General NOS question

[djtodd]

Ok, I'm a NOS noob, I'll admit to that. But I have a few questions.

What are the advantages/disadvantages of a wet vs. a dry kit. Seems to me a dry kit is the way to go without being forced to do lots of mods, due to the fact that the maf will sense more o2 and therefore input more fuel. Am I correct in that thinking? And, in a wet kit, how does the ecu keep your engine from running so lean? External fuel management?

Second, what are some general price differences between a dry, wet, and direct-port kit?

Third, I'm looking for about a 75hp shot. Would a dry kit be the way to go? At the moment I'm just running pretty plain-jane mods. Intake, exhaust, header, ported and polished head/intake/exhaust, about to get an Apexi S-AFC to play with.

Thanks in advance peeps!

[Syntax360]

i think a dry kit would be the best way to go if ur just after 75hp. I hope i'm not talking out of my *** here, but I think a wet/direct port kit is best when using more N20, and I wouldn't use a wet/dp w/o some kind of fuel management. I think wet kit + S-AFC would allow for more precise tuning, which is a definite advantage over a dry it, but ur not after much, so i'd use dry. btw, http://]www.ag.auburn.edu/users/gparmer/articles/neon/ has some good general info about N20 and adding extra fuel supply.

[Aries]

there's a nice little faq about nitrous at the top of this forum...

[djtodd]

Yeah I read it before posting.

[sapix @ RHIT]

First, its nitrous, not NOS, also, NOS is three letters, not a word (just in case your trying to talk about it)

Wet kits are better than dry kits and Direct Port is better than a wet kit. Dry kits the nitrous is sprayed into the intake manifold and then the fuel injectors are forced to spray more fuel. The added fuel is usually done by sending some kind of fake signal to the ECU telling it that it needs to add more fuel because more air is entering the engine than it really is. Another way to do this is to increase the pressure to the injectors.

A wet system on the other hand injects the nitrous in the intake manifold, but this time it also injects the needed fuel with the nitrous. Wet systems are nice because your injectors don't have to work harder, but there are down sides. The number one downside to a wet system is that your intake manifold is not designed for fuel to flow through it. Often times specially designed manifold is helpful. I've also heard wet are better for Turbo/Supercharged cars (don't say forced induction, but nitrous is often considered forced induction)

The third type, Direct port is by far the best, and most expensive. Rather than injecting the nitrous in the intake manifold where it might get distrubited unevenly, it is injected directly into each port. Direct port is great, but not very practical in a street car just because of the difficulty of it. It is a very complicated system and usually left to race cars, not street cars.

So now that you know a little about nitrous, your still trying to figure out what system to get... remember, if you get a Dry System, you're probably going to have to upgrade your injectors (at least with that 75 shot you will) because I'm pretty sure the injectors can't support too much more power. Most kits will come with the equipment needed to fool the ECU into providing more fuel, or the equipment needed to increase the preasure at the injectors. But it is something that would be a good idea to ask the company your buying from.

[Aries]

the stock fuel system will support a 100 shot with ease.any more and it will begin to lean out drastically.

[MaineExport]

I had originally ordered an NX dry kit, but after a bit of research I ended up swapping it for their wet kit. The dry kit actually sprays they N2O before the MAFS so that the ECU will adjust for the needed fuel. This will distribute the FUEL evenly... but not the N2O.. leaving some cylindes running rich for no reason. The wet kit will at least distribute the extra fuel AND N2O together so that the mixture is corrct where it is needed. The wet kit is a little more expensive, but in my opinion it is worth it.

Also, I intend to upgrade to a Walbro fuel pump and Nismo has a nice presure regulator that I've had my eye on. Does anyone know a good source for the fuel pump? Heavythrottle has one but the bio says it's for the SR.... should that even matter?

[Syntax360]

[email protected] posted a reply once and said he could get a walbro for $90. check it out. And no, it doesn't matter if it says SR.

[Nismo1182]

I had originally ordered an NX dry kit, but after a bit of research I ended up swapping it for their wet kit. The dry kit actually sprays they N2O before the MAFS so that the ECU will adjust for the needed fuel. This will distribute the FUEL evenly... but not the N2O.. leaving some cylindes running rich for no reason. The wet kit will at least distribute the extra fuel AND N2O together so that the mixture is corrct where it is needed. The wet kit is a little more expensive, but in my opinion it is worth it.

Also, I intend to upgrade to a Walbro fuel pump and Nismo has a nice presure regulator that I've had my eye on. Does anyone know a good source for the fuel pump? Heavythrottle has one but the bio says it's for the SR.... should that even matter?

The wet kit is the one that would distribute it unevenly. The manifold for the ka sucks for N2O. It would puddle at the bottom and cause uneven shots in each cylinder. The dry shot would be a bit better IMO. Please explain how the dry shot would distribute the N20 gas unevenly.

[djtodd]

The only way I see to really make sure your dispersing fuel/Nitrous evenly is with a direct port kit, correct?

What are some of the more popular dry kits for the KA?

[MaineExport]

The wet kit is the one that would distribute it unevenly. The manifold for the ka sucks for N2O. It would puddle at the bottom and cause uneven shots in each cylinder. The dry shot would be a bit better IMO. Please explain how the dry shot would distribute the N20 gas unevenly.

Sorry if I was unclear, this is what I am TRYING to say:

Neither the wet kit or dry kit will dispense the N2O evenly... PERIOD. The fact that the gas has to pass across the fuel rail means it will NOT be dispersed in even increments.

BUT, the wet kit will distribute the N20 AND FUEL TOGETHER evenly... not to each cylinder evenly... but the mixture of N2O and fuel will be even in whatever cylinder it happens to get into.

