92 corvette tuning tips and questions.

[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.

[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?

[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.

[NomakeWan]

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.

So those injectors are from a bunch of Dodge products, primarily the Neon. They're 22.5 (23) lb/hr at 43.5 PSI. Stock '92 Corvette injectors were 22 lb/hr at 43.5 PSI. However, even though the 1992-1993 Corvettes came with 22 lb/hr injectors physically, the stock BIN is programmed for an injector rate of 23.79 lb/hr. Very curious choice by GM.

For comparison, the '94 Corvette came stock with 24 lb/hr injectors, and is programmed for a rate of 24.873 lb/hr.

[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.