DIY live mapping with a piggyback
 

Bought a new impreza, 2003 blob WRX. Plans are to change exhaust and put on a bigger turbo, all diy as cars are my hobby.
Now I could take it to one of the many reputable tuners and have it remapped (and trust me i had thought of this) costing around 450 quid first time and then a further 300 everytime I change something. The other option is some of the software out there to diy tune the factory ecu, but with no ability to live map this and my lack of knowledge and anyone I know able to show me how to use it has put me off this route.
This brings me onto my chosen route, yes there are other options but this is the one I have chosen. I am familiar with tuning turbo cars having around nine years experience with lots of good results and a few lessons learned making mistakes (the best way to learn!) Having done several NA to turbo conversions all built and mapped by myself, mostly with standalone magasquirt or KMS engine managemnet, some recently with AEM piggybacks. An example of which is my mates 205 GTI-6 turbo running a standard engine with standard management and AEM piggy back, at a mere 5 psi this was dynoed at 236bhp. My recent golf 2.016v 4x4 turbo sported a rather large HX35 turbo running 1.8 Bar boost and an estimated 380 bhp.
So my obvious, easiest and cheapest choice to allow me to map my car was to put on an AEM piggyback. im sure those out there with the software and ability to map the factory ecu might find this a strange route, thats fine, you are probably not willing or available to share your software and secrets with me.
The AEM is a piggy back, it relies heavily on the std ecu, the way I have installed it and have it set just now the car drives 100% factory, no modifications are made to the factory map.
However all the injectors, the Crank sensor, MAF sensor and MAP sensor inputs have all been cut and put through the AEM, this allows me to have full control over the fuel MAP, ignition retard, Boost cut limits and MAF limitations. A few pictures to help explain what ive done.
http://i959.photobucket.com/albums/a...ps16a2e8de.jpg
I have been out data logging the factory settings so I have a base point to work from, have monitored boost, rpm, inj duty cycle, MAF voltage and MAP voltage.
http://i959.photobucket.com/albums/a...psa58eaa2a.jpg

http://i959.photobucket.com/albums/a...ps6a593c51.jpg
http://i959.photobucket.com/albums/a...ps1c780b13.jpg
http://i959.photobucket.com/albums/a...psb5e94eb8.jpg
http://i959.photobucket.com/albums/a...ps928b2e5b.jpg

Hi there

Great thread,but still this AEM is not very popular over here and never will be.More people will go with AlcaTek or Syvecs on their cars,yes over in US AEM is very popular like other ECU such as Hydra and many others,plus Open Source with tactrix cable is still unbeatable for price and performance ratio plus with old-new CarBerry ROM you can have awesome features

Looking forward to progress

Jura

Cheers Jura. Went out today with wideband and calibrated boost gauge in toe. Seems car is running 1.1 bar boost tapering off to .8 at redline. Also afr is extremely rich in boost at around 10.8:1! Led to believe this is norm afr for factory scoob. Boost however is a little higher than std. All other AFR's seem spot on, all round healthy factory tune I would say.
Need to put exhaust and turbo on now then the fun can begin!

Good luck, sounds similar to what I was doing a year or so ago!! Learning my way around ESL!

Cheers, more than one way to skin a cat as they say! I'm not chasing mega hp with this car, just a small turbo and exhaust upgrade. I only need to be able to tweake the map slightly at the top end, great fun!

Sounds fun, I had the same thought... Slowly got more and more carried away with tuning! Ended up now with a excessively powered monster street car!!

Yeah, im not chasing big power with this car though. Done that before! I ran an HX40 on my 2.8 24v V6 golf 4x4 at 1.5 BAR, it was a monster. Not very practical for day to day use though!

Sorry to have to be the one to point this out !
You're wasting your time tuning a Subaru with a piggy back ecu as the OEM ecu is self learning for both fueling and ignition.
IE if you tune the fueling away from the base target AFR, it will richen up until such point as it get's back where it came from.
It's why tuners favour mapping the OEM ecu or fitting a proper aftermarket ecu.
If you want to tune it you could always do what everyone else does and buy a tactrix cable and learn to map the OEM ecu.

