alex_cristocea

As my old DME started to show its age, I had two options: one was to purchase a used or new DME, and the other was to switch to a standalone ECU. The first option would have been the easier route since it's plug-and-play, more cost-effective, and retains stock reliability. However, it also keeps 40-year-old sensors like AFM and TPS, which are hard to find these days and have their limitations, not to mention the old engine harness. So, I went with the second option, which is a bit harder to set up but offers more flexibility in the long run. It's also a bit of unknown territory for me, as I could not find any threads or information regarding this type of ECU installed in a 951, so I think it's better to post the project details here.

My car is an '87 951, and the engine was rebuilt a few years ago. The ECU is an Ecumaster EMU Black, and I decided to build a new engine electrical harness to accommodate the new sensors. The design will resemble the original harness. I also intend to keep the original DME relay and its function, the 14-pin connector under the hood, and the 8-pin under the glovebox.

I want to ask if anybody has installed this type of ECU in a 951 because, for me, it's not clear how the crankshaft sensors should be wired and configured in the ECU

Droops83

Hi Alex,

Zero experience with the Ecumaster, but I do have a VEMS ECU, and one of the things I learned during my research was that the VEMS is one of the only aftermarket standalone ECUs that works well with the 132+1 speed and reference sensor setup as used on the 944 and other early Bosch Motronic DME systems of the era. The analog-to-digital signal processor chip was apparently quite advanced for the time, and it seems that later versions didn't need as expensive of a chip with 60-2 flywheel trigger teeth.

I would check with Ecumaster if their product works well with the early Bosch speed and reference sensors that use the flywheel ring gear teeth and reference mark studs. Otherwise, you will need to use an alternative 36-1 or 60-2 trigger system. The most popular option is an aftermarket trigger wheel mounted on the front crankshaft pulley, all of which seem janky to me since they attach to the drive belt tensioner arms and place the sensor in a vulnerable era.

This TTV 60-2 flywheel would be the best option because in addition to the mounting issues, front pulley-mounted crank triggers are prone to ignition timing inaccuracies due to torsional vibration of the crankshaft. The downside, of course is the TTV flywheel is expensive and is labor-intensive to replace:

http://ttvracing.com/product/porsche...cturer=porsche

Nowanker

Zero experience with either of the above...
But Haltech boasts of adaptability to a wide variety of different sensors.
Might be worth a look?

SirLapsalot

Yes, have installed this type of ECU into a 951.

From your question, it sounds like you are expecting to run the OE speed and reference sensors? If so, as Droops mentioned, there are a couple ECU's which support that. You'll have to check if ECU Master does.

In my case, I ran an ECU that did support that (Link) but decided not to go that route. There's a few things to to consider, but finally it just comes down to personal preference. So might be helpful to know if you are planning on running the OE 132tooth setup, or if you are open to other solutions.

alex_cristocea

I did check before and ECUMaster states that the ECU supports Porsche 132 + 1 trigger setup only with an aditional camshaft sensor. So I added the cam sensor, but I would like to keep the original crank trigger system. I like the TTV racing flywheel, but it's a bit over my budget and the front mounted trigger wheel it's something I don't like for now. My problem for now is to find where to wire the second flywheel sensor on the ECU.

alex_cristocea

The plan, for now, is to run OE flywheel sensors plus a cam sensor. If it does not work, I will consider other solutions. I must admit that a few months back when I purchased the ECU, I did not know too much about Link ECUs, and now I hear and see good things about them, and I see they have good technical support.

Also, I would like to ask you what coil/coils configuration did you choose? Due to the fact that coil-on-plug is almost impossible to fit on a 951, I'm thinking of installing individual coils with plug wires. If you have any suggestions regarding the coils, I am glad to hear them

Droops83

We in the US have abundant options for GM LS coils, which are individual coils with a short wire going to the spark plug. I have seen numerous 944s using the LS coils, just needs a simple bracket for each that bolts to the camshaft housing.