With the dry kit... the FUEL will be distributed evenly, but the N2O will not... meaning certain cylinders will get the proper mix of N2O and fuel, and others will just get more fuel... creating and overly rich mixture for THAT particular cylinder.

At least with the wet shot... the mixture of fuel and N2O will be proper... regardless of how evenly it is distributed. The NX shark nozzle vaporizes the mixture to help prevent the pooling of fuel that you are talking about. No, it's not perfect, but it is regarded as the best fogger/nozzle on the market from all of the independant sources that I have found.

djtodd... yes you are right.. the only way to ensure the proper mix is to use a direct port system.

[Mayhem_J30]

Sorry if I was unclear, this is what I am TRYING to say:

Neither the wet kit or dry kit will dispense the N2O evenly... PERIOD. The fact that the gas has to pass across the fuel rail means it will NOT be dispersed in even increments.

BUT, the wet kit will distribute the N20 AND FUEL TOGETHER evenly... not to each cylinder evenly... but the mixture of N2O and fuel will be even in whatever cylinder it happens to get into.

With the dry kit... the FUEL will be distributed evenly, but the N2O will not... meaning certain cylinders will get the proper mix of N2O and fuel, and others will just get more fuel... creating and overly rich mixture for THAT particular cylinder.

At least with the wet shot... the mixture of fuel and N2O will be proper... regardless of how evenly it is distributed. The NX shark nozzle vaporizes the mixture to help prevent the pooling of fuel that you are talking about. No, it's not perfect, but it is regarded as the best fogger/nozzle on the market from all of the independant sources that I have found.

djtodd... yes you are right.. the only way to ensure the proper mix is to use a direct port system.

That's a big 10-4 :Werd can i get a niner in there?

With the wet at least you'll never go lean. The dry is a risk you take. I have recently went with a wet system myself. I've weighed the price and reliability for my needs and wet wins hands down. I don't have to buy larger injectors, don't have to purchase a JWT ECU nitrous module etc. Which means I save lots of cash to accomplish the same thing at half the labor.

Like DJtodd said, direct port is the way to go but that's $$$

[djtodd]

Sorry for all the questions, but you guys have some good brains to pick.

First, in a wet kit, how (physically) is the nitrous injected? Are there jets mounted into the intake monifold? Or is that a direct port kit?

That being said, unless a wet kit injects N2O into the intake manifold right before each intake valve/injector, how can it distribute N2O any more evenly than a dry kit being as they would both be injecting N2O before the intake collector/lower manifold.

Second, how much $$$ are you talking about for a direct port kit?

Thanks for all the info by the way guys.

[Nismo1182]

Sorry for all the questions, but you guys have some good brains to pick.

First, in a wet kit, how (physically) is the nitrous injected? Are there jets mounted into the intake monifold? Or is that a direct port kit?

That being said, unless a wet kit injects N2O into the intake manifold right before each intake valve/injector, how can it distribute N2O any more evenly than a dry kit being as they would both be injecting N2O before the intake collector/lower manifold.

Second, how much $$$ are you talking about for a direct port kit?

Thanks for all the info by the way guys.

Wet kit has 2 lines (one for gas and one for N20) running to one nozzle. Little jets inside the end of the lines determine how much gas and N20 goes thru. So you set whatever jets to give you 25, 50 or 100 shot etc.

The nozzle itself is set about 6" give or take from the throttle body. One solenoid controls the N20 and one olenoid controls the gas at the same time when the gas pedal switch is activated. Thats is how the mixture of gas and n20 is even, its sprayed at the same time and mixes as it leave the nozzle.

Direct port is the best and you can save a lot of money if you know how to fabricate the small lines.

I myself have dealt with wet kits. Never dealt with dry kits and thats why i was curious as to the mixtures.

[MaineExport]

Originally posted by djtodd "]First, in a wet kit, how (physically) is the nitrous injected?

Most wet kits will require you to drill a hole in your intake between 2 and 6 inches from your TB(throttlebody)... the nozzle is a Y-adapter that combines the fuel and N2O and then vaporizes it as it sprays towards the TB.

That being said, unless a wet kit injects N2O into the intake manifold right before each intake valve/injector, how can it distribute N2O any more evenly than a dry kit

It doesn't dispribute it any better... as I said in my previous posts.. the advantage is that the fuel and N2O are mixed properly.

Second, how much $$$ are you talking about for a direct port kit?

Actually, NX now makes a "bolt-on" direct port kit that includes a universal fuel rail with all the N2O plumbing and solenoids completely selfcontained. It supposedly requires no drilling. It is about $1200 for the complete kit... but most NX kits can be upgraded to this system for about $600 (I think... so don't quote me on that).

[Nismo1182]

ok so the same rule would apply to the dry kit, i.e: the first cylinder would run a bit more rich than the last cylinder?

[djtodd]

Ah ok(big light bulb), thanks maine, I get ya loud and clear now.

I didn't understand that in a wet kit, fuel AND N2O are injected, vs with a dry kit, just N2O is injected.

Thanks a bunch guys, I found out what I wanted to know, and as always, more.

[MaineExport]

ok so the same rule would apply to the dry kit, i.e: the first cylinder would run a bit more rich than the last cylinder?

Well, in theory, all 4 cylinders will get equal amounts of fuel... but:

The first will get more N2O with equal fuel = possibly too leanThe second and third will get less N20 with equal fuel = not badThe fourth will get far less N2O with equal fuel = possibly too rich

[Mayhem_J30]

ok so the same rule would apply to the dry kit, i.e: the first cylinder would run a bit more rich than the last cylinder?

If you consider the closest cylinder to the TB the 1st cylinder then just the opposite is most likely to happen. It should run lean and richen up progressively as you go back to the 4th cylinder.