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-   -   Remapping improve MPG??? (https://www.scoobynet.com/scoobynet-general-1/818304-remapping-improve-mpg.html)

pslewis 12 March 2010 08:01 PM


Originally Posted by dunx (Post 9281824)
Because nobody else would/does.....

Simples !

dunx

P.S. My warranty is the fact that I can go a buy a new one from any dealer tomorrow as they can't seem to sell them.....

Well, Subaru could stun the world and be the first!!

They don't offer one because that holy grail of 550 BHP when wanted and 30 mpg when not is a pipe dream ..... only visible in the minds of hobbyists :D

Don't understand your ps?

StanS 12 March 2010 08:24 PM

You cannot seriously expect us to believe that, with your wealth of engineering experience and knowledge of engines that all you need to get 550BHP is a re-map.:lol1: (or are you just old with no experience of anything outside a PC screen !)
You are trying (and failing) to distract the argument (again) - what fun! The original point was that a remap can improve mpg, which is true. Also it can improve engine efficiency. Nothing to do with 550BHP cars. (Nice try)
Why do they spend £750K to produce a rally car if all you need to do engine wise is a remap ?! Think of the money they are wasting. You must tell them they only need to remap a std engine.

We have agreement - a 550BHP version STi would not have mass appeal for the reasons I mentioned. Their 300BHP STi is a compromise for the enthusiast who wants some performance. More enthusiastic drivers can then spend more to get their prefered compromises in their car. Are you suggesting that Subaru could produce (and sell at a profit) a 550BHP STi for under £35K???
:lol1: You must get out more :lol:

As for your "banning" comment, once again generalise and throw in a distractor comment ! Adding a few smilies is another good distractor.

Now bored with your game. I have a life away from the computer. (I don't intend ever getting to 25000 posts ! lol)

Scooby Jonni 12 March 2010 08:38 PM

I'm pretty sure you get a better MPG from a bigger engine and less boost when it is producing its maximum power so any MPG benefits would be outweighed.

As said it would cost no more to build a higher capacity engine with less boost as you wouldn't need to use forged parts which cost more to manufacture. Drivability and getting it though the emissions test would also be a major issue. Building a 2.5lt engine with 550bhp makes no commercial sense.

IainMilford 12 March 2010 10:19 PM

This thread will go forever because its one, maybe two people versus the entire 100K population of scoobynet, there will always be a new performance car enthusiast coming along to respond to the same old questions that ssu/pslewis keep posting, if they are different people ?? lol

GC8 12 March 2010 10:50 PM

Ignore the trolling fool.

dunx 13 March 2010 08:52 PM

If it eventually breaks I'll go and buy a hatch, £23K for a 59 plate STI isn't bad.

dunx

P.S. You have managed 10 years with yours, you aren't helping their cause by NOT buying a new one....

pslewis 13 March 2010 09:00 PM

I see your point now ...... yes well if you have a modified Impreza then you have rendered it worthless - more or less - so there is nothing to be lost in a re-map blowing apart the engine.

porteouz 14 March 2010 03:15 PM

Worthless? lol

pslewis 15 March 2010 07:52 PM

Well, not worth very much then .... not compared to a standard car - it's how it has always been.

You rally wannabbees spend £££££££££££££££'s modifying and then have a huge shocked when no-one wants your pride and joy when it comes to selling it.

porteouz 15 March 2010 10:17 PM


your pride and joy
You hit the nail on the head there. I personally couldnt care what its worth when I go to sell it. All that matters to me is how the car makes me feel when I see and drive it. If spending money to modify it to how I want it to be makes me feel better then who are you or anyone else for that matter to tell me Im doing it wrong

FCCWRX 09 May 2016 07:03 PM

Hi all I know these are really old posts and maybe no one is reading them anymore. I have just bought a WRX Impreza bug eye, with 3 inch cat less, modded air filter one of those K and N jobs and some noisy BOV. Apparently I get the orange engine light on, as I was told by a mechanic because of this mod. They said I need it to be re mapped. Currently with steady motorway driving at 60mph, with only a few foot downs to 80mph or so, over 3 tanks of gas so far, I get approximately 288miles/tank.

