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Old 03-28-2012, 01:24 PM   #19 (permalink)
Cyborg ECU
California98Civic's Avatar
Join Date: Mar 2011
Location: Coastal Southern California
Posts: 5,218

Black and Green - '98 Honda Civic DX Coupe
Team Honda
90 day: 64.33 mpg (US)

Black and Red - '00 Nashbar Custom built eBike
90 day: 3671.43 mpg (US)
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Originally Posted by mja1 View Post
california98civic - do you have any small logger or scan gauge device able to measure engine knock? A widely used way to tune for gas mileage is to increase advance until knock then back off slightly, but then because you have no access to multiple tuning tables (VE, spark, throttle, pressure, airflow, rpm etc), you'd have to test for knock at WOT to be safe, then back off if it was knocking some at WOT
I have a scan tool that I bought for diagnostic purposes, and it offers some data my ultra gauge does not. But since I don't have a MAF sensor, I would not have that data on the tool either. By "spark" do you mean a timing advance readout or something else? Because the timing advance data would be inaccurate once I jump the system and start changing timing at the distributor.

Originally Posted by mja1 View Post
Have you thought about a Hondata tune or do you already have one?
I have thought about Hondata, and looked into it. My specific OBD2 ECU is not ideal for their services, though other 6th Gen Civic trim levels are (such as the EX). I wish I had a 2005+ HX. Its redesigned ECU is specifically cited as one that Hondata will tune for MPG if desired. That would be cool.

Originally Posted by mwebb View Post
peak combustion pressure will happen before the piston has reached TDC
which is

this is a very bad idea -
This would be true with a more aggressive advance, which I did not do, and with more aggressive driving, which I don't do. I advanced 2* and the car never crosses 2500/2600 RPMs. It will sit at lower cruise levels soon, when I switch-out the final drive gear for a VX 3.250:1 gear.

Lastly, I advanced the timing last May and have driven at least 10,000 miles since then. I'm fine.

Thanks for your concern and for offering your cautions to readers.

[EDIT: btw, I just remembered that one of your fixes I already do... I have been running 89 Octane for months.]

See my car's mod & maintenance thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape and color. My minimum fuel economy goal is 55 mpg while averaging posted speed limits. I generally top 60 mpg. See also my Honda manual transmission specs thread.

Last edited by California98Civic; 03-28-2012 at 06:47 PM..
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