MoTeC Global Forum

I would like to use two igniton maps on my engine, with a M4pro, an agressive one on the limit for the times I'm on the track using 100+ octane fuels and one more conservative one for road useage.
Can't get 100+octanes when on the road.
Don't see any possibilities for it. Any ideas?

Not sure what your question is.

Its easy to have different maps for different fuels.

Are you wanting to switch maps on the fly?

If so, how are you introducing the new fuel?

Hugh wrote:Not sure what your question is.

Its easy to have different maps for different fuels.

Are you wanting to switch maps on the fly?

If so, how are you introducing the new fuel?

Hi Hugh,
I'll try to explain better. I got a Caterham with a higly tuned 2.0XE engine outputting around 260Hp.
The ignition timing has been setup for 100 octane fuel, and is pretty close to the knocking limit.

To be safe for the times I use the car on the road, and not always have access to 100octane fuel during travels, I would like to be able to switch to a bit more conservative ignition advancing, to prevent the danger of knocking.
I could inject more fuel, but my thought is that it's nicer to adjust the ignition table or maybe a combination with the fuel map.

I know I can adjust the fuel map with the secondary map.
I don't need to switch on the fly, just after refueling.

Don't know the situation outside of europe but the quality of fuels is getting worse with the addition of ethanol, which also causes other problems.

bouma175 wrote:...
Hi Hugh,
I'll try to explain better. I got a Caterham with a higly tuned 2.0XE engine outputting around 260Hp.
The ignition timing has been setup for 100 octane fuel, and is pretty close to the knocking limit.

To be safe for the times I use the car on the road, and not always have access to 100octane fuel during travels, I would like to be able to switch to a bit more conservative ignition advancing, to prevent the danger of knocking.
I could inject more fuel, but my thought is that it's nicer to adjust the ignition table or maybe a combination with the fuel map.
...

Jamie A~ did a multi position switch on a Cortina, and could knock the spark forwards or backwards.
That would take care of the ignition, and if you had a way to sense knock that would help.
Perhaps there is also a way to add fuel in similar fashion 1D or 2D table(?).

I am assuming it is naturally aspirated.
What compression are you running?

Hi,
My engine is NA with TPS for load sensing since it uses multi runners. The compressionration is 11.0

http://db.tt/HaYL1lc4 (don't know if this is allowed, but it are some images of my car and the engine)

The M4 I'm using is the pro version, and the only reason I'm a bit reluctant to use a secondary map is that I use the lambda maps. Adding the extra fuel would also require a change in the Lambda mapping in order to prevent that the extra fuel added is countermeasured by the lambda feedback.

In the case of modification, or as with the cortina you mention by an offset, of the ignitiontable, the lambda feedback would also change the required amount of fuel.
I know it isn't very neat, but my theoretical knowledge lambdafeedback, should make this working, or am I totally missing the nail of the ECU calculations.

So back to my original question: How is this spark advancing or retarding done with the ECU. I don't see any option under the digital input to do this.

The only way you can do some of what you want with a M4 is use either the Aux temp or Aux volt inputs. You could connect a switch through a resistor or use a multipostion potentiometer if you want more than one setting. Then use Aux temp comp or aux volt comp to subtract timing from your map. Note though that this type of setup can only add or subtract a common amount of timing from the whole map - you cant for instance have a 3d table where you take more timing out on boost etc...

The simplest way to do this is to load up a new map, when you change to a different fuel.

Is that too complicated for you?

AdamW wrote:The only way you can do some of what you want with a M4 is use either the Aux temp or Aux volt inputs. You could connect a switch through a resistor or use a multipostion potentiometer if you want more than one setting. Then use Aux temp comp or aux volt comp to subtract timing from your map. Note though that this type of setup can only add or subtract a common amount of timing from the whole map - you cant for instance have a 3d table where you take more timing out on boost etc...

Thanks Adam, That's exactly what I'm looking for. Currently I'm not using the aux inputs. Will look into this.
The total shift of the map is more than enough for me.

Hugh wrote:The simplest way to do this is to load up a new map, when you change to a different fuel.

Is that too complicated for you?

Hi Hugh,
Ehmm, not complicated, but I'm not always carrying a laptop with me when I'm touring. Most of the times the missus joins me, so the only space in the boot left for me is for some undies, socks and a toothbrush.

If you're touring, you'll never have 100 octane or need it...so no need to change maps in the first place lol.