why is the VR4's mapping so s**t?

[psbarham]

Why did mitsubishi feel the need to make the mapping so crap on the vr4?

for example why is there a 10mpg difference between 4th and 5th at the same rpm and throttle position with 5th being the winner on fuel?????

also why is it they felt the need to add 60% more fuel for a 10% increase in revs?

oh and for those that are using the wideband to lean their car out, don't the car uses more fuel at 16:1 cruise than at 15.3.

fecking thing is pissing me off now to the point that autotrader has become a daily read.

[swinks]

You shouldn't fit UTCOM methinks... :)

[Wodjno]

So whats your average MPG Paul ?

[foxdie]

You could try advancing the timing just a little around the cruise points for a bit more fuel economy perhaps? :)

[psbarham]

You could try advancing the timing just a little around the cruise points for a bit more fuel economy perhaps? :)

not gonna stop the ecu dumping **** loads of fuel in when the throttles moved 3 or 4 %

its either piggy back or remap time. or just say fvck it and flog the fvcker.

Wodg, the average is 28.4 with soley local journeys, but driving like miss daisy.

[foxdie]

the average is 28.4 with soley local journeys

Lucky, I don't even get that :)

[psbarham]

Lucky, I don't even get that :)

thats with doing 4 mile each way at 40-45 and 15% throttle

[Ghost_2008]

I get no where near 28 mpg, on a long journey cruising I have achieved such a dizzying height but usually I must get about 15 mpg, local journey's with lots of speed humps and traffic lights..... you gotta love London......

[scott.mohekey]

I think what you're referring to is acceleration enrichment. From memory, it's discussed on a US website dedicated to the Mitsi GTO. Something along the lines of firing all injectors at once during acceleration. http://www.stealth316.com/2-fuelinjection.htm

[VR457]

thats with doing 4 mile each way at 40-45 and 15% throttle

You can walk that. And its really economical.

[Wodjno]

not gonna stop the ecu dumping **** loads of fuel in when the throttles moved 3 or 4 %

its either piggy back or remap time. or just say fvck it and flog the fvcker.

Wodg, the average is 28.4 with soley local journeys, but driving like miss daisy.

Well i would class your local as a nearer Combined than Urban driving. With real world MPG figures, they are bloody good dude.. I average 23mpg with local driving, but now always driving like Miss Daisy..
Take a look at some real world MPG figures for Modern 2.0 upwards petrol engines.. You will be suprised at what u see /Hmmm

[Wodjno]

thats with doing 4 mile each way at 40-45 and 15% throttle

And i bet they are mostly from cold journeys ?

MPG figures you see in Car Mags are not based on 4 miles at a time from cold!!

[horndog]

the average is 28.4 with soley local journeys, but driving like miss daisy.

The trip computer on my 2.0t Saab 9-5 shows ave. mpg of 23 with similar journeys. Wife uses it for shopping/taking kids out etcso not getting too much stick.

[Wodjno]

The Below figures are Manufacturers figures.. I can't find the site with the real world figures :( I found a few sites but not the one i've been on a few times before and was gobsmacked by the results of cars with half the bhp and less than 2.0 cars /help

Saab 9-5 My2006 5 Door Estate 2.0 Lpt With Tuning Kit Petrol 1985cc Manual 5 Speed
Urban: 20.8 MPG
Extra Urban: 40.4 MPG
Combined: 30.1 MPG

Honda Accord 06 Tourer 2.0 I-vtec Se Petrol 1998cc Manual 5 Speed
Urban: 28 MPG
Extra Urban: 47.9 MPG
Combined: 38.2 MPG

Citroen C6 3.0i V6 Petrol 2946cc A6
Urban: 19.2 MPG
Extra Urban: 39.2 MPG
Combined: 28.2 MPG

Bmw 5 Series E60/e61 525i Touring 2996cc Manual 6 Speed
Urban: 26.2 MPG
Extra Urban: 47.9 MPG
Combined: 36.7 MPG

