[Rotrex kit on Ebay]

http://www.ebay.co.uk/itm/Rotrex-VR6-Supercharger-Kit-/221362699749?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item338a3ebde5

 

Yes its mine.

Bye Bye Rotrex, been fun.

Hello Turbo

[VR6 running rich?]

My mates VR6 is running rich and I haven't got a clue why, anyone got any ideas?

What I've found:

Using VAGCOM it seems that when temperature gets above 90degC it all goes wrong. I just will not trim fuel down to 1 on the lambda reading.

It throws no fault codes other than 00537 - Oxygen Sensor Regulation.

It's had a new lambda sensor.

Clocks temperature matches ECU temp.

When engine temperature is below 90degC it does seem to regulate occasionally and unplugging the MAF makes the engine cut out.

However when above 90degC unplugging the MAF makes no difference! WTF.

Someone please help as it's already failed one MOT!

[DIY turbo guide]

Cheers for the info guys.

Top findings once again Kev, pretty much what I expected, but good to know it's been tried and tested.

[DIY turbo guide]

I'm interested to see how you find the VAG regulator, also are you using the 3 or 4 Bar reg.

I'm sorting my fuel system this winter so do you think the standard in tank pump plus in line Bosch 044 will be good for 400Bhp?

Also where did you get those charge cooler couplings as they look just the job.

Cheers

Joni.

[VR6 Remap guide]

Ok, I have now sorted the checksum issue. I was correct as above. Obviously the engine doesn't need to be running to throw this fault up. Doh!

[VR6 Remap guide]

The checksum on these OBD1 ECU's wont start the engine from running' date=' it just throws a fault ode

[/quote']

I had a look earlier and think I may have sussed it on my 258CP code unless it was a fluke, I believe the checksum is just before the ECU software version number which is at EF00 (sum of 0000-EEFF) in my version, however I couldn't make it work on another couple of binaries I have (258AF and 258AP) but the software version number is at a different location but even when I modify the checksum location and range I can't get it to match. I'll test my 258CP attempt next time the engine is in a runable condition.

If anyone else has any idea's of checksum ranges and locations that would be very useful as I'm quite new to Bosch software.

[VR6 Remap guide]

Excellent. Is the checksumm in this causing you any problems?

Ah, I was wandering when this would come up, yes and no is the answer. Yes in that it throws up a fault code, but no it doesn't seem to have any adverse effects.

I have managed to get TunerPro to generate a checksum for the whole EEPROM, but this is wrong. I.e. I cant get it to match an original map. I can only assume that there is multiple checksums, one for the code and one for the map data, at some stage I will get round to finding the EEPROM ranges for each checksum and post my findings.

That is of course if anyone else doesn't beat me to it.

This is only a side project of mine so I don't spend too much time on it. So the checksum issue may be a while.

[VR6 Remap guide]

Ok, now its possible to drive flat out you might also want your engine to idle nicely.

I determined idle fuelling levels by taking note of the fuelling adaption levels in block 6 using VAGCOM, basically with my setup I hit the idle adaption level limit without any tweeking (I believe this is about +/- 0.3). On initial setup I set up partial throttle adaption level to as close to 1.00 as possible, i.e. 14.7 on the AFR gauge when driving under partial throttle. This was done by tweeking the MAF potentiometer, I'd highly recommend using a multi turn potentiometer as a single turn pot is very sensitive.

Once you have a good partial throttle adaption level (near to 1.00 as possible) and remapped the WOT you should only be left with a problem with the idle adaption level, I saw idle adaption levels of ~0.7 which threw up a fault code. Initially I took a full 30% off the idle fuelling levels, this was way too much and the idle adaption levels went to ~1.3 which gave me another fault code. I found that about 85% of the origional fuelling levels gave me acceptable results (i.e. didn't throw up any fault codes)

[VR6 Remap guide]

VR6 Motronic remapping at home courtesy of VR6Joni!

What you will need:

EPROM programmer, I doubt one exists that will not program a 27C512.

A few 27C512's as it's annoying waiting 20mins to blank them!

A UV Eraser.

A 28 pin DIP socket.

Soldering skills.

A fairly technical mind!

A laptop.

VAG-COM

A wide band AFR controller.

First of all read which ECU you have with the VAG-COM or look at the label on it. It should look something like this:021 906 258CP. The CP is the important bit, this is the code revision which also means the maps will be at different locations in the memory. I have details of where the maps are located for AF or CP revisions up to press and will distribute them on request (PM me). This will make life much easier although I had to work out the locations for myself on my CP ECU so it is possible to do on other versions, just needs a bit of extra work.

Remove the ECU! I'm sure there are several guides online, if you need to use them you probably

shouldn't be doing this anyway.

