Okay so I have logged a few times now. about an hour of driving i think. went to put it into a history table and lucky me $da2 doesn't have any made yet... Followed a tutorial by eagle mark to create one and I couldn't figure it out. When making the History table i put Right BLM in the (Z output), RPM in the (X AXIS), and MAP in the (Y AXIS). it doesn't populate VE it only puts BLM in the table.
I don't use the Excel method, I use Trimalyzer, but generally the VE table isn't "populated," it's something you yourself have to define based on your tune. For example, in Trimalyzer, you can select from "low VE table" and "high VE table" because on $EE there are two separate VE tables. But I would expect an Excel spreadsheet to work the same way, in that you would have to define the layout of the VE table(s) present in your tune yourself so that the spreadsheet can populate it with recommended changes to each VE cell.Originally Posted by BlackW1dow
Also, if it's at all possible, I would like to ask a favor of you since you own a '92 Corvette. Over in another thread we are working on reverse-engineering several aspects of the Corvette CCM. We generally know how a 94~95 works, and we know how a 90 works. But a 92 is a question mark. If you wouldn't mind terribly, would you consider downloading a program called EEHack and then recording an Idle Module Scan? It would create a text log, which if you could share would be really cool. If you are interested in helping out, the program can be downloaded here: http://fbodytech.com/eehack-2/download-eehack and the Idle Module Scan is located by clicking "Raw Cmd" and then "Idle Module Scan (TEMPORARY)". Do make sure that the correct COM port for your ALDL cable is selected in Settings.
If not, totally understandable, and I thank you for reading anyway.
Last edited by NomakeWan; 09-23-2021 at 07:25 AM.
1990 Corvette (Manual)
1994 Corvette (Automatic)
1995 Corvette (Manual)
one thing you need to understand about tuning fuel is you're rarely populating a table with new values, you are adjusting the existing values based on feedback.
in simple terms the ECM says "5!", but your o2 sensor says "...but we had to add 2% of fuel there" so you might change the value to "7" and then try again.
in real terms, since you're tuning a VE table, the ecm actually says 'for 2000 RPM and for 50KPA of MAP, the engine is 43% efficient'.
it then injects its fuel on the assumption that the engine is actually 43% efficient at that RPM (there are other things affecting fuel but just worry about the VE table for now)
you then get feedback as a BLM from the trim system that says "trim in this area is 150"
since 128 is 0% trim, we can calculate the trim as 150/128=1.171 (17%) (in other words 150 is 17% higher than 128)
so the ECM had to add approx. 17% extra fuel to achieve the proper mixture.
since we had to add 17% of fuel, we can assume that instead of being 43% efficient at that RPM/MAP value, it is actually 50% efficient. so you could change that value to 50.
but a better way to tune would be to get multiple data points from that area and average them together, because big piston engines are not a precise instrument.
you then have to 'interpolate' or 'guess' the values to smooth the table in between your adjustments, because there's no way you'll have good data for the entire table.
if this sounds time consuming, and like it's something a computer could do for you with way less effort, that's why i wrote trimalyzer (but then you have to learn to use that properly, too, and have some common sense in case it makes a mistake.)
the other reason tools like trimalyzer are good is because you can't always trust trims, you can only trust them once you are in closed loop, and the engine is warmed up, and you aren't in power enrichment, and whatever else. trimalyzer is good at filtering data.
edit: it's also good at taking HOURS of logs and crunching the whole thing...
Last edited by steveo; 09-23-2021 at 05:17 PM.
So I am messing around with the ve tables and my car is getting hotter than normal. Not sure if it’s bc I removed the EGR and air system or the tables..
Removing EGR and AIR should have nothing to do with engine temperature.
If you want to know if your VE modifications are having an adverse effect, revert them back to what they were and see if the problem resolves itself. If not, then something else has changed. Is it hotter out? Did one of your fan relays die? Are you just doing a lot of testing while the car is sitting still rather than driving around at speed? The C4's cooling system isn't the greatest, and if any part of it isn't working at its full potential, things can get out of hand pretty easily. I found that out from experience, hahaha.
1990 Corvette (Manual)
1994 Corvette (Automatic)
1995 Corvette (Manual)
Don't know about the LT1 OE fan-on thresholds for '92 & '93, but they were set so high from '94-'97 that the powertrain usually runs considerably much hotter in stop'n'go traffic than on the highway. NomakeWan's observations about the cooling system are absolutely spot on.
I can sort of get why GM would prefer LT1s to run 32°F hotter in stop'n'go than on the highway (except for sedans & wagons with big ol' mech fans that cost 10 peak horse), but this is easily fixed by lowering the fan-on thresholds to keep temps more consistent across driving conditions.
If both fans are on by 212°F / 100°C instead of 235°F / 113°C, it's one less thing to worry about, and a much larger safety margin.
THEY are NOT Lying to You.
You are NOT Even Lying to Yourself.
You ARE Being Lied to ... by Your SELF.
The Last Psychiatrist, aka ... Alone ...
According to the stock BIN, the fan thresholds for the '92 Corvette are 219F Lo 227F Hi for 0MPH, and 227F Lo 235F Hi for any speed over 0 MPH.
1990 Corvette (Manual)
1994 Corvette (Automatic)
1995 Corvette (Manual)
219°F Lo 227°F Hi = 0MpH
227°F Lo 235°F Hi >0MpH
GM's $EE Y-LT1 fan-on thresholds are identical. The $EE F-LT1 & $EE B-LT1 fan-on thresholds do not change based on MpH, but are also too hot for me.
Given that:
LT1 cars' OE programs lead to running hotter in stop'n'go than on the highway
LT1 sedans and wagons with V08 mech fans run cooler than LT1 cars with electric fans
I don't see a reason against lowering the fan-on thresholds so that coolant temps remain consistent across environments, especially if this can be done without a mech fan.
THEY are NOT Lying to You.
You are NOT Even Lying to Yourself.
You ARE Being Lied to ... by Your SELF.
The Last Psychiatrist, aka ... Alone ...
So after throwing all my logs into trimalyzer, thank you steveo, I came out with this graph. i know there is a smooth button on tuner pro, but what's the best was to smooth it? do I smooth everything up on the right side to match the rest or should I leave it the way it is and do some more logging?
Does the logs just never touch those cells and that's why it isn't changed? I have attached the graph from trimalyzer as a reference to what I'm working with after about an hours worth of logging.
I'd keep the fixed part for now. The rest that never got touched I would pull up. Pick those cells only and multiply them all by 1.13 first so they all come up close to the corrected part. If that correction isn't right then do another one until you get them close. After that, hand blend them into the corrected part to make the whole curve look nicer in the area transitioning between the corrected and the not corrected parts.
As for the corrected part, it looks pretty good. It doesn't have to be smooth, factory VE tables aren't. Just hand knock off any big peaks or valleys a bit which you really don't have to do here right now.
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