Understanding tuning of Electromotives TEC

[rags]

I think I'm finally starting to understand how the TEC is supposed to be tuned. Can anyone tell me if I'm right or wrong? What I think needs to be done is to concentrate on the TOG setting first and get the engine to do a full pull at WOT and get the AFR's where you want them, 11.5-1 or so on a turbo L6 from what I am reading. When you get the TOG set, you then turn your attention to the IOT setting, manipulating this setting to get the engine to idle with a resonable AFR My car likes 13.5,7-1. Once those 2 are set you can record a few log files to create your VE table. Do I have it? Am I close? I'm getting tired of paying for tuning sessions where the "tuner" keeps asking me how to make changes and I leave with the car no better than it was before but my pocket much lighter.

 

Joe

[RB26powered74zcar]

AMEN Brother..... I'll drink to that!! Please do me a favor... let me know once you find out for sure.

[MONZTER]

I don’t think that’s quite correct, as the TOG and the IOT work together. If you dial in the TOG and then change the IOT the curve will move down or up requiring you to modify the TOG again. It is a balancing act to get the car to idle correctly and do a full throttle pull. Once you get this worked out it time for the VE correction. I recommend lots of reading: Check out this manual http://www.directignition.com/pdf_files/tec3r.pdf

look at pages 61 down it has a good explanation of what you are trying to do.

Here is another good source of info http://www.thenewspaper.com/auto/info/tecfaq.htm it is about the Tec II, but still really the same. It is in a forum format so it is a little more real world.

[rags]

MONZTER,

 

Great links! I used to be on Shiv's forums a lot. What part of my post are you not agreeing with? I agree that the TOG and IOT are tied together. There still has to be somewhere to start tuning after your initial injector settings. I still say TOG goes first and IOT after you have figured out what TOG works well at WOT. This seems to be working for me and it's the first time I am actually understanding what changes are going to have what effect. I'll try other suggestions as I'm pretty confident that I can duplicate what I've been doing lately.

 

Joe

[MONZTER]

Hey Rags,

I did not mean you were wrong, just wanted you to know that the two were tied together. I just did not want to see you spending money on dyno time to get the TOG perfectly dialed in, only to find out it needs to be changed after modifying the IOT to get it to idle. I did my initial tuning on the street with the correction factor set at 50%. Once I got my TOG and IOT within 5% correction, I went to the dyno to tune the VE table. Even after the VE tune on the dyno I found some more power from data logging and doing an auto tune function, and then smoothing it out on the graph. I posted some of my tables on this link. http://forums.hybridz.org/showthread.php?t=122406

Good Luck

Jeff

[RB26powered74zcar]

Hi Joe, I forgot which Tec your using. Have you went to the Tec3r yet? I'm fixing to switch over, as I picked up a brand new Tec3r a couple weeks ago, but its still sitting in the boxes.

 

I remember that forum back then (Shiv's). It was the only forum that touched on the Tec2 & 3. Its a shame there never has been a help forum for the Tec. Its a art to tune with it, especially if your using the WinTec software...

 

 

There are guys that know what their doing when it comes to tunning the Tec, its just most don't want to share...

[rags]

Jeff,

 

I feel better now. I thought you were saying I didn't understand what I was doing which would have put me back into that gray area I've been in for about 4 years. Getting back to what I'm doing now, I have turned off the EGO correction all together. I want to get the TOG set so I can get as close to 11.5 WOT at 10 lbs as I can, adjust IOT so it will idle and I can continue, go back out and test WOT again. If I can maintain 11.5 or so I up the boost a few lbs and check WOT again and the whole process starts over again. It's time consuming but I figure I won't break anything by doing it this way and once I turn on the correction it can only make things that much better. Also, the only 2 points I'm actually working on by doing things like this is WOT and idle. 11.5 for WOT and 13.7 for idle. The 13.7 seems to be rich compared to other maps I've seen (yours being one of them) but my car won't idle worth a crap if I go much leaner.

