Parameters->Temp Compensation->Ignition Compensation

K-Series Programmable ECU installation questions / support issues
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chunky
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Parameters->Temp Compensation->Ignition Compensation

Post by chunky »

I was wanting some clarification on these tables. The help file goes into detail about the Fuel Compensation on the Temp Compensation tab, but has no information about the Ignition Compensation.

1) does the same high/low load threshold apply for the Ignition Compensation?

In the help file, this is stated for the Fuel Compensation:

"There are two air intake temperature compensation tables; one for low load and idling conditions and another for medium to high load. As a guide the low load table is used below 3500 rpm at light manifold pressure, 2000 rpm at medium manifold pressure and 1000 rpm at high manifold pressure."

All of my knocks are happening in city driving, with IATs going through the roof, and below 3500ish RPM. Hopefully I can use this feature to dial out the knocks I'm getting with my 12.5:1 compression motor.

2) Is there any way to change the temperature index values on the ignition comp. table the way you can in the fuel comp. table? I suppose I'm asking for that feature to be implemented since it does not appear to be possible at this time.

3) Just to verify, since the value in the 2nd row of the ignition compensation table is a "retard" value, I don't need to include a negative sign if I want to remove timing. A negative sign would result in ignition being added. Correct me if I'm wrong on that.

It would be useful if the help file for this tab was updated to have some ignition compensation specific comments.

Thanks in advance.
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Hondata
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Post by Hondata »

1. Yes.
2. No. (or not easily). If the indexes are shared between many other tables then they can't be changed without affecting the other tables.
3. Yes. A positive number retards.

Go back one step. What are your IATs? Is your intake getting hot engine bay air?
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chunky
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Post by chunky »

Hondata wrote:1. Yes.
2. No. (or not easily). If the indexes are shared between many other tables then they can't be changed without affecting the other tables.
3. Yes. A positive number retards.

Go back one step. What are your IATs? Is your intake getting hot engine bay air?
Thanks for the response.

I have a custom cold air intake that pulls air from the void space in the bumper in front of the front left wheel (ep3 chassis). I've seen IATs in the 120 to 130 deg F range while in downtown traffic. Ambient temps are in the high 80s low 90s. When the car gets moving at freeway speed, IATs come down into the 90s, and there's no knock issues there. Coolant temps on the freeway are in the mid 180 range, in traffic the coolant temps will get up into the 200deg range, but the fan kicks on and the temps come back down.

Since the weather has gotten warmer, and I'm riding around with the A/C on, I've noticed these part throttle knocks, some of which don't set off the knock sensor, but I can hear them. I have fewer knocks with the a/c off, but there's still a few here and there in low rpm medium load situations.

I've lowered the closed loop threshold as well. It's at 63kPa so I can still cruise in closed loop (no knocks at highway cruise in closed loop), but in stop and go traffic, it will jump into open loop when the part throttle load gets to a point where knock becomes an issue. This has helped some.

Anyhow, I'll be trying to get things sorted before summer temps start to peak.
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chunky
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Post by chunky »

The feature works great. I've been able to sort out the knocks I'm getting when the IATs go up. It took 10deg of retard from ignition settings that work fine with IATs up to 80-90, but now even with IATs in the 130+deg range with ECTs in the 200+deg range, the knocks are virtually nonexistent.

I did learn one lesson though. A negative number is BAD news on these tables. I'm guessing that a negative number gets written to the ECU flash memory in 2's complement format and that when the program reads that value from the flash, it's looking exclusively for an unsigned value. So any negative number is going to give you some huge retard value. This was seen when I accidentally put in neg. numbers and as soon as any temp based ignition correction was applied, the ignition would go to -10deg. So yeah, negative numbers should be avoided totally when using this table.

Thanks for the help!
You can take me out of the race, but you can't take the race out of me.
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