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Initial Setup And Tune Questions 
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LQFP112 - Up with the play
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Joined: Wed Apr 13, 2011 2:35 am
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Fred wrote:
http://www.youtube.com/watch?v=YUh58pojOwo

Peter ignored my advice to drive slowly before tuning the car and seemed pleased with the result. This was on a flat VE map of just 60% with floating battery reference, and various other issues. It certainly sounds very healthy, though :-)

Frankly speaking, this video is not interesting to me. But your comments interest me much. You said that Peter run his engine leaving the VE map at 60%? That's means when I install the ECU properly and configure the ignition well and I can idle my engine by leaving the VE map at 60%? Then I can drive slowly and using my wide brand O2 to tune my engine?
I want the videos that reveal harness installation, first start checkout and two man tuning. I should ask all your Volve ECU building, installation and first starting video, nothing else


Sun Feb 05, 2012 3:51 pm
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Short answer: Maybe!

Long answer:

The engine will idle if the timing is between about 5* BTDC and 25* BTDC AND the AFR is between about 13:1 and 16:1 very roughly speaking. 15 degrees BTDC of timing is a good place to aim for, typically, and stoich or a bit richer fueling wise.

If you setup your engine's physical parameters correctly and accurately, then there is every chance it will fire up and idle at 60% VE. This is what you need:

  • Scheduling needs to be right with the correct number of injections per cycle value set.
  • Injector dead time curve needs to be right with reasonably values at different voltages.
  • Battery reference voltage needs to be right and free of electrical noise
  • Cylinder volume needs to be right
  • Injector flow needs to be right, note, this is specced at 100% duty, not 85% which is common on the net.
  • Lambda table needs to be realistic and close to what you finally want, stoich or leaner at low loads and richer at full throttle
  • VE needs to be close to what it really is. < tricky part!

I used to have the system setup to 80% flat VE as a default but that was always too rich for idle. I also used to have the lambda map flat at stoich which was too lean in boost. I've now got 60% flat VE and a nice tapered lambda map and it seems to work pretty well, though I'm sure we'll find a closer default map setup later with more data points and more complete tunes.

Read this for information on initial on-car setup: viewtopic.php?f=54&t=1083

BTW, most of the cars have been poorly setup and performed reasonably. The "slater" was on a flat 60% map too. Preston's 4age was on my truck map with a lean hole in low load/rpm and 80% flat elsewhere. Initial drive of my volvo was 80% flat, final maps are in png on the forum.

If you get the config good first it should fire up and idle fine. Then you can use the wideband to fix up the hot idle and get it free revving in neutral. Then you can take it for a drive and improve the higher load and higher rpm areas gradually.

Don't be scared, it's really quite easy, especially on low power non-turbo engines :-)

Fred.

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Sun Feb 05, 2012 6:10 pm
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