I have a wasted spark setup for my 951, which keeps it simple without the need for a cam sync. It uses an off-the-shelf Bosch coil pack that is used in Land Rovers and Ferraris from the early to mid 1990s.

If you need a cam sync, here is a good option:

https://www.clewett.com/index.php?ma...roducts_id=306

four0four

It seems that they intend for you to use the speed sensor (132 tooth sensor) and the cam sync to provide speed/tdc. You'll probably omit the reference sensor. VEMS (and other audi-focused designs) tend to use the cam sensor to generate a mask for when the reference sensor's TDC signal is allowed "through" to the ECU - it blocks off every other signal except for when the cam is also at tdc.

You could do something like that, but that does require timing the cam sync carefully (can you share how you mounted the shutter wheel on that, btw? I mostly finished something similar before switching to a Bosch motorsport sensor that would let me just stick a bolt in the rotor collar. lazy )

Anyway: You'll need to run the reference sensor to primary trigger in. I don't see a differential input, so you'll need to experiment with polarity. Cam signal will probably just go to cam sync #1, I assume ecumaster will let you adjust offset angles to tdc? You might need to configure or provide a pull-up on the hall sensor's output, they're open drain/collector (meaning they only drive to 0, they cannot drive to +5v). I believe that sensor's output is active (meaning drives low!) when there is metal present, but I forget precisely - Check this on the bench first, do not forget the pull-up to +5v. Something 1k to 10k ohms should be fine. (edit: they claim to support 2k configurable pull-ups!)


Sorry if any of this is already old news to you


edit: pet peeve about the clewitt design: it's not timed well, so you either need to do sketchy things with the rotor adapter, mill your own, or use a system that doesn't rely on the audi-style masking trick. I have drawings for my design I'm happy to share, but won't be posting publicly until they're validated a little longer.

SirLapsalot

Hmm hard to be sure without seeing the rest of the manual or poking around the software. I think I read that as they are saying you can run the 132 as your primary trigger, then maybe the OE “reference” sensor as either “Camsync In #1” or “Camsync In #2” then set your actual cam sensor to whichever one you don’t use for the reference sensor.

I think others ECUs just assume you are running a distributor if you want to run the 132 tooth pattern. In this case it looks like ECU Master has set it such that you can run individual coils and sequential by adding your cam sensor to the crank + OE reference sensor setup. I.e. synchronize to 360deg instead of 720deg.

Seems to me you could also run the 132 as your primary trigger then your cam as your sync and just run wasted spark. That should be the multitooth option they have listed. No need for the reference sensor.

You should probably reach out to ECU Master to ask if can’t find a clear explanation in the help section though. I’m guessing there aren’t going to be many people here who have used ECU Master. Not because they don’t make a good product (they make great stuff and I’ve enjoyed some of their other products first hand with good success), but there aren’t that many 944 standalone installs around and ECU Master for some strange reason is often over looked.

FYI keep in mind if you aren’t already aware, the 944 crank sensor is a variable reluctor sensor. The 3 pins throw people off sometimes mistaking it as a Hall effect. The third pin is just a shield. You can use the screw driver trick to verify which pin is +\- when you go to make your documentation and harness build.

I think any of the popular GM coils would be a good choice. I run the LS1/6 coils bc I found a rennlister that made a bracket kit that mounts to the cam tower for a clean install. If you like fabrication you could run whichever you like and make a custom bracket to mount them. I think the IGN1A are a popular coil with aftermarket many ECU installs.

alex_cristocea

Mystery solved. I spoke today with ECU Master support, and they told me that if I use the factory flywheel-mounted trigger system, I need to wire the speed sensor to the primary trigger and the reference sensor to cam sensor 1. However, in this configuration, it is NOT possible to have sequential spark and injection. Instead, it runs in wasted spark mode with batch fire injectors. If I want fully sequential injection and spark, I need to install a 60-2 trigger wheel and CAM sensor. So, you were all right about this; it can't be run with the factory trigger system and cam sensor to have sequential ignition.

