Meth as "bandaid" only

[tyhackman15]

A bit of an odd question, but has anyone ran a small meth nozzle without "bumping up" the tune, for the main purpose of cooling charge temps and preventing detonation?

I'd be looking to run basic -20 fluid from the WW tank. The idea is that you have a tune that is safe for your current fuel (i.e 93 or e30) and then you spray a small amount of meth to help keep temps down, etc... Living in Texas this is mainly a concern in the summer of course, a FMIC can't fix 100 ambient temps.

Has anyone done this? Would it mess with anything (AFR, etc..)? I've done it with without issue on some other cars, but they were all older. I'm only asking because I already have a WMI setup just sitting in the garage.

[all4bspinnin]

I wouldn't recommend doing it without adjusting the tune. It will change AFR. What software are you using? Cobb? MHD?

[tyhackman15]

Originally Posted by all4bspinnin

I wouldn't recommend doing it without adjusting the tune. It will change AFR. What software are you using? Cobb? MHD?

Stock tune right now, will be going MHD since I have a 2012 DCT. My main reason for not wanting to adjust the tune is due to a lack of a failsafe. It's a basic meth kit. But if that isn't an option it can remain on the shelf in the garage.

[Rob_BMW_PNW]

It actually doesnt change AFR, the STFT will be adjusted and it will take away fuel to hit target

You can run it with no additional tuning, you will just see negative fuel trims on when it really kicks in

[mike@x-ph.com]

You could run but i would wait until you get a tune

[all4bspinnin]

Originally Posted by Rob_BMW_PNW

It actually doesnt change AFR, the STFT will be adjusted and it will take away fuel to hit target

You can run it with no additional tuning, you will just see negative fuel trims on when it really kicks in

It would change AFR hence the change in STFT's to keep it at the target AFR.

I suggested that because if he sprays to much he could max out STFT's (rich side). The car would be pulling fuel, if the meth stops for any reason he'll be lean.

The bottom line is, you could probably get away with it, but i would discourage you from doing so without a tune.

[Rob_BMW_PNW]

Originally Posted by all4bspinnin

It would change AFR hence the change in STFT's to keep it at the target AFR.

I suggested that because if he sprays to much he could max out STFT's (rich side). The car would be pulling fuel, if the meth stops for any reason he'll be lean.

The bottom line is, you could probably get away with it, but i would discourage you from doing so without a tune.

Doubt it would max it out
http://datazap.me/u/robertnguyen723/...1&data=5-21-23

http://datazap.me/u/robertnguyen723/...2&data=3-12-13

Bet you cant tell which one has meth spraying and which one doesnt out of the 5 logs, besides three of them being named 'with and without meth'

I can provide several more logs to prove my point

The most it will change is 10%, so unless you were already running -25% chances are, you arent going to cap out

AFR/Lambda is still the same across the board, it 'changes' for a split second and then the DME will adjust the STFT to compensate for that extra fuel for all of the time it is at that load target/area

[all4bspinnin]

Originally Posted by Rob_BMW_PNW

It actually doesnt change AFR, the STFT will be adjusted and it will take away fuel to hit target

Originally Posted by Rob_BMW_PNW

The most it will change is 10%, so unless you were already running -25% chances are, you arent going to cap out

Rob, you just contradicted yourself and confirmed my point. I said the AFR would change, you said I was wrong, then you come back and say it will change 10%. So yes, AFR will change but STFT's will correct for it.

I've seen several cars go from 11:5 AFR to 9:1 AFR when meth kicks in. It all depends on how much is being sprayed.

I don't know what size nozzle he would be using so we can't say the AFR will simply change 10%. Its an unknown in this case. It sounds like you have a lot of experience with meth on this platform and I'm sure you'd probably be right, but I'd hate to tell this guy it would be ok and he goes out and hits limp mode or worse, has a meth issue and it runs lean.

[tyhackman15]

I'd be running a 100ml/min snow performance nozzle. Tiny, shouldn't impact fuel trims much but of course I'd datalog to confirm. I just wanted to make sure the computer wouldn't freak out, and it sounds like it shouldn't be an issue at all.

[WhatsADSM]

If you just want the cooling affects with no worries about the tune then spray 100% water. Very safe if anything is to fail.

