dazdavies

iTrader: (22)

I'll be the first to admit that I know virtually nothing about the art of engine mapping but I had a conversation with someone today that's kind of stuck with me so I thought I'd share it on here.

I don't know this fella well but we are on a first name basis. Anyway we got talking about cars as you do and the subject eventually went on to mapping.
This chap said he reckoned mapping was a load of sh*te and he'd never have his car mapped as it was waste of money as it was just one map written for someone esles car and they are all generic.

I explained that whenever I've had my car mapped its been driven down the road by me with my mapper in the passenger seat with his Det cans on and listening for knock and thus changing the fueling and the timing accordingly.

Basically this guy started laughing and said I must use sh*t mappers then as thats definetly not the way to do it. I mentioned a couple of names of the mappers I used and explained what their cars do on the drag strip and the track etc still said it was nonsense.
I dropped a coupe of phrases in like closed loop knock control and he started to think a bit. Still arguing against this method of mapping.

So I said to him ok then how would you go about mapping. His answer? Priceless!!..

" I don't know you well enough to tell you"

Then he said well "turbocharging a car is cheating anyway"

After a bit more of his rhetoric he said he chose to keep matters like this to himself. I just said that he'd obviously surpassed his knowledge on the subject but couldn't admit it.

Someone please correct me if I'm wrong but mapping is pretty much about Fuel, air and ignition timing isn't it. Not something mystical that he couldn;t tell me because he "didn't know me well enough" lol

New_scooby_04

iTrader: (4)

Sounds like you know PSLewis, Daz

Says it all really, doesn't it!

What a numpty!

Ns04

R4LLY

iTrader: (1)

What a comedian,

"I Would tell you my Mapping Secrets...... But then I'd have to Kill You!"

joz8968

iTrader: (13)

He sounds like the classic, stereotypical 'pub bloke' gob s h i t e type, who 'knows' everything

andyxros

he must be listening to phil colins through his det cans instead then, because he dosent need to listen out for all important knock or owt and just tells his car not to det or knock and must have a good way with his right foot in controling air an fuel mixture then
i guarantee my car would be minus a piston if it had not of been mapped

dazdavies

iTrader: (22)

On the few occasions I've met this guy he seemed an OK lad but that went all out of the window today especially as he was so certain what he was saying was right.

He's got an Honda Integra Type R that looks like a bag of spuds. He's supposed to be and i quote" one of the most Knowledgeable people on the forums he goes on".

He then tried to tell me that Norris Designs don't build their own engines and some fella called Perry does them all!!
After he said that I realised he was an idiot and the conversation was going to go nowhere.

apalmer

iTrader: (8)

Sounds like one of those "You can map a car by ear blokes" from the BMC engine days. I've heard a similar argument in the past, tosh.

M535I

thats sounds lke some one that there loan wont stretch to a remap lol honda owner was he wearing burberry lol.

BlooSooby

Don't they all?

kylejennings05

sounds like an honda fan off youtube my honda does 0-60 in 2secs standard, smoked a 1000bhp skyline up mc'donalds last night

STiFreak

iTrader: (4)

The guy is talking out of his **** ... plain and simple.
A lot of time and effort goes into mappers base maps, but they will still tweak fuelling, boost, wastegate duty and ign adv in a normal mapping session. IMO, the skill is getting the ign adv close to the knock threshold where the best power is.

MarJay

I'm no expert on car mapping... however...

As far as I'm aware the only way to create an ideal fuel map for a specific engine (with specific mods and factory tolerances etcetera) is to strap the car onto a rolling road dynamometer. Even driving it on the road won't give you the conditions you need to map the engine correctly.

The dynamometer can give your car variable load conditions, it can let it rev from idle to redline in every gear and can measure all of this very precisely. A map done by a guy with a laptop sitting in the passenger seat cannot do that.

This guy is kinda talking bollocks because you need to have the car running with some load on the engine to even begin to do what you're talking about. And as for turbocharging? Considering that in engine terms a turbo equals 'free energy' for the car, then NOT turbocharging the engine is a waste of all those lovely energetic exhaust gases.

Turbo for the win, Rolling road for the win.

(I probably should point out again I'm no expert on car mapping but with regard to motorcycles it is a certainty that anyone who tells you that you can optimise the power gain for any bolt on for your bike without strapping it to a dyno is talking out of his backside. No free energy for bike engines though, unless you want to be able to do 250mph or have some kind of deathwish! )

Shaun

In a basic nutshell, yes you are correct.