Lexus Is Is250 Saloon Petrol 2500cc Manual 6 Speed
Urban: 20.9 MPG
Extra Urban: 36.7 MPG
Combined: 28.8 MPG

Mercedes-benz E-class Estate (s211) E280 225 Tyres At Rear Petrol 2997cc A7
Urban: 20.5 MPG
Extra Urban: 38.7 MPG
Combined: 29.1 MPG

Jaguar Cars X Type 2.5l Saloon Petrol 2497cc A5
Urban: 18.9 MPG
Extra Urban: 37.3 MPG
Combined: 27.5 MPG

Jaguar Cars S Type 3.0l Saloon Petrol 2967cc A5
Urban: 18.7 MPG
Extra Urban: 36.4 MPG
Combined: 26.9 MPG

Porsche Cayman 5-speed 2687cc Manual 5 Speed
Urban: 20.5 MPG
Extra Urban: 41.5 MPG
Combined: 30.4 MPG


Skoda Octavia Estate (>2006) Vrs 2.0t Fsi 200bhp 1984cc Manual 6 Speed
Urban: 25.9 MPG
Extra Urban: 45.6 MPG
Combined: 35.8 MPG

[Danzul]

dont get dishaertened bud!
lets face it, your leggy will upset pretty much all of those listed above by wodge and your mpg is better than some of them.

[Adam.Findlay]

I think what you're referring to is acceleration enrichment. From memory, it's discussed on a US website dedicated to the Mitsi GTO. Something along the lines of firing all injectors at once during acceleration. http://www.stealth316.com/2-fuelinjection.htm
pretty sure thats right, our cars do go from sequential injection to batch fire on accleration

[Wodjno]

I think what you're referring to is acceleration enrichment. From memory, it's discussed on a US website dedicated to the Mitsi GTO. Something along the lines of firing all injectors at once during acceleration. http://www.stealth316.com/2-fuelinjection.htm

So thats what the Acceleration Adjustment Map on the E-manage Ultimate is for /pan

Feck i coulda saved myself some serious amount of fuel over the years /help

So next job ..

Acceleration Adjustment Map
-100% fuel 0 - 8000rpm and 0-100% throttle :D

[pezza]

The only little relief I can get is paying half price for the fuel with lpg...

That acceleration adjustment sounds interesting ..hmm..

[scc]

Is it just bad mapping or is it simply impossible no matter how optimised your map is?
Or is it just that the ecu has a contract with OPEC?

Cheers
Scc

[scott.mohekey]

It errs on the side of caution, preferring to run rich rather than lean to reduce the chance of knock.

[lathiat]

Lol I get 35mpg on a good week, about 40 on a bad one. Not sure what you are complaining about :P

[psbarham]

I have no issues at all with the acceleration map and what it does, its how early in the rev range it does it, 1k - 15k rpm is a bit fecking stupid if you ask me.
can it be changed on the map?

[WOODY72]

Must be all downhill where you live! :evilgrin:

[Wodjno]

50192Sorry for cack picture :(
But heres how it can be altered through the Emanage Ultimate..

50191

[Wodjno]

Sorry for cack picture :(
But heres how it can be altered through the Emanage Ultimate..

50188

Dang :uhoh2:

Bare with me /popcorn

Pic now sorted :) Thanks to "Nutter Johns Online services" /yes :D

[Eurospec]

If you reduce the accell enrich you will come to the point where you get a lean tip. Reducing the accell enrich tps or kvf thresholds may help though. (ie to allow a bigger airflow or tps delta before accell is triggered.

Cheers,

Ben.

[lateshow]

What do you mean by lean tip?? Lifting your foot off the pedal and AFR goes straight to lean or what?

[Nick Mann]

I think Ben means the other way - put your foot on the accelerator and get a lean tip. If I understand it the ECU fires excessive fuel in as you press the throttle, to make sure that there is no lean moment on throttle position changes. I guess this is a good thing, but from what PSB is saying it is a "tad" enthusiastic. I think Ben is saying you can tone this enthusiasm down, but be wary of over doing it.

[Eurospec]

Exactly Nick!

