crcain

Another question!

c) Would it be possible to estimate how much meth you are spraying by seeing what effect the spray has on AFR?

crcain

Not to be pedantic, but increasing boost would not lean out the mixture. Unless you weren't tuned for the higher boost level. Which I think is what you were meaning. But if this is the case, I'd say that is a really bad tune if you a) aren't tuned for the higher boost, and b) you go lean when you get there.

Just wanted to clarify.

DeiPro

crcain,

You are a very intuitive person, and I have always enjoyed reading your posts.

Here are some of my thoughts:

One thing that I feel people get caught up in is AFR numbers. Heck wait till you start talking about FAR (fuel/air ratio), that really gets the head going, cause lean is rich and rich is lean..... lol!

What I have always found useful as I have grown as an engine calibrator is focusing more so on what the particular package needs to run strong and safe, rather than listening as much to what others have said.

When I calibrate, I look at lambda!

A) The assumtion that lambda at full boost for gasoline and methanol, or any alcohol for that matter, should be similar is partially correct. If you follow that logic, your calibration will be somewhat close, at least good enough for the car to run fairly well. I would use that logic more as a starting point, to get you close to where you should be. It is important to remember that all fuels have different properties, and that these property differences effect the required optimal amount of fuel.

It is also important to remember that as long as your fuel is not knock limited, you will make the same power with a wide range of Lambda or AFRs.

B) In my opinion, pump gas sucks, even though it can make decent power with a good setup. If we can help the gas out with additional injection, that is a great thing. If I am working on a mild (400-500 whp) car that will be using gasoline, I like to feed it as much meth as I can. The key is not to give it too much too fast (soon), or the engine will deffinatly bog. If you us a progressive contorller, I like to start spray around 200 KPa (absolute, 14.65 psi boost), and have it up to full spray by 250KPa (absolute, 21-22psi boost), and keep the injection pegged above those levels. It has always worked for me, but also depends on what it is, and what the ratio is of what you are injecting.

As for me personally, I like ethanol or other alcohols as fuel, instead of a secondary injection source! Good luck guys!

crcain

Thanks for the reply. Glad to hear your views and see we are not totally off track. We are in Antigua so no dyno, and tuner is England so he maps the cars and we tinker before and after. We are learning a lot so it's fun. We plan on adding meth to my friends pump and race fuel maps on his Evo 6 with Evo Green. Then I might consider adding it to my pump fuel map on my Evo 6 GT35R.

More info we can get in this thread the better chances we are successful so keep it coming guys!

DeiPro

No Problem, I feel that sharing knowledge is really important...

bnice01

iTrader: (4)

Meth produces its most BTU of 27400(british thermal unit) @ 4:5 to 1. While gas is as we all know 12.5, and it produces 19000 BTU's. So the more meth you inject the richer your afr should be. Here the problem like disguished in this thread you have to measure the mixture thru lambda because your mixing 2 different fuels, & some widebands dont have the option to read lambda.

Since methanol carries a higher octane rating than pump gas it has a higher activation energy. So this is were higher boost, higher timing, higher compression etc comes in. Another note meth makes more power is due to the temperature drop of the mixture as it vaporizes, which produces a more dense mixture (higher density = more power).

See I always thought that I wanted to have a leaner mixture low 12 to high 11 @ redline. Then I went to a 10.8-10.5 adding more timing (boost is already maxed out). Picked up 20+hp according to DLL. So a person that using a 50/50 mixed compared to someone with a 100 mixed should have a different target afr. Nozzle size/injector size plays factor as well too. Also innvote forum is a great place that has chart, conversion's, let alone education on lambda.

bnice01

iTrader: (4)

Alright here is my DLL higher timing richer mixture is my bench. I run a m5/m10 dual nozzle DIY kit w/ failsafe. The reason for the m5/10 rather than running a m15 is a better atomozation/smaller droplets.



The logs were done on the same road about a week a part. But I do routine logs to check things and never seen a power increase like that. I like to thank for wife for logging :P, not really here to "make an agrument" just sharing a good experience.

crcain

Great info bnice!

Keep it coming people.

ChuckP

iTrader: (7)

Best thread ever!
Especially for people like me who are going to be purchasing a kit soon.
So you guys with a wideband that reads lamba, is that what you use to tune with, or do you still use AFR when tunning meth?

ChuckP

iTrader: (7)

I thought a leaner AFR always make more power up to around 12.5:1? Why would richening it up make more power?
Also, when you say 10.8-10.5, is that your AFR of both Gasoline and Meth? Will you see your AFR change when you spray meth?

