Most of the modern Motronic ECUs can adjust for fuel changes. The degree at which it re-learns the fuel change is different. My knowledge and experience is not with the 996TT Motronic but mainly older versions. For the best results in most cases, you would need to reset all of the adaptations in the ECU. These adaptations are for timing and a few other things the ECU is smart about. The ECU will adapt as needed based on knock activity and other sensor inputs and store these changes as adaptations. Once these are learned the ECU is less likely to change the timing adaptations to most effective degree. If you reset the adaptations, the ECU is more effective to learn it's changes and store them as adaptations. So for example on the B5 S4 you could add tolulene to the tank as an octane boost and the car would learn the fuel change. But to get the best timing you would need to reset the ECUs adaptations and the timing would be better. I am not a Motronic guru, but hopefully this helps.

Maybe somebody like Tony at EPL would be kind enough to to correct me or add to this? He is the guru.

 

A water meth injection and using Methanol or Ethanol as a fuel additive serve two different purposes. The water/Meth intake injection is to lower IATS mainly. Using Methanol as a fuel additive will help in fighting timing retard through octane. The Methanol has less destructive knock tendancies at higher boost and IATs and will allow for a better timing advance due to it's octane. But Metahanol and Ethanol require more fuel flow. Guys who are running straight Ethanol usuall have to go with substantially larger injectors.

 

Per Tony @ EPL, it depends on how hard you want to be relying on the knock sensor to save your motor with the lower octane level. Outside of the knock sensor, there are no "automatic" timing adjustments for higher or lower octane fuel. In other words, if someone is advertising a single tune that can run on 91 and take advantage of 100 octane, there will be knock sensor activity when running the 91.

 

Exactly...people running pump gas and race gas with boost controllers are doing this all on 1 tune. On race gas, it's fast as hell, on pump it knocks like a bastard..ORRRR it runs OK on pump without TOO much knock, and on race gas you are leaving power on the table, UNLESS you have 2 files and you reflash with fuel changes...most don't...

 

Be handy if a tuner could chime in their thoughts.

 

It would be handy, but it's likely not gonna happen. That's their bread and butter...

 

Hey Bro, I like bread and butter!

kidding aside, I think you are right. If they were going to chime in, they would have by now. Someone needs to ask about mods, they will swarm.

 

Right!!!!

 

Bob,
Not sure if you saw it, but a decent thread here:
https://www.6speedonline.com/forums/...les-knock.html

 

Just for clarification, what is the specific question(s)?

 

I know of some people who tried adding meth to the fuel. I really like to keep it simple.. How do you know how much to add? How do you keep it consistent? Meth is destructive on the fuel system all so. I say just buy the race gas and run that. I feel the tuners will agree.

 

Does the ECU have the ability to learn/adjust to higher octane fuels and make gains? Softronic resellers certainly seem say so.

What % of meth (in tank) is most successful?

 

Simple answer is No... not on the 996TT

Predictive and time based ignition timing are relatively new. It can learn fueling, but it cannot advance timing past the target advance. As Tony and others will tell you though... it CAN pull timing WAAAAY down, but cannot advance past the targets unless you add code in the programming itself to go to another table when certain conditions are met(hit cruise control button 3 times, tap brake pedal twice, etc). Anything can be coded into the ecu as there is some extra room on the rom

Justin

 

up to 10%... already covered by every regulatory committee in trying to reduce emissions, and stretch the profits a bit more

Depending on where you are, you already have somewhere between E3 and E10 (3% to 10% ethanol content) at the pump.

Justin

 

This is why the GIAC flashloader is invaluable. Virtually instant switching of maps for entirely different tunes, not just turning up boost like most people do with boost controllers. PLUS you get to keep the stock boost controller with all the engine protection is comes with.