I have found that most OEM on board fuel economy gauges work off of injector pulsewidth. When fitting larger injectors the fuel economy numbers will show higher (better MPG) numbers due to the reduced injector pulsewidth at cruise. Perhaps this is where these fuel economy numbers are coming from?
The STi models since about 2004 (in the USA anyways) have an active center differential. It is a magnetically controlled wet clutch and can sink over 5 amps at full lockup. The diff computer controls lockup based on throttle position, foot brake status, steered angle, and lat/long...
So how will the spark signal indicate when #1 is on the compression stroke? I suppose a distributor based ignition scheme could do this. But why not just use a cam lobe or spoke of the cam gear as a cam trigger?
I believe that we started the engine first. It came separate from the car and we put it in. The ignition timing was set up in the ECU by shutting off the injectors and cranking the engine while observing the timing marks on the crank pulley. The CRIP angle in the ECU was adjusted until...
More information regarding the pistons. We got them back from the builder last week and there was evidence of cracking around the intake valve reliefs. 2 of the pistons look perfect, with the normal shiny spot on the skirt. The other 2 are heavily damaged on the skirts and one is damaged on...
The builder will provide absolutely zero information regarding build specs. He said that they used the CP Pistons recommendation but then went on to say it was ".002 or so". He has provided no details regarding the use of assembly lube on the cylinder walls either.
I originally started the...
I appreciate your insights and thanks to all who have offered their expertise. This has truly been helpful even though there isn't much I can do to convince the builder.
Unfortunately, the builder now has the engine and is not budging from his story. He still adamantly claims that 18* of...
My goal in posting this was not so much as to assign blame but rather establish a root cause so as to avoid it happening again. But yes, these situations are always difficult to deal with at best. I appreciate everyone's responses.
We are working with the owner and our usual machine shop...
None of those, but I have the sparkplugs still. They looked normal including a cut down inspection of one insulator (this is SOP for engines like this). No traces of det that I could see under the jewelers loupe.
I find it interesting that the damage starts at the skirt rather than the top...
Thanks to all for your input. The piston to cylinder clearance was .003" as per CP pistons recommendation (this CP spec of .0025-.003" has been sited by the builder). There seems to be a lack of documentation when it comes to this engine build and it is concerning to say the least.
It is a wet sump engine (BMW S14). For crank case ventilation, we are using the standard BMW oil/air separator which has served well in other applications but I am looking into several other options including an electric vacuum pump and controlled inlet orifice.
I was also surprised about...
I'm going to leave this a little vague, so bear with me.
A naturally aspirated, 13:1 big cam BMW race motor was brought to me for mapping of its Motec M4. The engine was built by a reputable builder. The car was started and the timing set using the CRIP page and verified using a timing light...
