On my active autowerke Supercharger M3 when I wanted to run race gas i'd simply wait till i needed gas, then add a good 5-10 gallons of the good stuff and go.

The ECU would readjust to the new fuel and add quite a bit of power, I could feel it getting stronger as I continued to do pulls... After a bit, it's fully adjusted and ready to go.

Do the 996TTs do the same thing? I have FVD software, what i'm asking is are these ECUs always testing the thresholds to see if it can add more timing for the change in fuel? I loved that about my M3, if I can simply add race gas and go, i'll be pumped.

Does some nice 109 unleaded work well on a K16 996tt with just FVD tuning?

Thanks!

 

Higher octane gas always provides faster fuel burning, combustion, etc. Answer is yes. Good results regarding timing etc, live dyno.

 

Same thing... DME adjust to the fuel and eventually compensates for the higher octane fuel. You'll feel the car get stronger w/ repeated pulls as it adjusts.

A

 

That is very true, but you get the best bang for your buck if you have a high octane program flash to take advantage of the higher octane.

 

The answer is NO, the ECU does not readjust for race fuel. You must have a race file and an OBD switcher if its a GIAC software or an EBC for PROTOMOTIVE. Now the 997 does readjust on its own when you change octanes.

 

Does anyone know if the FVD software adjusts? Or is that a No also.

Thanks for the help guys!

 

It does!
In 997 and 996 you have a me7 ECU system. Both can retard if knock is ongoing, if your fuel is a better one it wont pull the timing that much, but that means also your base tune allows more ignition than just with crap gas...

It looks different if a tuner has switched of the ignition retard functionality, but why should someone do this....

 

I'm not worried about whether or not it will adjust to retard the timing, i'm wondering if it'll adjust to ADD timing to suit 100-109 octane race fuel

 

It will not all by itself. You will need a special tune made specifically for high octane fuel, or you will need a boost controller so you can turn up the boost yourself.

The car does have octane sensors, but it will not up the HP itself...it needs some human help!

 

In general ECU's dont "self adjust". If you'er gaining any significant amount of power when adding race gas, your tune is bumping up against the knock sensor pretty hard.

 

That's what I figured...you get the most benefit running race gas if you have programming for it.

 

Best is to contact FVD and get a race file.

 

If I already have their software will they send a race file to me free you think?

 

So will 87,89, 91, 93, 98, 100 and 109 all have the same performance without tunes specifically designed for each octane????

Does "bumping up against the knock sensor pretty hard" lead to engine damage? Is this a problem (or as I am guessing a figure of speech)? Or is this just the DME doing what it is supposed to do?

If you add half a tank of 100 octane and your car runs stronger, is this a problem? Do you need a new tune? Or should you just budget accordingly and run 50/50 from now on?

A

PS In other cars, I've seen that a factory tune will 'compensate' for an octane of 95-96... any more and you see no benefit. Lower than that and, as you point out, the factory tune is pulling timing to prevent knock. Just like it was designed, no need to detune it with a special 91 octane tune.

 

Even if your tune is for 93 octane, does adding race gas at the track add a margin of safety against engine detonation?