Ok im trying to figure some things out. All these systems claim the jetting to horsepower is at the rearwheels!

hsw plate system

150hp 62/33
175hp 67/38

nitro dave's plate

150hp 62/38
175hp 73/38
200hp 78/46


nx shark nozzle

150hp 62/38
175hp 73/42
200hp 78/46


now according to this jet calculator
http://www.robietherobot.com/NitrousJetCalculator.htm

.67 =202bhp/172rwhp {175hp according to hsw}
.73 =240bhp/203rwhp {175hp according to nitro dave's/nx express}
.78 =274bhp/233rwhp {200hp according to nitro dave's/nx express}


so who's right?

 

I am not as expierenced as most of the people here, but I did stay in a Holiday Express for Crew Change.

Dave's plate uses NX Jets (which likely why they have the same values for the most part).

I believe HSW uses NOS style jets.

The jet charts are usually at the flywheel and not at the wheels (you should ask when ordering the kit if Flywheel or RWHP, if you want RWHP tell the vender you want RWHP jetting for 50/100/150, they will substitute for ya if you ask).

The charts are also estimates, and every engine is not going to have exactly the same results as a similiar car.

Jet charts from manufactures usually favor rich AFR for a safety factor.

It is your responsibility to ensure the car is tuned.

It was my expierence on a stock motor, Daves plate was a bit rich and I had to use a fuel jet two sizes lower than his recommendation. Other users with bolt ons found it a bit lean or spot on.

Start with the recommended values and tune accordingly (AFR, EGT, read the plugs).

 

I installed a hsw kit on my buddies f-body another friend has the nitro dave's plate and I run the nx nozzle. All are recommend for stock fuel pressure and 900-1000psi bottle pressure. All these kits claim it to me a jetting for rwhp.

 

Because when people make 250hp on "200 shot" they get real happy and feel good.

hahahahaha.

 

LOL. My thoughts exactly. Then they'll come on the interwebz and brag about how they made 250 out of a 200, never mentioning jet size. It's all a sales pitch.

 

King of that was the old TNT kits, they had about a 200 jetting advertised as a 150, everyone thought their kits were the best by a mile because of that.

The jettgin my nos kit came with for a 150 was a 63/44. How heavy on fuel is THAT

They seem to have the fuel jet right for about 75 hp more nitrous then they're giving ya. But for a street car that was tuned to a 13 to 1 a/f for n/a will have enough fuel with their jetting too... so I dunno.

 

Having the plate flowed will determine the correct jet sizes. It is money well spent.

 

Then how do you determine the correct amount of timing to pull out to be safe? the rule is 2 degrees per 50hp so you pull 8 degrees for a 200 shot but if its jetted for a 275 shot then you should require 11 degrees.

 

Timing is a whole different story. And, LT1's are different than LS motors when it comes to the actual number. I run 12-14 degrees while on a 300 shot. Start low, and let your plugs tell you what the motor wants.

 

Agreed. there is no damn golden rule. You start to play with fire using a "rule". I also start low and let the plugs tell me how much timing it wants, because also when you mess with fuel you will have to mess with timing. That "rule" does not apply.

On small shots you can get away with it because its hard to hurt these motors on a 100-150.

As far as jet sizes, flowing the plate will tell you the correct jet sizes and that may be where these companys are getting this info, but also some make a jet size bigger to either make people happy about their kit or make up for some other problem they have. All IMO and im sticking to it. haha

 

I have a buddy that got a plate kit and has the exact same jets on a 150 shot as I do....BUT his 175 and 200 shots use pills WAAAAAAAAY larger than mine...seems shadey to me.

How or where can you get the plate flow tested?

 

Not sure if any of the Tech Sponsors offer this but here are some non-sponsors you can try:
Induction Solutions, Applied Nitrous, Monte Smith Performance.

 

Not that Im agruing with you because I definately believe in reading plugs and watching afr. NITROUS OXIDE SYSTEMS has stated "the golden rule" as you put it for years as a safe conservative way to spray. I know alot of things also play a role in the amount of timing pulled ie {octane,fuel pressure,etc}.


So I ask you... if your spraying a 200 shot where would you start as far as pulling timing for safety? ls1 car...

 

and I dont care what they say. Every motor is different and likes a different amount of timing. You could have 2 motors same parts etc. and want a different amount of timing. It is what the motor wants and what the plugs say, not shooting blind and saying "oh this will work because NOS said it.". Look at their tuneups they keep changing based on new info they are learning... Going by something like that will hurt parts. Maybe not now but in the future when you go to step it up.

I dont know your setup or anything like that but I WOULD START at 15-16 degrees and go from there. But what do I know... prolly nothing...

