davsurfa

So I bought a NoS EFi wet shot kit, now I have read the manual cover to cover several times over. The kit is fitted, the bottle is full, but the jets are confusing me. In the manual and when I asked the place I got the kit from they said the same that using the 26 jet for nitrous and 18 on the fuel will result in 35 bhp, 30 on the nitrous and 22 for fuel =50 bhp and 36 n and 24 f =75 bhp but then I come on here and see this:

Nitrous Oxide Systems
34N/18F 40HP
37N/22F 50HP
39N/24F 60HP
41N/26F 70HP
43N/28F 80HP
46N/30F 100HP
52N/33F 125HP
61N/38F 150HP


BangHead.gif

The jets I've listed at the top are the ones I have available to me at the moment. Can someone please clarify which sizes would give me as close to 50 bhp as possible please.

JonGTR

What bottle pressure is it asking for? Some ask for 950psi, and some 1100psi. The sticky at the top is about 6yrs old, so the info could have changed in the new kits for any kind of reason. They may have added/subtracted for stability, or changed the psi rating to match up to other brands.
If your instructions state the fuel and bottle pressure, then I'd go by those jets. If not, then I'd call NOS to get that info.

It looks like they raised their bottle pressure.

DTN

The chart is old. Thank you for pointing that out. The entire automotive industry is switching mentality about what is "stoich". While 14.7:1 is a scientifically perfect burn, small variations cause that ratio to go lean and rich. It's safer to run a richer mixture. So now, Lean is the new TOO Lean, Stoich is the new Lean, and Rich is the new Stoich.

Hyundai has known this for years. That's why our cars run so rich and Hyundai was the first to offer a 10 year powertrain warranty.

I'll get that chart updated. Here's what I found from Holley http://www.google.com/url?sa=t&source=...0pw&cad=rja

Jetting Combinations @ 43 PSI Fuel Pressure
Cylinders-Nitrous/Fuel Jetting=HP
4 Cylinder-26/18=35HP
4 Cylinder-30/22=50HP
6 Cylinder-36/24=75HP
8 Cylinder-40/28=75HP
8 Cylinder-51/34=100HP
8 Cylinder 65/38=125HP

Thank you for the contribution.

DTN

Oh, Jon, since you're here, I don't want to step on your toes.

davsurfa

My bottle/line pressure guage is reading between 600-700 psi. I know the ambient temperature here is a lot lower than you guys have hence the order for a bottle heater and blanket that I'm waiting on. After reading what DTN posted I now have 30/22 jets in place. There is an obvious increase in power but not what I would expect 50bhp would feel like.

davsurfa

I've just found this http://www.robietherobot.com/NitrousJetCalculator.htm

I entered fuel pressure at 44

Bottle pressure at 600

Nitrous Jet size 0.036

Number of Jets/ports:
Single fogger/direct port/etc 1


Results

The Fuel jet size should be 0.018" or 0.454mm

A Nitrous jet size of .036" or 0.9144mm should produce:
58.53 HP with 1 port(s)

Actual HP to the wheels: 49.75 HP

Is this making sense to anyone yet cuz now it's all as clear as mud confused1.gif wtf.gif

DTN

Keep in mind that your gauge is not a calibrated instrument and should not be used as such. It is a reference. The bottle pressure will remain steady or higher then 740PSI @ 20 degrees Celcius(68F). This is the "Vapor Pressure". The Nitrous will turn from a gas to a vapor at 746PSI. It basically self regulates the pressure on its own. It's when it is colder then 60F or you've used some Nitrous and the internal pressure drops (because of expansion) that you need a bottle heater to bring the temperature back up. Otherwise, at 20C, you will always have 746PSI when there is liquid nitrous in the bottle.

Plug 740PSI into that equation. I think that calculator is broken. I just plugged 1PSI into that equation and it came out the same as 900. Either way, it's best to
A. Stick with the manufacturer's recommendations
B. Dyno-tune and assume the risk of whatever the manufacturer was trying to avoid

I'm not saying that B is a bad option. I'm saying that years of experience and lawsuits have forged A as the Holley/NOS preferred option and if you go with B, you have no one to sue if there is a problem. That's always been my logic. If the manufacturer puts it in black and white, and you do something other then that, you assume risk and have noone to blame but yourself. While you can gain power, you must ask if the extra power is worth the potential damage without at least a dyno tune so you have a shop to back yourself up.

davsurfa

"..... I'm saying that years of experience and lawsuits have forged A as the Holley/NOS preferred option and if you go with B, you have no one to sue if there is a problem. That's always been my logic. If the manufacturer puts it in black and white, and you do something other then that, you assume risk and have noone to blame but yourself. While you can gain power, you must ask if the extra power is worth the potential damage without at least a dyno tune so you have a shop to back yourself up."


I must admit this bit made me smile biggrin.gif The way I see it is that I fitted the kit on my drive so if it all goes horribly wrong in a big cloud of black smoke then the blame falls squarely on my shoulders. I don't even think I'd be able sue anyone either way over here in the UK, I don't think there is a solicitor(lawyer) that would entertain the idea.

I also tried changing the pressure on that calculator and it didn't make any difference so I won't be using that one again(cheers for letting me know about that). But just to throw a spanner in to the works I also found this calc http://www.dynotunenitrous.com/store/Scrip...rousjetcalc.asp which seems much better cool.gif Fuel Pressure = 43.5, Nitrous Pressure = 740, Horsepower Wanted = 55. Result = 35n 18f.
I ran with the 30n 22f set up and the dyno in my butt said 'There is no way that was a 50bhp increase' and the 29 yr old blonde scream-o-meter looked at me with complete dissappointment, so I pulled up swapped the jets to what the new calc reccommended and tried again. This time the butt-dyno reckoned if anything it's over 50bhp and the scream-o-meter responded with "Now that's what I was expecting!!" Anyways, not this weekend but the weekend after it'll be on the rolling road and run up to see what's what. All I've gotta do is refrain from 'playing' till then mad.gif

davsurfa

Quick note on re-reading this, I had been running fuel jet 0.18 and nos jet 0.36 and developed and mis-fire when using the system. Whipped the plugs out and scoured the net for a few hours, it would seem that there wasn't enough fuel and this happened



So new plugs went in and I tried this set up "4 Cylinder-30/22=50HP" and it just didn't "feel" right. Quick call to Dan Dan the Nitrous man, he refills my bottle and knows his stuff about all thing gaseous, and he said to run fuel 0.22 nos 0.36 and all will be good in the world. I did as I was told and although the initial kick seems reduced the acceleration is more than there and feels like it pulls a lot more than before. Obviously new plugs help, but I'm not sure if it's just in my head or it's pulling better now. Either way I'm a very happy man smile.gif