budget orientated M52 tuning options.

[Kurtisja]

So one of my current projects is building S50 ITB adapters for my M52 engine. To got with these i've got some bigger cams, an exhaust, 3.5" MAF and potentially larger injectors. Honestly, the physical side of what is on the engine doesn't matter. Im looking for tuning options. Im building this engine (and car) as a way into the racing scene. Ideally i don't want to spend huge money on it, as more than anything else its a learning experience. A big part of this is i want to tune the car myself. I havnt really given myswelf a budget, but im also not gonna drop $1500 on a standalone, so basically my options are as follows (as far as i can tell):

1)OBD1 convert, run a miller war chip, tune myself, happy days.
Pros: A common swap, with a fair amount of support. Easily available software, i know i'll be able to achieve what i want to.
Cons: the bosch motronic system simply isnt as good as the siemans. Allot of expense involved in gathering various different parts.

2)piggyback ECU. Ive been looking at a few, but my favorite for now seems to be the AEM F/IC 6.
Pros: Lots of good info out there, seems simple enough, relatively cheap.
Cons: Really i can only control fuel delivery. Not a whole lot of options other than that.

3) Freeware tuning software. Ive had a bit of a look at things like "tunerpro" and Galletto etc. There are a few threads around mentioning them.
Pros:freeware (mostly) should accomplish everything i need.
cons: Freeware, developed by others with their own interests in mind, may not necessarily achieve everything i need.

At the moment im coming down in favor of the piggyback, it seems the simplest and the cheapest way to start learning. But please, offer whatever valuable input you can.

[328 Power 04]

First maybe let us know which car and ECU this is for, as the 92 320i did not have a flashable MS41 ECU.

Second, the 3.5" maf is only needed when you actually max out your current MAF capacity, which usually requires displacement over 3000cc.

[Kurtisja]

First maybe let us know which car and ECU this is for, as the 92 320i did not have a flashable MS41 ECU.

Second, the 3.5" maf is only needed when you actually max out your current MAF capacity, which usually requires displacement over 3000cc.

Sorry, the car has an M52B28 engine swapped into it. I planned on using the 3.5" mac purely to make the instal neater (euro s50's come stock with the 3.5". Also eventually I'm gonna have some larger cams and some head work, so hopefully ill be outflowing stock M52's.

Honestly it doesn't really concern me which MAF i use, as long as the option i go for has the flexibility to upgrade.

[328 Power 04]

So... which ecu do you have? Including hardware number.

The MS41 ecu is very tunable, and has been deciphered and defined almost fully. Not using TunerPro, but rather RomRaider. Of course you have to know how to tune correctly, using logging tools and all, but that's no different than a piggyback or standalone.


I was saying about the MAF because you can't just plug a different maf in. It has to be defined correctly in the tune for it to work properly. Same thing with injectors. None of these are 'plug and play'.


Going to OBD1 would be a massive step backwards.

[pbonsalb]

So... which ecu do you have? Including hardware number.

The MS41 ecu is very tunable, and has been deciphered and defined almost fully. Not using TunerPro, but rather RomRaider. Of course you have to know how to tune correctly, using logging tools and all, but that's no different than a piggyback or standalone.

I was saying about the MAF because you can't just plug a different maf in. It has to be defined correctly in the tune for it to work properly. Same thing with injectors. None of these are 'plug and play'.

Going to OBD1 would be a massive step backwards.

Megasquirt may do a plug n play, but it wont be cheap by some definitions of cheap.

[Kurtisja]

I couldnt tell you which ECU number off the top of my head, but it is an MS41.

I downloaded rom-raider a while ago, but couldnt find the BMW ECU definitions?

When you say defined correctly, for the maf, do you mean telling the ECU what the MAX load signal is, and what the MIN load signal is? IE when signal x is output the engine is at max load, when y signal is output the engine is at min load, and then whatever values inbetween?

