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Old 09-04-2014, 08:51 PM   #1 (permalink)
ERTW
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Join Date: Jan 2012
Location: Toronto
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Ecotec burning oil

Hey all,

I've been reading up on combustion efficiency, mixture motion, mixture preparation, et.al. I want to modify my LE5 Ecotec for improved FE, and I noticed that every picture of the heads is coated in heavy carbon. I hope that the Ecotec is reasonably efficient, and that it's not soot buildup. Instead, I believe it's oil from the PCV system. The intake manifold is coated with oil, as well as the ports (up until the fuel spray), but the air intake and throttle body plate are clean :/

http://i.imgur.com/aQDfo.jpg

First order is to fix the oil burning. I've seen some catch cans that are supposed to eliminate this almost entirely. Oil doesn't burn too well, and it masks other symptoms of poor combustion.

RX Catch Can w/ Single Check Valve

I would like to port and polish the head, as the stock ports are pretty rough. Reducing pumping loss is a 1:1 FE improvement. I work with a very talented porter, and I just have to pay for parts, and R&R.

I want to install flat faced valves, to minimize shadowing, and improve the burn. I'm looking to increase compression well beyond 11.0 (from 10.4:1). It should be fine with 87 octane at idle/cruise, when the intake closing is retarded, and dynamic compression is low. It will improve efficiency, as well as throttle response.

I have HP Tuners, and enough credits to edit my ECM. I've considered lean burn (16.1:1) to improve FE by ~10%. fwiw, stable combustion, and a stronger ignition will enable even leaner operation.

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