anesthes

iTrader: (12)

Really. If you have a cam with any sort of overlap, your wideband is going to be off anyway. For the purpose of dialing in VE tables to produce a 14.7 on idle and cruise/part throttle, everywhere except PE it's impossible because your not seeing the true AFR.

What do you guys with bigger-than-stock cams do?

I've always dialed my PE for most power, regardless of AFR. But I want to dial in my VE tables to 14.7 and disable closed loop. (mainly because closed loop is horrible on $8D because the 02 constants are global, rather than flow based. $6E has far superior 02 thresholds).

$58 is a little better since you can rough in different idle 02 thresholds vs mid range and high load, but with only 5 programmable cells it's still garbage compared to $6E.

-- Joe

junkcltr

iTrader: (1)

The latest SAUJP has a mod. that allows CL only when the RPM is greater than a value set by the XDF file. A lot of larger cam engines like CL only above a certain RPM.

Personally, I use the wideband O2 for closed loop all of the time and set low map conditions for around 15-17 AFR. High Map conditions are CLed for about 13.8 AFR. I read in the WBO2 and convert it to a linear 0-1 volt signal and use the stock WBO2 tables for CL.

$8D actual uses MAP based tables and O2 error based tables. They are for the PROP, INT, and PROP/INT timer. Take a look at the sticky that RBob did for the 747 ECM called O2 swing points or something like that. It applies to the $8D also. The problem is that the normal XDF and TDF are missing some of the tables and they are important. I think even some of the O2 constant tables were missing from the public XDF file.

Once you use a WBO2 for CL, then you will never want to run open loop again. The fuel savings and driveability are almost night and day. For large cams, CL needs to be disable at very low RPM due overlap intake/exhaust mixing.

EDIT: what kind of overlap are we talking about here? What is the duration at .050" for intake and exhaust? What is the cam centerline?

anesthes

iTrader: (12)

Am I reading this right. So SAUJP only switches to closed loop when the RPM is higher than a threshold? What needs to be changed for that?

I was thinking of doing that, but what about cam overlap? Your still not going to get true AFR?

I don't see any such tables in my tunercat XDF.. Ugg.

222/230 @ .050, 112 lobe seperation on a 107* centerline. Installed @ 107.
Exhaust centerline (max) is at 117, aww heck here is a link to the card:

http://www.cranecams.com/index.php?s...31&lvl=2&prt=5

I was trying to 'fix' idle but $8D doesn't have programmable 02 thresholds like $58 or $6E so I got aggravated the other day so I decided to replace the exhaust instead. (long story) Of course once I finish that this weekend It will be back to chasing BLMs, getting them dead on, and then walking behind the car (two cats) and going "damn that smells" wtf.

I got soo angry a few months ago I sold my wideband btw. I'm on the fence about buying a new one. The more I think about this issue, it's a problem with the theory of using a sensor to measure 02 content. Then again, maybe the problem is with my Brain.

I think I'm getting worse at this as I get older. Or maybe 'good enough' is less acceptable now. not sure which.

-- Joe

junkcltr

iTrader: (1)

It is actually a code change. I will take a look at how I did it with my code and see if I can fit in your stick code. Send me your latest bin and I will hard code OL for less than a certain RPM. What do you want the RPM set at?

True, I run open loop under a certain RPM with moderate to large overlap cams.


Yeah, Tunercat doesn't list the tables. TunerPro didn't have most of them either and the $8D hac had some mis-labeled.

The overlap at .050" is ((222+230)/2) - 2*112 = 226 - 224 = +2*..........that is in the range of intake / exhaust mixing at low rpm. Yup, you want OL at idle.


It does have O2 thresholds for idle. They are constants. There are stickies about them. The non-idle O2 thresholds are tables. That is what I modify for the 13.x - 17.x AFR tuning. You would tune the same. I think it was Traxion that used to mess with the idle O2 thresholds alot to make them leaner. I like just running OL instead of messing with the tables at idle.

