Mapping a car - The insider

[Mike1]

What exactly is a remap?

I understand the concept of a remap fully. I understand everything. Its the management of the engine etc etc and what it does etc etc.

What baffles me though is what exactly it really is. Is it binary etc?

Its all good we all buy a remap for the car. All get improvements all round but nobody actually fully understands how a map on a car works. Thats like buying a yacht because it looks nice but you know nothing about yachts. Its a bit blind.

So I have some questions I have been begging to ask:

1. As a developer. Where do you start when it comes to creating an improved map? Do you take the manufacturer's existing map and improve it? Or do you create a new map completely?

2. What is a map? Is it programming like when you program a small java application? Is it just a bunch of numbers put into a spreadsheet? Is there any industrial standard that tuners use to create maps? Does it have a designation? Like a word document is ".doc"

3. How do you create it? Do tuners have a special program? Do tuners all use the same program? How long on average does it take to create a basic map for a new car?

4. Have you ever harmed a car during the creation and testing of a new map? How do you test the map? Do you have a test car? Who provided the car? (Avis hahahhaa) Or is it all theoretical? (I dont expect you to answer this questions if you dont want).

5. Are tuners ever consulted by major manufacturers? What is the relationship between the tuners and OEM manufacturer? We know remaps are not liked at dealers... Just wondering about the bigger picture.

6. What is the oldest car you have worked on in creating a map?

7. Does every car brand require a different method of mapping? For example when you set up a map for a BMW engine is the method the same as when you set up a map for say an Audi or Volkswagen?

I have a few more questions but they are all silly questions so wont bother asking.

Please understand this isnt an attack. Im simply curious about how exactly it works and would like more info. These are questions I have been burning to ask for a while.

I would appreciate it (and other members would too I think) if you could answer my questions and give us an even better understanding of remapping.

Thanks!

Mike

 

[50/50]

Mike Larry why :slap:

 

[clutchplate]

Damn, you're a curious 'lil bugger arn't you

just to start off, everything eventually ends up as binary (aka, 0's and 1's), because thats how IC's interpret things, with gates and switches, on or off. However, map files are ussualy compiled in HEX and then uploaded to an eeprom chip that the ECU's CPU can read..

a MAP is just a table or array of intake manifold pressure values in Kpa related to a engine speed in RPM, it tells the ECU how long to open the injector's valve and when to open it according to the intake manifold pressure.. essentialy thats what it is... tuners use information from dyno's to modify the fuel map at specific points where they think they can increase power by adding/removing fuel from the mix while keeping it as stoichiometric as possible..

I'm not an engine tuner, but I do work with digital electronics and I have a relative idea of how this stuff works, I'm quite certain someone else here will be able to give a better answer...

 

[Mike1]

What I do wrong?

If anything by giving us a better understanding more people may be open to remaps. I love them and what they do.

 

[netercol]

wow, thats enough questions to write a book about i will try to answer a few,given that i have played around alot with mapping on my nissan's (a 300zx and 200sx) , strictly for my own amusement though..
although older ecu's differ from modern ecu's in how operating code and maps are stored, the principle stays roughly the same..

the first thing to understand is why there is a market for this type of thing at all!! i mean does anyone actually think that a manufacturer like BMW does not spend tens of 1000's of hours on the dyno , perfecting the STOCK maps on your pride and joy?? so why can aftermarket tuners actually get more from a given engine by remapping?
simple : because manufacturers are CONSERVATIVE in their mapping.. they try to minimise repairs they have to do under warranty by not running the hardware at the absolute limit, extracting the max power. things like avaidible fuel quality in a given country also play a role in how a car is mapped. so there usually is a margin that can be exploited, this is very much dependant on the spesific engine.

ok, so what is inside a ecu? think of it as a typical computer motherboard , with a cpu doing the thinking, memory for storing programs running in, non volitile memory (think hard drive ) to store maps, opcode ect in when the power gets switched off.

a loose comparison perhaps, but gets the picture across. in a typical ecu the "motherboard" would be the circuitry supporting the cpu ect, and of course the circuitry running the injectors,mafs,sensors,ignition ect,ect..
the "memory" would be the non volitile device storing the operating code (think .exe file) and maps, usually a eprom (erasable programmable read only memory) or in modern ecu's a eeprom (electrically erasable programmable read only memory) or even flash memory in some ecu's.