How does it know what the AFR is on boost?

It uses it's pseudo wideband fitted in the headers.
It's a very, very clever ecu as far as stock systems go.

Interesting, wasn't sure if it had widenband or not. Why would you ever need to remap one then? Only to increase boost cut or lean off slightly? I can trick the O2 sensor with the aem if need be

Because people will insist on changing things ;)
Injectors, turbos, intercoolers, exhausts, headers etc etc etc and remapping properly to suit them is a must.

I don't get what your saying really? If the ecu adapts the ig timing to suit and also adjusts the afr then you won't need a remap surely?
Done some research on pseudo lambdas, seems they are like narrow band lambdas in their operation except work on a broader scale. The voltage vs afr can be replicated by the aem to keep the std ecu happy with its afr targets.

Voltage vs afr respectively

V
1.56 1.71 1.87 2.02 2.18 2.34 2.49 2.65 2.80 2.96. 3 3.12 3.27 3.43

AFR 9.78 10.17 10.56 10.92 11.38 11.96 12.51 13.1 13.75 14.52 14.7 15.76 17.63 20.21

Alternatively I could run it like my old bug with the front lambda disconnected completely

You're somewhat missing the point.
If you have access to the original ecu and can remap it, you can change the AFR target to what you want it to be, not what the original map says you have to have.
You can also change the amount of correction that will or won't be applied by the ecu.
Like wise with the ignition, you can change what the advance multiplier starts at, the jumps in correction due to knock, the amount of ignition you want to allow the ecu to try and add on top of your base ignition map and so on and so on.

I wouldn't unplug the AFR sensor if I were you, they tend to run very poorly if you do and don't tell the ecu it's not there.

Will this software still work on my ecu even though its already been remapped with ecutec?
Maybe my targets afr's are ok too as the current lambda sensor is not working. If that is the case all I
Need to do is alter the on boost injection pw to suit the new exhaust and turbo and leave everything else as is.

Turns out the factory wideband can't read lower afr than 11:1 and also you can't set the target afr lower than that either. 11:1 is about where I would tune to anyway, so can't see a problem if the car is even running closed loop in boost.

The target AFR will go lower then 11.1 and can be set lower (the standard 2003 WRX is down in the 9's at WOT IIRC) but the pseudo wideband won't record any lower hence your logging of the standard wideband will flatline.

An aftermarket wideband in the exhaust or tailpipe will give you the real reading.

Regular Opensource software won't read or flash an ECUTEK ECU due to the licence lock. But there are ways around this if you do some homework ;). The tactrix cable and the relevant software will still come in at 1/2 the cost of a ECUTEK map and every map after that is free ;)

Running the AEM may also cause errors to be logged, as Martyn says the ECU will try to adapt to achieve it's mapped targets. If it has to adapt the fuelling more then 14% you will get a fuelling related error code.

I've never seen an aftermarket wideband read lower than 10:1? So there's no way the ecu can run closed loop at lower than 11:1 then. How will it bring up errors if the actual afr is the same (or slightly richer like it is just now) to the target afr?
Ill conduct an experiment this week, ill lean my WOT afr off to mid 11's from about the mid tens it is now. And see if anything happens regards the factory ecu trying to richen it back up (technically it won't know what I've done as the factory O2 sensor doesn't read rich enough, cos its not a proper uego wideband like the one I'm tuning with)

How about this; for example say my target afr on boost is 11:1, great. So I change my turbo and increase my boost .3 bar. Do a wee pull and she's lean and hits boost cut. Oh.
So I mod the map voltage so the boost cut is higher, sorted. And I also map the fuel so that its 11:1.
The factory ecu is happy cos its hitting its target afr abd also ist hitting boost cut. The knock sensing will look after the timing good enough, although the aem can be used to retard the timing if need be.
Anyone see any issues here?
The only issue I can see is IF the ecu has been set closed loop in boost (which we don't know if it is or not) if I try and run a leaner afr than target the factory ecu will get upset, however:- if I send the desired voltage to the ecu for its richer mixture that would keep it happy anyway, so this isn't a problem either.
Remember I'm not reinventing the wheel here the car is already turboed and working well, all I'm doing is changing a few bits of hardware and tweaking the mixture back to where it wants to be.

