stoich should just mean that a higher boost map should be capable of giving more when your right foot asks for it, when the right foot isn't asking for it it should behave the same!
The only way to save fuel with a different cal would be to pull fuelling out, in which case you'll run leaner, run hotter, lose efficiency, risk det.
There might be a compromise to find? there might be a way to input exhaust temps into a motorway specific map which leans it off to a safe upper EGT limit? Theres some pretty advanced mapping requirements going on here though and if your venturing into lean then your risking venturing into det.
Im no expert, but I was origionally sold on the idea of having switchable maps to get a frugal map, but on investigation there didn't seem to be any replacement for a lighter right foot.
Interested to see if your findings differ though.
The only way to save fuel with a different cal would be to pull fuelling out, in which case you'll run leaner, run hotter, lose efficiency, risk det.
There might be a compromise to find? there might be a way to input exhaust temps into a motorway specific map which leans it off to a safe upper EGT limit? Theres some pretty advanced mapping requirements going on here though and if your venturing into lean then your risking venturing into det.
Im no expert, but I was origionally sold on the idea of having switchable maps to get a frugal map, but on investigation there didn't seem to be any replacement for a lighter right foot.
Interested to see if your findings differ though.
27 October 2015, 03:06 PM
#16
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So in the spirit of getting all the data together for this ad-hoc "experiment" here is some info about my car (none of which is going to change, the only item changed is the hi/low boost):
MY98 JDM STI;
Aftermarket ECU (I forget which);
3in decat exhaust
Undertray heat shield has been removed as it was falling to bits anyway;
18 in wheels with 215/35 tyres (good wet grip, cant recall exact brand), only about 3000 miles old;
No further mods.
Daily drive to work in traffic, no "spirited" driving
Occasional long journey.
27 October 2015, 03:07 PM
#17
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27 October 2015, 03:12 PM
#18
I've mapped mine so I can hit full boost at half throttle,boost comes in earlier so engine loads Higher at lower rpm(high boost map) I've had to add fuel and pull some timing on this.
So if mapping a low boost(economy map) in theory I should be able to lean the map back again. I'm definitely no expert but I would have thought if mapped correctly then a low boost map will save you fuel?
So if mapping a low boost(economy map) in theory I should be able to lean the map back again. I'm definitely no expert but I would have thought if mapped correctly then a low boost map will save you fuel?
27 October 2015, 03:43 PM
#19
29 October 2015, 01:41 AM
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This will be interesting to see. I put quite a few miles on my car taking in all types of raods and traffic conditions. I have four maps (0.5, 1.0, 1.3 and 1.4). I always run 1.4 so next time I fill up, I'm gonna swap to the 0.5 and see if there's a dfference.
Another test can't harm this thread...
Another test can't harm this thread...
06 November 2015, 08:35 PM
#22
If the off boost area on all maps is the same, unless altered specifically by the mapper, then it will return the same mpg when kept off boost.
I tried running 15.5 afr on my last 98 wrx and on a controlled run to work and back during the week (10 x 22 mile trips) it made maybe 1 mpg difference versus the previous week at 14.7. Both weeks were pretty much same conditions and driving style.
Not really worth it imho.
I tried running 15.5 afr on my last 98 wrx and on a controlled run to work and back during the week (10 x 22 mile trips) it made maybe 1 mpg difference versus the previous week at 14.7. Both weeks were pretty much same conditions and driving style.
Not really worth it imho.
Last edited by Welloilbeefhooked; 06 November 2015 at 08:37 PM.
16 November 2015, 11:13 AM
#24
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If the off boost area on all maps is the same, unless altered specifically by the mapper, then it will return the same mpg when kept off boost.
I tried running 15.5 afr on my last 98 wrx and on a controlled run to work and back during the week (10 x 22 mile trips) it made maybe 1 mpg difference versus the previous week at 14.7. Both weeks were pretty much same conditions and driving style.
Not really worth it imho.
I tried running 15.5 afr on my last 98 wrx and on a controlled run to work and back during the week (10 x 22 mile trips) it made maybe 1 mpg difference versus the previous week at 14.7. Both weeks were pretty much same conditions and driving style.
Not really worth it imho.
As an update I've been on holiday and the car has only done about 100 miles since switching, so I dont have any numbers yet.
16 November 2015, 01:51 PM
#26
what you have done is a far better idea than running a high boost and low boost map as comparison, after all we spend 99% of our time off boost in a closed loop cruise situation. I think 1 mpg is a good average improvement by leaning off the cruise mix.
Changing from hi to low boost maps isnt going to make any difference at all if your on an economy cruise off boost is it?
Changing from hi to low boost maps isnt going to make any difference at all if your on an economy cruise off boost is it?
16 November 2015, 05:26 PM
#27
what you have done is a far better idea than running a high boost and low boost map as comparison, after all we spend 99% of our time off boost in a closed loop cruise situation. I think 1 mpg is a good average improvement by leaning off the cruise mix.
Changing from hi to low boost maps isnt going to make any difference at all if your on an economy cruise off boost is it?
Changing from hi to low boost maps isnt going to make any difference at all if your on an economy cruise off boost is it?
I was trying to help by stating that the cruis area of any map will indeed be closed loop and therefore nothing to do with boost profiles, but what would I know.
16 November 2015, 06:30 PM
#28
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Have you read all of the thread? We know! I am doing to assuage my own curiosity and have offered to share my results. To you guys saying there is no point in doing it, thanks for sharing your experience, hopefully I'll get the same results.
16 November 2015, 08:30 PM
#29
I'm not arguing with you, just trying at add information to the discussion. If you are running lean enough to increase mpg significantly it can have an adverse effect on engine components due to raised egt's.