this binary image residing in the non volitile memory on board the ecu is basically what runs your engine and car, the "windows"
of the ecu if you will, without it the ecu is just a pile of silicon.. this is usually written in the native machine code of the cpu used, for speed of executing. this is not usually the parts that gets altered, messing around with the operating code can lead to the software behaving very oddly, (imagine your ecu throwing a bsod! )

imbedded in these binary images is the maps , these are read by the ecu as a lookup grid, for example say a grid of 32x32 elements, each "block" having a predetermined value. the code running on the ecu will for instance run like this :

rpm is 3000, maf intake 48%, temp 89'c ect, for this calculated value , look at row 5, block 6, which has a value of 10ms.. which means i should keep the injector open for 10ms to inject enough fuel to maintain ideal afr.. (this is a VERY loose aproximation of how it really works, but should do for this explanation)

now we get to what gets modified in a remap.. if a tuner knows where in the binary code this grid is located, a simple substitution of say 11ms in the place of the 10ms in the example above, will cause more fuel to be injected .. voila.
by reworking all these "grids" to give more or less fuel, more boost, more ignition angle, less ignition angle, ect. and the replacing the existing software on the ecu with the modified software, you have a remapped vehicle..

---

1. As a developer. Where do you start when it comes to creating an improved map? Do you take the manufacturer's existing map and improve it? Or do you create a new map completely?

a: existing binery has to be deciphered, (figure out wher the maps are) then the maps can be changed

2. What is a map? Is it programming like when you program a small java application? Is it just a bunch of numbers put into a spreadsheet? Is there any industrial standard that tuners use to create maps? Does it have a designation? Like a word document is ".doc"

a: no standard afaik, these grids (maps) are imbedded in the binary image

3. How do you create it? Do tuners have a special program? Do tuners all use the same program? How long on average does it take to create a basic map for a new car?

a: some programs can be had for some manufacture's some of them very costly.. remember every change has to be tested.. you gonna load your car with software some guy has put together on his pc without even smelling a dyno?

4. Have you ever harmed a car during the creation and testing of a new map? How do you test the map? Do you have a test car? Who provided the car? (Avis hahahhaa) Or is it all theoretical? (I dont expect you to answer this questions if you dont want).

a: i have , easy to run too lean or rich with agressive changes

5. Are tuners ever consulted by major manufacturers? What is the relationship between the tuners and OEM manufacturer? We know remaps are not liked at dealers... Just wondering about the bigger picture.

a: manufactures generally dont like remaps, because it pushes their hardware futher than they intended, and then they sit with warranty claims..

6. What is the oldest car you have worked on in creating a map?

a : my 300zx?

7. Does every car brand require a different method of mapping? For example when you set up a map for a BMW engine is the method the same as when you set up a map for say an Audi or Volkswagen?

a: each ecu is differant, maps in differant places, ect

hope this helps you understand a bit, please bear in mind i do NOT do this profesionally, its a hobby i have had for some time..
for more in depth explanations try this link.. a long read, but worth it..

http://www.ztechz.net/id10.html

 

[Hellas]

:thumbsup: I'm helped.

 

[Jandre]

I'm confused.:bawling:

 

[M3_FTW]

It goes behind just fuelling and timing.Tuners change things like cam timing, ie Vanos etc. But most gains come from getting the timing spot on.

 

[nawtiboy]

i'm a bit confused. :mmm:

a lot of cars ecu's are ROM.:mmm:

how are they changed or can they be changed ?:mmm:

i guess this were the piggy comes in ?:mmm:

 

[netercol]

a lot of cars ecu's are ROM.

how are they changed or can they be changed ?

in older ecu's where the eprom is not programmable through the diagnostics port (electrically) the ecu has to be opened, the eprom desoldered, a socket soldered in, and the modified software burned onto a new eprom, which can then be socketed back into the ecu.. hence the term "chipped"

But most gains come from getting the timing spot on.

so what you are saying is that bmw never got the timing spot on in all their development hours on their dyno's? :mmm:

a piggyback ecu means just that.. it piggybacks on the standard ecu, letting it do all the work, then modifying the standard ecu's output..
for example, it gets wired in between the stock ecu and the injectors. so the standard ecu has calculated a value of 10ms to keep the injector open for, the piggyback ecu intercepts this output and modifies it, keeping the injector open for say, 11ms.. thereby achieving the same result as a modified map.

