some n2o dyno testing

last friday, i did some testing comparing ny-trex to nx. got to wondering why nx says .063/.033 jets was 150 rwhp and ny-trex says 150 motor. got some feedback on ls1tech. then nx sent me a nozzle to try out. then spiraled from there a little.

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

test #1 nx vs ny-trex nozzle
only change was the nozzle. nx made 8 rwhp more. noticed the nx nozzle also leaned the mixture out by a half of a point. which leads to test #2

test #2 nx (.063/.033) vs ny-trex (.062/.031)
this brought the two setups to the exact same a/f ratio. nx still made 3.5 rwhp more. minor in the big scheme of things. still was nowhere near the 150 rwhp. nx = 115 rwhp ny-trex = 111 rwhp

test #3 small solenoid (.081 orifice) vs large solenoid (.125 orifice)
the main difference between nx and ny-trex was the n2o no id. nx supplies a larger one with their kit. this netted some interesting results. by only swapping to the larger solenoid and using the same .062 n2o jet, i gained 18.5 rwhp. i know doesn't make sense why you would make more when the small solenoid orifice is bigger than the jet you are using. two things come to mind. one, the orifice is freezing up and making the hole smaller. two, is an equation that you can only flow about 80% jet to orifice size.

test #4
seeing the larger solenoid also leaned the mixture out more, i put the .033 fuel jet back in. made about 5 rwhp less.

test #5
i went back and did the same test as in #1. went to the nx nozzle to see what would happen. again, nx nozzle made 6.81 rwhp more. but, at the expensive of leaning the mixture out. I could have run another test making the A/F ratio the same for both nozzles, but using what was found out in test #2, it would have made it about even.

NA vs test #5 shows just that. NA vs n2o runs. nx = 131.48 gain ny-trex = 124.67. again, at the expensive of leaning the mixture out.

overall, nozzles are within 3 rwhp when a/f ratio is the same. looks like you'll never get 100% flow out of a solenoid.

still missing about 22 rwhp off the .062/.033 jetting nx says is 150 rwhp. which leads us to the next round of testing. nx is sending me one of their n2o solenoids and bottle valves. Ricky says the side in/bottom out design is better flowing than the traditional side in/side out that many use. we'll see.

Interesting, thanks.

Rich

interesting, that is probably a good idea to use their solenoids and bottle valves, any little difference in flow can affect the output a little.

I can't wait to see the results. Keep us posted and nice work.

This is probably one of the most infomative posts I've read. Thanks for the effort.

A couple things based on what I believe to be true.

What are you using to calculate fly wheel hp and rear wheel hp? And, how do you know either is absolute? You'd have to calibrate the chassis dyno and trust conversion numbers. You do have good apples to apples tests here.

A statistically significant test sample minimum size is 30. Yes, I realize the expensive and time required to test every setup 30 times. Usually, and that was early on, I'd regularly make 5 runs (data logging acceleration tests) before I'd pass judgement on the results of a single change. Yes, later on based on confidence level and common sense I to would make judgemets based on fewer runs, but only if clearly there were no outstanding circumstances during testing.

Solenoids have a Cv (coefficient of volume) factor that corrects flow in gallons per minute under specific conditions, and Cvs are different for different solenoids. Likely, but not abosolutely, the larger the orifice the higher the flow will be (you still can't ignore the Cv factor). You will likely find the bottom out solenoids to be less restrictive, and why not the fluid makes fewer turns prior to exiting the solenoid body. This should reduce the nitrous solenoid restriction making the overall nitrous circuit more jet dependant. Which should be good.

Speaking of overall circuit restriction, I think another thing your testing shows is the overall circuit restriction to flow on both the nitrous side and the fuel side with the different solenoids and the different nozzles. When it comes to flow, typically, you are only as good as the smallest restriction. Beyond that you need to consider the overall circuit restriction as a sum of all the next largest restrictions (assumes everything's sized similarly). Far easier to test than calculate. I think your fuel side jetting changes accomodated that overall restriction. Likely there are small differences in the nozzles which determine the overall flow of both nitrous and fuel (inside diameter, changes in flow direction, and perhaps any suction the high pressure nitrous exiting in close proximity to the fuel might have (fuel side specific)).

I think your tests show excellent attention to detail and prove you can't just swap nitrous parts around an assume the tune is fine. Additionally, fast guys take the time to test and evaluate changes one at a time, attention to details.

Good post!

GREAT POST !!! I wish there was more to read. You can never be too knowledgable of this subject....can you? :D :D

Anyways...thanks and keep the test results coming !!!! :thumb: :thumb:

PS- I think this post also helped me to make up my mind with which brand and model noids I was going to buy.:cool: :cool:

just received the NX n2o noid and bottle valve today. it'll be at least a week before i can give them a few runs.

we'll see brand solenoids this go around. the big thing learned here is don't buy small. bigger is better.

just received the NX n2o noid and bottle valve today. it'll be at least a week before i can give them a few runs.

we'll see brand solenoids this go around. the big thing learned here is don't buy small. bigger is better.

That's pretty much what I got out of it. Thanks !! :D