The ECU doesn't run closed loop on boost.
It runs closed loop at idle and cruise, upto or normally around the 0psi level or what ever the switch over level is set at or has been changed to (each ECU is slightly different).
Then it will switch to open loop fuelling.

All readings taken during idle and cruise by the pseudo wideband are used to establish a fuel trim factor which becomes the open loop fuelling offset.
When running open loop the MAF reading tells the ECU what the airflow is and using the offset calculated during closed loop it applies the correct level of fuel for the metered air volume, to achieve your target AFR (or thereabouts).

A correctly mapped car will have a very low offset of correction, less than around 5%.
if the ECU finds it has to make upto 14% (IIRC) fuel correction to achieve 14.7AFR at idle and cruise, it will log a fault, normally a bank running lean error or similar.

I would suggest you nip over to the Romraider site and crack off a few hours of studying over the Christmas period. But don't get too bogged down as some over there go to a whole new unnecessary level IMHO......

Hi there

As above Scott pointed out,Romraider form will be good starting point and cheaper and maybe better on longer run

Tactrix and EcuFlash/Romraider combo is hard to beat as for DIY or Open Source mapping,if yours ECU is locked by EcuTek then you can easily to unlock ECU if you know how to do

As above Scott recommend,ditch the AEM and get Tactrix and Romraider/EcuFlash combo.

Romraider forum is good resource for DIY mappers and really I would recommend this forum

Here is link on Base maps(ROM) for Romraider/EcuFlash

http://www.scoobypedia.co.uk/index.p...patibilityList

I would recommend download CarBerry ROM,which will allow you to run Mafless(ditch MAF),ALS,LC etc

Jura

Thanks guys, i will look into it. but can't help thinking now if I'm not touching the off boost map at all and I'm only tweaking the on boost map that is open loop then there is no problem? The aem is wired in the car now an I had it lying around anyway. Worth a bash is it not? I'm only looking to tweak the very top load lines as the rest will be fine.

Well, I have replaced the discs with grooved and drilled ones, mintex pads. Oil and filter change, cleaned my blue cotton panel filter and put a new timing belt on with a fresh coolant change.
Now the car is running 1.2 bar boost and an AFR of 11:1, amazing the difference cleaning the air filter made. Feels quicker too.
I have a 3" system sitting ready to go on, along with a td05 16g turbo I have just won on eBay that I will convert to front entry. So at 1.2 bar I'm probably looking at over 300bhp.
Oh looks open loop on boost too since its leaned off after cleaning the air filter

Converted my newly bought 16g to front entry ready to fit in the next few days along with a complete turbo back 3" system. Maybe just make a decat uppipe
http://i959.photobucket.com/albums/a...ps2e58e5b8.jpg

As said above, if you want to map yourself, get carberry rom downloaded onto stock ecu and go from there.
Your really wasting a lot of time and effort (should of researched into it a bit more instead of doing what your doing)

Lol, aem will work and is a simple and easy solution. I've done 300 miles so far with the car aem'd no hassle at all so far
I don't see doing something that I am familiar with and that will def work a waste of time and effort. I've put aem on two cars before. Also megasquirted an impreza with great success, not many people have done that.

Kudos for the attempt, but trying to fool the ECU with a piggyback isn't as good a solution as mapping the ECU, and it is more expensive. Chopping up the harness is also nugatory work. You will also devalue the car by fitting a piggyback. If you have also ran a scoob on ms then you must like the road less travelled! It's not a popular application for a reason.