92 corvette tuning tips and questions.

[NomakeWan]

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.

[LeMarky Dissod]

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.

[BlackW1dow]

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.

[lionelhutz]

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.

[NomakeWan]

What lionelhutz said is correct. Once you take the suggestions from Trimalyzer and put them into your tune, open the graph in Trimalyzer and just smooth any sudden jagged edges by hand. It may help to open a stock BIN and look at how its 3D graph is laid out to get an idea of what GM deemed acceptable. Getting the suggested changes from Trimalyzer is science. Smoothing the table transitions visually, that's art.

[BlackW1dow]

going back to the temperature scalers, how do yall know that the low MPH is based on 0 MPH and the high is anything greater than 0? Just experience or is there something that says it?

Also what is too hot relative to coolant and oil temp? oil temp stays about 219F

[kur4o]

BlackW1dow,

Can I ask you to make a eprom dump of ccm, using steveo flashack tool over aldl line. It will help us decode one more piece of the ccm puzzle, maybe add support of editing some of the eeprom stuff too.

I am sure it will work with dumping the pcm too[If you haven`t already try it].

[LeMarky Dissod]

going back to the temperature scalars, how do yall know that the low MpH is based on 0MpH and the high is anything greater than 0MpH?
Just experience or is there something that says it?

Also what is too hot relative to coolant and oil temp? oil temp stays about 219°F / 104°C.

My experience is with $EE '(94 & '95).
'vettes make use of a separate scalar: 'Fan Vehicle Speed Boundary' in TunerPro, or 'Fan Hi/Lo Vehicle Speed Threshold in TunerCAT.
The vehicle speed boundary / threshold is 0MpH, so anything OVER 0MpH uses the higher speed fan-on settings.
Although GM did not bother to use this feature with F- & B-cars, they can also use this feature by specifying different 'High' fan-on settings.

To answer your 2nd question:
examine oil & coolant temps while cruising on the highway, then use the fan-on settings to maintain similar temps in stop'n'go traffic.
If the coolant is clean & the radiator heatercore & cooling fans all work properly, I see no reason why the coolant should get hotter than
221°F / 105°C.
I prefer lower temps - I typically turn on the primary fan @ 203°F / 95°C & the 2ndary (meaning both) @ 212°F / 100°C (coolant temps).

[steveo]

i have to say that a VE correction table like that reeks of a bad constant. it tells me that injector size (or a related input such as fuel pressure) or engine displacement does not match the calibration. i wouldn't apply that correction from trimalyzer - i'd fix the botched constant and run more logs. not saying that correcting the VE table wont work, it's just bad practice. when your engine VE changes, it changes shape, it doesn't just move the entire table up.

[NomakeWan]

going back to the temperature scalers, how do yall know that the low MPH is based on 0 MPH and the high is anything greater than 0? Just experience or is there something that says it?

Also what is too hot relative to coolant and oil temp? oil temp stays about 219F

In your XDF, you will find a parameter called "Fan Low/High MPH Threshold," which will be set to 0. This means Low is 0 MPH, and High is anything over 0 MPH. You can change this value if you want to change this behavior.

Coolant temp is up to you. The OEM thermostat is designed to actuate at 180F. Due to the reverse cooling of the LT1, this means the engine tends to operate in the 195F range.

Oil temperature is a factor of the oil itself. For Mobil 1 Full Synthetic 5W-30, the stock factory fill, it can more than happily handle oil temperatures of 356F. It will, for short durations, handle temperatures above 392F. This property of the oil is why the oil cooler was removed when GM switched the Corvette over to this oil in 1992.

[lionelhutz]

i have to say that a VE correction table like that reeks of a bad constant. it tells me that injector size (or a related input such as fuel pressure) or engine displacement does not match the calibration. i wouldn't apply that correction from trimalyzer - i'd fix the botched constant and run more logs. not saying that correcting the VE table wont work, it's just bad practice. when your engine VE changes, it changes shape, it doesn't just move the entire table up.

That's a good point Steve, change the injector constant only first maybe and try logging again until the error isn't as high. Then start adjusting the VE table.

[BlackW1dow]

i have to say that a VE correction table like that reeks of a bad constant. it tells me that injector size (or a related input such as fuel pressure) or engine displacement does not match the calibration. i wouldn't apply that correction from trimalyzer - i'd fix the botched constant and run more logs. not saying that correcting the VE table wont work, it's just bad practice. when your engine VE changes, it changes shape, it doesn't just move the entire table up.

After pulling my stock tune it matches the bin I was tuning with. I can about 99% sure rule out the cylinder volume as the issue which leads me to the injector flow rate. The rate in the bin I was using matches the stock rate. That being said I know the injectors have been changed but I have no idea what brand or flow rate they are.

I have looked up the numbers on the injectors but it comes up with like 10 different options. how do I determine their flow rate so I can correct in the bin?

[stew86MCSS396]

After pulling my stock tune it matches the bin I was tuning with. I can about 99% sure rule out the cylinder volume as the issue which leads me to the injector flow rate. The rate in the bin I was using matches the stock rate. That being said I know the injectors have been changed but I have no idea what brand or flow rate they are.

I have looked up the numbers on the injectors but it comes up with like 10 different options. how do I determine their flow rate so I can correct in the bin?

Well gee...perhaps someone who's more web savvy can search the make and part number if you would post it.

Edit: If any one caught what I had posted/edited out, hind sight thought...if you're running lean based on the trim graph^^^you posted then my suggested increasing the injector constant is going to make you leaner.

[steveo]

That being said I know the injectors have been changed but I have no idea what brand or flow rate they are.

I have looked up the numbers on the injectors but it comes up with like 10 different options. how do I determine their flow rate so I can correct in the bin?

see? you've changed a fundamental fuel parameter without accounting for it in your bin, but you're calibrating a table that represents airflow. you will get better results if you start over and fix that constant. from your trims i'd say they are about 15% smaller than the stock injectors. so you could simply multiply your injector constant by 0.85 and get close. ....but this works better if we get proper specs. what numbers are on the injectors

[BlackW1dow]

see? you've changed a fundamental fuel parameter without accounting for it in your bin, but you're calibrating a table that represents airflow. you will get better results if you start over and fix that constant. from your trims i'd say they are about 15% smaller than the stock injectors. so you could simply multiply your injector constant by 0.85 and get close. ....but this works better if we get proper specs. what numbers are on the injectors

Okay so I have found which injectors I have. The number is 280 155 703. They seem to be Bosch injectors commonly swapped in Jeeps. I didn’t swap them out the previous owner did. Thank y’all for your help again, I am slowly learning this art.