[tptrsn]

I just started playing with RomRaider over last weekend, and it is SWEEEEEEET! I'm running an M52b28 with an MS41.1, and once you figure out how to handle some of the nuts and bolts of the RomRaider process, it is much easier than using WinOls for tuning with Galletto uploads. I haven't figured out how to use the RomRaider logging yet, but I'm already a huge fan.

Hopefully I will become familiar and proficient enough with RomRaider that I feel qualified to make up a "BMW Specific Getting Started Guide." Currently it is necessary to piece together a lot of bits from various threads on the MS41.1 Development forum.

[328 Power 04]

I couldnt tell you which ECU number off the top of my head, but it is an MS41.

I downloaded rom-raider a while ago, but couldnt find the BMW ECU definitions?

When you say defined correctly, for the maf, do you mean telling the ECU what the MAX load signal is, and what the MIN load signal is? IE when signal x is output the engine is at max load, when y signal is output the engine is at min load, and then whatever values inbetween?

The definitions are in the BMW subforums. I believe you have to have some posts to see the attached definition files.

Regarding MAF: a maf voltage signal is not linear, so it isn't just about defining max and mins. It is about having every point defined. The MS41 has 256 points between 0-5 volts, so the proper characteristic curve has to be applied, specific to the intended MAF. So as long as you have the MAF and intended characteristic curve (sometimes available online), then you can define the sensor correctly.
If you were to just plug in a 3.5" maf, your load scaling would be way off.

[Kurtisja]

Im still playing around with romraider, do you have to have an ECU plugged into it to get all the tables etc? Im currently running it on my desktop PC so its a bit of a pain to get an ECU powered, and plugged into it.

Furthermore, regarding the MAF issue - turner motorsport sells a kit for the 3.5" porsche MAF, that includes a tune. If i cant find a characteristic curve, would i be able to use this tune, then use rom raider to pull the charectristic curve? IE rather than trying to tune from a base ECU, start the tuning from an already flashed ECU?

[328 Power 04]

Romraider just interprets the flash data you pull off with your flasher cable of choice. I use the Siemens MS41 Flash Tool and a USB KKL cable. Once you pull the 24kb flash (the tune), then you use RomRaider to edit it.

And yes, you can base yours off a Turner flash just fine, just more expense.
I keep on wanting to adapt a MAF from the M54B30, but just don't have enough time.

[Kurtisja]

So what is the purpose of the siemans MS41 flash tool? Ive just had a cursory look, It is linked from the romraider page. Can you not just write to the ECU with the flash tool?

[tptrsn]

The flash tool does a couple of things for you that are really nice. Firstly, if you haven't seen to your checksums with some other means, it corrects your checksums as it uploads your new tune into your DME. Secondly, it instantly recognized my (China eBay) K+DCAN cable, and made it an extremely intuitive process to go through the steps of the upload.

There is a third potential benefit of it that is it **MAY NOT** be as sensitive to system voltage as uploads done by a Galletto or something. The word I've heard is that with the Galletto you need to have a good solid system voltage at about 13V, or you can have ghost uploads where you think you uploaded the tune, but it really didn't take. Granted I've only used the MS41 flash tool one time so far, but it made no mention of system voltage, and just did the upload nice and smooth, on nothing more than battery voltage.

There are some other benefits of the tool that I haven't dealt with yet, such as the ability to pull down a full 256k read instead of just the 24k partial that contains the information about the tune. Also apparently there is a facility in the flash tool that allows you to basically image one DME onto another too. All in all, it is WELL WORTH THE MONEY!

[328 Power 04]

So what is the purpose of the siemans MS41 flash tool? Ive just had a cursory look, It is linked from the romraider page. Can you not just write to the ECU with the flash tool?

Siemens MS41 reads and writes the flash to the ECU. It also corrects checksums automatically and makes it easier to convert between software versions. Yes you need a way to read and write the ecu flash.


RomRaider only interprets the data from the read. RomRaider is not live tuning. You read the flash, edit the flash data with RomRaider, then write the flash back to the ECU.