 

Joel,

 

Still using the TEC II. I figured why would I want to double my pain with a map that is twice as large if I can't figure out the smaller one . As for the guys that know, I don't think it's a matter of not wanting to share but more of a frustration factor when you don't get what they are saying. Ever try to teach something that you know like the back of your hand to someone that doesn't know what a hand looks like? My problem is I've never been around someone that knows what they are doing. I learn much faster by seeing how things are done. Unfortunately I haven't found anyone in my neck of the woods that really knows the the TEC. I'm really counting on getting the car to the convention to watch one of the masters at work.

 

Shiv's list was great. And I haven't been able to find anything like it since. Looks like we need to revive a list for us "Inliners".

 

Joe

[Scottie-GNZ]

Figuring out IOT and TOG has been a point of some frustration for me with the TEC. There is a good formula that helps you figure out a ballpark TOG. Only problem is, that formula uses IOT as a factor so it seems like you have to determine your IOT first. Problem is, I have yet to find anything that tells you how to figure out a ballpark IOT.

 

To me, it makes sense to come up with a starting point IOT and use that IOT in the formula to come up with a starting TOG. The focus then should be on tuning for a good idle and if the IOT changes, then reformulate the TOG. After you have a good idle, then focus on the TOG and WOT tuning.

 

As I understand it, IOT has an effect on TOG but TOG has little effect on IOT. A change of 1.0 in the TOG has a 12.5% effect on WOT fueling. Problem is, every time you change the TOG, the entire VE table needs adjustment.

 

What I have been looking for is an explanation of how to derive an IOT and a layman's explanation of cause and effect. Hopefully those links in this thread will help.

[rags]

Scotty,

 

I don't know if I'm right or wrong but I'm looking at TOG and IOT as 2 seperate values that can effect each other but are not derived from one another. The way I am looking at it is TOG is determined by injector size, max rpm and kpa. IOT is then used to massage that value to get a decent idle. Because of this, if you tried starting out with a good idle by first adjusting IOT, you run the risk of being way off on the top end (max rpm, big kpa). If your lean you know what happens. By finding the correct TOG for max boost/max rpm, you can then adj the IOT for idle. This will effect the TOG. With O2 sensor correction turned off, I then increase or decrease the TOG by the IOT amount and do the process over again. IOT will still need to be adjusted again but it should be less. I have done this until I am satisfied with the AFR's during a WOT pull and have a decent idle. Then I turn on the o2 sensor correction.

 

I'm sure there is an easier way but this is what I'm comfortable with.

 

Joe

[WizardBlack]

I used to have a TEC III so I'll take a stab at this. It's actually pretty straightforward, but they make it sound more confusing than it needs to be:

 

IOT-Injector Offset Time. This is specified in milliseconds. Whatever this number is is added EVERYWHERE and at ALL TIMES. It is intended to be used to specify an injector response time. Every injector needs a certain amount of time to respond to the "open" command. This is the injector offset time or injector response time, etc. It is usually around 0.7 to 1.25 milliseconds depending on the manufacture of your specific injectors. If you already have a map and you want to change the IOT, you must change the entire base fuel map in the opposite direction by the equal amount to have no change in the map. If it's zero (or whatever) and your car runs fine; leave it be. It doesn't HAVE to accurately reflect the injector pulsewidth; just know that the computer is always adding this amount to the calculated pulsewidth to adapt for the injector's time to respond.

 

TOG-Time on for One Gamma. Specified in milliseconds. Another questionable naming example. They later changed this to UAP; User Adjustable Pulsewidth. Essentially, they try to make use of a "horsepower calculator" when you first set up a new map with all your relevant details to figure out what amount of fuel is going to be required in all situations assuming 100% Volumetric Efficiency. As such, when you plug in a value for TOG, this is the pulsewidth injected at 5.0 volts on the MAP sensor when you leave '100' in the VE table at that rpm and load point. It comes from a rather simplified (IMHO) thought process that an engine flowing twice the air pressure requires twice the fuel. As such they suggest that you should just be able to specify a ratio between load and pulsewidth. Twice the load, twice the pulsewidth. That's what the TOG is; the ratio. You simply tweak it from there with the 'VE Table'.