[1and1]

Originally Posted by tyhackman15

I'd be running a 100ml/min snow performance nozzle. Tiny, shouldn't impact fuel trims much but of course I'd datalog to confirm. I just wanted to make sure the computer wouldn't freak out, and it sounds like it shouldn't be an issue at all.

Progressive controller? That is a small nozzle, so shouldn't be a worry (no.2)
Do you have e85 nearby? A gallon of e would get you the same net benefits without the hassle of doing the install or keeping an eye on the tank level. Much like using a larger nozzle or higher meth percentage, using more e wouls also require tuning, but just a gallon to a full tank would keep your specific gravity in range so no worries.

What are you logging with? If you're planning on tuning with MHD it's worth noting they have great logging that doesn't require the tuning part.

If the meth kit is the final answer for ya, then be sure the check valve is in good shape. Start with baseline log, then log with just water, then progressively add meth logging at each increment to monitor and learn the resulting changes to the fuel trims. Easy-peasy.

[tyhackman15]

Originally Posted by WhatsADSM

If you just want the cooling affects with no worries about the tune then spray 100% water. Very safe if anything is to fail.

-20 WWF is the plan. Only ~30% meth.

[tyhackman15]

Originally Posted by 1and1

Progressive controller? That is a small nozzle, so shouldn't be a worry (no.2)
Do you have e85 nearby? A gallon of e would get you the same net benefits without the hassle of doing the install or keeping an eye on the tank level. Much like using a larger nozzle or higher meth percentage, using more e wouls also require tuning, but just a gallon to a full tank would keep your specific gravity in range so no worries.

What are you logging with? If you're planning on tuning with MHD it's worth noting they have great logging that doesn't require the tuning part.

If the meth kit is the final answer for ya, then be sure the check valve is in good shape. Start with baseline log, then log with just water, then progressively add meth logging at each increment to monitor and learn the resulting changes to the fuel trims. Easy-peasy.

Previously ran a simple boost based controller. I do have e85 locally, and it definitely crossed my mind, but I wasn't sure if it would yield the same benefits in terms of temperature.

I'll have to play around with both options. I use the gallon of e85 technique for summer track days in my turbo miata without issue. I appreciate all the feedback/info.

[1and1]

With the e, it's not cooling anything, rather just makes the temps irrelevant if you're seeing symptoms of knock/timing reduction.

On the other hand if you're hoping for cooler charge air, that'll be for the meth. I've even seen folks use pre-turbo meth with the intent of denser air for the turbo to bite on, but I'm honestly not a fan of that route.

Test & play, log it all and have fun. It's all good experience.

[Rob_BMW_PNW]

Originally Posted by all4bspinnin

Rob, you just contradicted yourself and confirmed my point. I said the AFR would change, you said I was wrong, then you come back and say it will change 10%. So yes, AFR will change but STFT's will correct for it.

I've seen several cars go from 11:5 AFR to 9:1 AFR when meth kicks in. It all depends on how much is being sprayed.

I don't know what size nozzle he would be using so we can't say the AFR will simply change 10%. Its an unknown in this case. It sounds like you have a lot of experience with meth on this platform and I'm sure you'd probably be right, but I'd hate to tell this guy it would be ok and he goes out and hits limp mode or worse, has a meth issue and it runs lean.

Christ, the STFT will change 10% and 25% not the AFR, look at my log and compare every single one at say 6k~ rpm, and the lambda with with and without meth, if it is in the same load cell table, the lambda will be the same Both links are two different maps, compare the logs from the same link to each other.

You probably saw a PORT injected car or a car that was in OPEN loop while at WOT. No closed looped car will skew from target AFR as it will always be correcting with STFT.

And you cant run lean with meth especially when untuned on a N series >.> shows you what you know.

[Rob_BMW_PNW]

Cite your source on N54/55 on the car that you 'saw' drop nearly 2 (11 to 9) points of AFR at wot and didnt misfire instantly

[all4bspinnin]

Originally Posted by Rob_BMW_PNW

Christ, the STFT will change 10% and 25% not the AFR, look at my log and compare every single one at say 6k~ rpm, and the lambda with with and without meth, if it is in the same load cell table, the lambda will be the same Both links are two different maps, compare the logs from the same link to each other.

You probably saw a PORT injected car or a car that was in OPEN loop while at WOT. No closed looped car will skew from target AFR as it will always be correcting with STFT.

And you cant run lean with meth especially when untuned on a N series >.> shows you what you know.

