Project Armo "330i" M-tech 1

[Skarpa]

There was this rattling coming from the exhaust when lifting the accelerator. Like a small stone in a vacuum cleaner pipe. That was the final trigger to get started with installing the Supersprint exhaust. I bought an E36 328i catless front section.


I didn't fit right away because I've redone the pipes in front of the resonator to fit an E36 exhaust in E30 and keep as much ground clearance as possible and clear the 6-speed transmission. So I had to cut off the front pipes from the Supersprint resonator and clean up the holes to fit my own pipes there.



I bolted the exhaust in the car and tack welded the pipes in the resonator. Then I took them off again for full welding.



Now I have full stainless exhaust that I'm very happy with. Now I can rest assured that there are no restriction in that area. In future I may swap also the rear muffler for a Supersprint one to bring the noise down a bit. The Scorpion catback is pretty loud.
The sound didn't really change in any way when changing the front section. I wasn't expecting any major change anyway . I haven't run logs after changing the exhaust but I doubt I found any missing horses with this modification. The rattling sound turned out to be a protective metal cup from one of the O2 sensors that had come loose. So nothing serious. The O2 sensor still works. Although, while doing the exhaust work I was driving a 1,5 l Nissan Almera so finishing the exhaust actually brought a significant performance gain :D

[Skarpa]

Video about the exhaust installation here:

https://youtu.be/umrsWFsay8A

After installing the exhaust I did a few full throttle pulls on Testo and the exhaust didn't really do any difference. But that's not a bad thing. I'm not that familiar with tuning engines and reading logs so I asked for some consultation from Pazi 88. The engine has some real potential. The maximum engine load ie. the amount of air / stroke the engine is sucking is 25% greater than in stock M52B28 and the engine load won't start dropping until 6500 rpm so it's really pulling in some air. The AFR also stays good for the entire rev range so next we need to look at the ignition advances which seem to be pretty low. I'll probably ship my ecu to Pasi for changes in the tune when I put the car away for the winter. Eventually the car will also be actually tuned in dyno once I find someone who knows how to work with Siemens or when I make a 600 km road trip to meet Pasi. (or change the ecu to speeduino)

[Skarpa]

Lately I've been familiarizing myself with remapping Siemens MS41 ecu. I downloaded Romraider and MS41quickflash and added a switch for write enable voltage to my diagnostic cable.





I made it with an indicator led so I can see at a glance when I have the writing enabled. Then it was a matter of testing. I read the tune from the ECU and discussed it with pazi88. For some reason there actually was a pretty weird-looking ignition advance map in the ecu. There's been some mistake with this. On the left there's the ignition advance map from the car and on the right there's an ignition map from a British tuning company that used to sell remapped M52 ecus. I don't know if they are still in business but their remap for Siemens ECU is pretty widely available nowadays and works well as an off the shelf tune up. Mostly it has higher ignition advances and a bit more fuel programmed in.


To test writing a program in the ecu I changed all the ignition advance tables according to the "British" tune. According to the Testo Logs I'm using the last two columns on the right at full throttle. The maps should probably be rescaled to take that into account but this should already be a change for the better. I made a couple of other changes as well. I dropped the rev limiter to 6700. It was at 7000 but would allow the engine to rev to about 7200 which felt a bit too much for a B30 crank with a stock vibration damper. I also lowered the vanos switching point 500 rpm lower because the torque seemed to be already dropping before the vanos kicked in. Final change that I made was dropping the "throttle closed" TPS threshold from 1,9% to 0,9% because I was getting occasional unwanted fuel cut when cruising on very light throttle or during gear changes. Then it was a time to cross the fingers and try writing the binary in the ecu. It went with no hickups.

When driving the car I noticed immediately the lack of unwanted fuel cuts. I had also tightened the throttle cable a little. There was some slack in it when the throttle was closed. Now the flaps will start opening immediately when you press the pedal. The car is now so much nicer to drive in the city and when cruising. All together the car seemed to pull more evenly but I didn't feel tremendous improvement in the full throttle performance. I did a few full throttle pulls and logged them on Testo. The effects seemed positive. After 3000 the ignition advance stays in the range of 23-26 and that as well as the vanos switching point change had positive effect on the engine load graph.







The dip at the 5000 rpm has disappeared and the graph is smoother and higher all through the rev range. While some improvements were made it didn't really feel like I found all the 50 or so newtonmeters that I was missing up top according to dyno. Before returning to dyno I will probably try setting the intake cam timing for less overlap. After discussing this with various people more experienced than myself that seems worth trying in a vanos engine. My current overlap at TDC is 1,25 mm for the intake and 0,9 mm for the exhaust cam. Before dyno I'll also disable the lambda correction and make a lengthy log of various driving to give Pasi some data for evaluating my fuel map. But we'll see if I have time for all that before putting the car away for the winter.

