Which replacement ecu & which mapper?

[Caveman]

Guys,

I have decided to take the plunge and get a replacement ecu fitted/mapped- both to maximise the potential that can be derived from the standard turbos, but also to improve every day fuel consumption. I have calculated that if I can improve my mpg by 5 miles per gallon, it will save me over £700 per year at current fuel prices.

Obviously, the ultimate outcome of a replacement ecu is dependent on the skills of the mapper as well as the quality of the ecu.

So the question is - which replacement ecu is recommended, and which recommended mappers are able/willing to map the VR4 successfully? I have heard Autronic is the one to go for, but am struggling to find a mapper who does anything more than Sccobs or Evos.

Any ideas?

Cheers,

Mart.

[Nick Mann]

You'd do worse than a MAP 2 ECU mapped by Ben at Eurospec.

Although it is a piggy back rather than a replacement.

[Nutter_John]

Don't expect to save 5mpg from a remap , it really only saves fuel when on boost

[Beastlee]

Don't expect to save 5mpg from a remap , it really only saves fuel when on boost

That should be at least 75% of the time then LOL

Does mapping affect the on boost economy by much at all?

[Nutter_John]

well normally on full boost you are pushing afr's of below ten , when tuned you will be running low to mid 11's , as to how much you will save I would say a little

[Beastlee]

Yep my AFRs were 9.8 for WOT in 4th and 5th.
I was led to believe the ECU would help the economy by stopping it chucking a load of wasted fuel in when not at WOT. Is this not the case?
I am fitting my emanage blue this weekend and I also have the injector harness and I'm considering the ignition one to complete the lot. Is there any hope with all of that?

[Nutter_John]

Lee I recon you will trim a little across the range when on open loop but at best I would imagine something like 1mpg , don't forget when in closed loop the ecu is trying for 14.7 and when your cruising it will be in closed loop

[Beastlee]

hehe 1mpg is about 10%, not a bad increase if you ask me!

[Turbo_Steve]

If you're fitting a piggyback, I'd suggest altering injector compensation to reduce partial throttle enrichment. This will massively improve economy. Then measure AFRs on WOT and enriched if required.

With regards to which model of ECU to fit, the Emanage and the MAP2 are both the cheapest and easiest routes to a remap.
There are limits to what they're capable of, but as you're only looking at some relatively small adjustment, so should suffice.

The complete, aftermarket, replacement ECUs on a legnum are a big ask. Autronic rocks, but is pricey, and I believe brad had some issues getting it working. mutters something about autobox, and TC.

Motec is awesome. But you're looking at ages to set it up, lots of work. It can interface with your AYC too and do all sorts of neat stuff. It costs a fortune. You'll have to do some wiring to get it working. It's just not worth it.

[bradc]

Autronic + Auto = no go, however remember that I'll be able to send you my map so your tuning price with an Autronic would be less than other ecu's

[Beastlee]

Steve, i'm interested in your comments on part throttle enrichment. I'm just about to leave for the motor club and do the install, it will be running it as standard till I get home. I am going to install the injector harness as well but as far as I can tell it only increases your injectors duty cycle, allows injector logging and to controls sub-injectors. Can the EMB do what you suggest?

[Eurospec]

Into a VR4, i think i would go autronic for a full standalone. The trigger wheel will need to be changed though i think.


Cheers,

Ben.

[Eurospec]

Ah, just saw brad said it wont go with the auto!

Any idea what the issue is, i'm imagining its the outputs required to the stock tcu from the ecu? If so, any idea what the issue is as it might affect other standalones too.

Cheers,

Ben.

[bradc]

no idea, but they could get it to do the functions of a auto vr-4 gearbox at standstill, ie p r n d and then in tip mode 1st and 2nd, but they never managed to get it to come out of 2nd!

[Turbo_Steve]

The whole ECU TCU relationship on these cars appears to be something of a mystery!

Lee, I have to confess I'm no EManage expert, but I would look at having the EMB adjust the injector size a tiny bit, which should make the whole car run much leaner. Closed loop should correct itself fairly quickly. Then you just need to richen up the fuel tables as appropriate. (generally can be done with a tank of fuel, some driving and a decent AFR meter.

Once you've got it driving normally, you can start nudging the ignition forward wherever possible, which should improve the responsiveness and driveability.
Keep an ear out det, of course (det cans are ideal).
Best bet is to map it on "non-premium" fuel..i.e. 97RON, quite aggressively (i.e. so ECU is doing tiny amounts of correction) and then run the car on 99.
You will usually find that advancing the ignition and reducing the boost gives you more power. Usually, but there are no hard & fast rules to mapping.


Brad, Do you know how the Autronic was wired in? My understanding is that the Autronics try and do Gearbox control internally, so was it bypassing the factory TCU and controlling direct (in which case it sounds like a solenoid not actuating) or was is comms signals of some kind to the TCU?

Cross country, our legnum is more econonomical flat-out that in it is in "mixed" driving. It's also better with 99 fuel (of course).
To get any real economy you have to treat the throttle like a newborn baby..slow, smooth, gentle, soft. Not ideal in a VR-4

[bradc]

yeah, cause anything more than slow smooth gentle and soft gets the insta-boost turbos kicking in and the AFR goes to hell on the stock turbos

Mitsi should have put in TD04's, it would have made fuel economy better, and made more power!

[Beastlee]

My old SAAB 9000 Aero weighed more than the VR4, produced 225bhp and bags of torque using a TD04. It returned a steady 26mpg+ no matter how hard I drove it, I saw 50mpg on a run once and that ws at 60mph. It was matched for 0-60 on a stock VR4 too even if it did spin in 1st - 3rd, FWD really let it down.

[phosty]

I’ve been attempting to improve my fuel economy by experimenting with the Analogue #1 output from my LC1 WBO2 (configured to replace the stock O2 sensor). By default the LC1 outputs 1.1V at a Lambda of 0.958 (AFR of 14.08) and 0.103V at a lambda of 1.022 (AFR of 15.02).

I tried tweaking it by adding 0.01 increments to both the default lambda values (keeping voltages fixed). As the ecu is attempting to cycle around 0.5V then by shifting the curve to the right it should lean out the closed loop control point.

And it works – up to a point. Adding up to 0.03 to the lambda values I could get the engine to idle and cruise around an AFR of 15ish. The trouble is that adjusting the lambda values by more than 0.03 didn’t make the closed loop AFR change any higher. I assumed that the ECU had exceeded its closed loop trim adjustment and that was as far as I could go.

Has anybody else tried this and managed to get higher AFRs in closed loop?

I averaged about 19 mpg before I started fiddling. I’ve not had enough tank refills to see if the tweak has made any difference to that yet.

I just assumed one of the reasons I get low cruise fuel economy on the VR4 was because the compression ratio was so low (8.5:1) yet you are barely on boost when cruising…..as well of course the fact that it’s an auto.