Now, I have two options: 1 - Finish the harness like this, keep the distributor, or install a wasted spark coil, call it a day, and leave sequential injection as a future project. 2 - Install a trigger system (but I really don't like the front-mounted trigger wheel and bracket). The best option for the 60-2 wheel, in my opinion, is a flywheel. If I go down this road, I also think the IGN1A or LS2 that you recommended are a good option

alex_cristocea

Sure. It's not finished yet; I have to drill the holes that hold in position the shutter wheel. The sensor is a hall sensor

alex_cristocea

I am thinking of setting up as you did. It is way simpler, it would save me some time and $$$, and would give me more time for setting up and tuning the ECU.

Thank you all for the advice; I will keep you posted with the progress.

four0four

Thanks! I think I was just planning to trim and tap the rotor insert, before I found out how difficult it was to find more of them (seriously, try)!

Unfortunate to hear that they won't support all three sensors audi style. I don't know how flexible the config is wrt trigger counts, but if you use the cam hall trigger to mask the reference sensor signal, you could tell the ECU you have 270 teeth and go from there...Probably best to get everything else working before playing with that though

For what it's worth, I'm also using wasted spark, probably with the same coil as Droops83. They're available all over the place. I think that's probably a good route to take just to get things running, and leaving sequential triggering/injection as a tinker project for a later date.

SirLapsalot

OK that makes more sense and aligns with what other ECU's do, but it kind of contradicts what they have in the manual you took a screen shot of. At least the way I read it, it does. That being said, it still seems to me if you had the speed and reference sensors wired like you/they describe, then you now are synced to 720 degrees, so IF you then added a CAM sensor (like their manual states) you could now synch to 360 deg and run sequential. However, it must be that their SW is not actually designed that way, to take both cam inputs as a trigger sync, since that's not typical.

Regarding your two options. I came down the same decision path, and like you I also do not like the front mount trigger option. TTV flywheel is clearly the best option, but yes it's expensive and a much bigger job if you weren't planning on removing the engine etc. If you do decide to look into option 2, have a look at the Clewett front trigger kit. It's what I went with and is the cleanest/least fussy or failure/error prone setup I've seen --> https://www.clewett.com/index.php?ma...products_id=30. It's meant to use a VR sensor like the OE speed/reference which are more reliable and robust than a hall sensor.

For what it's worth, I don't think running sequential will actually lead to any measurable or significant gains in power or efficiency. However, depending how ECU Master handles them, it will make a difference with some functions like knock control, traction control, etc. With sequential, these functions can provide individual cylinders cuts/trims, whereas without sequential they will just treat all cylinders the same and cut where it might not be needed. So the effectiveness of these things might be somewhat reduced, however to what degree IDK.

Just running batch fire/wasted spark is definitely the easy button and you will still get ~all the advantages of a standalone, and you'll still have plenty of fun tuning and calibrating. So depending on your budget/goals it might not be worth it to go sequential. Maybe just keep in mind though, depending how you build your harness, it could be difficult to go back and change your wiring without building a completely new harness if you decide to add sequential later. So whichever route you choose might have to be what you stick with, unless you're ok with a complete tear up down the road.

SirLapsalot

Oh, one additional thing worth mentioning or considering. I have a fairly new OE standard 951 clutch in my car and above ~1.22 bar of boost on a modified K27 turbo it will begin to slip... So if you're chasing the >340whp area when you begin tuning, you'd need an upgraded clutch anyway, so if you had gone the route of TTV from the start, installing an upgraded clutch at the same time, then you wouldn't have to worry about clutch capacity as you tune and optimize. Maybe you already installed an upgraded clutch when you rebuilt the engine, but anyway, worth considering.

Slippery slope!!