To much meth/water?

[lisa33]

I find this post from Razor in a old thread

"One thing to look at is air fuel as your going down the track. If the air fuel starts to drop the further your in it.. your shooting way too much methanol. I'll see if I can get some datalogs to show this up. Richie's car was spraying way too much.. and his injector duty cycle was constant.. yet the air fuel would drop past the 1000 ft mark.. Turned the gain down a tad.. badabing.. cleaned it up. Last night he ran 9.59 again at 140.xx off the foot brake."

My logg act like described www home.koping.net/u3243a/tillfalliga/Lambda.JPG
So to the Q, why does the A/F drop???
This is on a supercharged LT1 383 non intercoold running 20+psi fuel is a 50/50 mix of 93oct/E85 water alky is injected from 2 M15 nozzels (at 90psi)

 

[pacecarta]

AF dropping means going rich

if you are going rich and fueling as he says was constant (looking at injectors) than stands to reason that the alky is the cause and it needs to be trimmed back

to be clear
you are running 50/50 of 93/E85 in the fuel tank ..and... injecting an alky/water mix (you didnt state ratio) through twin M15s

thats a strange blend youve chosen to try to make a clean burn on

 

[lisa33]

The meth/water is a 50/50 blend, have plans to make it 75meth/25water.
Havent really tought so much aboute why its getting richer down the strip beacuse i dont belive that i loose so much time on it and it safer to go rich the last seconds on the strip. Wasent beafore i read Razors replay i begin to wonder...
Could be that the IAT gets lower and the Injectors add more fuel (have seen that in some runs but not in the one i posted above)

My blend, Last year when the engine was in a camaro 95 we run a FMIC, this year we have a new chassie and there wasent enough room for a big FMIC so the plan was to run straight E85 but i dont think that i have pump and spark capasity to get away widh it so tried a 50/50 blend.
Strange? you cant copy everybody else if you should be faster then them :wink:

 

[Razor]

If you oversaturate the motor with injection.. you will drop HP and this will drop air fuel as the boost and injector duty cycle has remained constant.

I've read the post and like Pace, dont understand your E85 thingy. How do you keep a stable mix of E85 and gasoline whereby its always EXACTLY 50/50.. as this mixture would have an effect on your tuneup if it changed.

And why even run the E85 if the meth system is handling your detonation suppression?

 

[lisa33]

If you oversaturate the motor with injection.. you will drop HP and this will drop air fuel as the boost and injector duty cycle has remained constant.

I've read the post and like Pace, dont understand your E85 thingy. How do you keep a stable mix of E85 and gasoline whereby its always EXACTLY 50/50.. as this mixture would have an effect on your tuneup if it changed.

And why even run the E85 if the meth system is handling your detonation suppression?

I proberbly missunderstand, the A/F drops a lot at the last 1/2 of the race, injector constant was almost constant. Cant understand why its getting richer and richer down the track when it doesent add any extra fuel???

Stabil mix? why should that be a problem, 3gallon + 3 gallon = 50/50
We have had a aprox 95/5 mix of gas/etanhol in the pumpgas here since many year now.. Im not worried if the mix is 49/51 or 51/49 eighter, widh this mix i get a fuel that should be euqal to aprox 96 octan (PON)and that gives me a little saftey marginal beacuse i dont go for maximum combustionpressure (its a pumpgas engine)
The meth injection is mostley for lowering the high IATs from the maxed out procharger F1 (so higher boost isnt an option)

 

[Razor]

I proberbly missunderstand, the A/F drops a lot at the last 1/2 of the race, injector constant was almost constant. Cant understand why its getting richer and richer down the track when it doesent add any extra fuel???

Stabil mix? why should that be a problem, 3gallon + 3 gallon = 50/50
We have had a aprox 95/5 mix of gas/etanhol in the pumpgas here since many year now.. Im not worried if the mix is 49/51 or 51/49 eighter, widh this mix i get a fuel that should be euqal to aprox 96 octan (PON)and that gives me a little saftey marginal beacuse i dont go for maximum combustionpressure (its a pumpgas engine)
The meth injection is mostley for lowering the high IATs from the maxed out procharger F1 (so higher boost isnt an option)

Call me spoiled I just go and fill up at the gas station with 93.. and dont play chemist with fuel jugs. Thats wayyyyy too much trouble on a street car.

If your boost is constant, timing is constant, and injector duty cycle is constant.. your injection kit is creating the issue of you getting richer going down the track. More than likely from losing HP. You need less fuel when your power goes down. If you keep the same fuel, the air fuel will drop as what is happening.

Maxed out F1 should probably running a lot higher than 96 octane. Hence the meth injection for detonation suppression.

I would ditch the water portion and bet that clears it up. But only do this if the system allows for it.

 

[lisa33]

Oure car isnt a street car anymoore, Race only so there isnt so much trouble to mix the fuel...
Aboute the dropping A/F, Will make a test widh 75/25 and se whats happening, The other thing i have notice is that i have IAT dropping a lot at the end of the race so that could be a part of the "mystery"
I havent worried so much aboute it beacuse i like going richer the last seconds, i dont belive i loose so much time anyway so its better to be safe, was just curios if had a good explination...

 

[Sean94Z]

If the IATs and AFR are dropping at the end, and the timing and injectors are constant, then it seems obvious that you are spraying too much meth at the end.

 

[lisa33]

It can look so but why? the injection (pump, hobs switch and 2 M15 nozzels) starts at 10psi boost and boost is over 20psi all the way down the strip so the amount of injection should be the same or?

 

[Sean94Z]

How is your tune w/o the alky? Does it go rich at the end of the run as well?

Maybe you have the alky coming in too strong at the end of the run. You are probably seeing more boost at the end of the run then any other part of the run.

 

[pacecarta]

you come on here quoting razors post and sig stating two nozzles
so we assumed you have a razor kit
now you say its a hobbs set at 10psi so it is not a razor kit but rather a DIY kit
seems we are talking different beasts here since your system is not progressive

 

[pacecarta]

fact still remains , injector is constant so the richness has to be from another source and thats the alky

my 86 runs WB correcting with sensor at 1/12 sec update and progressive kit and a boost controller that does not allow any boost changes i still see injector duty rise through the run

 

[lisa33]

Havent run it widhout Alky.
About Razors kit, Opps didnt know that it was progresiv, then the quote was unnessery :redface:
Dont think that i see so much more boost at the last part of the run, after the start RPM never drops under 6100 not over 6800 RPM, widh an old converter i only saw rpms between 6500 - 6900.
Since im running a procharger there is no way that boost should increse like on a turbo widh to small wastgate valve...