I can give you my insights; for what they're worth.
My chip(as I recall) is a 98 octane variety. Some where around 23/21 on the timing. Don't knw why I went that route but it's still OK, because the T+ is so infinitely tuneable to what you're doing.
It's kind of a fine balancing act between
timing, octane(always know exactly what you have in the tank, no guessing),
and boost.
There are no hard fast rules because changing any one of those three can radically affect the end result. So you could hear a dozen different ways to set up the T+. Throw alky into the equation and things get just a little more murky (since the resulting octane equivalent isn't quite known at any given point in time). You'll certainly always need to closely monitor knock retard so you back out of any changes that kick it up too high.
Reminds me of another good rule of thumb about knock retard. When on the street on pump gas and fairly low boost (under 18#) the engine can tolerate a little knock retard, nothing over 5* though and for very short durations like on shifts, and try to keep any knock retard in 3rd gear (highest load) below 2.
When racing with higher octane and higher boost (usually over 20#) Never alow
ANY knock retard, ever, espesially if you start approaching 25#of boost (hard core high octane runs)
Now, as to timing; While I was in CA, the best gas we could get was oxygenated 91 octane, and I kept the BASE timing pulled back from the chip's 23/21 to 19/17 which allowed me to comfortably run 17# of boost in 1st and 2nd gears, but only 15 in 3rd. My car is either street driven or raced. No in-betweens (commonly called street racing). So the fuel in the tank is either pump gas or 114 octane race gas.
When running 114 octane at the track I run the boost up to 25-27#, and turn the timing up to 29/27.
In most cases these timing adjustments can be made primarilly with the BASE switch. There are ocassions however that may require some finesse. Weather and track conditions will dictate how you choose to attack the problem (problem: spool up on the line). Weather and track altitude will have a huge affect on how you get off the line.
But basically here's how it's done. At high altitude tracks or if the weather is causing slow spool, etc. the best way to quicken the spool up on the line is to pull out timing, so as to spike the EGT's up and get the turbo spinning quicker. With that said, I might go so far as to leave my BASE timing at 0(23/21 on my chip) and set the WOT switch to bring the timing in and up to my 29/27 desired level. As most T+ users know the WOT timing is brought in at just above 3,000 rpm. This generally works out quite nicely since most or all of your spool up time on the line is done below that rpm.
If you're going to be running 100 octane or so, and are confident that's the octane in the car, then I should imagine a good timing level for that (assuming sane boost levels of around 20 or less) would be around 23/21.
If you bump up to 110 octane, it will allow higher boost, and MAYBE higher timing(depending on boost). If you stay around 22# or less of boost you could probably get by with timing around 25/23.
See the trend?
CAUTION:
When at the track, always know exactly what your timing knobs are set to before leaving the pits and heading for the starting line!! This holds true no matter where you're driving, even the street.
My last head gasket can explain to you the reason for that caution note.
You'll get the hang of it over time. But as you can see it's a balancing act. Knowbody ever said tuning a car for max performance without breaking anything is ever easy. But don't over complicate it either.
Before you make a change in the translator, have an idea in your mind of what results you expect. If you're not sure about what will happen when twisting a dial or throwing a switch, don't.
Now that I'm in WI, and after I've gone through several tanks of pump gas (to get the residual race gas cleaned out) I'll be able to get a better feel for what kind of timing and boost I can run on the 93 octane gas we have out here.
