john s

3/8 tank of AKI 93 Exxon, air temp. 74°F, 225QC
Timed 4 runs (2 in each direction) 2nd gear cruising @ 2000 rpm, floor the pedal time to 6000 rpm. 4.3,4.2,4.2,4.2 seconds
added 1 gal. toluene (methyl benzene) drove 23 minutes for mixture to circulate.
ran same test same spot; 4.3,4.5,4.2,4.5 seconds
air temp. @ end of test 73°F
about 1/3 of time was turbo lag, better test would be to nail it at a lower rpm (say 1200) and measure from 2K to 6K in 3rd gear for more time span without spool-up time.

If someone with a 180Q wants to compare turbo lag 2nd gear is exactly the same ratio.

Colonel Bogey

needed to take advantage of higher octane brew. I believe APR's 100 octane code mainly advances timing to obtain more HP where detonation normally occurs with 93 octane.<p><img src="http://pictureposter.audiworld.com/AudiWorldPics/2000/cbsigx.jpg" borders="0">

Don

until the ECU "learns" about the new octane. You might be able to help it out by resetting the ECU in the same manner people are doing for their DV's. Even if you do that, you still will have to drive it for a while, maybe several tankfuls, before you can make any judgments about it.

PanTTher

In order to minimize the effect the computer's having on the fuel try this. Fully fuel the car using correct ratios of Tolulene to give you whatever octane ratting you want (100 sounds like a good number). Reset the computer the best way you know how. Get a notebook and record the atmospheric conditions (amb. Temp, bar. pressure, rel. humidity and wind dir. and speed if you can). Record the test time as well. Pick a time span during the day that the temperature doesn't change much (maybe very early in the morning). Run your time trials. Don't do too many runs because you'll heat soak the intercoolers. Make sure you record the data.

Drive the car for the next day or two until you use up all the fuel. Refuel without adding anything else to it. Wait for a day with similar atmospheric conditions, reset your computer and run your test again in the same manner you ran it before. Standing starts have too much variation in them so a rolling start or a timed run say from 2000 to 4000 rpm or 3000 to 5000 rpm should yield more reliable data. Use second gear for all the runs but make sure you hold the revs steady for a few seconds before punching it. The data should really be interesting then.

Emil

Ulmer

You don't want any of that race gas tainting the 93 octane runs.

Brett / APR

Using any fuel rated over 93 Octane (RON+MON/2) with stock programming or most chips will produce only minimal (if any) performance increases without commensurate ignition timing adjustments (ECU code modifications). Ignition advance learning on the current Motronic systems is a one way street- adaptation can cause the timing to be pulled back from the baseline advance table values but adaptation will never allow the timing values to exceed the ignition table baselines.

To take advantage of 100 Octane fuel, we are releasing a full line of programs that will be available with our EMCS chips. The 2.7TT 100 octane programs have been available for several weeks. We will have the TT 180hp 100 octane program available within the next few weeks. It is required to use true 100 Octane unleaded race fuel with this program. On the 2.7TT engine we have seen power increases of 30-40hp with the 100 octane program compared to a similar 1bar chip running on lower grade fuel. Increases on the 1.8T engine with 100 octane fuel should be approximately 20-25Hp.

Thanks,

Brett
APR

PanTTher

A small (emphasis on small) percentage of high-octane gas would be acceptable.