Basically the stock system without accel enrich will work like this:-

You open the throttle, instantly there will be a very large change in air volume entering the engine, which will decreasese over time. Like shaking up a can of fizzy pop and cracking the lid. At first it shoots out quickly, but also quicly dies down. Same thing happens as you move the throtle plate. The bigger the movement in the throttle plate the bigger the amount of shaking and consequent panda pop loss.

If left to its own devices, without accell enrich, the ecu would not catch up with this change until the pressure wave went back through the intercooler, through the turbos, through the inlet and back to the maf. The maf would then read the change in air volume and pump in the fuel. In practice the propagation of this wave will take about 0.5 sec to 1 sec. The resultant would be push the gas nothing happens- oh here we go. THe so called lean tip in.

Accell enrinchment helps by seeing a tps change, and firing in extra fuel immediately to prevent the lean tip. The effect is normally bigger the bigger the tps delta is. To dumb it down and keep the fueling more constant you could say for tps deltas less than say 7% have zero accel enrich. The other thing is also to keep closed loop enabled for small ish tps deltas. (normally tps delta will cause a drop out of closed loop.

Quite how much of this is defined in the existing xmls i dont know, but it will be there in the ecu somewhere.

Cheers,

Ben.

[foxdie]

Quite how much of this is defined in the existing xmls i dont know, but it will be there in the ecu somewhere.

That it is...

50194

Taken from a default 7202 ROM image (Auto Non-TCL). Highlights exactly how bad it is ;)

[jayp]

I'm assuming the percentages on the right are percentage of extra fuel to add, so to calm it down a bit would be a case of lowering the values slightly? Or am I getting the wrong end of the stick?

Sent from my HTC Desire S using Tapatalk

[VR457]

Can this be done via an ecu flash?

[foxdie]

I'm assuming the percentages on the right are percentage of extra fuel to add, so to calm it down a bit would be a case of lowering the values slightly? Or am I getting the wrong end of the stick?

I'm not 100% sure but I'd say these were percentages of the current fuelling value to add, for example if you're injector duty cycle is at 12% and you press the pedal fast enough to trigger the 12.5% delta, you'll temporarily change the duty cycle to around 18% (50% of 12% is 6%).

If anyone knows different please pipe up because I'm interested in learning the truth :)


Can this be done via an ecu flash?

Yep, I'll try what Ben says of disabling acceleration enrichment below 7% and smoothing out the rest so it comes on pretty quickly but not suddenly, maybe something like this;

50208

Anyone think the above is bad? Also, I could do with some suggestions on how to reliably test this.

[BCX]

Also, I could do with some suggestions on how to reliably test this.

I've got a couple of addresses that you could use via MUT to log this kind of stuff (possible tps delta, and perhaps a enrichment address - i'll have to have a look at my disassembly). Other than that, a scope on one of the injectors (and if you had a two input scope, one on TPS) to see a difference in duty cycle.

[jayp]

That's the way I understood it, I'm guessing the ecu interpolates the values between what is defined in the tables.
I guess its a case of small adjustments and drive and log making sure it doesn't lean out with initial boost surge, but at the same time keeping the smooth drivability.

Sorry if it seems my questions are a bit bone, I'm just starting to teach myself about ecu's and mapping.

Sent from my HTC Desire S using Tapatalk

[psbarham]

I thought the % in the left column was the amount the throttle was moved from a constant position?
eg, cruising at 23% then give the throttle a prod up to 30% the ecu then increases the injector duty by X amount?
or have I missed the mark?
if i'm right then couldn't the enrichment be ignored for the 1st 10% below a certain rpm? eg below 2k for round town use?

[foxdie]

Unfortunately you don't get that degree of control (TPS delta vs engine speed), the table is a global setting. The way I foresee this working is it'll only enrich the fuelling if you press the pedal down faster than a set speed, it's all about how fast the pedal is travelling;

If you press it down slowly, to maintain a constant speed going up a hill for example, the delta will always be low. In this situation either the engine speed will be increasing slowly or load will be slowly building up, there won't be a sudden change so there won't be a need for enrichment as the other ECU functions will make sure the engine gets a satisfactory amount of fuel.

