Retarding ignition when going from CR 9:1 to 10:1

oleg535i · Post by **oleg535i** » Mon Jun 30, 2014 2:47 pm

Hello,

Situation:
535i, Euro, 218hp, M30b34, Motronic 1.0 CR 10:1

Changed from Motronic 1.0 (061 ECU) to Motronic 1.3 (179 ECU)

Motronic 1.3 is from an e32, M30b35 with CR 9:1.

Issue:
Using ECU from B35 with CR 9:1 to B34 with CR 10:1, lost some torque/power, pinging at low RPM under load etc. due to CR difference.

Changed/retarded the ignition timing by 5 degree in Low and High load Maps.
It's better, but not perfect.

Questions:
1. Increasing CR by 1 unit, how much do I need to retard the ignition? how many degrees?
2. Should it be changed only in Low and High Load maps?

Thanks in advance for any help.

Falkenberg · Post by **Falkenberg** » Wed Jul 09, 2014 10:11 am

What octane gas are you using?

tcolt · Post by **tcolt** » Fri Jul 11, 2014 8:30 am

Are you re-programming your 179 ECU chip?

oleg535i · Post by **oleg535i** » Tue Jul 15, 2014 4:36 am

I'm using 98 RON now with 179 and before with 061.

I'm not changing the original files, just copied them to a new EEPROM chip to play with them, not affecting the original chip.

Just downloaded TunerPro, it's much easier to see all maps.

oleg535i · Post by **oleg535i** » Tue Jul 15, 2014 10:27 am

Filled with 100 Ron /Premium petrol
it's an improvement.

This suggest that timing is the issue.

tcolt · Post by **tcolt** » Tue Jul 15, 2014 11:40 am

I put a ...179 and a B35 head on my Euro b34 motor and it runs great, but I bumped the CR up to 10:1 so I never had any problems with it...
Now I want to convert to Megasquirt which I just bought but I'm looking for someone who will help me with some fuel and ignition maps for my Frankenstein motor, to get me started a little better than the startup maps that they give you...

oleg535i · Post by **oleg535i** » Tue Jul 15, 2014 12:55 pm

If you'll use Megasquirt, to have performance, just replace VAF with MAF or even MAP, individual ignitions.

What Airflow meter are You using?

With stoc 179 chip, even idle are at 950-1200 rpms

tcolt · Post by **tcolt** » Tue Jul 15, 2014 7:36 pm

With the Megasquirt I won't have to use any AFM anymore because it has a MAP sensor built into the ECU. Full circle. My original 3.0CSi also worked with manifold pressure...
But I'll be able to program the whole thing whether I increase the CCs to 3800 or whatever... I just would like to speak to someone who has already done it. Do you know of any threads or web-sites that talk a lot about Megasquirt and BMWs? I thought I once saw a lot of discussion here on this board, but I can't find the thread...

oleg535i · Post by **oleg535i** » Thu Jul 17, 2014 3:34 pm

unfortunately I don't know anybody who understand well MS.

But it should be lot on info on the web and on forums
also some maps which can be used as a starting point.

oleg535i · Post by **oleg535i** » Tue Jul 29, 2014 2:42 pm

Solved!
bought a chip from Conny (Coneus) from Germany, he has good reputation on Germans forums.

Now the engine is sow nice!!!
acceleration from idle to ~6700 rmp, no hesitation, uniform, less noise.

more torque at low and middle RPM

Now she like 100 RON fuel

Firstfives.org

Retarding ignition when going from CR 9:1 to 10:1

Retarding ignition when going from CR 9:1 to 10:1

Re: Retarding ignition when going from CR 9:1 to 10:1