So say your WOT, 4th gear 6k rpms. You're spraying meth with AFR around 12:0 (obviously stock targets 10.8 but for the sake of discussion), STFT's are in the negative. Meth has an issue and stops, you're saying the car for not even a split second would run lean? Obviously the fuel would correct itself pretty damn fast but there wouldnt be a second where AFR jumped?

FYI, im not out to prove you wrong. Im just speaking from first hand experience with other platforms - evo/sti

[Rob_BMW_PNW]

Originally Posted by all4bspinnin

So say your WOT, 4th gear 6k rpms. You're spraying meth with AFR around 12:0 (obviously stock targets 10.8 but for the sake of discussion), STFT's are in the negative. Meth has an issue and stops, you're saying the car for not even a split second would run lean? Obviously the fuel would correct itself pretty damn fast but there wouldnt be a second where AFR jumped?

FYI, im not out to prove you wrong. Im just speaking from first hand experience with other platforms - evo/sti

Incorrect stock doesnt target anywhere near that number as that low of AFR at high loads will cause random misfires.
http://datazap.me/u/robertnguyen723/...data=3-7-12-13
Stage zero (stock) no meth, just a test run
Even without meth, my trims are negative. Meaning it is removing fuel, not adding, so I dont see where your lean argument even comes into play while not tuning for meth. You run RICHER with meth if you dont compensate for it, and that is why my fuel trims got even more negative.

The car wont run lean, this is a UNTUNED car we are talking about, see the original post about not tuning for it. If you tune aggressively and depend on meth and it stops spraying, yes, bad stuff will happen.


And Evo and STIs are both open looped fueling at WOT, the only exception is the new WRX with the FA motor that can be forced Closed loop 100% of the time. I own both of these as well.

This is how our cars can run a few gallons of ethanol on a pump map and not run lean, while if you do it on a regular port injected open loop fueling car, it will run lean as it doesnt do any corrections at WOT. Fuel scalar work wonders

http://datazap.me/u/robertnguyen723/...og=0&data=4-20
Map is for E20
I have E30 in the tank and 1 gallon of pure methanol in the gas tank as well, Methanol requires 2x the volume to equal one part of pump, ethanol 30% more to equal one part pump. In a port injected car like an Evo or STI, this motor would have popped because it would not correct the leaness from ethanol.

[Rob_BMW_PNW]

And more food for thought, the Evo and STI are closed loop fueling for basic city driving and spool
So if you have any logging capabilities you will see fuel trims (AF correction 1 if Subaru) swing from one end of negative to the other end of positive when driving around
But when you go WOT and it switches to open loop, your correction will(should) goto Zero.
http://datazap.me/u/robertnguyen723/...&data=1-6-9-24

Was on a knowledge bomb roll, sorry

[all4bspinnin]

Originally Posted by Rob_BMW_PNW

The car wont run lean, this is a UNTUNED car we are talking about, see the original post about not tuning for it. If you tune aggressively and depend on meth and it stops spraying, yes, bad stuff will happen.


And Evo and STIs are both open looped fueling at WOT, the only exception is the new WRX with the FA motor that can be forced Closed loop 100% of the time. I own both of these as well.

Rob, I'm familiar with the open/closed loop transition on the suby stuff. I tuned my personal STI and a few others. Haven't touched a suby in a few years since I sold my STI so it was a good refresh. Out of all of this, the only thing I didn't know is you could force the 2015 WRX to 100% closed loop (shows im behind in platform developments) so that's pretty cool. I'll read up on them again tonight.

When I made the post above I was thinking back to the stock AFR table that targets 10.8 above ~150 Load. I wrote the post quickly and forgot that these cars stock never hit those higher load targets and usually see ~140 so it would never see 10.8 AFR. Your correct there.

Thank you for the information on spraying meth. You have more experience with it than I so its good reading.

[Jeff@TopGearSolutions]

You can run a small nozzle, say M3 or M5 nozzle, 50/50 mix and do no changes to the tune and reap the benefits of the octane bump and IAT cooling.

The DME will adjust fuel trims accordingly.

[ShocknAwe]

Honestly, with all the work BMS has done on methanol integration and safeties on N54 and N55 engines, I'd strongly recommend getting their kit and pairing it with a JB4 for the failsafes alone. Takes a lot of the guesswork out of this and is probably the safest way to spray.
http://www.burgertuning.com/meth.html