Coolant temp trims. Tuner guys, Help!

[Skylar]

Hey dudes,

We're almost finished tuning Nikkojoe's 4agte but there's a few things I'm not sure about. Mainly the coolant temp trims for timing and fuel.

With the fuel trim, I'm thinking just try to maintain "high" on the user defined engine happiness index by richening it up. Something to do with the fuel being cool and condesing/sticking to walls??? Anyway, engine seems to idle and run happily like this. Should we be getting the AFR's to stick to some number while warming up?

I don't really know what to do with the ignition trim. Seems you advance the timing when cold for and zero it off for running temps. The theory behind it being a colder charge takes longer to burn. What I don't get it is, how do you decide how much trim at XX temperature? Haltech's platinum manual says it isn't really required unless the engine is unhappy while warming up. Car seems happy to me not that I've been paying too much attention to it while it warms up, so should I just leave the warm up part as zeros and pull a little bit of timing when engine gets hot(95+)?

Thanks guys.

[biggo]

FWIW I would run your "high" fuel trim whilst worming up combined with some advanced ignition trim until say 40-50 degrees.

My theory, some advance combined with a bit of fuel will increase the revs = less warming up

I have never played with a haltech tho, so i dunno. I can give you some numbers off my adaptronic map if you want them?

[Skylar]

Car runs an adaptronic. I was using the haltech manual as a reference as that was one place that told you what to do with them.

I do agree with what you're doing but I want to know how much more fuel and how much more timing to add. Just make the engine happy? Tune to 13:1 during idle warm up?

How much do you kick the idle up by? I think Tom's car runs the cold start idle up valve so won't need timing to kick up idle.


Post up the numbers if you don't mind, biggo. the engine seems to warm up fine so I don't think I'll touch it but it won't hurt to compare.

[biggo]

Ill have a dig around tonight. Ive got a few different maps i can send you if you want.

[biggo]

Fuel trim on my map (under corrections) starts at 15% at 0 degrees tapering down to 1% at 55 deg.

For my ignition its set static at 16 degrees till over 1000rpm then backs off to 12 at 1500rpm. I dont run an idle up so i dunno. But the wideband 02 is the best thing for watching what nikko's moator is doing.

You still got the same email dude? Ill dig some other maps up and send them to you if you want.

[Skylar]

Biggo, it's almost the same, except instead of the underscore, it's a dot and now at gmail.com.

this warm up is like 50% at 0 and taper down to 0 by 65 deg. It's like 12.3:1 at idle while warming up. throws HC readings way up for no reason.

Where does yours idle. I got tom's to idle rock solid at ~850 warm with variations of 20rpm up or down. The spark difference between the 500rpm cell and 1000 rpm cell is pretty savage though. I need to take some advance out and try putting some fuel in.

Have you touched the coolant temp ign trim at all?

[LittleRedSpirit]

Ive got mine pretty sorted now, wne it starts up dead cold, say 10-15 C, the air temp and coolant ignition trims are putting extra advance to the spark. I think the ecu datascan says its almost 17degrees BTDC. As it warms up the advance is dropping back to 12-13 degrees by the time it is warm. Dead cold idle is about 880-900rpm, hot is around 1250rpm. It used to shudder a lot dead cold before I added the extra advance. It used to idle lower, around 750-800rpm, and didnt sound happy at all. It also used to drop right down to about 500rpm when you got off the throtlle cold, before huntig back up to about 900-1000 like normal. This has ceased now. I'mvery happy with it.

As far as fuel goes, I have 22% enrichment for the fist 3800ms each time it starts, after that it is governed by the ideal gas law which I translated into the Coolant temp fuel trim table. There is a Buell tunign website that has a good graphical example of this law in a table, which is exactly what Buell do to control trims, and hopefully the Map sensor does enough meter changes in Barometric pressure.

[Skylar]

What ecu are you using?

Can you explain to me why are you running the ideal gas law into the coolant temp trim table? Shouldn't that be in the inlet temp compensation table? or something to do with heat transfer from head to air? I got the air density table in an old uni book and made an excel worksheet to centre it around operating temp the other day.

With the cold advance, does both the intake temp and coolant temp trim taper off to zero about running temp or does one hit zero before the other one does? Any real method to how much advance at what temp?

I guess the only way to know whether the fuel and timing is right is to put it on a gas analyzer and look for a complete burn.

[LittleRedSpirit]

What ecu are you using?

Can you explain to me why are you running the ideal gas law into the coolant temp trim table? Shouldn't that be in the inlet temp compensation table? or something to do with heat transfer from head to air? I got the air density table in an old uni book and made an excel worksheet to centre it around operating temp the other day.

