Remapping improve MPG???
05 March 2010, 04:32 PM
#271
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There is enough explaination in the thread as to how you can improve the over MPG in conjunction with gaining more power in WOT (Wide Open Throttle) conditions.
Since the amount of fuel for a given running condition can be finely controlled, if it is reduced for no loss or even a gain in power, then you can travel at the same speed or accelerate at the same rate while using less fuel.
I've know cars that are still clocking up the miles, at least 50,000 miles after the initial increase in power via hardware and ECU mods.
Since the amount of fuel for a given running condition can be finely controlled, if it is reduced for no loss or even a gain in power, then you can travel at the same speed or accelerate at the same rate while using less fuel.
I've know cars that are still clocking up the miles, at least 50,000 miles after the initial increase in power via hardware and ECU mods.
I really don't see why everyone is so upset about this.
A Subaru map will give a massive margin for error/parts failure/wear and tear without the engine destroying itself. A re-map takes out some of that margin and trades it for performance. This is why Subaru can confidently offer a warranty. A warranty from a mapper would be worthless because it would be impossible to tell the exact cause of an engine failure. It would likely be a combination of various after-market parts, wear and tear and tighter margins from the map. It still amazes me when I hear people on here talking about re-mapping high mileage cars.
As far as I can see the only way a re-map could give better mpg is if the owner could drive at the same speed but with smaller throttle openings than before. This is unlikely and impossible to quantify…….not to mention plain stupid! If you’re worried about the cost of fuel, save yourself the cost of the map and drive slower
.
I can understand the desire to get more power out of a second car as a hobby - in the full knowledge that things could go wrong - but to go down this route with a car you have to rely on to get to work, take the kids to school etc.. seems foolhardy to me.
A Subaru map will give a massive margin for error/parts failure/wear and tear without the engine destroying itself. A re-map takes out some of that margin and trades it for performance. This is why Subaru can confidently offer a warranty. A warranty from a mapper would be worthless because it would be impossible to tell the exact cause of an engine failure. It would likely be a combination of various after-market parts, wear and tear and tighter margins from the map. It still amazes me when I hear people on here talking about re-mapping high mileage cars.
As far as I can see the only way a re-map could give better mpg is if the owner could drive at the same speed but with smaller throttle openings than before. This is unlikely and impossible to quantify…….not to mention plain stupid! If you’re worried about the cost of fuel, save yourself the cost of the map and drive slower
.I can understand the desire to get more power out of a second car as a hobby - in the full knowledge that things could go wrong - but to go down this route with a car you have to rely on to get to work, take the kids to school etc.. seems foolhardy to me.
05 March 2010, 04:56 PM
#273
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05 March 2010, 06:26 PM
#274
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SSU just go away and start OEMnet and leave us to our fun.
dunx
P.S. I hate having an extra 50% bhp and torque, not to mention the 2 mpg decrease I have to endure for 6000 miles each year....
dunx
P.S. I hate having an extra 50% bhp and torque, not to mention the 2 mpg decrease I have to endure for 6000 miles each year....
05 March 2010, 07:42 PM
#275
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I really don't see why everyone is so upset about this.
A Subaru map will give a massive margin for error/parts failure/wear and tear without the engine destroying itself. A re-map takes out some of that margin and trades it for performance. This is why Subaru can confidently offer a warranty. A warranty from a mapper would be worthless because it would be impossible to tell the exact cause of an engine failure. It would likely be a combination of various after-market parts, wear and tear and tighter margins from the map. It still amazes me when I hear people on here talking about re-mapping high mileage cars.
As far as I can see the only way a re-map could give better mpg is if the owner could drive at the same speed but with smaller throttle openings than before. This is unlikely and impossible to quantify…….not to mention plain stupid! If you’re worried about the cost of fuel, save yourself the cost of the map and drive slower.
I can understand the desire to get more power out of a second car as a hobby - in the full knowledge that things could go wrong - but to go down this route with a car you have to rely on to get to work, take the kids to school etc.. seems foolhardy to me.
A Subaru map will give a massive margin for error/parts failure/wear and tear without the engine destroying itself. A re-map takes out some of that margin and trades it for performance. This is why Subaru can confidently offer a warranty. A warranty from a mapper would be worthless because it would be impossible to tell the exact cause of an engine failure. It would likely be a combination of various after-market parts, wear and tear and tighter margins from the map. It still amazes me when I hear people on here talking about re-mapping high mileage cars.