[mjweimer]

Lately I've been familiarizing myself with remapping Siemens MS41 ecu. I downloaded Romraider and MS41quickflash and added a switch for write enable voltage to my diagnostic cable.
Final change that I made was dropping the "throttle closed" TPS threshold from 1,9% to 0,9% because I was getting occasional unwanted fuel cut when cruising on very light throttle or during gear changes.

Prepare yourself for a stupid question - is the throttle closed TPS threshold easy to change with Romraider? I too experience throttle cut at light throttle as well as an occasional "surge" when de-clutching at low speeds. My M52 swap is running a MS41.1 OBD2 with an OBD1 manifold and throttle body unlike your fully custom arrangement. The swap is great except for this annoying issue. I don't have an OBD2 port on my swap which I thought was needed to flash with Romraider but clearly you are using the main diagnostic connector.

I am not a tuner and have zero experience hence the somewhat ignorant question(s). I'm not even sure where to start looking for the right information.

Thanks!

[Northern]

I've never considered raising the throttle closed threshold, but I get that as well so I will give it a shot.


Worst part about romraider is getting everything setup and working.

Cables are cheap and sometimes DOA from fake FTDI chip inside.
Need to add programming voltage ( https://sites.google.com/site/openms...1/enable-write )
Need quickflash (via the wiki/gumroad) or the old MS41 flash tool (from MS4X.net )
All of romraider/romraider logger/ECU definitions/32bit Java/FTDI cable drivers are easiest to install/configure correctly using the MS41 ECU Portal app
( https://sites.google.com/site/openms41/tuning )

[Skarpa]

Prepare yourself for a stupid question - is the throttle closed TPS threshold easy to change with Romraider? I too experience throttle cut at light throttle as well as an occasional "surge" when de-clutching at low speeds. My M52 swap is running a MS41.1 OBD2 with an OBD1 manifold and throttle body unlike your fully custom arrangement. The swap is great except for this annoying issue. I don't have an OBD2 port on my swap which I thought was needed to flash with Romraider but clearly you are using the main diagnostic connector.

I am not a tuner and have zero experience hence the somewhat ignorant question(s). I'm not even sure where to start looking for the right information.

Thanks!

I have no problem with stupid questions or rather don't consider this stupid. I'm not a tuner myself either and had no previous experience. I'm just asking stuff from more knowledgeable people and reading up as I go.

The change itself is very easy. You just type in a new value in this cell.


But you can't flash anything with Romraider. Romraider is just for modifying the maps and logging. To actually read the maps from ecu and to flash it you need a different program called MS41 Quickflash. Romraider is free but Quickflash costs 25$. In addition you need to download engine and ecu definition files and install them but if you're well versed using diagnostic cable and reading fault codes the installation should pose no problems. It's similar stuff. There are good instructions on openMS41 website and Romraider forum.

To flash the ecu you also need to provide the write enable voltage to the ecu. You do this by connecting pin 14 (battery plus) to pin 18 (write enable) in the round 20 pin diagnostic port. (what I did with my switch). You can flash through the round diagnostic port or through the OBD2 port inside the car. If you want to do it throught the OBD2 port you actually need another jumper in the x20 port. That's not needed when flashing through the x20 connector.

https://sites.google.com/site/openms41/read-write-ms41/enable-write

A little note on flashing: It takes around 30 seconds and during this time the voltage should not drop below 12 V. Otherwise you risk terminating the flashing procedure halfway and may end up with a dead ECU. I think they are salvageable in most cases but it's best to only flash ecus with a good and full battery in the car.

Pazi88 has a great video series on his youtube channel about tuning Siemens ECUs:

https://www.youtube.com/playlist?list=PLS-cVHPi-DmNij4dilXd2Oa45CmYYyliC

For just a simple change like the throttle closed -threshold it's probably easiest to just find I guy who can do it for you but if no one's available or you want to do it by yourself and learn the stuff it's not too expensive or difficult.

[Northern]

Easy enough to hook up a battery charger/tender while flashing too.
Probably a decent idea if you flash in your car with a battery is under-spec in size or not brand new.

Or make a bench flasher if you find yourself doing this a lot, any sort of 12.1~14.5V DC power supply works for that.

[mjweimer]

Thanks for all the info guys, I've been spending time reading the Romraider forum over the past several days. Seems like folks do a lot of additional tuning work to rid themselves of the "rev hang" issue...most of that is way over my head.

Northern I'll be interested to hear if adjusting the throttle cut threshold improves the funny idle/off throttle issues these MS41 swaps experience from time to time.

[Skarpa]

Thanks for all the info guys, I've been spending time reading the Romraider forum over the past several days. Seems like folks do a lot of additional tuning work to rid themselves of the "rev hang" issue...most of that is way over my head.