If you press it down faster, to overtake or to change lanes, the delta will be higher triggering partial enrichment to cover waiting for the MAF to see more air travelling into the engine.

If you slam the accelerator pedal to the floor, you know, because that BMW totally just insulted you by being on the very road you're driving on, this will trigger the maximum 49% enrichment to cover waiting for the MAF to register more air :)

[Eurospec]

I could do with some suggestions on how to reliably test this.

Jason, if you can datalog your wideband do this vs throttle position and then try some gentle accelerations before and after and see the effect. If it lean tips you will feel it and see it on the wbo2. As long as O2 remains within a sensible range when you accelerate, then happy days.

Cheers,

Ben.

[Kenneth]

Thread from the dead!

I knew this thread was around somewhere and I wanted to update it. I changed the accel enrichment in my ECU some time ago and never had any real issues with it, until the other week at Taupo racetrack. After a couple of laps, any acceleration over about 60% throttle was causing CEL to light up (CEL on knockcount >= 3)
Reverting the Accel enrichment got rid of this.
I had some other minor tune issues causing CEL here and there after the first few laps every session, unfortunately I didn't take my logger so didn't really do much about it, other than reverting the accel enrichment.

Probably worth noting that boost was around 15psi maximum for the track day.




I'm not 100% sure but I'd say these were percentages of the current fuelling value to add, for example if you're injector duty cycle is at 12% and you press the pedal fast enough to trigger the 12.5% delta, you'll temporarily change the duty cycle to around 18% (50% of 12% is 6%).

If anyone knows different please pipe up because I'm interested in learning the truth :)



Yep, I'll try what Ben says of disabling acceleration enrichment below 7% and smoothing out the rest so it comes on pretty quickly but not suddenly, maybe something like this;

50208

Anyone think the above is bad? Also, I could do with some suggestions on how to reliably test this.

[Downundersir]

Any more info on this topic..... Bcx, foxdie, euro spec, late show etc. your insights were very beneficial in years gone-by.

[lateshow]

Yesterday I was tuning an Evo 8 for bigger injectors (ethanol, again) and it seems that accel enrichment with standard settings and bigger injectors cause the afr to go way too rich. I'm actually planning bigger injectors for my vr4 too (a beginning of a td04 project).

[Davezj]

Back to accel enrichment table will the value that is see by this table be a min of 12% as this is the lowest value ever displayed by the throttle position sensor min is 12% ish max is 96% or is there some kind of rationalisation that 12% is 0 and 96% is 100.

If not then at idle we will be getting about 45% more fuel than necessary. But I don't think this happens.

[Davezj]

Please ignore my previous post above. obviously it is a delta change % and not an absolute % as i mentioned above.

[Barlow]

Just for the record, i get 8mpg average. £100 at £1.36 a litre gets me 120 miles...just incase anyone was feeling depressed about their economy :-P

[Davezj]

chris, you have something very wrong with your car, it is probably in some kind of fail safe mode, due to a sensor failure or something like that.

it must be running mega rich, you should hang a bucket under the exhaust pipe tip to catch all thet raw petrol that is getting blasted out of it, lol.

[Barlow]

I know mate, but ive had the car for 12 months now, so it seems normal lol. Trying to get my hands on a 7202 in hope that will fix fuelling issue along with additional horses ;-) but no engine management light or anything :-/

[giblet]

Something seriously wrong there. My worst ever figures were 147.2 miles to 38.75 litres (137.9p a litre) and that equates to 17.27MPG. That involved a fair bit of WOT and silly speeds out in the countryside too.

[Davezj]

I know mate, but ive had the car for 12 months now, so it seems normal lol. Trying to get my hands on a 7202 in hope that will fix fuelling issue along with additional horses ;-) but no engine management light or anything :-/

i can have a look at the 7201 ecu to see what rom is in there. and check to see if the mapping is standard or if someone has messed with it.