 

Interesting!!! So what your saying it to not listen to the nitrous companies for any baseline settings. NOS claims a starting point of 2 per 50hp, nx claimed a starting point of 1 per 50hp and you who I can only assume work for hsw says to start at 15-16 for a 200hp which is 4per 50hp. So whos right? You can turn this into a personally attack if you want "what do you know!!" comment!! personally I dont know you so your right "what do you know"? I have friends that run in the true10.5 class with two foggers that use the 2per 50hp rule for a baseline and work from there. They run high 7' and low 8's trapping 170's!! Asking simple questions and dont need the additude.


My question is why are the jettings for the shots different? its it better systems requiring smaller jets or bhp vs rwhp or is it a sales pitch? And if so Im lets be real here but if you jet a car for a 175 shot and put whatever timing you would think would be safe its gonna be different if the 175hp shot is really a 175 shot or a 250 shot. So that being said whats a good baseline or {rule of thumb} to start?

 

Really there are way to many factors to say this or that will get you exactly 150rwhp. For the most part, what each company rec is a starting point and you should generally get close with a safe A/ratio and be reasonabley close to the HP suggested.

Things that are considered for HP rating, and things that will effect outcome:
1. System bottle PSI per company
2. fuel to N2O ratio (jets)
3. solenoid size
4. nitrous Line size
5. Nozzle design and style
6. Engine CI
7. Engine Volumetric Efficiency
8. Real world system PSI
9. Timing
10. A/F ratio
11. Kit rated at RW or flywheel?
12. More things...

All of these things conspire, effecting what we see at the rear wheels. What it takes to get John Stripmaster to 150hp, may not be the same that gets Leroy Burnout to 150hp.

The only way to get exactly 150hp to the rear wheels on any combo is to jet and tune for it. The combo that eventually gets you to the 150rwhp mark, may not be what the company stated to use. That does not mean anything is wrong at all.

One company has a great marketing ploy, and the reason every one thinks man brand K really hits hard compared to Brand J. What they do is supply jetting for a 135hp hit in there recommendation for a 100rwhp shot. Absolute true story. Then there are the companies that fudge just a little with generally bigger nitrous jets than most of the other companies. That way, they are more likely, or the percentage goes up, for guys posting "Man I got 168rwhp on my 150hp jetting". Doesn't mean their product is better, just that their fuel to jet ratio on the jetting is more aggressive (and likely leaner).

I would suggest using the bottle pressure and jetting rec by the company and fine tuning from that point to get what ever you want.
Robert

 

Just my opinion, knowing the guy a little bit, i don't think he was being smart azz at all. Just his style, nothing personal.

The good safe rule of 2 degrees is blanket statement designed to save one's motor. You will be very safe on a 150hp hit doing this. Most stock motors with no added timing, at that level, with good gas and colder plug don't necessarily need any timing pulled and most companies will state this if asked.

Here's the thing with the LSx platform. They like more timing pulled than motors of past decades. Why? It has to do with head design and how extremely well they work. What happens due to volumetric efficiency, the cylinder once ignited accelerates much quicker than motors of past. Then we add nitrous and all of a sudden we are firing at a time (has sped up) when the piston is traveling up-wards on the compression stroke. This is really preigintion and leads to detonation. What we want to do is re-time the firing to a down traveling piston, the power stroke. This we do by pulling timing. because the LSx heads work so damn well, the amount of timing needing to be pulled is for the most part, greater than most other cars. I tried to cram a lot of information into a quick paragraph, and hope we made some kind of understandable sense?

Here's the lead paragraph (below) in my timing pull write up, maybe this explains things better. Just remember, the LSx likes a lot of timing pull, and for max power, this will need to be done. Like has been stated, the best way to figure out what your motor likes, is by reading the plugs. If reading is not available, then use the 2 degrees per 50hp rule, IMO.

Watch the video below for a good example of how nitrous speeds up the combustion process. Then we can easily see how the cylinder firing can quicly get to the upward traveling piston, and thus the need to pull timing to get it back to a retreating piston.

http://s108.photobucket.com/albums/n...t=MOV00443.flv[QUOTE=Clean94Z;12671860]

Robert

 

First of all, I DO NOT work for HSW, so please do not reflect my posts with their business and have any bad thoughts towards them. I think they are a great company and I support their products.

I like to tell it straight, no bs or anything like that. Sorry if it comes off as with an attitude or a know it all but just how I like to type. This shouldnt be turned into a pissing match. Nitrous companys do have their rules, and some work and some dont. Those are general guidelines, like I have been trying to say. A different combo needs a different amount of timing taken away based on fuel, jet, valve angle and so on. The 1-2 per 50 doesnt work on everything and doesnt seem to work on the lsx motors. That is what im saying.

Now for the jet sizings, I believe as in my opinion some are for a sales pitch and other must be based on how their plate/nozzle water flows that jet. Hope that clears it up

 

I definately appreciate everyone's input!


I know nx jets are different then nos jets. Would a .67 nx be the same shot as a .67 nos jet?

 

There may be slight differences due to machining tolerances, but a 67 is a 67 The main difference is in stem design. Some have a flared,or skinny, or fat stem