StickyMicky

i have never had my 97wrx mapped

i have had

vf22
vf23
vf24
vf28
td04
ported td05
turbos on it

changed the fuel pump, full exhaust, decat, ported headers, zerosports upipe, lightend bits and bobs, blanked off dumpvalve etc etc etc


still running on its 276bhp stock jdm ecu with the boost raised to 1.44bar via a dawse device, and has run this for years and years and years (about 5 years at 1.44bar)

"some" people say i am just "lucky"

i have my own thoughts, i have no doubts that it could be optimised a little bit, especially off boost lower down, but its putting out the stock torque figure at 1krpm lower then a standard car + more available over this so i am reluctant to have somebody "fix" something thats simply not broken

afr is fine on boost, very rare to see any knock retard going on, its all sweet as a nut

i am planning on getting a ecu fitted when the 2.5 is dropped in mind

although i will probably run it in on the 97wrx ecu, just to **** off a few of the doom mongers

it did blow up once a good few years back, but this was after i held it on the limiter for about 5 mins solid in top gear, so thats to be expected

AshMurc

realy??!! are you having a jam bath?!

ps RE the bloke who is the subject of the post-- i think we all have met people like this in one way or another-- a very small amount of knowledge and a shed load of "i AM right!!" mentality. like they can't deal with maybe being wrong one of the most anoying things is walking away and thinking of all these things you could say to blow him out the water... but it still wouldn't get you anywhere with people like that

mickywrx

iTrader: (29)

Gayer.

StickyMicky

really

fact of the matter is, that sometimes the stock ecu can take quite a bit of modding if you know what you are doing

its the n00bs that dont have a clue that

1. end up spending loads of cash
2. blow things to smithereens

as i have proved that it can be done, it means i am ***** ****en elite as hell

LOL @ mickywrx, he never mapped his either

i am going to run it on the stock ecu tho, so not totally gay

would be awesome if it ran the 2.5 with no det once it is ran in, i would run it non stop just to **** people off

dazdavies

iTrader: (22)

You're dreaming!!!
on a 2.5 it'll be det, det, det bang, rattle, rattle

The rookie

iTrader: (1)

I can well believe, fuel and ignition are mapped against airflow, and mapped safe to the boost cut the manufaturers have set, you may not be getting the most from your mods (its too rich as stock anyway) but I have long argued that running below the boost cut with most bolt on mods is as safe as thrashing a stock car......I RR checked mine after upping boost from 0.5 stock to 0.7 bar and the AFR was the same as before, and no det, since then I've done a whole raft of mods to improve the details and the wideband still says the AFR is safe and my det can still says no det'.

Simon

nom

Well...
If you're talking NA, mapping once for all engines of that type is probably good enough - there's so little scope for improvement of engine VE (what mapping all comes down to) that it won't make any difference. So he's right there - sort of - but he obviously hasn't got the foggiest about forced induction engines.
Forced induction can massively change the engine's VE at which point the original map goes out the window. However! If you are using a MAF (therefore directly measuring the air density entering the engine), there are a huge number of mods that can be done without needing to have the car remapped, assuming that the original map was created with this in mind Fortunately for StickyMicky, Subaru have done their work (presumably taking into account the average Impreza driver!) and have programmed fuel/air density maps well past what the standard model can do, so there are an enormous amount of changes that can be made without trouble - the one thing that does need to be controlled outside the normal map is the turbo, easily enough done with its own boost control unit. But making these changes without changing the map means you're not getting the performance you could do - there is (necessarily) a huge safety margin built into standard maps to take account of varying manufacturing quality, global-market weather variations, very different fuel availability, etc. meaning that - for example - full boost on a standard map gets as rich as 10.2:1 - terrible for power, great for durability (as long as you don't do it long enough for bore-wash). And if there's no remap, you're screwed if you go beyond the maximum scaling for the MAF (or other sensor) as it'll likely read the same value at the airflow at, say, 1.3 bar as at 1.4, at which point the engine runs out of fuel & pops...
Erm, so, anyway... NA mapping pretty unimportant, forced induction much more complicted!

