I ran a dry kit injecting the nitrous into the MAF sensor with a 50 horse jet and it worked just fine. I was running 24 lb. injectors and a 190 pump. I dont think I would do this with out a good pump but you never know until you try.

 

Good question - I was under the impression that when under WOT the computer goes open loop.

So, - - - Does it still take readings from the MAF and adjust accordingly,

or does the computer just deliver fuel according to what the look-up tables say to deliver??

 

Good question - I was under the impression that when under WOT the computer goes open loop.

So, - - - Does it still take readings from the MAF and adjust accordingly,

or does the computer just deliver fuel according to what the look-up tables say to deliver??

That can't be true or a supercharger wouldn't work.

 

I was told by C&L Performance that this was not a good thing to do. There is a potential for the NO2 to freeze and then crack the glass-covered wire element.

 

Open loop doesn't mean that it doesn't use the maf signal to measure the amount of air entering the engine. At w.o.t. in open loop it doesn't use the O2 sensor feedback to tweak the mixture; it still measures air mass and uses tabular data to calculate fuel.

The maf is designed to measure the mass of air entering the engine and from that it calculates how much oxygen and thus fuel is required. It would not accurately measure additional fuel requirements by spraying N2O upstream of the maf. The amount of oxygen per mass unit of N2O is different than the amount of oxygen per mass unit of air. That's why N2O is so effective - you get a bunch more oxygen for not much mass. Not only is it unknown what effect it would have on the maf, you've got a good chance at really screwing the mixture up and hurting the motor. There aren't any shortcuts here -- get a good wet or dry nitrous system and install/operate it as the designers had in mind. They all introduce the nitrous downstream of the maf.

 

Michale Yount has it exactly right. Do it after or you risk very serious consequences. The MAF is aways being read. Like he said the O2 is out of the equation under WOT. Good luck!!!

 

I have had my set up this way (injecting in front of the maf sensor) for awhile and have had no adverse or detrimental effects so far. I am using a 50 horse jet and it is worth 3 tenths and 2-3 mph in the 1/8 mile by just hitting the button in 3rd and 4th gear. I fully agree that anything bigger than a 50 horse shot could be dangerous.

 

Marc - I'd say you got lucky more than anything else; I wouldn't use your experience to conclude that it's ok for others to do it that way as a matter of course, regardless of the size of the shot. But I'm glad it's worked out for you and haven't hurt anything.

 

As said, you shouldn't spray in front of the MAF. For a number of reasons. Just some:
o The MAF is a hot wire maf. If nos hits the wire, it will *cool* the wire.

o Nos has a different mass than "air".

o The spray will effect the air flow, which effects how accurately the air mass measurement is made.

o At WOT, the main thing the EEC uses is the maf (for maf cars, rpm/vacuum for SD cars). The EEC ignores the O2 sensors.

 

"If nos hits the wire, it will *cool* the wire."

You know, it just occurred to me why it might be 'accidentally' working in Marc's case. With cooler N2O hitting the wire, the more current it takes to maintain the hot wire temp (200F I think). Because of the cooling effect of the N2O, the meter thinks more air (plus N2O) is flowing than actually is flowing, and it's dumping in more fuel to compensate. Could be that with a 50 lb. shot, it just happens to be dumping in enough extra fuel to keep things rich enough so no damage is done. It's not the mass of the N2O it's picking up; because of the thermal affect, it's 'fooled' into thinking more air is flowing. Just a guess though - as is that set up. Marc - if it were mine, I'd get that thing set up differently.

 

Michael I think you are correct. When I juice the engine the MAF sensor simply thinks the ambient temp is extremely cold! The reason It works on my set up is because the MAF sensor voltage is not maxed out under w.o.t. without the juice. I will not and would not say that this will wok with anyone elses combo but I did put quite a bit of thought into mine before doing it. I started with a 25 horse jet and worked all the way up to a 75 horse jet but things started getting a little lean with the 75 horse jet. I always check plugs and dont run to much timing when I use the juice. I just like to try different things and this was fun to play with.

 

I've always seen good things from spraying in front of the MAF. I know of a few people here in Jax that have had it work really well for them.

A friend of mine has the Compucar bottle in a bag kit on his '03 Cobra with the largest jet(86 hp jet) and picked up 150 hp from it. I know it's from the cooler boost temp but he's never had a problem spraying before the MAF.

With the N.O.S. LS1 kit, It sprays before the MAF and works EXTREMELY well. Stock LS1 longblock, Yank 3400 stall, and stock 2:73 gears, and full exhaust went 11.7 @ 122 mph with a crappy 1.9 60'. The motor has been through countless bottles(150 shot) for almost a year and a half.

I don't see what the big deal is...

 

I'm not sure what systems you guys are using, but the small dry kit I'm familiar with has hose that splices into the fpr hose that raises fuel pressure when the nitrous is activated. The computer isn't gonna compensate in any way fast enough to keep pistons in the engine. Injecting nitrous into a maf is the craziest thing I've ever heard of too. It's best to tap a hole at the inlet of the tb to ensure the line stays put and seals properly. I thought the whole purpose of a dry system was to raise existing fuel pressure (like forced induction) as opposed to injecting extra fuel to compensate for the gas........

 

onlyone07 - sounds like the N.O.S. kit for the LS1 is designed to work that way. I believe what's being asked about in the thread is whether or not it's appropriate and/or safe to try and create a set up yourself by spraying in front of the maf with components that weren't originally intended to be used that way. Big difference between the two scenarios. Like you, I don't see what the big deal is using the N.O.S. kit the way it was designed to be used on an LS1. But that's not what the poster here was asking about. Most of the dry kits that I'm familiar spray downstream of the maf (many are even downstream of the throttle body), and they use the type of fuel enrichment system described by Grey above.

 

Well shoot Michael, I evidently am not familiar with the Ls1 setup then. Maybe I should look into that since everyone and their brother seems to own one........