As an example, a common N/A engine is going to use at most, say, 8 ms of fuel in any situation. This will probably be around peak torque and max load (100kpa). This is the TOG number. If this is the case, at 50 kpa it will inject 4ms unless you tweak it with the VE table. It will inject 6ms at 75 kpa, 2ms at 25 kpa and 0ms at 0kpa, etc. You get the idea. The TOG number is the other point needed to determine a fuel 'slope' if you graphed fuel pulsewidth versus load (MAP). The other point is 0ms for 0kpa. TOG is the number at max load.

You should determine this as best you can with their 'calculator'. Next, look up the injector response time for your injectors (or estimate) at normal voltage and plug this in for IOT. From there, you get the car warmed up however you can and proceed to tune the VE table with the enrichment maps zeroed. Use a coolant temp and an air temp correction map from another vehicle (even another type of ECU is fine) and make sure they are yielding ZERO % adjustment to the fuel pulsewidth (FPW) at normal conditions. They can add fuel for colder and subtract for hotter, etc. than normal but they shouldn't be doing anything at normal cruising, etc. Once the VE table is right you can go back and do acceleration enrichment, warmup enrichment and startup enrichment, etc (probably in that order). Last step is to turn on EGO correction and keep it's range of authority at +/- 10% or less and do a lot of datalogging. I personally don't like to use TPS/MAP blending and go for straight MAP unless you have a funky ported-to-all-heck N/A car with some lopey cams. You may find a little bit of TPS based fuel accelration is needed to tweak that last bit of drivability, though. By the point you need to mess with that you should have a little bit better feel for the car.

 

I hope that helps. I kinda taught myself most of it, too. The TEC computers are a bit different from most ECU's. They probably have the most in common with the megasquirt.

 

I will keep an eye on the thread or send me a PM if I can be of help.

 

Mark

[WizardBlack]

Figuring out IOT and TOG has been a point of some frustration for me with the TEC. There is a good formula that helps you figure out a ballpark TOG. Only problem is, that formula uses IOT as a factor so it seems like you have to determine your IOT first. Problem is, I have yet to find anything that tells you how to figure out a ballpark IOT.

IOT is your injector minimum time.

To me, it makes sense to come up with a starting point IOT and use that IOT in the formula to come up with a starting TOG. The focus then should be on tuning for a good idle and if the IOT changes, then reformulate the TOG. After you have a good idle, then focus on the TOG and WOT tuning.

Again, IOT doesn't need to change. Just put something in, like 0.8ms and leave it at that. You can tune the car from there.

As I understand it, IOT has an effect on TOG but TOG has little effect on IOT. A change of 1.0 in the TOG has a 12.5% effect on WOT fueling. TOG is a pulsewidth for max load. It isn't always a 12.5% change. Problem is, every time you change the TOG, the entire VE table needs adjustment. Absolutely. Just get a TOG that's ballparked and adjust the map with the VE Table for there on.

 

What I have been looking for is an explanation of how to derive an IOT and a layman's explanation of cause and effect. Hopefully those links in this thread will help.

IOT is simply a flat amount of fuel (in milliseconds) added everywhere. It is usually used for injector response time at standard voltage. Elsewhere in the TEC maps you can specify how this response time varies as battery voltage varies from standard voltage. It's measured in milliseconds per volt. You can look up the response times a lot of places.

This link:

http://forums.hybridz.org/showthread.php?t=121843

shows the IOT for various Datsun injectors. It's the 'Topen' column.

 

See my above comments in this color.

[JSM]

Subscribed. I know it's old just trying to gather info.

[PR280z]

JSM, I`m with you! Thanks for the repost.