You can learn from my errors though! Which were the connector latch pulls further out then you may expect and no matter what you might think the ECU will come out with the bracket attached. Once it's out you need to take the the EPROM off the PCB, it's the 28 pin though hole device as pictured. You really should use a rework station for this which has a soldering iron and hot air blower in one unit. I was too eager to wait until I was in work so just used a bog standard hot air gun on LOW! in combination with a soldering iron. I find its easier if you remove excess solder first using a solder sucker. Take note of the orientation of the chip, it should be pin 1 (pin 1 is indicated by the notch on one side of the chip) closer to the centre of the PCB. Once the EPROM is removed, remove excess solder and fit the socket. Now your ready to MAP and REMAP.

Original EEPROM

Socket Fitted

Newly Mapped EEPROM in place

Now you will need to set up your EPROM programmer and read the memory with the included software and save it as a binary, make 2 copies, one as an original backup and one to modify. I save a different copy at every stage of the REMAP.

Now you will need to download a copy of WINOLS Demo and TunerPro. With TunerPro you need a MAP definitions file called a .XDF, this contains information for the various MAPs in the binary file taken from your ECU's EPROM. The XDF is basically just a list of MAP labels, memory location and conversion factors etc. I have XDF's for the CP and AF ECU's at the moment these may be compatible with other versions though.

Install TunerPro and run it, then open a XDF file, the correct one if possible. Then open your .bin file, you should then be able to open various MAP's and you should be looking at a pattern of numbers in a table, if they are random or all the same your probable gonna have to modify the XDF to suit your ECU revision, if it looks like good data ignore the next paragraph.

If you need to modify the .XDF file install WINOLS and run it. Create a project with a known binary eg. AF and allow it to find all potential MAPs. Then create another project with your ECUs binary. You should see 2 sets of very similar potential maps, what I would recommend you do is write the address of each known map down in order and look where they are in the potential maps list. Eg. you could find fuel wide open throttle (12x12 MAP) is between a 4x8 MAP and another 12x12 MAP, which just happens to be idle fuelling and WOT map 2. You should be able to see this pattern in your binary with very similar numbers if not the same. Continue this process until you

have found all the MAPs that you wish to edit. Note down all the locations and then modify the XDF file to suit. Hopefully now you should have what looks like valid data in TunerPro.

Now its time to remap.

I'm assuming you've probably done some significant mods by this stage and want to make the use of it so I'll start with WOT maps. If you've done something serious like turbo or supercharge your VR you may well have used Crazy/SensibleDaves (Big thanks to Dave for this) potentiometer mod to get you going, I used an active electronic version to guarantee a linear output. Adjust this to minimise adaption values in measuring block 6 using VAG-COM, you'll have to clock up a few miles for these to appear. Otherwise adjust it so that AFR is good on initial startup and driving.

Now you have a drivable car its time to generate some logs, I log ignition timing with VAG-COM and the AFR with Logworks2 software which was included with my Innovate LC-1. Find an airstrip, start logging, stick it in third at idle engine speed and floor it to the redline making sure AFR's stay at none engine killing levels, repeat this logging procedure a few times.

For Fuel WOT maps:

With your results generate an error factor value table throughout the rev range, I do this by taking a reference point I.e. when you change into 4th, using that point in time write down the AFR's logged next to the engine speeds from the VAGCOM log and work your way backwards referencing the times on the AFR log against the times in the VAGCOM log. Once you have an error factor table copy the Fuel WOT MAP from TunerPro into a spreadsheet and multiply the values by the corresponding engine speed error factors. Then copy the results back into TunerPro, I converted them to an integer in the spreadsheet using the following formula:

New Map Value =int(OldMAPValue*ErrorFactor)

Example spreadsheet used to calculate corrections required

I found that just changing Fuel WOT MAP 1 works, so what MAP 2 does if a mystery, answers on a postcard please! Or a PM will do.

Ignition is a bit more of an art, I look at the timing in the logs and simply adjust timings to try and eliminate detonation. You can tell that knock has been detected as you'll see that the ECU has retarded the timing away from the map values, it does it in quite large steps and is obvious as you see timing jump away from the MAP values by about 5 degrees at a time. (see 5800rpm on example spreadsheet)

When you are happy with the changes that have been made save the binary and program a new EPROM with the binary file saved in TunerPro. Plug the new EPROM into the ECU, put the ECU back in the car and take it for a blast, once again logging everything. Repeat the steps above as many times as it takes until your happy, blank the

EPROM in the UV eraser as soon as you remove it as when it comes to making smaller tweaks it gets annoying waiting, hence having a couple spare.

Original maps as viewed in TunerPro

My slightly tweaked MAPs

Example AFR Log

[VR6 Remap guide]

Thought I'd post my current progress with remapping a Motronic on here for you guys. It still requires a bit of work, but hopefully others are gonna contribute!