Forum » General Tuning Discussion » Digital widebands for Porsche engine

Digital widebands for Porsche engine

General Tuning Discussion

Discuss all things tuning in this section. News, products, problems and results. 

Page 1

In the near future I'm planning to modify a normally aspirated flat-6 aircooled engine from a Porsche 911. The spec will be roughly as follows:

- Individual throttle bodies.

- Standalone EFI.

- New injectors, coils and fuel pump. Single spark plug per cylinder.

- Either two knock sensors on the heads or one on the block.

- Wideband lambda sensor(s). Probably one sensor per bank (see photo of exhaust below).

I'm trying to decide which would be a good ECU that fits my requirements. I'm currently leaning towards Motec or Link but nothing is decided yet.

My main concern is about the wideband lambda sensors. Can they be connected as conventional analog inputs or do they need a special input/CAN?

Looking at the specs of the various Link G4+ ECUs, I see that only the most expensive model (G4+ Thunder) allows for 2 "lambda sensor control". As far as I understand, this is for 2 digital wideband sensors that send the lambda information via CAN. Does this mean that the wideband sensors will need their own electronics box that sends CAN messages to the ECU?

Many thanks for your help!

The exhaust will look roughly like this:

With the Link Thunder you have 2 onboard wideband controllers so you don't need additional controllers. The lambda sensors are wired directly to the ECU header. MoTeC offer this as a software upgrade on their Mx00 ECU range too. The alternative is to use an ECU that has no internal wideband and then add a wideband controller. In the case of the MoTeC M1 range you need to use the MoTeC LTC (Lambda To CAN) or Dual LTC which communicates via CAN. The Link is a little more flexible and you can use a CAN based controller such as the Link CAN-Lambda (my preference by the way), or any number of other CAN or analogue devices.

Thanks very much for your answer, Andre! It is clear to me now that one cannot simply plug a wideband lambda sensor to an analog input of the ECU.

I'll need to figure out what is the best ECU or ECU + lambda CAN controllers for my six cylinder engine. I'm finding MoTeC's options, logging licenses and development licenses quite confusing...

Do you know if Link offers the equivalent to a development license where one can develop its own code and run it on the ECU?

I just answered questions for a similar 911 engine, let me just copy what I send my customer. These prices are for US customers, but it gives you a feel for what is required and the relative costs.

Initial request was asking if an M48 ECU would work for his engine.

While the M48 will certainly control your new engine, it is very old, has been discontinued by MoTeC, and the software only runs in DOS -- so it's getting more difficult to support. Unless you've got a really smokin' deal (i.e. its free), I would not suggest starting with this.

I would recommend that you consider a new MoTeC M84 -- this is only one generation old and priced very competitively ($1760 including 1MB of logging memory, and a single onboard lambda controller - sensor required). I would suggest the upgrade to dual lambda ($180), so you have one sensor in each cylinder bank. The software will run in Windows 10.

In order to tune, download data, or run diagnostics on the M84, you will also need a MoTeC USB-to-CAN adapter (known as "UTC"). Engine Tuners and builders will typically have a UTC so you don't necessarily have to have your own. You can sometimes find those used, but they are available new for $295. I would consider that part of the harness, and you should probably budget for that.

Since you were talking about the M1 -- an M130 ($2340) would be capable of running a 911 engine, and would require at a minimum a GPA ($700) or GPR ($1160) package license and an external Dual Lambda-To-CAN wideband controller (LTC-D, $844). So you can see an M1 could be used, but an M84 is very capable of running a 911 engine very successfully -- however the M84 does not have support for knock sensors, while the M1 does. Is the improved M1 Tune user interface, Ethernet connection, dual knock sensing, more logging potential (optional upgrades) worth about twice the cost. Only you can decide.