Techtom MDM-100 people!

[bruinbear714]

Anyone with a techtom obd-2 scanner located in Orange County willing to spend a day with me to loan me the unit for some DIY tuning? I'm installing my turbo kit this weekend and would love to borrow that to meter timing on the engine.

I'm using the full emanage setup but have no way to meter total ignition timing.

I'll take you out to dinner and you get to ride in my boosted KA @ 7psi when it's all done! (assuming I don't blow the engine! )

[WDRacing]

With the emanage can you just leave the ignition map stock? With only 7 psi I wouldn't even bother retarding it at all. I wouldn't worry about knock until boost levels over 8 psi.

[bruinbear714]

With the emanage can you just leave the ignition map stock? With only 7 psi I wouldn't even bother retarding it at all. I wouldn't worry about knock until boost levels over 8 psi.

If my theory is correct, by altering the MAF signal to compensate for injector pulse width, we are also altering the engine load that the ecu sees, which means the timing will be somewhat screwed.

This is a huge concern of mine especially when going from 270cc injectors to 550cc injectors using emanage. For simplicity, say by going from 270cc to 540cc, the emanage halves the MAF voltage, which in turn creates a smaller injector pulsewidth. While this works for fuel, ignition is a completely different story.

The ignition maps are based off rpm and engine load (maf voltage in this case). By halving the maf voltage, the ecu is going to be picking an ignition value that'll represent half the actual engine load.

And under a condition where you have 550cc injectors and the MAF is physically maxed out at 5V @ 6000rpm, but the piggyback halves it to compensate for larger injectors, the ecu will see 2.5V and 6000rpm, look at its internal timing table at those points and fire - when we expect it pick a timing value at 5V and 6000rpm.

And without any way to data log total timing at stock, stock + 550ccs, and 550ccs + 7psi of boost, I'm pretty much blindly adjusting ignition.

I know people have recommended retarding timing by 0.5-0.75deg/psi, but I'm assuming that is for stock injector size with a boost dependent fuel pressure regulator.

This may not even be that big of a deal, but being an electrical engineer, I tend to do a lot more critical thinking when it comes to systems.

EDIT: This is assuming that injector corrections on the emanage is done by modifying the MAF voltage.

[Red Lightning]

I think the eManage with Injector Harness directly cuts injector pulse width, so I don't think you timing will be affected much.

[WDRacing]

Very interesting theory...Do post your findings when your testing is complete. I'm very interested.

[240driver39]

Very interesting theory...Do post your findings when your testing is complete. I'm very interested.

not really much of a theory, enthalpy on freshalloy recently posted a thread regarding this subject, and also included a excel chart mapping out the ignition timing values vs maf load values. Very informative.

[bruinbear714]

not really much of a theory, enthalpy on freshalloy recently posted a thread regarding this subject, and also included a excel chart mapping out the ignition timing values vs maf load values. Very informative.

Yes, his thread is what got me thinking about the emanage... SAFC and emange are similar, except one would think emanage will do a slightly better job since it has access to injector pulsewidth and ignition control. That would mean injector corrections would be done by directly altering the pulsewidth.

Anyhow, I dropped in my injectors today and did the injector corrections in the software, updated, and it DOES INDEED COMPENSATE for larger injectors by altering the MAF voltage.

That's going to screw up timing a lot!

[240driver39]

bump back the stock timing and it will be okay for the lower power ranges. Ultimately this isnt the solid answer, but didnt u say with the emanage that the ignition timing values could be tuned? if so, then gather input on ignition timing on the ka for boosted applications, or take it to a professional (better idea) and set it up. Just what i would think would be the ideal route.

[bruinbear714]

bump back the stock timing and it will be okay for the lower power ranges. Ultimately this isnt the solid answer, but didnt u say with the emanage that the ignition timing values could be tuned? if so, then gather input on ignition timing on the ka for boosted applications, or take it to a professional (better idea) and set it up. Just what i would think would be the ideal route.

The problem is that with such a large injector over factory size (more than double), the piggyback cuts the MAF voltage by an amount that may cause the stock ecu to look up the wrong timing value. In this case, the timing value for a lower maf voltage than actual is about 10-20 ADVANCED than what it should be.

But yeah, ultimately I am going to get it dyno tuned - I just want it to at least run and idle fine. It doesn't have to be under boost as I can drive granny style until its tuned.