I've run a coolingmist stage 1 trunk mount system for many years. Last year I finally had a pump give out (after 5 years of hard use) and so I upgraded to their new 200psi pump, super atomizing injector (CM5), and check valve to make sure all is up to snuff.

I use the car for track events where I'm driving 20-30 minute sessions. Car is on stock twins running 13psi. I've never tuned for water, just used it as a safety device. It's always worked well and helped with AITs, but I knew that wasn't its primary job. In the summer months I still get creeping AITs up around the 65C/150F range. I've been contemplating running a small methanol mixture to help out with intake temps but keeping it mostly water to keep things simple and costs down (I go through about 5 gallons a weekend).

My plan was to take the premix boost juice (51water/49meth) and then just dilute it with the distilled water I normally run down to about a 23% meth ratio. Is there any harm in running the meth untuned? I realize I will get zero power gain and likely lose some power from running more rich just like I do with the water, but if it'd give me the extra security of lower intake temps along with my typical water knock resistance I'd be plenty happy with that.

 

a "5" nozzle is good for 315 CC at 100 PSI. assuming (and every figure is an assumption) you now have 200 psi your delivery would increase by 41%%,

315 X 1.41 = 444 CC/Min. let's say you are at 40% meth...

.4 X 444 = 178 CC per minute.

assuming you are running around 300 rwhp....

300 X 1.92 = 576 CFM / 14.471 = 40 pounds of air/min

40/10 = 4 pounds of gas = .63 gallons per minute or.... 2385 CC/Min

178 CC of meth / 2385 CC of gas... = 7.4%

meth has 49% the BTUs per gallon of gas so

7.4 X .49 = 3.6% additional BTUs

so your, say 11.3 AFR might go to 10.9... of course you are also adding water which more than offsets the meth BTUs w negative BTUs.

so, as you suspected it is no biggie. of course the question is what will happen to your IATs. alcohol does flatten them. i measure mine w a thermocouple so it is accurate to almost the mS and degree and a larger amount of 100% meth will lower them into the 40s F.

i don't have your answer on IATs but it will be interesting to find out and the meth will do you no harm.

i imagine others might have the answer.

good for you for being on track and using AI.

Howard

 

Thanks Howard. I bought some boost juice that I'm going to dilute and try at my next event so I'll report back on the findings. It won't be super scientific but I'll try to run a session or 2 with water only before adding the meth.

 

A 50/50 mix or less doesn't generally need to be tuned for fuel from what I understand. I'm unsure of any added cooling of the intake charge of meth when it is mixed with water like that. I'll have to let someone else chime in there.

 

As Howard stated, the Meth is a fuel and will richen up the mixture. If you are running closed loop fueling your ECU may trim the additional fuel out. If you are in open loop you will end up richer and may loose power slightly.

What ecu you have, what sensors you are running, and who tuned it will also weigh into an answer. I think the short answer according to Howards math is, No.

You may also want to consider continuing to run water and carrying a slightly larger nozzle for when you see your temps creep.

EB Turbo

 

Forgot to mention I'm running a PFC, so no automatic compensation.

I went to the track this past weekend. On Saturday the temps got up to 90 ambient so it was a good test all around. I started with around 10%-ish meth mixture and then went up to 23%-ish mixture by weight (not being crazy exact with my dilution). In the morning when temps were lower I was running water and the intake temps got up to the mid-high 40s C so I think that shows my water injection is working correctly and might have had a hiccup the past event where I was seeing in the 60s C.

When the temps went up Saturday I ran 2 afternoon sessions with ambient temp in the high 80s to low 90s. During those sessions I ran the 23% meth mixture and through a full 20 minute session the intake temps stayed rock solid at 47C/117F. I run a PFC SMIC so a medium core and have a heat shield for the intake. I'd say that getting to 27F over ambient intake temps on the stock twins at 13psi is pretty good results.

I didn't notice any major power dips over what I'd typically see with water alone and it being a hot day the car would feel down on power anyway. I wasn't having any issues with igniting the mixture with stock coils, 9 heat range plugs, and a twin power.

Hopefully that helps others make up their minds. I may look for different ways to obtain meth if I want to keep running it. I think it was pretty good results here and I'm sure I could justify it for the hotter months. I'm sure I could also justify running it in the cold months too to have some extra fuel to combat the cold/lean air.

 

were you running Mid-Ohio?

really nice IATs given you are running the turbos into their in-efficiency range. my guess is you are around 300 F between the turbos and IC. your IC should remove 100+F and the rest is from your AI.

meanwhile you are super cleaning your internals... win win.

how do your plugs look?

 

yes running at Mid Ohio. I spend a majority of my track time there since it's so close to me.

I haven't pulled the plugs yet and have run 2 events on them since they were new. I'll let you know when I pull them, but in the past even with water and the twin power I only replaced them annually and they always came out with a light brown color.

 

totally loved Mid-Ohio... very much a driver's track. whoever designed it was diabolical.

first turn, blind due to bridge, off camber and a left! since almost all road courses are clockwise there are always more rights than lefts so really well set up cars run more inside (right) weight. i ran 54% inside... which makes lefts a bit more work.

so what do you get when your tires are cold and low pressure after the green? a 3rd gear left.

(although recently some of the races start on the main straight.)

the keyhole and big braking after the straight followed by a succession of rises that get your car almost airborne. and the last left before the flag. an awesome track.

say "hello" for me.

Howard

 

Went to Mid Ohio again this past weekend and it was HOT. Low 90s ambient both days and Saturday was 100 heat index. I didn't test pure water compared to water meth this time, but ran my diluted boost juice which is about 22% meth mix.

I did accidently test out water/meth compared to none at all and it's a BIG difference. Was running a session and AITs were 47C and then the tank lost prime (was pulling too much vacuum and actually sucked in the sides of the tank before losing prime...fixed by drilling a very small vent hole in the cap). In just 1 lap I went from 47C intake temps up to 75C! The real way I noticed was also that my water temps went up 4C in one lap which was weird and why I looked everything over.

I will continue to run the 22%-ish mix in the warmer months and likely go to a lower mix or just pure water in the colder months. I have noticed some red residue from the boost juice around the throttle body bypass last time I had the elbow off, but nothing I'm concerned about at this point, nor the corrosion explained in the other thread.