# Tuned for meth but not using



## clifborder4fm (Jul 13, 2007)

Hey guys, few months back I got my ecu reflashed by C2 and they tuned it for meth. I am only just getting it next week. How much of a difference will it make when I do use it? I recall a month ago I used octane booster and it seemed like a night and day difference so I was just curious on much adding the meth will affect me. I know it does not add power but when you are tuned for it and not using it...


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## BLSport (Dec 24, 2005)

I would imagine the water/meth tune adds some timing, and might even pull some fuel out of the map regions in which boost would be expected; water/meth entering the combustion chamber does the job that the extra fuel was originally designed to address in a non-water/meth setup, only better: remove excess heat via latent heat of vaporization, helping to keep detonation at bay.

If you're not currently using water/meth with this tune, the ECU is likely pulling out a lot of timing to counteract onset of detonation. With the octane booster in the fuel, you were able to take advantage of some, or possibly all of the extra timing written into the tune. With your water/meth injection system operational and properly tuned, you should again feel this increase in power, and likely more so.


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## clifborder4fm (Jul 13, 2007)

Im glad your the one who answered. I have a question for you. How much boost would you recommend me running on stock compression with meth? and what percent mixture water/meth do you recommend? I wanted to go to 12 or 13 psi on h2o meth...


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## BLSport (Dec 24, 2005)

The amount of boost you could run depends on a lot of factors; everyone's setup is a bit different, so it's difficult to put a hard number to what yours would safely tolerate. My recommendation is to be methodical in your approach, similar to/same as follows:

Note: To err on the safe side, the following steps should be performed under worst-case conditions; i.e., hot ambient temps relative to where you drive, and with heat-soaked components.


Run baseline timing-pull logs at your current boost level with water/meth system turned off
Run timing-pull logs with water/meth system turned on
Tune water/meth system if/as required to reduce/eliminate timing pull
Increase boost by one or two PSI
Repeat Steps 2 through 4 until you’ve either reached your desired boost level, or can no longer reduce timing pull to a level with which you’re comfortable 


I’d start with a 50/50 mix of water/meth based on mass (translates to approximately 44/56 mix of water/meth by volume), and tweak it from there if so desired.


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## clifborder4fm (Jul 13, 2007)

Ok and I can do this with VAG-COM right? I am currently boosting 8psi. the difference between 8 and 10 is crazy for my car... or that could just have something to do with the manual boost controller... not sure but can't wait to get it back in.


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## BLSport (Dec 24, 2005)

You got it, VAG-COM will get it done. Best of luck to you, and have fun! :beer:


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