Tuning For Meth
Thread Starter
Senior Member
Joined: 07-18-05
Posts: 2,130
Likes: 0
From: Canada eh!
Tuning For Meth
Just wanted to start a discussion on tuning for methanol injection.
So I run a 60/40 meth/water mix. I don't see any cooling effects from it but I can run more timing. I'm spraying before the supercharger with a 5GPH nozzle. My IAT2 temps still get up to 150 with the 2.6" pulley and dual pass mod.
My afr before meth is at 11.8, once meth is added it comes out to around 10.5 to 10.8. Does anyone know the optimal afr? Should I be taking away fuel when adding meth? I've heard lots of other things and would like to get to the bottom of it.
So I run a 60/40 meth/water mix. I don't see any cooling effects from it but I can run more timing. I'm spraying before the supercharger with a 5GPH nozzle. My IAT2 temps still get up to 150 with the 2.6" pulley and dual pass mod.
My afr before meth is at 11.8, once meth is added it comes out to around 10.5 to 10.8. Does anyone know the optimal afr? Should I be taking away fuel when adding meth? I've heard lots of other things and would like to get to the bottom of it.
Senior Member
Joined: 03-20-05
Posts: 6,313
Likes: 1
From: Rutherford, NJ
Dude, ive been running 10.5 afr's without meth.....but then again my car seems to like it there....i go into the mid 11's and she doenst like it....im definatly gonna lean her out though when i use meth
Thread Starter
Senior Member
Joined: 07-18-05
Posts: 2,130
Likes: 0
From: Canada eh!
Senior Member
Joined: 03-20-05
Posts: 6,313
Likes: 1
From: Rutherford, NJ
Yeah i know but there's something wrong with my car....it's always been way different than every1 else's car....i used to complain like a little girl on the forum....i still do kind of lol
Junior Member
Joined: 02-06-07
Posts: 432
Likes: 0
From: Corning, NY
The optimal AFR for meth is 11.2 so you're honestly not that far off. I have my car set up to run about 11.0 flat at WOT with the meth. Without it i'm at about 11.4-11.5. I'm also running about 22-23 degrees of timing with zero knock. I have the GM dual pass, front mount h/e, ported blower, and meth ont he 2.5" pulley and i see right around 155-165IAT's at WOT 3rd gear.
well saw this a little too late.... lol
but yeah what they said is pretty much correct. With a higher concentration of meth (50/50 and up) you want it to run rich since meth has a lower stoich afr... and it's actually more around 9.0:1 at WOT, but since it's less than 25% of your fuel at WOT the rest being gas, you should be in the 10.8-11.2 range to stay safe. and I run 25 degrees of timing at a 10.8 afr on a 2.55 pulley and the car pulls like a raped ape
but yeah what they said is pretty much correct. With a higher concentration of meth (50/50 and up) you want it to run rich since meth has a lower stoich afr... and it's actually more around 9.0:1 at WOT, but since it's less than 25% of your fuel at WOT the rest being gas, you should be in the 10.8-11.2 range to stay safe. and I run 25 degrees of timing at a 10.8 afr on a 2.55 pulley and the car pulls like a raped ape
watch with that -40 deg stuff it contains glycol and is really not a good thing to use. Switch to -20 degree cheap stuff with no detergents and no glycol and you should see a nice difference
Thread Starter
Senior Member
Joined: 07-18-05
Posts: 2,130
Likes: 0
From: Canada eh!
Nice info guys, thanks. Another think I was thinking about. I was reading up on a/f mixtures, the articles I read said at higher elevations like me you should run leaner than other guys at sealevel. The calculated altitude here is usually around 3500 - 4200feet.
Junior Member
Joined: 02-06-07
Posts: 432
Likes: 0
From: Corning, NY
I'm currently running the stuff that 06Blackg85ss mentioned and it's been working great. I have a 30 gallon barrel of meth on order for both the Cobalt and my Cavy. I used 100% meth in the car a few times so far and IAT's dropped slightly, I did not try adding any more timing.
Thread Starter
Senior Member
Joined: 07-18-05
Posts: 2,130
Likes: 0
From: Canada eh!
So what kit is the better between them all i am trying to understand what the 2.5 bar **** means. I have heard good thins about snow performance because it is progressive and does not just spary wide open at a certain boost it does it in increments.
Rent me! per hour
Joined: 03-22-07
Posts: 24,161
Likes: 20
From: Still fixing others mistakes.
David, I was at the exact same point as you. Should I lean it out or not?
I decided to lean it out a bit and it makes a HUGE difference in how the car pulls, much stronger now.
I used to run 10.90AFR just recently I leaned it out from 1-3500rpm 11.60 - 11.40 11.20 redline and when meth kicks in at 9PSI it bring me to 10.80AFR.
Im running over 22 degree of timing and my IAT2 never go up more then 130 degrees seems to be working good for me now that I added -40 degree winshield washer fluid.
I think 11.2 AFR is perfect as you dont want to lean to much or add too much timing as you dont want your engine to be on life support (If the meth pump dies
LSJ)
I decided to lean it out a bit and it makes a HUGE difference in how the car pulls, much stronger now.
I used to run 10.90AFR just recently I leaned it out from 1-3500rpm 11.60 - 11.40 11.20 redline and when meth kicks in at 9PSI it bring me to 10.80AFR.
Im running over 22 degree of timing and my IAT2 never go up more then 130 degrees seems to be working good for me now that I added -40 degree winshield washer fluid.
I think 11.2 AFR is perfect as you dont want to lean to much or add too much timing as you dont want your engine to be on life support (If the meth pump dies
LSJ)
sucks man, but I"m pretty damn sure anything rated under -25 degree has glycol in it, so see if you can find anything else... glycol will "gum" up in the motor and cause bad things