Still that aside. The Dart 205cc heads are in. There is a little casting flash and the chambers arnt polished. But I dont think Ill get around to doing much with them. Id have to pull the valves off. Make sure they went back on the right ports and be careful of not damaging the seats. So for the extra bhp from removing the very minor flash, I think Ill leave them as is.
Car is booked for later in the month to get all the goodies installed. I have a trip to France to do before then. Pity I couldnt have it done before then.
So anyway back to tuning. Ive been helping a fellow LS1 owner sort out their tune. The o2 sensors were placed back pre cat as the previous tuner had put them post cat. Well what do you know, the car now passed fast idle test, which it used to fail with excess CO emissions. The guy was having fuel consumption issues so we dropped idle speed and advanced up the timing a little. It idled nicely at 650rpm. However perhaps because of this it failed the natural idle test. Again excess CO. I read somewhere that a nice hot engine and faster idle and strangely enough more retarded ignition should sort that out.
Im now wondering if thats why the OEM tunes run such low timing and high idle speeds. Not for fuel consumption, but for economy. Anyway Ive offered to return idle to stock so he can get the emissions checked out again. I think we might have it sorted if thats the case.
Otherwise Ive been playing with fuel octane and without changing any spark timing running a higher octane, 98 RON seems a little more peppy. I need to do another tank of regular 95 RON before I know for sure which is better. Mind you come the 11:1 Dart heads and I think I will have to use 98 RON anyway.
Id been having some issues with efilive OS3 where commanded fuel did not match acutal AFR. Basically the efilive guys had seen the issue before and the PCM was entering PE mode and not exiting from it. So AFR was at PE even when off the throttle. Anyway I decided to change more PE triggers and not just the MAP trigger. I set TPS to 100% for all RPM points as well as setting commanded PE AFR at 14.7:1. Since Im running a fully flexible AFR map as in my last post I should never need PE mode. So in theory I never went into PE, except that I was! Anyway it now seems like that little monster is sorted. Ill have to recheck a few more times to be sure as it was intermittent in any case.
When I said all my parts were in, I actually meant all my parts except my otrcai, which should really have been in months ago. I had comitted to one last year. Apparently its been ordered and is on its way. Still my brother lives in Oz, so getting him to mail me one shouldnt be a major issue if the one I have lined up falls through.
Hopefully my next post will be with all the parts installed and no issues to relay, except excess power and lack of traction.
For those looking at getting good power on a budget here is the basic run down.
Parts: (Prices in $US)
- LS6 intake and injectors, bought from ebay in OZ from MantaLS1 (Thanks dude) $175
- Crane Cam HR14400067 grind, same as Vinici cam and known as SDPC custom $310
- GM MLS OEM Head Gaskets
- GM OEM Head Bolts
- Dart 205cc LS1 Pro1 heads $1295
- GMPP LS1 Oil pump $69
- Rollmaster timing set $99
- Various gaskets for timing cover, pulley bolt etc $100
Stock the engine was rated at 345bhp, Im hoping to see near on 500bhp on completion. I might need a new clutch and injectors, but Ill worry about that later.