You don't *need* a WBO2 for tuning. I got way deeper into the code than I wanted to end ended up using it for CL and liked it. That isn't something everyone needs. Yeah, some seem to get pickier when they get older.

Send me you latest bin and the RPM you want OL to be forced on at. I will see if I can fit it without doing a complete disassemble of your bin.

Grim Reaper

That is only true at low rpms, not high rpms. I base this on a number of vehicles with various ECMs and some pretty lopey cams (solid roller 248/256 @ .050 with a 110* LCA).

I tend to not worry too much about AFR at low rpms, just the where peak HP occurs. And I typically find peak HP at an AFR between 12.6-13.0. And the difference betwen 12.6 and 13.0 is not that great when I've dyno'd an engine at those two AFR ratios. There is a difference BUT for the average person, the HP difference is maybe 3-5% between the where the actual PEAK occurs and tuning using 12.6 and 13.0 AFR ratios.

Again, this is on a wide variety of engines, ECMs, and cams. I too am concentrating on peak HP on a dyno and I have always found peak somewhere at the AFR range of 12.6-13.0.

As for low rpm, I am more concerned with trying to find the smoothest idle at the lowest rpm. On that above solid roller cam, I got it idling pretty descent @ 800 rpm. It DEFINITELY sounds like lopey, but not bad. And I agree, I don't really concern myself with AFR for idle.

Dominic Sorresso

My cam had a 54d overlap and I used Traxion's advice for modifying O2 sensor cross over points. Worked great for idle.

junkcltr

iTrader: (1)

anesthes,
You have mail. The RPM was set at 1,100 RPM. Below this RPM Open Loop is forced on.

JP86SS

iTrader: (1)

The o2 values are adjustable in the $8D.
The constants are for idle, the tables are for off idle with a coolant modifier.
There is a spreadsheet included with the SAUJP V4 that shows the relationships between the tables. I made it so you could see what the values are as you adjust them using the coolant table as a bias.
The XDF & hac file should have all the correct descriptions etc IIRC.

To get OL idle with the V4, set the two threshold values. that's it.
When it drops below the RPM it will go to OL. When RPM comes up past the other it will go back to CL.
You don't really need too much o2 control at higher RPM because you tend to be in PE at that point.
I'm running a 224/230 @112 with a bit lopey idle at 800 RPM.
I had to change the o2 constants at idle by 50 mV to get the "smell rich" to go away as well as give it about 28* closed throttle SA.
The V4 also gives you the ability to use the closed throttle SA table or not.
You can just run the main table if desired to keep your thoughts straight till you get dialed in.
WB is jumpy around idle but gives a general idea of where it is.
I'm actually leaning more towards EGT with respect to WB for my adjustments. I bought a new display for the WB and am installing a new EGT gauge too. Numbers lie when individually taken as a fact. In combination with another reading can tell a better story.
HTH

anesthes

iTrader: (12)

I'm not using AUJP. I have a 6-speed corvette, using AXCN. I don't think AUJP has things like oil temp input, and other vette specific things.

28* huh? Whats your compression ratio? If I give it any more SA at idle I won't have an advance curve anymore.

Think about it. 28* at idle, low 40s cruise, and 26* wot. More like a RETARD curve!

If i didn't have a blower I'd probably run around 36* total timing, but my IAT temps out of the blower outlet are around 250f. knock knock, who's there?

I was considering making that code change to my bin. I've done it in the past to clean up pops on decel.


-- Joe

junkcltr

iTrader: (1)

AUJP does have oil temp. input. I use it with the AUJP. I put a bung on my oil pan and use a stock TPI MAT sensor (brass MAT / oil temp. / trans. temp sensor).


240*F.......I wonder why so hot. I get about 190*F at 9 PSI non-intercooled on a 90*F day with a couple of 60 trim T3s. Where do you have your inlet air coming from? Cold air intake?

