Q for Chip Burners: Programmable Parameter List

[Two Lane]

QUESTION(s) FOR CHIP BURNERS:

1.) When preparing to burn a custom chip, what are all the significant/important combo variables to consider?
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Chip burning in 2003 is likely more comprehensive than ever.

2.) With that in mind, what options over the various functions exist for the customer to determine how the chip might be set up?

(There may be functions the customer might wish tweaked, if they only knew they were tweakable)

TIA!!

 

[Two Lane]

TIA!!

T T T

 

[2QUIK6]

From the various chips I have from various people, timing seems to be the main change at the higher rpms and changing the boost scalars for 3rd and 4th gear to 90-99%.
And changing the speed when the TTC locks up.

That's about all most generic over the counter chips have done. If you burn your own, then you can do lots more using your scan tool....change the MAF scalars to give you close to the maic 128 BLMs at all cruise rpm ranges...change fueling based on rpm range during PE mode...change temp for fans to come on and off, make PE mode happen faster, etc, set idle, set startup idle, etc...the possiblities are endless. But these are things you can't just blindly do without seeing what the car is doing with the "current" setting with a scan tool....this is why the dyno tuners charge $300+ for custom chips.

 

[Two Lane]

T T T

Thanks, Rob!

You reply is very much appreciated!

 

[BM Computer Src]

Two Lane,

I wanted to send you some info but need your email. I tried the PM but your box was full.

Bob

 

[BJM]

Richen the warmup fuel both by coolant temperature as well as the timeout fuel which fades away after a period of time after starting based on initial coolant temperature. The factory used a lot of timeout fuel to get you started and a little coolant based fuel. This leaned you out quickly for emissions but leaves it lean to early. Swap the proportions around to have more coolant fuel and less timeout fuel and the car will drive much better when cold.

I bump the C/L threshold up to around 140 F and have 5% enrichment by that temp in O/L for a nice transition.

Lower the cold coolant temp IAC park table values to prevent the normal overshoot in RPM when first starting cold. I do not like over revving a freshly started engine.

You can populate the timing versus MAT table which is zeroed out by the factory to pull timing when the inlet air gets really hot. Or do what I do, use a boost sensing harness and add timing at low boost and pull extra timing at high boost.

If you add some timing just below your normal idle speed I find it helps like a poor man's stall saver, as the idle dips the timing goes up a bit to try and speed the idle up again. Works a little bit.

I find a boost scalar of .95 in 3rd and .90 in 4th gives my car the same boost in all gears so if you want to pull boost in upper gears you have to scale it down a little more than shown.

You can try an O/L idle to smooth things out. Set the warm and cool coolant idle A/F ratios to something other than stoich (14.8:1) and set the O/L idle timer to $1 (becomes 1/5 or .2 seconds in C/L before going to the richer O/L mixture). It still learns if the INT is outside of 122 and 135 (I think) and then drops into O/L idle.

If you are starting with a factory PROM the PE-RPM table goes lean at low RPM and about 17% rich in the middle of the RPM band before settling on something normal looking. The hump is useful but too high, I lowered mine to about 10%.

If you get creative you can use the Boost spark and Fuel Decay parameter to add timing by gear but that is a bit advanced until you are experienced.

Spend time getting your MAF curve accurate and getting your BLMs accurate so you can have at least some confidence that a commanded 12:1 A/F under power is at least close. You will want to verify everything with a Wide Band or else you are guessing.

Change your TCC lock up value tables to release the TCC at lower throttle settings so the engine can rev nicely and build boost while cruising and hitting the gas suddenly. IT can also prevent part throttle knock.

 

[bruce]

Originally posted by BJM

You can populate the timing versus MAT table which is zeroed out by the factory to pull timing when the inlet air gets really hot. Or do what I do, use a boost sensing harness and add timing at low boost and pull extra timing at high boost.

Better yet, relocate the MAT sensor to the plenum, and you can allow for heat soak, and elevated MAT temps from being in boost.

Then set the PE enable higher then what you stage at, and use the Time in PE enrichment for a top end enrichment. Might get you past having to cut the Wastegate in high gear.

 

[2QUIK6]

Originally posted by bruce
Then set the PE enable higher then what you stage at, and use the Time in PE enrichment for a top end enrichment. Might get you past having to cut the Wastegate in high gear.

I just discovered the "time in PE" table a while back and hope that solves my diving O2 readings after getting into 3rd gear. I studied dozens of Direct Scan recordings at the track to calculate how many seconds elapsed in PE before hitting 3rd gear, and it is a whole lot easier if your not in PE mode until you floor it with a race chip, on the street you may not want your PE set that high. I found I have 10# of boost built with a TPS of around 2.75-3.25v so that was plenty, and that will help lean it out some when trying to build boost at the line.