white2001s10

iTrader: (4)

I stole the pic from someone else on another board
still funny though

ATVracr

iTrader: (5)

This is the dumbest 5 page argument I think Ive seen on here in a while. Ruling out someone putting a nozzle a half inch away from the maf wires, which would be not the smartest thing to do - theres a very easy way to see who is right and who is wrong

Put the 25 shot jet in it, with the nozzle far enough away from the maf it has enough time to expand, and log injector pulsewidth. Put the big pill in it, and log injector pulsewidth. There is your answer.

Homeslice (tm)

Moving the nozzle completely changes the whole idea. What don't you seem to understand about this? The state change of the liquid N2O is what makes the whole thing work.

So since you are abviously going to change variables until you get a solution that makes your opinion right, what makes it so dangerous? It would seem to me that if you took MAF correction out of the equation by maxing it you could allways count on that same amount of fuel and tune your pill to that number. It also seems to me that your method involes a lot of guessing and introduces a whole lot more variables into the fueling equation.

Bottom line is that the method that White2001S10 and I have spelled out works... my car is the shining example of this. You can call it dumb all you want.. the proof is in the pudding.

BMN

ATV is rite, if you fog the airbox with a 25 hp jet, then u fog the airbox with a 150 hp jet, you will see a longer injector pulse width with the 150 jet. There are no other variables that could be changed to make it match an opinion this way, just jet size.

BMN

I do find the ideal of maxing out your maf then jetting up the N20 untill you hit your target A/F interesting. I would imagine that you would have to place the nozzle fairly close to the MAF and aim it directly at the wires. I have heard of some folks that run into problems directly hitting it and solve it by pointing it slightly away to keep from actually freezing the wires. The are perty small and making them super cold, I think, would make them perty brittle, and I think they are already delicate.

? for Home and or White. By doing this, do you notice that you have a perty rich A/F at lower RPM's and then it kinda hits what you want closer up top? Any A/F charts from the dyno or data logs?

Another thought, are you maxing your MAF or your injecetors out?

GrannySShifting

iTrader: (10)

The above post wasnt from ATVRacer it was me logged in under his name

Some of you are talking about two different things, freezing the maf is physically making ice on it maxing it out is exceeding the limit it can report back and the gms/s that is corresponding to that hertz reading. Ive maxed out a couple dozen MAFs, and ATVRacers car doesnt run too bad, a 3600lb car went 10.4 first 3 passes, missing shifts and a bunch other excuses, on much smaller then a 200 something shot. The discussion wasnt about "will the world end if you max out the maf", it was "can a MAF add more fuel on a 100 hit then it will on a 25 shot" from what I read

You dont have to get defensive homeskillet, I wasnt siding with one camp or another, just saying quit arguing, and go try it out. I dont know what variable your talking about, but spraying nitrous a half inch from the maf IS going to freeze the element into uselessness I would think. Placed a reasonable distance away (in the airbox or something where we put ours) the nitrous should run the the MAF more consistantly. Its seems to me my method of testing would be more consistant then hosing the maf down, but I dont know I dont have 2,432 years of nitrous testing.

Shuddup, throw a 25 jet in it, and log the pulsewidth at 5000 rpm in 1:1 gear. Throw 150 in it and log the pulsewidth at same rpm/gear. Simple eh?

Homeslice (tm)

I HAVE tried it and went 11.0 on a bone stock drivetrain . It's not about anything other than if you arrange your nozzle the right way the FACT is that your MAF will read the same regardless of the shot, because liquid N20 making a state change is same temp regardless of how much is going in there. Both a 50 shot and a 200 shot spray liquid N2O... hense.. the wires will be the same temp. If you put in in the airbox then you are no longer dealing with constants but an average.

If I do testing as you say it would read the same because I am spraying it on the wires... they are just as cold regardless which is what I was saying in the first place. To do your test changes the entire scenario and we are no longer talking about the same thing. If you want proof go put your nozzle near the MAF and do your own test.

NXRICKY

iTrader: (1)

QUOTE=Homeslice (tm)]Nitrous leaves the nozzle at about -129 degrees. No amount of ambient air is sufficient to raise the average temp of the charge to a degree that the MAF is capable of discerning.

This statment is not totally correct. you spary a 50 shot into the air box. There is a large amount of ambient air so you will not have the same air temp decrease as you would on a 150 shot. When I have seen dyno sheets on dry kits the a/r look close to the same from 35-175. There was a marginal amount of difference but nothing that would make you jump up and down about. The only way I could see your description doing what you are describing is if you aimed your nozzle directly at the MAF sensor. And Ithough that was bad. But again I am not a dry guy, I like mine wet.
Ricky

It would run very rich indeed until you supply enough oxygen (in my case via N2O by jetting up) to bring the AFRs back into your desired range. In my case it took a nozzle with no jet to deliver enough nitrous to bring my AFR's up to where I wanted them.