As far as I can see the only way a re-map could give better mpg is if the owner could drive at the same speed but with smaller throttle openings than before. This is unlikely and impossible to quantify…….not to mention plain stupid! If you’re worried about the cost of fuel, save yourself the cost of the map and drive slower
.I can understand the desire to get more power out of a second car as a hobby - in the full knowledge that things could go wrong - but to go down this route with a car you have to rely on to get to work, take the kids to school etc.. seems foolhardy to me.
Re-maps are really for cars you are willing to have blow up on you, track cars and racing/rally cars - they are being taken outside of their designed operating parameters and there is a reason Subaru don't do it.
And this is where we all came in ... will a re-map result in better mpg? I say no for a couple of reasons.
It cannot be proved or quantified - an improvement of 2 mpg simply cannot be measured with any accuracy and, even then, was it just the re-map which achieved it? ... usually there are other modifications done at the same time as the re-map.
And, why have a re-map to get better mpg? No point - even if it were true (which I don't believe it is) ...
Anyway, where does the extra fuel go which Subaru are pumping into the cylinders? It's not sitting on my CATs that's for sure or they would have broken up by now.
05 March 2010, 07:45 PM
#276
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500 BHP and 28 mpg
Priceless ..... are you watching SUBARU????
Look what hobbyists can achieve! .... why don't you offer me a 500 BHP Impreza which returns me 28 mpg!?!?!?
Mad? I'm foofing fuming!!
05 March 2010, 07:46 PM
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05 March 2010, 07:50 PM
#278
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There are highly qualified engineers at Subaru who give me the best possible map in respect of longevity, reliability, fuel efficiency, emissions and noise
05 March 2010, 08:22 PM
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05 March 2010, 08:38 PM
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It is burnt but produces extra (and additional wasted) heat rather than forward motion. The most fuel efficient cars are excellent at converting chemical energy in fuel into kinetic energy. Adding extra fuel as a safety margin helps cover all eventualities in terms of engine reliability but makes the car less fuel efficient. One reason why a remap can increase efficiency - it's really not rocket science
That heat comes from an explosion - so a re-map must reduce that explosion to reduce the heat, therefore less power ..... now, I can see why there is a better mpg in a re-mapped car, there is less fuel - less explosive power - less heat.
OH, hang on a minute .... the higher explosive power is what gives the higher BHP, now you have confused me even more.
Next you will be trying to convince me that a re-map changes the flow of gas inside the cylinder
Last edited by SunnySideUp; 05 March 2010 at 08:40 PM.
05 March 2010, 09:03 PM
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I really don't see why everyone is so upset about this.
A Subaru map will give a massive margin for error/parts failure/wear and tear without the engine destroying itself. A re-map takes out some of that margin and trades it for performance. This is why Subaru can confidently offer a warranty. A warranty from a mapper would be worthless because it would be impossible to tell the exact cause of an engine failure. It would likely be a combination of various after-market parts, wear and tear and tighter margins from the map. It still amazes me when I hear people on here talking about re-mapping high mileage cars.
As far as I can see the only way a re-map could give better mpg is if the owner could drive at the same speed but with smaller throttle openings than before. This is unlikely and impossible to quantify…….not to mention plain stupid! If you’re worried about the cost of fuel, save yourself the cost of the map and drive slower.
I can understand the desire to get more power out of a second car as a hobby - in the full knowledge that things could go wrong - but to go down this route with a car you have to rely on to get to work, take the kids to school etc.. seems foolhardy to me.
A Subaru map will give a massive margin for error/parts failure/wear and tear without the engine destroying itself. A re-map takes out some of that margin and trades it for performance. This is why Subaru can confidently offer a warranty. A warranty from a mapper would be worthless because it would be impossible to tell the exact cause of an engine failure. It would likely be a combination of various after-market parts, wear and tear and tighter margins from the map. It still amazes me when I hear people on here talking about re-mapping high mileage cars.
As far as I can see the only way a re-map could give better mpg is if the owner could drive at the same speed but with smaller throttle openings than before. This is unlikely and impossible to quantify…….not to mention plain stupid! If you’re worried about the cost of fuel, save yourself the cost of the map and drive slower
.I can understand the desire to get more power out of a second car as a hobby - in the full knowledge that things could go wrong - but to go down this route with a car you have to rely on to get to work, take the kids to school etc.. seems foolhardy to me.
Sensible post ...
Re-maps are really for cars you are willing to have blow up on you, track cars and racing/rally cars - they are being taken outside of their designed operating parameters and there is a reason Subaru don't do it.
And this is where we all came in ... will a re-map result in better mpg? I say no for a couple of reasons.
It cannot be proved or quantified - an improvement of 2 mpg simply cannot be measured with any accuracy and, even then, was it just the re-map which achieved it? ... usually there are other modifications done at the same time as the re-map.