Peanuts

iTrader: (15)

its hard to hold a laptop steady on pillion lol
other than that, a complete load of bollocks

MarJay

I've since spoken to some more knowledgable people than I, and as far as I can tell, the fuelling is all down to it being a closed loop system. Whatever you set the fuelling to in the map, the readings from the Lambda sensor will adjust it to be correct. I did not know this, as very few bikes have a closed loop system (and I've only just been able to afford/insure and store a nice car!). Ignition timing and boost however are not precisely managed by readings from the lambda sensor, apart from keeping the ignition timing in an acceptable range (I'm guessing the WRX has a knock sensor somewhere in the system from which the ECU takes readings. When it detects knock I also assume that it backs off boost and ignition timing to very conservative levels).

So, from what I can gather you /can/ adjust boost and ignition timing using a 'drive down the street' method, the only downside you have is repeatability. You have to repeat it in the same conditions each time you do a 'run' otherwise your results are affected I am told that even fuel load might be a factor in this. It might not be by much, but when you're adjusting for peak power, every little helps. A rolling road however, does have its own set of disadvantages, the primary one being that you can't get the same airflow over the intercooler as you get when driving down the street, unless you've got a special air hose or something I suppose. Its kinda swings and roundabouts.

I remain convinced that a rolling road is the best way to do it, but I was incorrect about not getting a good map from 'drive down the street' mapping.

But then, there is a difference between a 'good' map and a 'near perfect' map I suppose...

Oh and my knowledgable mate also said that because of the closed loop system many normally aspirated engines can have a 'standard map' for tuning, as it only really advances the ignition timing a bit.

amahrap

MarJay,

I'm firmly with Andy (Peanuts) on this one - repeatability of wheel loading on the dyno is hardly repeatability worth having due to all the other factors involved. A dyno can't repeat with any true accuracy intake air temp, aerodynamic load (which as you know is exponential anyway), air pressure, air ram, heat soak etc, etc, etc

You really don't need the repeatability to work on a dynamic system where the parameters all interelate as you can see in real time what they are doing from the sensors.

Without wishing to open the same old Scoobynet can of worms my background as an aircraft engineer would lead me to belive that there is only so far that you can go on a dyno.

StickyMicky

:l ol1:

"people" used to say that about a full exhaust system

STiFreak

iTrader: (4)

The ECU can run in both closed and open loop dependent on a whole lot of conditions defined in the ECU ... as a general rule though, it will run in closed loop in the low load, low rpm area of the map for emmissions reasons, keeping AFR as close to stoich as possible. On wide open throttle (WOT) or under load, it switches into OL (the stock lambda sensor is only narrow band, so it not much use once you put your foot down).
The ECU has very advanced knock control built in and will learn to pull timing from areas of the map where it detects knock. If knock gets very bad, it will pull boost and then as a last resort switch into limp home mode. It is way to complex for me to explain here, but if you are really interested here is a detailed article RomRaider • View topic - Subaru's knock control strategy explained
This is probably the main reason some people get lucky and don't kill their engines when making mods and not remapping ... but I would never recommend this course of action because you may still cause damage and your engine will not be running optimally for all the mods you have spent so much money on - it's just a false economy.

MarJay

Cool!

I'm glad you've all replied with sensible responses, a lot of other forums I go on would have been well into flame war territory by now.

Top stuff!

dazdavies

iTrader: (22)

Go on then clever cloggs. Drop your 2.5 in without mapping it, wrag the **** off it and see how long it lasts.

You're depending on too many variables. Especially non too reliable MAF sensors for one. But hey crack on though, when it goes pop I can tell you now I'll be the first to laugh my knackers off

jonny_693

iTrader: (5)

Thought I was being daring running a Y-pipe and centre decat with no map, this makes me feel much better
Mapping a car on the road in a real world situation can only be better than on a RR which is using simulated conditions IMO

joz8968

iTrader: (13)

Yeah, that's a very comprehensive article on the OEM ECU's knock control strategy... if a little heavy-going for the layperson, LOL. Here's a 'simplified' - i.e. easier to grasp - article on it from EcuTeK's website...

Active Ignition Timing

mit

iTrader: (10)

I fitted a 2.5 to my last scoob,running standard ecu with plug n play chip,and 380's. Ran it for 1000 miles,no more than 3000rpm to run it in,no probs.First week i started giving it some welly it went pop! Massive det,and burnt piston. All down to being impatient and not fitting the 740's and pfc before playing!

Mit