Northern I'll be interested to hear if adjusting the throttle cut threshold improves the funny idle/off throttle issues these MS41 swaps experience from time to time.

Great if I can be of some help!





I checked what's the recommended timing for Catcams cams with similar profile. It seems to be intake open 0,6mm at TDC and Exhaust 1,15 mm. I actually had them almost the opposite with intake at 1,25 mm and exhaust at 0,95 mm. I decided to test the Catcams timing specs. I ended up with 0,55 mm and 1,2 mm. Getting them exactly to Catcams specs would have required another round of adjusting but I figured the difference doesn't really matter. Timing cams is kinda tedious because to get a reliable result you first need to set the engine to TDC, measure and adjust the cam and then turn the engine two full rotations to get back to TDC with the timing chains properly tensioned to verify the adjustment. At least for me, adjusting one camshaft takes at least two iterations to get it close to correct timing and after adjusting the second cam you still need to doublecheck the first one because both adjustments are behind the same bolts. In an E30 the job is further complicated by the narrow space between the engine and the radiator but there's just enough space to turn the engine and with a mirror and a light you can see the timing marks.






We have been working with Pasi for a new tune for the engine. The MAF reads very high values which puts the tune at the very edge of the map. We figured it's because of my bigger MAF and how it's been scaled in the tune. Pasi used the MAF scaling from Alpina which also uses the bigger MAF but he suspected that Alpina also had some hardware change in the ECU to go along with it. So my MAF is actually showing too much air flow. It's not a problem as such because it still shows a logically changing value. But the fuel and ignition maps had to be rescaled for the higher MAF readings. After adjusting the cams I flashed in new maps that Pasi made and I have to say that the changes made a huge difference. The car is now much more civilized and nicer to drive. It's funny how much better it is now even though I didn't have much to complain about even before. I'd say you no longer notice the ITBs in a negative sense. The car is surprisingly smooth to drive. Although there is some extra play in the drive line. I suspect the dual mass flywheel and the CV joints at the half shafts. Previously I had some misfires at idle and have been planning to tackle that issue but adjusting the cams got rid of those. It kinda feels like I lost a little bit grunt at the bottom end but after driving it for a while I think it's just that the torque curve is just more even now so I've just gotten rid of some peaks and valleys. It was difficult to say if I got any more high end power since lately it's been rainy in Finland and on wet pavement it's hard to assess because of traction issues.

After the changes we did some more logging and work on the fuel map and then it was time to take the car to the dyno again to get objective data. The plan was to make a duno pull with the intake cam fully advanced and another one with the cam constantly at basic setting (retarded) to see when the vanos needs to change it's position. The green lines are vanos advanced and the pink lines are vanos retarded. The red lines are the previous run before adjusting the cams and ignition advance. The colors are not great for making distinction between the lines.



The optimal switch point for vanos seems to be at 4500. I programmed the vanos to start turning at 4300 to give it time to change. For some reason the mixture was very rich despite Pasi actually pulling some fuel from it before. It may have something to do with how the fuel map was rescaled or with previous adaptations messing up the logging. Anyway I tried pulling some fuel from the WOT enrichment table be we were not able to test that because the car started to run very badly like it was only running with five cylinders. I thought I had made some mistake with modifying the maps and tried reverting the changes but to no success. I checked if there was any obvious issue like oil in the spark plug well or something like that but couldn't find anything. I suspected a faulty coil and we wrapped up the dyno session. However, when driving home the car worked perfectly normally even with full throttle and high revs. The issue may have been as simple as a wet spark plug because of excess fuel. The fuel map needs to be checked.

The dyno pulls that we managed to make give me an idea of how the engine works. If you combine the green curves before vanos switch point with the pink curves after it you can see that until 5500 the engine works a lot better than before. The curves are pretty smooth and we got rid of the massive dip at 4900. After 5500 the operation is pretty much identical to before. The engine produces the max torque really low at 2400 and the RPM of the max power is also pretty low. The max power leaves much to be desired. With these cams and this displacement I should be looking at max power of 230 - 250 hp at around 6000 - 6500. So the power band should be moved higher up. I'll probably try retarding the intake cam even more. Maybe even to the point that the intake valves are fully closed at TDC without the vanos engaged. Shortening the intake channels would also be worth trying. Currently the length from the plenum to the intake valve is around 415 mm which is pretty long. Shortening the distance will require some work because I actually need to fabricate shorter intake runners (trumpets) for the plenum. Probably I should first do some kind of test setup using cheap standard velocity stacks and then fabricate or maybe 3D print something more refined. But the weather is starting to look pretty bad so for now we just try to get the fuel map right and then the car goes away for the winter. I wish I had a shop but haven't found anything suitable.