Individual Cylinder Tuning - new blog post at apexspeedtech.com

[Apex Speed Technology]

I've added a new blog post at www.apexspeedtech.com. I'm trying to incorporate a mix of articles that tell people about products, project and technical info. I'm shooting for good discussion starters, have a look at tell me what you think!

http://www.apexspeedtech.com/benefit...ylinder-tuning

-Neel

[oddjob2021]

very cool man, ill be sure to bring this topic up to people who know tuning or are into cars really at all, lol, its a cool topic, if it helps or not.

[Sticky]

This is pretty above me but from what I read you said a power gain can be realized from motors close to the detonation threshold? So high compression pump gas motors for example should see a benefit if this was applied? Or does the factory BMW ECU already do a good job of monitoring each cylinder, say in an S65?

[5mall5nail5]

Ion sensing would be the best way, but theres no easy aftermarket setup for that. I am interested in the AEM 4 channel EGT controller, as right now I am running Innovate TC-4 4 channel EGT controllers, but they don't have outputs, so instead I have a laptop just for displaying 8 EGT probes but have nothing logging them with the rest of my ECU. It looks like the AEM will do 0-5V outputs which would be handy to feed back into the ECU.

[Sticky]

Ion sensing would be the best way, but theres no easy aftermarket setup for that. I am interested in the AEM 4 channel EGT controller, as right now I am running Innovate TC-4 4 channel EGT controllers, but they don't have outputs, so instead I have a laptop just for displaying 8 EGT probes but have nothing logging them with the rest of my ECU. It looks like the AEM will do 0-5V outputs which would be handy to feed back into the ECU.

The S65/S85 already feature ion sensing but I guess retrofitting this to older motors isn't really easy or feasible?

[5mall5nail5]

No not really - going from a factory setup to a retrofitted setup wouldn't do much because not only do you need ion sensing hardware (usually involved capacitive discharge coils/system and some processing) but you also need an ECU that knows what to do with the information.

The VEMS group has been flirting with the idea of a universal ion sensing controller. Some progress has been made but its expensive overall. A cool idea too is an in-cylinder pressure sensor. What happens when you knock is cylinder pressure goes up exponentially. So you can detect peak pressure and measure low vs high vs spike. You can then tune the spark map in closed loop based on pressure. Problem is you need to run a modified spark plug that is usually around $1,000 each. Obviously you wouldn't run it 24/7, just for tuning of the spark map, but still.

Saab has run ion sensing for a long time but its so difficult to retrofit a factory system into another car that it isn't really investigated much.

[Apex Speed Technology]

This is pretty above me but from what I read you said a power gain can be realized from motors close to the detonation threshold? So high compression pump gas motors for example should see a benefit if this was applied? Or does the factory BMW ECU already do a good job of monitoring each cylinder, say in an S65?

High compression or force-induction motors benefit the most. The stock S65 system is excellent but like everything else, setup around the stock installation and the stock chassis. So in swaps and race cars, it isn't usable.

-Neel

[Apex Speed Technology]

Ion sensing would be the best way, but theres no easy aftermarket setup for that.

No not really - going from a factory setup to a retrofitted setup wouldn't do much because not only do you need ion sensing hardware (usually involved capacitive discharge coils/system and some processing) but you also need an ECU that knows what to do with the information.

The VEMS group has been flirting with the idea of a universal ion sensing controller. Some progress has been made but its expensive overall. A cool idea too is an in-cylinder pressure sensor. What happens when you knock is cylinder pressure goes up exponentially. So you can detect peak pressure and measure low vs high vs spike. You can then tune the spark map in closed loop based on pressure. Problem is you need to run a modified spark plug that is usually around $1,000 each. Obviously you wouldn't run it 24/7, just for tuning of the spark map, but still.

Saab has run ion sensing for a long time but its so difficult to retrofit a factory system into another car that it isn't really investigated much.

We've worked with companies investigating this, and the problem is it involves fairly intricate calibration. Unless you have an engine dyno with in-cylinder pressure measurement that is crank-synchronous, calibrating ion sensing is nearly impossible. And when you raise compression or add forced induction, the calibration parameters change - so you need to correlate cylinder pressure with your signal processing. Assuming you have access to the signal processing setup for the ion-sensing signals, this becomes a very complex and expensive endeavor. Its not just the $1000/cylinder sensor cost, you also need a DAQ with a very precise shaft encoder (60-2 crank trigger isn't accurate enough) and the ability to sample at a very high rate. We did do this on a project that was run in conjunction with an OEM customer and the University of California-Berkeley Engine Research Center which used Kissler in-cylinder pressure sensors and a National Instruments LabView system. I also did this back in school when working at the UW Engine Reserach Center. The data was impressive - you're actually look at traces of crank position versus cylinder pressure, and the correlation between that and timing events is extremely revealing.

I am interested in the AEM 4 channel EGT controller, as right now I am running Innovate TC-4 4 channel EGT controllers, but they don't have outputs, so instead I have a laptop just for displaying 8 EGT probes but have nothing logging them with the rest of my ECU. It looks like the AEM will do 0-5V outputs which would be handy to feed back into the ECU.

We're very happy with it, and have been selling a few. I works very well and is reliable.

-Neel