And, why have a re-map to get better mpg? No point - even if it were true (which I don't believe it is) ...
Anyway, where does the extra fuel go which Subaru are pumping into the cylinders? It's not sitting on my CATs that's for sure or they would have broken up by now.
Re-maps are really for cars you are willing to have blow up on you, track cars and racing/rally cars - they are being taken outside of their designed operating parameters and there is a reason Subaru don't do it.
And this is where we all came in ... will a re-map result in better mpg? I say no for a couple of reasons.
It cannot be proved or quantified - an improvement of 2 mpg simply cannot be measured with any accuracy and, even then, was it just the re-map which achieved it? ... usually there are other modifications done at the same time as the re-map.
And, why have a re-map to get better mpg? No point - even if it were true (which I don't believe it is) ...
Anyway, where does the extra fuel go which Subaru are pumping into the cylinders? It's not sitting on my CATs that's for sure or they would have broken up by now.
It is just a pity that the more than overwhelming technical expertise on this thread is in total opposition to the 'engineering' expertise that is the foundation of Pete's point of view.
By the way Pete when is your 'friend' at IM who asks for your frequent advice going to make an appearance?
05 March 2010, 09:13 PM
#282
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that I think that they could actually benefit from the professional mappers on this forum, after all they really could not do a worse job could they. 
After all word of mouth is the best advertising possible; it is just a pity that your foot is in yours.
I'm not saying don't have fun - I've never said that ... far from it - just don't tell us Engineers that you have re-written the laws of physics in the back of your garage whilst tinkering
There are highly qualified engineers at Subaru who give me the best possible map in respect of longevity, reliability, fuel efficiency, emissions and noise
There are highly qualified engineers at Subaru who give me the best possible map in respect of longevity, reliability, fuel efficiency, emissions and noise
05 March 2010, 10:01 PM
#283
Try 550 bhp and almost 30 mpg here.
Very happy for you to sit beside me for 300 odd miles on a tank full of fuel pete to verify this as it seems that the only way you will believe anything is to see it. You still dont get it or you are just being a pillock for the amassed audience to uphold your excellent reputation.
As previously stated I am happy to give you a free try before you try but that seems that it wouldn't help your cause of being provocatuer here.
Read what has been stated here by the various other people and with your engineering mind do some research into afr and power to understand more. The answer is out there.
Very happy for you to sit beside me for 300 odd miles on a tank full of fuel pete to verify this as it seems that the only way you will believe anything is to see it. You still dont get it or you are just being a pillock for the amassed audience to uphold your excellent reputation.
As previously stated I am happy to give you a free try before you try but that seems that it wouldn't help your cause of being provocatuer here.
Read what has been stated here by the various other people and with your engineering mind do some research into afr and power to understand more. The answer is out there.
Last edited by dynamix; 05 March 2010 at 10:03 PM.
05 March 2010, 10:09 PM
#284
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I dont think it matters what Simon/Paul/Duncan or anybody else says. Pete is a re,map hater end off.
I love the qoute from Pete remaps will make your car blow up! Mine is mapped a number of times running 400ish BHP, couldnt tell you the MPG as i dont care, i drive a diesel golf for that. Pete if it blows up, i will rebuild the engine, and yes you guessed it get it mapped again.
I love the qoute from Pete remaps will make your car blow up! Mine is mapped a number of times running 400ish BHP, couldnt tell you the MPG as i dont care, i drive a diesel golf for that. Pete if it blows up, i will rebuild the engine, and yes you guessed it get it mapped again.
05 March 2010, 10:54 PM
#285
Why not grab a ride with Duncan, he uses his race car as a daily driver ??
It is possible to have a high power car and return reasonable mpg when driven so, obvs not when you're using your 500 ponies.
05 March 2010, 10:57 PM
#287
It produces extra heat, more heat than a re-map then? .... all that heat must have burned a hole in my pistons by now, surely?
That heat comes from an explosion - so a re-map must reduce that explosion to reduce the heat, therefore less power ..... now, I can see why there is a better mpg in a re-mapped car, there is less fuel - less explosive power - less heat.
OH, hang on a minute .... the higher explosive power is what gives the higher BHP, now you have confused me even more.
Next you will be trying to convince me that a re-map changes the flow of gas inside the cylinder
That heat comes from an explosion - so a re-map must reduce that explosion to reduce the heat, therefore less power ..... now, I can see why there is a better mpg in a re-mapped car, there is less fuel - less explosive power - less heat.
OH, hang on a minute .... the higher explosive power is what gives the higher BHP, now you have confused me even more.