 

[Twinz]

wow...enough info for that book of yours, Mike :thumbsup:

 

[Sherwin@xcede]

Wow loads of questions here. Looks like most have been answered.

 

[zaleonardz]

Yep, most answered very nicely as well.

I want to expand on this with some further questions to our local tuners

What factors of the motor cannot be configured while using a unichip, we know VANOS cannot handled.

Data logging, what is possible to log, or does that all depends on how well you know the chipher and hex addresses.

Is the rumour true that a BMW ECU can only be programmed 10 times, after that the ECU is useless and cannot but updated, and is essentially scrap ?

THE GM,SA,VIN code details, if you do not have them, is there another source of obtaining them without phoning BMW, and is there somewhere data available that tells you what is where, for example, chaging the coding of the vehcile to add for example DSC for a car that does not have DSC. Lets say I wanted to add DSC to my 540, is it a case of doing the physical ABS pump replacement and adding the additional brake line for the rear, and recoding the ECU/IKE/Other modules with a modified set of the 3 codes.

Good thread mike, I actually learnt quite a bit :thumbsup:

 

[clutchplate]

Lenoard:

unichip-B only changes air/fuel.. dunno about Q

you can program your DME 15 times, then its becomes a doorstop

you can use your INPA/Edibias cable and software to get your GM/SA/VN numbers, OR you can use a GT1 with DIS.. you can extract the GM/SA/VN numbers from your EWS and IKE modules only, when you reprogram your DME it reads the values from your EWS and IKE modules and programs your DME with software related to the options you've chosen.

yeah, You could add options like DSC, but getting the wiring right lol, eish, that will not be so fun.

Maybe someone else would elaborate on the Unichip capabilities..

 

[zaleonardz]

Cluchty, I am having a problem with NCS Expert in obtaining the codes for my E65, I know its supposed to auto detect the numbers, but if memory served, you battled as well on the E39. I also could not pick it up using DIS using the EDIABAS emulation to OBDII

Guess I am just going to have to play...

As for the wiring on the DSC, I have not researched this project at all, but what wiring would need to be done, I would need an additional brake line, that is for sure as the rears are common, but the way that I understand DSC it uses identical inputs as what ABS would, ie the 4 wheel sensors, and instead of releasing hydraulic pressure on a specific output like ABS would, it adds pressure to a certain channel to slow that wheel or both down until you get traction,

The only additional wiring in my mind would perhaps be the DSC switch in the cabin ?

Or am I beling a complete noob, this is on my DIY list to do, for no other reason other then it shall be really fun

Edit : and as for the uni/uniQ, surely it must have some inputs as well, such as exhaust temp and those, so that the piggy back can make an informed decision ?

I am going to do the uniQ on my E34 myself so that I can figure out the wiring with a help of a forum member, and then he can do the dyno, man im in the wrong profession, this is such interesting stuff...

 

[clutchplate]

lol, it is interesting. but ok like, dude DSC retrofit is like beyond our spec I reckon hey. those units are really complicated, REALLY complicated. I think it might be easier to find some kind of opensource stability control project and try use that.. I did hear of something somewhere, I can't recall exactly what it was called, but I know something does exist.

lol, g'luck with the unichip man, I removed mine from the E39.. btw, got all the rest of the electronics on my e39 working tonight, reverse,PDC and starting function works properly now after the manual conversion.. gonna update that old thread of mine with photos and diagrams.

 

[zaleonardz]

That would be a good read clutchy.

However, I am not too sure its going to be that bad, the IKE does have a DSC light, and it was an option.

That one Hellas was looking at had a DSC switch... I'll start the research on this one soon and let you know, I think its just a case of changing the ABS pump and recoding the car, the harness should be standard... but i donno

 

[clutchplate]

ok dude lol, your talking about ASC ... thats a completely different can of beans ... you had me going there for a while..

you get ASC and ASC+T .. DSC is the newer generation stuff we have on the E39 and newer.

 

[zaleonardz]

Ok... ya, my bad.

Now I get you, DSC will be a complete differant ballgame I agree, not only that, the bus is not the same, the DSC's , thats not going to work, cause where do you stop changing out systems, you would have to upgrade virtually if not all modules, and cables and go for a labotomy in order to get this one done..

but ASC is possible :thumbsup:

Dont forget to wash behind your udder imp:

 

[clutchplate]

LMAO! you are a funny guy ..