With the cold advance, does both the intake temp and coolant temp trim taper off to zero about running temp or does one hit zero before the other one does? Any real method to how much advance at what temp?

I guess the only way to know whether the fuel and timing is right is to put it on a gas analyzer and look for a complete burn.


Im using an Adaptronic e420c.

I Have both the timing cold advance doing similar things, I think the air temp advance gets back to zero before the water temp does, the water temp has about a 2:1 stake in the extra advance control. If youre really keen then I can try to screenshot the graphs for you.

As for runiing the ideal gas law in the coolant trim table (edit, Im not! Im running it in the air temp trim table, sorry, didnt mean to say coolant, meant to say air),

I figure what we really are talking about is charge temp, and by the time the charge is compressed in an engine just prior to firing it would have been given a bit of heat from the compression of the gas and from the surrounding hot metal casing its in, so I think in general terms as a starting point, the ideal gas law applied to the edit: inlet AIR temp of the motor is a good start, at least in establishing a trend to follow.

Ive done a fair bit of experimentation previous to installing those values, and decided on a slightly different gradient to the buell graph through experimentation, then tried the values I found in the buell table (which was worked from the ideal gas law) and I find its better, especially dead cold and through the warmup. I've been playing around with this a lot lately and have tried a lot of different things, but nothing has yielded a result as nice as some extra advance based on cold air and coolant and a better enrichment on a cold start (given by the steeper gradient of the cold enrichment table that I copied from Buell). And above all else Im still playing. Its fun.

Edit: Just reread and its confusing, to clarify I copied the values from a table that i found on a website about tuning buells. I just copied how they did their air temp enrichment. I didnt generate my own information based on the ideal gas law, I used Buels which claimed to have used the ideal gas law in assesing the rate of change of air density with temperature.

The table I used:
http://www.ecmspy.com/tgv2/images/fuel_air_density_correction.gif

Sorry bout the fuss, seems I had a dyslexia moment. Ill look up how I did the coolant enrichment and get back to you.

[Skylar]

Cool dude, thanks.

Yeah, so air/charge temp trim is sorted; follow the ideal gas law. What I plotted looks the same as the buell except I made mine centre around running temp so it'd show zero trim at op. temp. Cool.

Coolant temp fuel: I can look at this two ways.
Richen it up during warm up to get a smoother idle while leaving ignition timing trim at or close to zero as the higher charge density in the combustion chamber will burn faster requiring less advance
OR just let the engine follow warm idle AFR(14.7-15:1) from cold to warm while running more timing to compensate for the cooler combustion chamber creating a slower burn. By tuning to 14.7 during warm up, it should warm up the quickest as 14.7 has the hottest burn temperature. I dunno how the engine will react as I haven't tried this yet.

I'll play with the ignition trims and see if I can get the thing to run better through warm up.

[LittleRedSpirit]

I think in general terms, the car should be a touch too rich cold, Id aim for maybe WOT afrs during warmup. 13 ish, 12.9 even. Then the advance added makes it idle quicker and stronger, since that was what I wanted dead cold. I think biggo said it the simplest above.

I looked, I have no low map enrichment curve, but I have some data in the high map enrichment curve. Every map I have from a different source has different data so I need to do a little further experimentation. I also need to copy the table and show you how its done, looks kinda like a half a parabolic curve, which I think is an error, as it should be more of a linear relationship, not strictly linear but not far from it.

At least with atmo cars, I know Id need to leave some bad bad settings in for a good while to hurt anything so experimentation is my best friend, but maybe not yours if this is all being applied to a 4agte.

[Skylar]

Bringing this back with a quantifiable answer.
From MSExtra manual:
"When an engine is cold, advancing the timing a little above the base map, can help the engine run smoother and idle faster, this can also aid warm-up times a little. In the example below the engine will run an additional 1 deg of advance for every 10C the coolant is below 50C.
The Maximum allowable added advance can be limited to stop too much advance being added in extreme temperatures. A value of around 4-6 is suitable. "

and for those with boosted engines:
"The inlet air temperature has a massive effect on how much advance you can safely run, if the temperature increases above the norm, due to sitting in traffic, long/hard runs in boost, etc, the amount of advance can be retarded proportionately with the temp increase to help prevent detonation. This works in much the same way as the coolant related ignition but it RETARDS the ignition from the base map. In the example the ignition will be retarded by 1 deg every 5C the air temperature rises above 60C, so at 80C the spark map will be retarded by 4 deg. " which is about what I've found but on the higher(safer end).