Saturday, November 19, 2005

The road well travelled

Ok some major advancements recently.
My 2000 PCM had pretty shocking knock values and not just the Burst Knock tables. Im talking attack and decay values as well as sensitivity etc. Default was for all cylinders to act the same. Of course with the sensor sitting right besides some cylinders and further away from others, this doesnt make sense. I basically put the table from the 285KW HSV in there, though I understand the 02 Camaro is also a good baseline for testing. Anyway my weird hesitation from 2000-3500 is now gone, the car is running much better than it has done before. Timing is quite hardcore at around 32deg. I read that the ideal timing is around 26 deg or there abouts. So with this in mind I pasted the spark table from a friends tune in. He had spent months on his and was rewarded with 240rwkw on a stock engine with standard bolt on's. His timing table looked much closer to the ideal. I have also commanded my AFR at all RPM and Load points using the custom OS table in EFIlive. At low loads I have 14.63, heading to 12.9 at 3600-4400 then back to 13.1 to redline.
I did this based on some threads on efi101.com discussing the ideal AFR ratio for performance on LSx engines.

So in theory if my VE table is good things should start coming together soon. Speaking of the VE table. Some interesting observations there. On a long trip with 9dec IAT temperature I was running a little leaner than commanded, however around town it showed as richer, maybe due to IAT sitting at 40deg.. I was considering messing with the new IAT table, which I did in fact do, putting a 5% correction factor in, though I cleared that until I get the VE done at one temperature as it was making me chase a moving target. So the plan is now dial the VE table in fully then configure the IAT correction table in the custom OS to correct mixture. I think it will only be around 3% as my 5% factor was too much.

Cam install is penciled for March 06. I should have all the bits together by then. Im tossing up whether I should get some comp 918 springs as I understand I have 915's in there already, but this is not confirmed. The lower seat pressure of the 915's might be better for the components.

Ill almost certainly order a new Powertorque Over the radiator cold air intake (otrcai) to cement my tune in mafless mode.

I have a trip to Yorkshire next week, so lots more logging and ve table tuning to do. Im pretty sure the frequent parts are tuned already. I guess I should do some smoothing to make it look normal as at present it looks like the rocky mountains with a nice smooth valley in the middle.

Read an interesting article on octane. Basically no point running a higher octane as it actually burns slower and with less energy than the lower octane UNLESS your engine is designed for it. (ie) High compression etc. Basically if you can run timing at the perfect point without knock, then running higher octane may well lose you power and cost you more. So I guess thats well and good that I have been happy to use 95 octane and tune for that rather than mess with 98. Perhaps if I was running 11:1 I might.

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