Next you will be trying to convince me that a re-map changes the flow of gas inside the cylinder
Higher BHP does mean more fuel at full throttle but we're talking about part throttle here and MPG when cruising.
I'm confused now - are you just monumentally thick or do you have an incredibly large chip on your remap-hating shoulder?
05 March 2010, 10:57 PM
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05 March 2010, 11:01 PM
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Are you trying to tell me that the map controls the flame front burn? Nowt to do with the piston shape, then?
The maps job is done the instant the spark plug fires - can you at least understand that bit?
05 March 2010, 11:05 PM
#291
It cannot be proved or quantified - an improvement of 2 mpg simply cannot be measured with any accuracy and, even then, was it just the re-map which achieved it? ... usually there are other modifications done at the same time as the re-map.
And, why have a re-map to get better mpg? No point - even if it were true (which I don't believe it is) ...
I dont know anyone who has had a remap purely just to get better mpg, its always for more power and generally after some mods which all contribute
05 March 2010, 11:06 PM
#292
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I get jehovah's witnesses round my house trying to tell me that their way is the right way, they even have friends with them to help them out .... doesn't mean they are right.
So, do you think I take everything at face value? Nah, I'm way too clever for that - I like to question things ...... like getting 30 mpg from 550 BHP and, of course, re-writing the laws of physics - as I have said.
So, do you think I take everything at face value? Nah, I'm way too clever for that - I like to question things ...... like getting 30 mpg from 550 BHP and, of course, re-writing the laws of physics - as I have said.
05 March 2010, 11:10 PM
#293
I get jehovah's witnesses round my house trying to tell me that their way is the right way, they even have friends with them to help them out .... doesn't mean they are right.
So, do you think I take everything at face value? Nah, I'm way too clever for that - I like to question things ...... like getting 30 mpg from 550 BHP and, of course, re-writing the laws of physics - as I have said.
So, do you think I take everything at face value? Nah, I'm way too clever for that - I like to question things ...... like getting 30 mpg from 550 BHP and, of course, re-writing the laws of physics - as I have said.
I've only just worked that you like to question things, thats why this thread has gone on for 10 pages and I hav'nt got any work done today
05 March 2010, 11:13 PM
#294
It moves across the top of the piston ... your lack of understanding does you no favours whatsoever.
Are you trying to tell me that the map controls the flame front burn? Nowt to do with the piston shape, then?
The maps job is done the instant the spark plug fires - can you at least understand that bit?
Are you trying to tell me that the map controls the flame front burn? Nowt to do with the piston shape, then?
The maps job is done the instant the spark plug fires - can you at least understand that bit?
Except that the map's job is to determine how much fuel to squirt in before ignition takes place. If the mixture is on the rich side, slightly less fuel can still produce a flame front that is equally effective at shifting the piston down the cylinder while improving MPG
05 March 2010, 11:28 PM
#296
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Well, gents I would love to stay and discuss the finer points of combustion and persuade you into the light ... but, my bed calls ... I've got some brake pads to do tomorrow (that's if I know which way to put them in!!)
05 March 2010, 11:30 PM
#297
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I'm no ally of anyone; I just have a car that I need to start and run without fault every day. My Impreza has been pretty much faultless for 10 years now.
I really can see the appeal of a high power Impreza but the fact that you have a diesel Golf aswell kind of validates my point.
I really can see the appeal of a high power Impreza but the fact that you have a diesel Golf aswell kind of validates my point.
05 March 2010, 11:34 PM
#298
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I have to admit though SSU that you are so resolute in your opinion that you could easily sort out the Middle East if they sat around the table and you chaired the meeting.
Traps them more like, I bet they are literally breaking down doors to get out.
05 March 2010, 11:35 PM
#299
So where does PPP - the "official remap" fit into all of this?
If Subaru can confidently offer a 3 year warranty on X bhp, then how can Prodrive match the 3 year warranty for another 20% power? Surely by the reasoning of some on here, that extra 20% power is outside the magical "designed operating parameter".
Either Subaru or Prodrive have fouled up on their risk of failure projections and therefore one party of engineers don't know what they are doing?
If Subaru can confidently offer a 3 year warranty on X bhp, then how can Prodrive match the 3 year warranty for another 20% power? Surely by the reasoning of some on here, that extra 20% power is outside the magical "designed operating parameter".
Either Subaru or Prodrive have fouled up on their risk of failure projections and therefore one party of engineers don't know what they are doing?
05 March 2010, 11:40 PM
#300
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I have only owned Imprezas for 18 months but I haven't had a problem standard or modified.