Matty was having an issue when the EU converts his Duty Cycle values in his fuel map to Duration, so I looked into why.

From here: http://www.stealth316.com/2-calc-idc.htm

Basically, IDC(%) = RPMxIPW/1200 or conversely IPW(ms) = IDCx1200/RPM.

Using Stealth 316s example, if IDC=75% and RPM=6000, IPW=15ms, but the EU says 7.5ms.

Greddy incorrectly used the time for one revolution instead of two revolutions.

6000rev/min x 1min/60sec = 100rev/sec
1/100rev/sec = 0.01sec/rev = 10ms/rev, so two revolutions takes 20ms.

This is where Greddy went wrong.
7.5ms/10ms = 75% duty cycle

Correct result is
15ms/20ms = 75% duty cycle




Dandy,

Can you check your BETA version to see if this is still an issue? If it is, pass it on to Greddy.

 

Also another point, the I/J Add map is limited to +/-20ms.

So, if you use a Duty Cycle in a low RPM cell and convert, the EU support tool limits the Duration values to 20ms. Then if you convert back to Duty Cycle, the limited value is used, so you end up with the equivalent Duty Cycle instead of the original value.

Pretty cool 'feature'...haha.

 

Oppps edit. At 6000 rpms my bad.

7.5 = 75%

BTW, I have new software

 

Yes, should be 15ms@6000rpm.

 

Dandys beta version?

 

Although it does not apply in our case, Greddy's conversion would be accurate for engines that use simultaneous multi-port fuel injection (injectors are all fired simultaneously once every crankshaft revolution)

 

True......I'll try some of the others to see if they work correctly.

 

Doesn't seem to matter what vehicle...

 

That could be why it's set up that way. I'll see what they say, but I have been aware of this for a while too. Will check my latest version. BTW, they are saying end of the month for the update now. I guess they keep adding things into the update. For the VQ30 it's ready but it sounds like they're doing other things for other engines also and rolling them out together.

 

Hmmmm...found something else interesting.

Back when I was having issues with my injectors going static, logs showed IPW=11.2-11.5ms while DC=100% from 5323rpm-6400rpm, which isn't correct.

Later, whatever I did by accident fix it and the logging is correct.

 

Sorry to bump this, I dunno if this was discussed earlier but in Dandy's EU file he said he didn't know if the DC to Duration conversion was fixed.

In version 2.20 it is fixed. I am going to use AutoTune to help me start my tune today and wanted to check if the conversion was fixed and it is

 

Yes it was fixed. Also, when I was running the EU I went into the menu section where you input before/after injector sizes and my car ran great after that. I didn't even make many adjustments to the maps.

 

where do we get updates ? Its been so long since I messed with the EU

-matt

 

Sorry for this bump in, I'm about to buy a PC laptop for the tuning with EU and was wondering what OS are you guy using ? Most new laptop come with W7 but I have an extra licence of WXP32 if require.

Thanks

AA

 

My laptop had Vista and the EMU did not like vista. I ran XP and had no issues.
Zack

 

I am using XP, I just installed in WinXP compatibility and it runs fine

Matty, go to greddy's website for the lastest update

 

I finally bought a MSI laptop with a 17" screen, they are now shipping with W7 pre-installed, I'm going to try W7 otherwise I'll just make a partition for XP32.

Thanks for the answer.