Jump to content
  • When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

Oxygen and timing- tuning strategy- John N. whadayasay


Guest Anonymous

Recommended Posts

Guest Anonymous

So heres what I am thinking. Now I have this nifty device that can record o2 and rpm and graph it very accurately. But timing- that is a good problem.

Is it true that the goal of the ignition timing is to get a complete burn?

That would mean that given no change in A/F ratio but a change in timing I would see a difference in O2 readings- right? If so then I can find the best timing for each range by making adjustments and looking for the lowest o2 readings-ie most complete burn. could I use this method to find the best timing for a given rpm and then plot a curve for the range by methodically testing every 500 rpm or so?

Link to comment
Share on other sites

Guest Anonymous

what is the relationship between timing and EGT? Is it just a matter of how much combustion is taking place in the exhaust? Can EGT be used to figure timing curves?

Link to comment
Share on other sites

Guest Anonymous

standard.jpg

EGT would seem to be tough to use as an accurate and repeatable constant for timing set. Do you have a temp sensor in the system, like the modern cars do?

Link to comment
Share on other sites

Guest Anonymous

If you're trying to get the optimal timing, you're going to need to adjust both the amount of fuel you supply and the timing for each load point on the engine.

Engine load is difficult to measure directly without a dyno, for a practical solution, you could either use some sort of a MAF sensor to measure the amount of air you're pulling in or measure MAP (absolute pressure in the intake manifold). Both give you effectively the same information. Because it is difficult to keep a constant load on your engine (outside of a dyno that is), this means you need to log a lot of points, sort through them and try and identify the valid data from the misc. crap. There are some tools some of the MegaSquirt guys wrote that you might be able to adapt (check the group archives for MSTweek).

I'm going to be firing up my electronically controlled (Ford EDIS) spark system soon, but I was going to start with the original Tii distributor map and pretty much leave it alone until I started to add boost.

The 'ultimate' solution is to measure the ionization in the cylinder after combustion. There is apparently some interesting work going on that indicates you can use the ionization to determine the precise optimal spark advance. I think I lost the papers in a computer crash, but if you're interested I could go look for them again. Measuring the ionization is one of the goals of the UMS (Ultra MegaSquirt) project I posted about earlier.

Cheers!

John N

Link to comment
Share on other sites

Guest Anonymous

from one engine speed to another (totally consistent) for my test and just set the timing for this load (still using the stock distributor without vac advance) How will timing effect the o2 content of the exhaust?

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • BMW Neue Klasse - a birth of a Sports Sedan

    BMW Neue Klasse - a birth of a Sports Sedan

    Unveiling of the Neue Klasse Unveiled in 1961, BMW 1500 sedan was a revolutionary concept at the outset of the '60s. No tail fins or chrome fountains. Instead, what you got was understated and elegant, in a modern sense, exciting to drive as nearly any sports car, and yet still comfortable for four.   The elegant little sedan was an instant sensation. In the 1500, BMW not only found the long-term solution to its dire business straits but, more importantly, created an entirely new
    History of the BMW 2002 and the 02 Series

    History of the BMW 2002 and the 02 Series

    In 1966, BMW was practically unknown in the US unless you were a touring motorcycle enthusiast or had seen an Isetta given away on a quiz show.  BMW’s sales in the US that year were just 1253 cars.  Then BMW 1600-2 came to America’s shores, tripling US sales to 4564 the following year, boosted by favorable articles in the Buff Books. Car and Driver called it “the best $2500 sedan anywhere.”  Road & Track’s road test was equally enthusiastic.  Then, BMW took a cue from American manufacturers,
    The BMW 2002 Production Run

    The BMW 2002 Production Run

    BMW 02 series are like the original Volkswagen Beetles in one way (besides both being German classic cars)—throughout their long production, they all essentially look alike—at least to the uninitiated:  small, boxy, rear-wheel drive, two-door sedan.  Aficionados know better.   Not only were there three other body styles—none, unfortunately, exported to the US—but there were some significant visual and mechanical changes over their eleven-year production run.   I’ve extracted t
  • Upcoming Events

  • Supporting Vendors

×
×
  • Create New...