EDIT: I think you could run the AUJP bin, but you would need to use your calibration (CAL) section from your AXCN and modify the new V4 variables for your application.

JP86SS

iTrader: (1)

I never compared the two to see what all is different besides the communication. If you have a list I'd like to know what those are. Might help with the IAC control on the manual trans setup.

Yes it would be going down as boost comes up.
I'm N/A at 9.3:1 (can't afford pressurized air yet)

That is surely not helping. My CAI doesn't fit right and have been running a TB air filter until I can figure a solution. 170+ IATs pulling off the radiator start throwing knocks under load after about 40 mins of driving. I can imagine that 250 is keeping the SA down farther than you could be running.

I imagine you started tuning without boost and then added it in. Is the IAT temp swing adding to your issues since it would have been setup at basically N/A temperatures?
Not sure how much yours would respond but I see quite a difference when I put the CAI on and run that way.

JP86SS

iTrader: (1)

Anyway, to get back on track...
I get my AFR (using the WB) to read flat across the PE range where I think it should be. Then I will use the EGT as a guide to go richer or leaner.
Like I said before, I don't trust any one reading because at 13:1 AFR I'm not getting all the power I know is in there. There could be an offset or ground shift causing a 1/2 point error in the readings.
Until I see the temps drop when leaning it out, then I'll know where I'm at and start going the other way.

anesthes

iTrader: (12)

The Vette masks have support to become a slave on the ALDL link and talk to the cluster control module.


I have two problems with air temp. I'm hoping alky injection will cure one of them. I can't fit an intercooler. No room.


The issue is the location of my blower. When the car was N/A it had ram air.
I'll try to snap a picture tonight for laughs (yours, not mine, I'm still frowning).

There is a lot of things that are nice about the Corvette.. But engine bay room is not one of them.
----------
What pin does it input on? I'm running a '730 not a '727 so I don't know which PIN it was moved to.


My air cleaner is 1 3/4" away from the left header. No really, I'm not kidding. I'm considering moving the battery to the trunk and running some well insulated pipe to put the air filter where the battery is. Not sure that it will pick up MUCH cooler air, but at least it won't be pre-heated by the headers.

There is absolutely NO possible way to re-route the air cleaner to the front of the car. Let me see if I can find a picture.

edit - here is some pix I took back in April. I made a few changes to belt routing and re-made the alternator mount, but the plumbing and blower + air cleaner is in the same spot. I have about 1" of clearance from the top of the blower to the hood, and I allready cut the fender out to fit the blower. The blower is about 2" from the tire.

http://members.cisdi.com/~anesthes/april-motor/

Laugh away boys!

-- Joe

junkcltr

iTrader: (1)

When I disassembled your AXCN (vette, manual) bin I compared it to a disassembled AUJP disassembly. The code section is the exact same except for about 5 lines that differ. The lines that differ make your AXCN bin look like the ANHT bin.
Overall, I think if you took the AUJP bin and copied the complete CAL section incuding the ALDL parameter list........then the AUJP would work exactly like your AXCN bin.

I can post it tomorrow. I don't have my list of ECM pin vs. ECM variable table available right now.


That makes sense why you see hotter air at the intake. Not much you can do about it. There simply isn't much room in the engine bay and the SC design makes it more difficult. The water/alky will help a lot in your situation. Even hot boost is better than no boost.

jwscab

I'm guessing the battery is on the drivers side, next to the brake booster? seems like that is the best bet. Do those vette's have the cooling gills right there behind the wheel?

otherwise, how much room between the hood and the top of the miniram? would there be enough to get a pan there that you could use to pick up cold air off of the cowl in any way? I haven't looked at a vette in a long time.....sure would be sweet to have some kind of cowl induction there. I realize it's not an easy hood swap for those stupid cars....

then the alky will help with no intercooler. If you guys remember, grumpy was running without an intercooler in the GN for awhile, using alky and also trying out some additional fuel instead. neat stuff.