No one here seems to be saying at what speed they are driving? Like everyone of course is passing me at 60mph, at least 80mph plus, so I'm standing still. BUT if I punch the gas in 5th at 60mph I can easily catch them, if I want. Of course I literally see the fuel gauge dropping LOL.
For me before I get any remap. I want to be reassured that under similar driving conditions, i.e. motorway at 60mph (not trying to pass everyone in sight etc), that I'm going to be getting better than 288miles per tank or at least keep it at the same but certainly no less. Oh yeah I bought this car based on driving an XT turbo in Australia on loads of dirt (I'm from Australia), which I loved (the Subaru I mean + Australia LOL) but NOT just for power/weight ratio but for good handling on wet narrow roads and general driver comfort.

So any comments on 288miles/tank? as being good/could be better as I don't seem to see anyone stating 300miles/tank?

Norman Dog 09 May 2016 07:18 PM


Originally Posted by FCCWRX (Post 11831012)

So any comments on 288miles/tank? as being good/could be better as I don't seem to see anyone stating 300miles/tank?

288 miles per tank :lol1:
You're not driving it properly, I used to get a maximum of around 230, 175ish if I was having fun. :D

That was in a 2003 WRX remapped to around 280BHP, 2.5 STi I had afterwards was even worse.

So to answer your question about a remap improving fuel economy, mine was no worse on juice but not noticeably better either.

RS_Matt 09 May 2016 07:24 PM

I get about 250-350 miles off £60, how much money to fill a tank?

FCCWRX 09 May 2016 07:25 PM

Hi LOL, yeah well I forgot the additional information that I now have a small child sitting in the back of the car...... Like today "dad" punched the gas a few times for some fun needless to say mum was not in the car. Ok that's good advice/info, thanks. So in that case, I'll be asking a lot of questions Before any remap as I don't need a divorce just yet LOL!

FCCWRX 09 May 2016 07:27 PM


Originally Posted by RS_Matt (Post 11831021)
I get about 250-350 miles off £60, how much money to fill a tank?

I don't let it go past 3/4 of a tank and am using on V power, so ok the more expensive fuel. So that's about 40 quid I guess to fill it up from 3/4 empty.

Norman Dog 09 May 2016 07:36 PM


Originally Posted by RS_Matt (Post 11831021)
I get about 250-350 miles off £60, how much money to fill a tank?

Assuming super unleaded around £69, if you don't run the thing totally empty, say fill up at the red light, around £60ish.

If you're getting 350 per tank :Whatever_ take it you do a lot of off boost motorway driving? :wonder:

RS_Matt 09 May 2016 07:45 PM


Originally Posted by Norman Dog (Post 11831028)
Assuming super unleaded around £69, if you don't run the thing totally empty, say fill up at the red light, around £60ish.

If you're getting 350 per tank :Whatever_ take it you do a lot of off boost motorway driving? :wonder:

I live in the countryside and often have kids in the car. Car is stripped. I don't drive silly and let off the gas well before junctions.

Driving style off-boost is quite variable amongst Subaru drivers. You get some claiming as little as 18mpg and some as high as 38mpg.

Some Subaru owners cruise at 30mph in 3rd with short ratios and some Newage WRX owners cruise at 30mph in 5th with ratios as long as Tom's Pinocchio Nose.

TBH all models should roughly be 25-30mpg combined with up to 40mpg extra urban for some 2001> models.

mickywrx 09 May 2016 08:22 PM


Originally Posted by Norman Dog (Post 11831028)
If you're getting 350 per tank :Whatever_ take it you do a lot of off boost motorway driving? :wonder:

I got over 400 miles to a tank once, that was mainly steady cruise on M roads.

It's quite easy to use half a tank in under 40 miles though. :D

Dvddan 12 May 2016 04:19 PM

Not sure how you get more MPG from a re-map and not causing damage to happen faster than the norm, surely you re-map the car knowing things WILL need changing on a regular basis, well a lot more so than a standard car and the fact you are taking the BHP up will make the car drink petrol faster when putting your foot down, so on average you will never get a better MPG on a remapped car without causing damage to it.
Do you guys honestly think a mapper would tell you what he is doing isn't good for the car, if he did he wouldn't have a business, of course remapping will never be good for along life of the car as Subaru would send them out mapped this way.
Our cars are mapped to be a daily drivers with no issues or as little as possible and of course we need to remap the cars to get the insane figures we see but at some point money will need to be thrown at them to repair the damage caused.Just ask the Subaru rally team

