1993 Camaro LT1 Tuning

[Polyalphaolefin]

Hi everyone. I'm a lubrication guru looking to get into tuning for my own car. I'm very green when it comes to this so bear with me. My previous experience with tuning is with carburetors so this is all new.

What I know...
- It uses a chip.
- It's speed density.
- Has the opti-spark.

This engine just has a bolt-ons with a canned tune. It's 100% track only as a bracket car. It's fairly consistent as it is aside from the fuel. I'm having inconsistency issues from one batch of pump fuel to another (different specific gravity and ethanol content) which is throwing off my predictability and forcing me to relearn the car every time I fill it up. I'm looking to convert to E85 (VP X85 or C85) for not only more consistency from one tank to another, but more consistent overall with the ethanol. I'm upgrading the fuel pump and injectors for this. That will of course require tuning.

I don't need real time tuning, I don't think. I would like to datalog a 1/4-mile pass and then be able to make adjustments and burn a new chip based on that pass. I think that's how it works. lol

Any advice for a newb is appreciated. Which burner? What software? Thanks in advance.

EDIT: I plan to delete the O2 sensors and run only on open loop.

[steveo]

ah super easy. i use a minipro from ebay on the cheap and it's worked great but you can go ahead and get something from moates.net if you want. get a few (i think) 29c256 chips and don't write over your original, that way no risk.

get the original bin from the original chip using your chip burner,

get tunerpro (free)

get an XDF file from here

http://www.gearhead-efi.com/Fuel-Inj...mation-DA2-DA3

load bin and xdf

make changes

burn new bin

swap chip

if you need to do LOTS of tuning which would involve taking the chip in and out a hundred times, then use an emulator and/or a zif socket so you don't end up breaking something

[Polyalphaolefin]

ah super easy. i use a minipro from ebay on the cheap and it's worked great but you can go ahead and get something from moates.net if you want. get a few (i think) 29c256 chips and don't write over your original, that way no risk.

get the original bin from the original chip using your chip burner,

get tunerpro (free)

get an XDF file from here

http://www.gearhead-efi.com/Fuel-Inj...mation-DA2-DA3

load bin and xdf

make changes

burn new bin

swap chip

if you need to do LOTS of tuning which would involve taking the chip in and out a hundred times, then use an emulator and/or a zif socket so you don't end up breaking something

Steveo, thanks a lot for the help. So it seems pretty straight forward.

Correct me if I'm wrong here. From what I gather, if I was looking to convert this stock LT1 over to VP-X85 fuel with a 255 lph pump and 36 lb/hr injectors while keeping the stock VE tables (since airflow isn't changing) and 43.5 psi fuel pressure... I would simply go in TunerPro and change the fuel flow rate to 36 lb/hr, change the stoich AFR to 9.81 (for VP X85), and then adjust the PE enrichment as necessary?

[1project2many]

Injector changes typically require changing flow rate, transient tuning (acceleration enrichment and deceleration enleanment), and injector corrections (voltage and small pulsewidth) at a minimum. In some calibrations you must fine tune single-fire to double-fire transitions for best low rpm operation. Changing fuel type requires changing stoichiometric AFR, power enrichment AFR, and cold engine tuning if desired. Changing fuel also typically requires adjustments to spark timing due to combustion characteristics of new fuel.

[steveo]

just out of curiosity, is E85 really that much more consistent? i was under the impression that E85 is almost never actually 85% ethanol... and the gas it's mixed with is the same inconsistent stuff that you get from the pump anyway, isn't it? i've heard that it's like 50-80% at most pumps because the only vehicles built for E85 are all 'flex fuel' anyway so the exact ratio doesn't matter

[Polyalphaolefin]

Injector changes typically require changing flow rate, transient tuning (acceleration enrichment and deceleration enleanment), and injector corrections (voltage and small pulsewidth) at a minimum. In some calibrations you must fine tune single-fire to double-fire transitions for best low rpm operation. Changing fuel type requires changing stoichiometric AFR, power enrichment AFR, and cold engine tuning if desired. Changing fuel also typically requires adjustments to spark timing due to combustion characteristics of new fuel.

Got it. I'm going to research the effect of each of those parameters and the manner in which they should be altered. Any links would be appreciated.

just out of curiosity, is E85 really that much more consistent? i was under the impression that E85 is almost never actually 85% ethanol... and the gas it's mixed with is the same inconsistent stuff that you get from the pump anyway, isn't it? i've heard that it's like 50-80% at most pumps because the only vehicles built for E85 are all 'flex fuel' anyway so the exact ratio doesn't matter

That's why I'm using VP Racing's X85 which is a consistent 85% ethanol to 15% gasoline every batch. The car is strictly a track only bracket car so being able to run the same elapsed time consistently round after round is vital. Ethanol is highly oxygenated (VP-X85 is 30.3% oxygen) and has a much lower boiling point of 173*F compared to 380+*F for gasoline. This allows it to flash to vapor quickly in the cylinder and create its own atmosphere for combustion that's less effected by atmospheric conditions. So if the weather changes from one round to another, I won't have to be as concerned about changing the elapsed time or changing the tune. The car is pretty much going to run the same number. (all else equal) From the points series last year, 4 of the top 5 in points were running either E85 or E98 with the one gas burner coming in 4th.