KevinD

iTrader: (56)

my zeitronix reads lambda and AFR. i just tune with AFR because as long as you know what you are reading, it doesn't matter if you tune with the lambda or AFR.

from my experience, the leaner you run the car with meth injection the more power it makes. at 10.8:1 AFR the cars are slow, misfire often, and have a very large cloud of black smoke. once they gets leaned out, the misfires go away, and the car runs far smoother (and noticably quicker). slowcar can attest to how much more power we made by leaning out his car from 11:1 to just over 12:1.

bnice01

iTrader: (4)

Yes 12.5 to 1 for gasoline produces its max power but for meth it 4.5 to 1.

Yes your afr's will change when spraying to to a richer mixture than before.

Yes 10.8 to 10.5 is for both 100% meth/gas mixed

Yo kevin whats up man, I thought the same thing but I started researching like a mad man these past few weeks. I still go thru my plugs like when I had it tuned for 12 -11.7, the cylinder pressure from the extra timing is helping out alot. Boost is still the same as well as my cam settings. The only thing I change was the afr's/timing, I will say even my wife says the car pulls alot harder up top with the change.

Thanks
Brandon

bnice01

iTrader: (4)

The reason its better to tune with lambda because the stoich value by adding methanol has changed (lower).
So you would either A. need to calulated your new stoich value and it seems to be better choice to use lambda

AFR in lambda:

Lambda = actual AFR / stoich AFR

which means:

actual AFR = Lambda * stoich AFR

I'm not doubting that a leaner mixture wont make power. But you will be surprised with a tab bit rich and more timing. Give it a shot bud

The LM-1 wideband has options were you can change your stoich value ex. It will display 14.7 AFR for gas 1.0. If you set it to 6.5 for meth the LM-1 will show 6.4 AFR for Lambda 1.0.

Another example lets say overall your setup is 40% meth/60 gas%. Your new stoich value will be 12.72 ( 14.7 gas stoich + 6.5 meth stoich - 40% meth (aka new gas) ). Lets say you have a lambda of .8 would be in AFR 10.17 (consider way rich in gasoline). Now its 20% rich just like a 12.0 is 18% (.82 lambda rember the formula Acutal afr/ stoich (for gas 14.7) ) rich with using straight gas because anything below stoich is rich and anything higher is consider lean. Now if you have the luxtury of the LM-1 enter in your new stoich, now you have tune your target AFR.

In lambda 1.0 is = your set stoich

bnice01

iTrader: (4)

Ok I'm a little bored lets see what my target stoich will be. Lets go over my fuel setup:

stock injectors
m5/m10 nozzle 100 meth

First we need to know my combine # of cc's for gasoline we are spraying. Here's a little formula to help out.



Stock injectors are 560 cc @ 42lbs, now I'm still on the stock 1:1 regulator/fuel rail. With my fuel gauge I see about 44lbs of static pressure @ idle and 77lbs in fuel boost. My old pressure will be what the injectors are rated @ (42) and the new is when I'm full boost (77). Do the math, I get about 758 cc's of fuel (dont forget to square root it after dividing the pressure). Now due to the fact that you pull fuel out and scale your injectors, we need to know the actual % of fuel spraying. First I need to know find IDC:

IDC = IPW * rpm / 1200 = % (Mine is 78%) by the way still stock fuel pump

Next I need plug in IDC to find the true % of fuel

IDC * (scaling/actual injector size) I got 71%

758cc*4 injectors*71%= 2152.72 (total cc's of gas)

Now moving to meth side of the house.

m5 flows 379cc @ 150psi
m10 flows 771cc @ 150psi

Meth is = 1150.12 cc's

To find the % of meth to gas would be

total meth cc's (1150.12) + total gas cc's (2152.72) = 3097.72

Now 1150.12/3097.72= 37%

So my car is 37 meth/63 gas setup. My new stoich is 13.3

Now 1.0 lambda = 13.3 (my new stoich)

My target afr shold be 11.3-10.64 (.85-.8 Lambda)

Now you see why lambda is important, if you keep it for gasoline (14.7) when mixing different type of fuels it will be offt. example say if you ran a straight methanol car would you tune it for 12's. probably not since stoich for meth is 6.5 and any thing above is lean. Plus it produces it most power @ 4.5. So i think around the 4.3 to 1 sounds good

C6C6CH3vo

iTrader: (9)

1st gear is the sloppiest and my AFR might hit 14.0 initially but will settle to high 12's. 2nd gear will be high 12's to low 13s through the power band and 3rd is about 0.5 richer. I guess a 4th gear pull would read 12.0 or something. Near redline in all the gears the stock turbo cant keep up so boost falls along with the AFR - I should employ nitrous after 6000rpm.

My steepest 2nd gear rpm slopes BTW are in the low 13s. This is with about 1* peak, 10* by 6000 rpm, and 20* redline, and with too much boost.