Hi there everyone,

As some of you have probably noticed this is my first post. I have done extensive searching along with browsed the FAQ's. The answer was barely touched upon. I am wondering how the MAF can adapt to a dry nitrous shot when it is sprayed pre-MAF as for the MAF to "adjust" fueling adequately for the nitrous. At least that is how I understand it. I would like to know how exactly that works.

Thanks

Joseph

 

The little wires in the MAF are heated. When air goes past them they cool down and they change there resistance. The computer reads the current running through the wires and adds more or less fuel depending on how much the wires are getting cooled down. The colder they are, the more fuel added. N20 is real cold, it cools down the wires even more. The computer adds the extra fuel to compensate. It thinks there is a whole bunch air running through it.

 

There are also calibrated MAFs out there specifically calibrated to take Nitrous into consideration

 

Who makes them?

 

The MAF reads velocity and temperature, then computer makes adjustment as needed. So on a dry shot the computer makes adjustment for a/f mix according to bottle press/lb's left, and utimately adjusts fuel to when bottle is empty so as not to run pig rich. On wet kit, that is controlled by a jet, you have the same amount of fuel flowing no matter what is happening, even if bottle is empty.

 

What he said.

 

As i run mafless does this mean i can only use a wet kit?

 

Granatelli makes them. However, do a search on Granatelli MAF's. You'll find a whole lot of negative comments. Best solution is to leave your MAF 100% stock. Don't even de-screen it. The screen's there to maintain an even, strait flow of air across the wires. De-screening allows more to flow across the top than the bottom, throwing off, well, everything...

 

I can understand what the MAF can do for NO2, but in NZL & AUS we find more power with a mafless tune, mine has never had one (hybrid) plus aftr mkt ECU. so does this mean a wet kit only.

 

some aftermarket EMS can control nitrous, you can set it up to add extra fuel via the injectors when you spray just like a dry kit on the stock pcm.what setup do you run?

 

I have a curiousity question. Since we have learned (or at least was stated in this thread) that the MAF tells the computer to add fuel as it get's colder, wouldn't that put the "freezing the MAF with nitrous and it goes lean" to rest????

How is it possible to "freeze" the MAF?? I have seen a couplepeople post about it, but myself, nor anyone I know that has run literally hundreds of bottles on a dry shot, has "frozen" the MAF.

 

This is my guess-

Maybe after spraying a big dry shot for too long, the maf wires get so cold that they max out thier reading levels ( i think 512 g/s ) and once the maf is maxed the car will add as much fuel as the maf reading will allow. One of 2 scenarios 1) you spray more nitrous throught the maf than the maf can read and dont get enough fuel to support it or 2) you stop spraying but the maf wires are still cold and the car is still dumping tons of fuel in when it doesnt need it.

This is just my thinking, feel free to comment.

 

Right, that's what I'm saying. It would cause it to run RICH, not lean. I would imagine that maxing out the MAF in your first scenario would require a LOT of nitrous, and when I say a LOT, I do mean it.

People are saying they are freezing with like 100 shots though

 

I guess than the question is what is the definition of "freezing". I wouldn't think a 100 shot would max the maf out! That limit is probably in the 200-250+ range.

A good way to tell would be to data log a run when the maf "freezes" and see what kinds of maf readings there are.

 

Wrong wrong and wrong. The MAF reads nothing it senses. The MAF sensor gets hot as stated about and the amount that it cools lets it know the velocity then along with the IAT sensor and the TPS sensor it determines how much fuel to put in the motor. The ECM couldnt care less about the bottle pressure or lb's left. It doesnt care when the bottle is empty either. All the computer cares about it how cool the MAF ends get over a given time. Nitrous causes them to get colder faster so the injectors add more fuel. When the nitrous runs out the ends dont cool as fast so it takes fuel away, so you were right saying it takes away fuel but your logic was all jacked up . Technically the MAF ends are supposed to stay the same temperature and the ECM just adds current to get the ends to the desired temp. That is what is read by the ecm is the current needed to make the MAF end stay the same temp.

Show me where on your car the ECM gets a signal from the nitrous bottle to measure the pressure and lbs remaining??

 

 

I think what he meant was, on a dry kit when bottle pressure runs low and consequently does not spray as much n20, the maf will sense the change. Basically no matter what the bottle pressure/amout n20 flowing, the maf will fuel correctly. Whereas a wet kit, with low bottle pressure, will start to run rich because there is less n20 and the same amount of fuel, or too much bottle pressure and the same fuel = lean on a wet kit.

This is why dry kicks ***.

 

But what happens if your MAF sensor goes bad? BOOM BOOM

 

what happens if your fuel noid goes bad?? BOOM BOOM

 

Nitrous is dangerous, period. I could careless which way people go just trying to disspell some bad info about MAF sensors