Does that make things a little clearer?[/QUOTE]

NXRICKY

iTrader: (1)

Ok would one of yall dry guys just post up you dyno sheets, with A/F on it from 50- whatever. The sheets I would like to see are the ones that did not change the tune-up in the computer. Then that should answer my questions.


Ricky

Homeslice (tm)

[/QUOTE]

Ricky, Yes aim your nozzle right at the MAF. My solution ONLY WORKS IF YOU SPRAY AT THE MAF FROM CLOSE RANGE. Changing the location of the nozzle changes the results for the worse. As for it being bad for your MAF... I would submit that racing is bad for your car period. Don't race if you are afraid to break things. I have done it for a long time on a old stock MAF with no problems.

Homeslice (tm)

I don't tune on a dyno. I use a WB, datalogger and a Vericom.

white2001s10

iTrader: (4)

These guys spraying into the airbox far ahead of the MAF will get different results and run significantly leaner, which is okay for a smaller shot, but then they limit themselves to how big they can pill it before a change in calibration is required either in the PCM or by using a CTS tricker.

Spraying in the airbox will give you resolution from the MAF because it won't be maxed out. The MAF cannot take into account the additional oxygen content of the N2O, so the bigger you pill it, then leaner you will get, and of course reach the dangerous limit on the AFR much quicker than a dry system that sprays directly on the MAF wires.

The difference is that by spraying directly on the wires, the state change from liquid to gas is localized in that area, and is NOT an average of N2O plus the air entering through the air filter. The amount of heat soaked up from the wire by this process is what maxes out the MAF reading.

The two setups just do not work the same way, so it's probably best to just drop the argument.

white2001s10

iTrader: (4)

back to the original poster's question,
the output from the MAF increases when the N2O passes through it.
This increased output tells the PCM to calculate higher load values which require more fueling. The injector pulse-widths increase and you get more fuel. Since N2O is higher in oxygen than natural atmosphere, this is not an exact tuning science, so AFRs will vary for each individual.
Where you place the nozzle will have a large effect on your MAF output.
For smaller shots, the airbox would be fine. For larger shots it's a better idea to keep the nozzle very close to the MAF.
1/2" was mentioned in an above post, but I never said that close. I think between 2 and 4 inches spraying directly on the MAF wires is a good solution.
Homeslice sprays approx 200hp about 3 inches or so from the MAF. His AFR averages around the mid 10's as measured with an LM1. It looks to be very safe but is probably approaching the volume limit of his stock fuel delivery system. I'm not sure it would be safe to increase the N2O shot without upgrading the pump at least, and maybe the injectors too.

NXRICKY

iTrader: (1)

hmmm interesting. Which nozzle? Not affraid to break things, or race. This is more a street question not all out race. Glad to hear you answered my questions.

Ricky
Ricky, Yes aim your nozzle right at the MAF. My solution ONLY WORKS IF YOU SPRAY AT THE MAF FROM CLOSE RANGE. Changing the location of the nozzle changes the results for the worse. As for it being bad for your MAF... I would submit that racing is bad for your car period. Don't race if you are afraid to break things. I have done it for a long time on a old stock MAF with no problems.[/QUOTE]

Homeslice (tm)

The nitrous nozzle (in my case NOS #13500NOS) pointed at the MAF 3-4 inches away. My car is a mostly stock daily driver.

GrannySShifting

iTrader: (10)

what mph does it run on motor, what converter if auto?

What your talking about actually FREEZING the maf I could see it flatlined, because youve physically exceeed the limits because you are subjecting the mad directly to -129 degrees. Why do that (and have it be 8:1 air/fuel on a 75 shot ) when if you back it up you will have some degree of adjustability - it wont peg the maf immediately?

white2001s10

iTrader: (4)

I think I can answer those ?
I believe he ran around 106 -107 on the motor.
He has the highway 3.15:1 gears & stock converter.

I started him out with the dry system with a .042 pill (about 100hp) and keeping it very conservative because he hadn't had the vette long and wanted to be cautous.

Now he has ***** and sees the jet as just a restriction so he took it out.

We were all surprise to see it put up the numbers it did with such a poor launch... and to be such a stock daily driver too.
I was impressed.

GrannySShifting

iTrader: (10)

holy **** no jet?

white2001s10

iTrader: (4)

nope, the nozzle itself is a restriction equal to around a .085 pill.
about 200hp shot.

ATVracr

iTrader: (5)

.085 is more like a 250 shot.