Target AFR's for Meth
Nov 6, 2006, 01:31 AM
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Target AFR's for Meth
Hi Guys,
what is the recommended target AFR range for a 75% meth/water setup. I have the Aquamist 2D kit with DDS3 failsafe in case meth fails.
I have read conflicting info... some are saying 11.5-11.8 others are saying 12-12.4.
Your help is appreciated.
what is the recommended target AFR range for a 75% meth/water setup. I have the Aquamist 2D kit with DDS3 failsafe in case meth fails.
I have read conflicting info... some are saying 11.5-11.8 others are saying 12-12.4.
Your help is appreciated.
Nov 6, 2006, 11:08 PM
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Depends on injector size and psi the pump is flowing at so yes, volume. Simply spray some meth through the injector into a volume container for a minute, that way you can see EXACTLY how much you're flowing. There are variables other than injector size that create a volumetric difference (ie pump as well as line thickness). 
. At ~660cc/min I tune for 11.0-11.3a/f on 93octane with 100% VP meth.
. At ~660cc/min I tune for 11.0-11.3a/f on 93octane with 100% VP meth.
Nov 7, 2006, 01:54 AM
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Car was tuned today, result was 315hp at 6400rpm and 420Nm at 4000rpm. Lambda was just over 0.8 and boost was 25psi falling to 22.5psi. Boost control needs some work and a bigger meth injector may help.
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Jan 21, 2007, 12:34 AM
#8
im using the 375cc nozzle from snow performance... i have my pump turned up a little higher than it came.. would that make a difference as to how much is being pumped... 375cc nozzle shouldn't pump more than that...
after my first couple logs it didnt seem rich enough for the addition of meth so i turned up the pump and it got rich... i turned it up again.. and it got rich... to the point where it wasn't getting any richer. its not up all the way, but its nearly there.
did i do something wrong?
after my first couple logs it didnt seem rich enough for the addition of meth so i turned up the pump and it got rich... i turned it up again.. and it got rich... to the point where it wasn't getting any richer. its not up all the way, but its nearly there.
did i do something wrong?
Jan 21, 2007, 08:51 AM
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the best way / safest way to tune for h20 injection is to keep the same standard a/f ratios and just run additional boost up to just before you hit the detonation limit. Use the fail safe to shut off the EBC hence ( base boost ). I have also seen applications where scramble boost is activated to when the water injection is spraying.
Using methyl injection this way will privide a measure of safety at normal boost levels and is easier / cheaper to tune on a dyno. By generating more boost at the same standard a/f ratios instead of a more aggressive tune at lower boost levels, more power can be realized while doing it a little more safely.
Tuning at normal boost levels can be done with water injection if desired ( ie: a/f , ignition timing ). I am not trying to say that this method should not be utilized. But the fail safe ( another map availability ) has to be 100% error free to avoid engine damage. Using tuning hardware ( ie: ecu-tek, AEM EMS, etc ) should work pretty well at triggering a safe fuel map with a good safe injection setup.
Using methyl injection this way will privide a measure of safety at normal boost levels and is easier / cheaper to tune on a dyno. By generating more boost at the same standard a/f ratios instead of a more aggressive tune at lower boost levels, more power can be realized while doing it a little more safely.
Tuning at normal boost levels can be done with water injection if desired ( ie: a/f , ignition timing ). I am not trying to say that this method should not be utilized. But the fail safe ( another map availability ) has to be 100% error free to avoid engine damage. Using tuning hardware ( ie: ecu-tek, AEM EMS, etc ) should work pretty well at triggering a safe fuel map with a good safe injection setup.
Last edited by The Devils Z; Jan 21, 2007 at 10:29 AM.
Jan 21, 2007, 11:01 AM
#11
i always set mine to spool up lean- but where you are going to hit peak boost (max tq) you want it around 11.5 to prevent knock, then as i presume u have stock turbo- the psi will begin to taper down- creating richer a/f - which is good you want it around 11.1 at redline
once you set these a/f then add timing and see where you can max it out without knocking- dont add timing first
once you set these a/f then add timing and see where you can max it out without knocking- dont add timing first
Jan 21, 2007, 11:05 AM
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i always set mine to spool up lean- but where you are going to hit peak boost (max tq) you want it around 11.5 to prevent knock, then as i presume u have stock turbo- the psi will begin to taper down- creating richer a/f - which is good you want it around 11.1 at redline
once you set these a/f then add timing and see where you can max it out without knocking- dont add timing first
once you set these a/f then add timing and see where you can max it out without knocking- dont add timing first
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