SmurfyBhoy 12 May 2016 04:28 PM


Originally Posted by Dvddan (Post 11832162)
Not sure how you get more MPG from a re-map and not causing damage to happen faster than the norm, surely you re-map the car knowing things WILL need changing on a regular basis, well a lot more so than a standard car and the fact you are taking the BHP up will make the car drink petrol faster when putting your foot down, so on average you will never get a better MPG on a remapped car without causing damage to it.
Do you guys honestly think a mapper would tell you what he is doing isn't good for the car, if he did he wouldn't have a business, of course remapping will never be good for along life of the car as Subaru would send them out mapped this way.
Our cars are mapped to be a daily drivers with no issues or as little as possible and of course we need to remap the cars to get the insane figures we see but at some point money will need to be thrown at them to repair the damage caused.Just ask the Subaru rally team

Not necessarily true,

2.5 always benefit from a remap if mapper is competent,

Also thought JDM cars benefitted from getting mapped to our fuel :)

Dvddan 12 May 2016 04:43 PM

Never re-mapped my Jap Import car plus you're talking about a car that was mapped for Jap fuel then being run on UK fuel, different kettle of fish.
I remember the good old days when the Impreza 1st hit the uk, ,mappers ALL claimed no damage to the cars, funny that as they were popping left right and centre.
Show me a 17 year old subaru that has been remapped with no damage to a single component on the car, because I can show you 1 that hasn't been remapped running on all the components fitted in the factory on day it was built bar the all service parts and 1 timing belt

FCCWRX 12 May 2016 09:15 PM

Ok so I had my car remapped as it had from previous owner a cat-less exhaust fitted. I will be keeping a close watch on performance. I'll take careful notes. The remap was for modifications only. My days of fanging the daylights out of it on dirt roads are unlikely these days.

8ulldog 12 May 2016 09:35 PM

My hatch STi normally gets just under 300 miles to a tank, the trip computer tells me I average around 26 miles to the gallon, this is with a few mods and a remap. I used to average just u der 24mpg before having it done.

Mainly just cruising, with the odd spirited moment.

FCCWRX 13 May 2016 07:21 PM


Originally Posted by 8ulldog (Post 11832241)
My hatch STi normally gets just under 300 miles to a tank, the trip computer tells me I average around 26 miles to the gallon, this is with a few mods and a remap. I used to average just u der 24mpg before having it done.

Mainly just cruising, with the odd spirited moment.

Yeah, That's exactly my driving style now, with those "enthusiastic moments" Anyway hoping for slightly better performance.

mickywrx 13 May 2016 09:11 PM


Originally Posted by Dvddan (Post 11832166)
Show me a 17 year old subaru that has been remapped with no damage to a single component on the car, because I can show you 1 that hasn't been remapped running on all the components fitted in the factory on day it was built bar the all service parts and 1 timing belt

You'll be showing us a car that's been neglected if it's only had 1 timing belt in that time.

Mine is 22 years old never been remapped and I'm on my 4th gearbox, so your claim is bullshit. :)

RS_Matt 14 May 2016 01:29 PM


Originally Posted by Dvddan (Post 11832162)
Not sure how you get more MPG from a re-map and not causing damage to happen faster than the norm, surely you re-map the car knowing things WILL need changing on a regular basis, well a lot more so than a standard car and the fact you are taking the BHP up will make the car drink petrol faster when putting your foot down, so on average you will never get a better MPG on a remapped car without causing damage to it.
Do you guys honestly think a mapper would tell you what he is doing isn't good for the car, if he did he wouldn't have a business, of course remapping will never be good for along life of the car as Subaru would send them out mapped this way.
Our cars are mapped to be a daily drivers with no issues or as little as possible and of course we need to remap the cars to get the insane figures we see but at some point money will need to be thrown at them to repair the damage caused.Just ask the Subaru rally team

AFAIK mapping involves the car running a little richer on boost which helps the cooling of the cylinders. Arguably increasing the longevity of an engine.

It's mainly off-boost where fuel savings are made and calculated. I'm not sure off the long term benefits or hindrances off running slightly richer in the lower rev range.

