ya know, i never knew if it was the noids, or if the car was doing massive KR. but, this weekend. went out and did some dataloggin on and off bottle. changed jets, only to come to find out. no matter what jet size above a 46 {nos} it did the exact same results.

46n
24f

vs

52n
30f

max kr was 5 degrees, and settled back down after that. pulled the exact same. the 52 is "said" to be a 150 shot. sure as hell didn't pull like it!

the noids im runnin are the lil guys, the same nitrous one used for the basic purge kits.

is my thinking correct on the noid not being able to flow enough?

bottle pressure was 900 on both runs. so thats not enough of a variable

 

What brand of nitrous system and what's the vehichle's fuel pressure? Are you running a colder plug, is it gapped right?

 

tr6's gapped to 32
N.O.S brand, everything, fogger, noids, jets
fuel pressure, under the assumption it's the same as a ls1, 58 at wot

 

according to my charts, a 52N jet is a 100 shot. 63N is a 150 shot. then again, i don't have a v6. but, to answer your question about the solenoid being too small, i did a test comparing a .081" orifice solenoid to a larger .125 orifice solenoid. this was with a 63N jet.

http://www.stealthram.com/nxnytrex.htm

i have since bought a better camera.

 

here's a jet chart by psi.

Ny-trex baseline calculations at 900 psi
EFI Single Wet Nozzle
HP -- 40 psi N/F -- 45 psi N/F -- 50 psi N/F -- 60 psi N/F
50 ------- 35/21 ------ 35/20 ------ 35/18 ------ 35/16
75 ------- 41/26 ------ 41/24 ------ 41/20 ------ 41/18
100 ------ 52/31 ------ 52/28 ------ 52/26 ------ 52/24
125 ------ 57/33 ------ 57/32 ------ 57/31 ------ 57/28
150 ------ 62/36 ------ 62/35 ------ 62/34 ------ 62/32

so, the 52N/30F hits right on the 40 psi range for a 100 shot. you might be getting fuel knock. throwing too much fuel at once can cause 'knock' and call for retard. maybe back off the fuel pill and see what happens. but, you should really find out what fuel pressure the motor does have.

 

That's about right. I use a CFN nozzle and it uses NOS brass flare jets, I think he's too fat on the fuel side also. The jets he's using are good for about 44 PSI of fuel (103 WHP shot). Running lower bottle pressure (1000 PSI) he could actually go 2 sizes smaller on the fuel size and run a .028 fuel jet and still be on the conservative side. Didnt know about the whole fuel knock thing though, pretty interesting.

 

well, the 46/24 set up i have right now, is 12.0 all the way up on a/f sniffer {at tail pipe} i really don't see the point in going leaner then this.
maybe a 52/28 set up perhaps. i never did the a/f sniffer on the 52 jets. i may do that this weekend to see whats up with it.

so, the noids may not be too small, but could be incorrect jetting. hmmmmm.

just an fyi, the car is a 5.3 v8. not a s/c v6 car. think new imp ss, and monte ss. same motor.

 

12.1 is lean enough spraying, I wouldnt want to go much more on the lean side. Do you have cats on this vehichle? Just curious about the accuracy of the AFR. I also just noticed your post earlier where you were assuming on your fuel pressure. If it were me I'd put a fuel pressure guage on my vehichle and see where I was at for sure. I know that with my stock pump with 50k miles in the WS6 it didnt make 58 PSI @ WOT, it made about 50. Just wanna play it safe is all I'm saying. Here use this jet calculator, it provides you with very good and safe info. The saying "Knowledege is Horsepower" is so true. http://www.coldfusionnitrous.com/calculator.aspx

 

i've talked with someone that did a before/after cat measuring. through the cat was 1 full point leaner. this was on a viper that he did the comparisons on.

 

i have a cat on the car. not like the 3-4 cats like a mustang or something. im aware of the cat sucking up some of the fuel on the a/f charts. which is why i jetted for it.

i have a few more things to try this weekend to see if i truely need bigger noids, or just correct jetting. we shall see

 

OK, I wouldnt put any stock in that after cat sniffer AFR reading. I personally am sticking with my first opinion that the AFR is too rich, you cant trust that reading after it goes through a catalytic converter. I wouldnt make a guess at your AFR but if you get at least an accurate fuel pressure reading you can use the jet calculator I posted the link to and get a very good starting point. It will take out all of the assumption which could lead to tearing something up or it just not performing properly. I dont think you need bigger solenoids.

 

range is 55-62. so average it out to be 58. give or take a few psi.
puts me right at the 52/26 area.

hmm, may step down the fuel jet to a 28 from the 30 and see how it does

 

Yeah, sounds good. Just make sure you dont see any KR if your able to monitor that parameter.

 

lots of kr is bad, a little kr, maybe a 2 degree isn't as much as people make it out to be. but im sure i'll get a datalog of it before i go off the deep end

 

I know I wouldnt want to see ANY KR on my car during a N2O log session. I run a .059N .030F with 1000 PSI in the bottle, timing is retarded from 34* to 28* on WOT acticvation and I dont have any KR at all. My AFR is mostly in the low 11's and high 10 on nitrous but I think this is because of my extremly rich NA RWTD tune (high 11 AFR @ WOT N/A). If I did show any KR I'd definatly back off the timing and see if that fixed it, if not track it down and fix it. How do your plugs look, are the edges of the ground strap or the electrode's rounded?

 

plugs are peachy, nothing wrong with them

 

Must be pretty minimal, but I'd still try to see whats causing the KR. When does the knock occur, is it just when you spray? I have heard that a exhaust pipe bumping on the floor can some times be interpreted as knock by the PCM. I know on my car when turning in a parking lot real sharp and slow the PCM reads the noisy Dertoit locker in back and retards the spark. Couldnt beleive it when I saw it, through me off the 1st time it happened.

 

basically i can hit the button, let off real quick, and hit it again. the first initial hit it knocks 3 degrees, then comes back down after 200-300 rpms.
but if i hit, and let off, hit again, it doesn't do it.
dunno. it might be the initial shock of it triggering something. it knocks 2 degrees on the motor, at maybe 3k rpms. then drops suddenly. next pass, nothing. might be an exhaust thing

 

Sounds like that might be your problem. One more thing to think about would be your line from the fuel solenoid to the nozzle, I know nitrous travles a lot faster being that its pressured a lot higher than the fuel. If you have really long lines from the solenoids to the nozzle that may be a contributing factor. If the KR happens on motor also then you may just have something bumping around, bad gas, or just too much timing in your tune. Hope you find the problem .

 

28 total timing
fuel line is 4 inches long
nitrous line is 8 inches

im not a complete newbie when it comes to nitrous, just new to a shot over 50, thats all.