TECHNOPUG 14 May 2016 03:58 PM


Originally Posted by RS_Matt (Post 11832917)
AFAIK mapping involves the car running a little richer on boost which helps the cooling of the cylinders. Arguably increasing the longevity of an engine.

It's mainly off-boost where fuel savings are made and calculated. I'm not sure off the long term benefits or hindrances off running slightly richer in the lower rev range.

Running leaner creates more power, it's usually the fuel that is trimmed on remaps, hence the increased efficiency and economy. Plus you have more power and don't need to rev the car so hard for similar performance.

TECHNOPUG 14 May 2016 04:05 PM


Originally Posted by mickywrx (Post 11832761)
You'll be showing us a car that's been neglected if it's only had 1 timing belt in that time.

Mine is 22 years old never been remapped and I'm on my 4th gearbox, so your claim is bullshit. :)

Mine's 14 years old with 158k and was remapped by the dealer prior to sale. No engine or transmission components have ever failed or been replaced other than service items.

A poorly mapped car will cause issues, equally a well mapped car that has aftermarket components exceeding the capabilities that the stock parts were designed for, will have issues. But that's not a fault of the mapping.

A sweeping statements that remaps are detrimental to the longevity of an engine shows a fundamental misunderstanding of what an engine map is, what is does and what effects changing it can have.

mickywrx 14 May 2016 07:00 PM


Originally Posted by TECHNOPUG (Post 11832956)
Mine's 14 years old with 158k and was remapped by the dealer prior to sale. No engine or transmission components have ever failed or been replaced other than service items.

A poorly mapped car will cause issues, equally a well mapped car that has aftermarket components exceeding the capabilities that the stock parts were designed for, will have issues. But that's not a fault of the mapping.

A sweeping statements that remaps are detrimental to the longevity of an engine shows a fundamental misunderstanding of what an engine map is, what is does and what effects changing it can have.

You must treat yours with a bit of mechanical sympathy. :thumb: Mines had its head kicked in too many times. :lol1: All I've ever broken is gearboxes.

Bang on the money with the second 2 paragraphs. :thumb:

Dvddan 16 May 2016 08:11 AM

Not sure how running a car lean will make the engine last longer, Surely Subaru would run all their engines lean if that was the case.
As for my bull**** regarding my Impreza only having 1 timing belt change in 17 years, (was SORN for 6 years) feel free to come and see it any time I can tell you its not a dog thats for sure, check my pictures out make your own mind up.
My last comment on the matter, if you guys think re-mapping a car and running lean, running silly power doesn't do more damage to a car that is in standard form, I.E factory settings then you are more deluded than I thought.
P.S 4 gearboxes you need to take a look at your driving style thats for sure,PMSL

Almost everything in common use today is based on lean burns. The negative effects of too lean effects are mentioned. One important factor missing is a "random" effect this creates in combustion.
Too lean will create an inconsistent combustion effect, thus no efficiency is realized and the opposite is achieved for "too" lean. An engine needs proper controls to handle and stabilize these conditions, an 02 sensor and Ron/Mon ratings (octane levels). The real problem is using a lean mixture the engine was not designed to handle. You actually can have combustion scattered and create knock if your engine can't control the mixtures. Pre-ignition is burning the mixture before the Sparkplug is supposed to ignite it. It happens due to hot spots in the chambers. If there are hot spots then the temp in the chamber is too high.

If you compensate with plugs and higher octane gas then you are increasing combustion chamber temps and ultimately increasing your cost and eliminating any savings.

High temps is the negative effect, you can actually melt pistons, burn holes in them, and throw a rod through the engine case with miscalculated combustion out of time with the engine. About as severe as you can get.

Engines are designed by engineers and have parameters involved. They are obviously designed to operate within these parameters. If you want to tweak the engine beyond it's designed limits in some way? Good luck with that, OK? If you succeed I'm sure the designers would gladly pay you for your achievement with out question and you could get a job especially in aeronautic type if the Japanese don't kidnap you first.
I totally understand that to get these huge power gains you MUST re-map the car, my point is that in doing this the long term affect will cause more damage to the car or replacing parts on the car a lot more regularly than if just left in the standard form


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