explain nitrous jetting {experienced people please}
this thread is awesome.
i was scratching my head about this for a while when i went with a NANO push system and using the harris speed works interface for fueling my dry plate.
NANO says to adjust fueling to account for 20% more flow, but then i wasn't sure how rich HSW's Interface would be.
i tried a .057 jet which the calculator figured 125 rwhp or 150 with the nano, however after dialing it in, i had to use fueling for 135rwhp with the interface which resulted (after everything including timing adjustment and doing my best to see all cylinders were happy) with 12:1 afr. then with a .59 jet (134rwhp per calculator and 171 with nano), i ended up with fueling for a 140rwhp shot with the interface to get 12:1 AFR. NA, the car is at 12.9-13.1:1 AFR. i'm not only using a wideband to dial in the shot, but it seems to end up at 12:1 when everything is in the right place.
i haven't taken it to the dyno (also have a 2.5str 3600 stall that eats numbers), so i don't have a clue how much power its really putting down. i do know it hits right and the car seems to like it where it is. my guess is that i'm making more rwhp than 140 and that i dialed it in to where my end resulting BSFC is much lower than that of manufacturers' recommended setup. then again, i'm no pro, so please feel free to critique my thinking here.
this is just my experience which i think supports a lot of what has been stated in this thread.
i was scratching my head about this for a while when i went with a NANO push system and using the harris speed works interface for fueling my dry plate.
NANO says to adjust fueling to account for 20% more flow, but then i wasn't sure how rich HSW's Interface would be.
i tried a .057 jet which the calculator figured 125 rwhp or 150 with the nano, however after dialing it in, i had to use fueling for 135rwhp with the interface which resulted (after everything including timing adjustment and doing my best to see all cylinders were happy) with 12:1 afr. then with a .59 jet (134rwhp per calculator and 171 with nano), i ended up with fueling for a 140rwhp shot with the interface to get 12:1 AFR. NA, the car is at 12.9-13.1:1 AFR. i'm not only using a wideband to dial in the shot, but it seems to end up at 12:1 when everything is in the right place.
i haven't taken it to the dyno (also have a 2.5str 3600 stall that eats numbers), so i don't have a clue how much power its really putting down. i do know it hits right and the car seems to like it where it is. my guess is that i'm making more rwhp than 140 and that i dialed it in to where my end resulting BSFC is much lower than that of manufacturers' recommended setup. then again, i'm no pro, so please feel free to critique my thinking here.
this is just my experience which i think supports a lot of what has been stated in this thread.
Robert
"Determining the correct ignition timing for an engine using nitrous oxide is not cut and dry as it is dependent on many variables.
Variables such as piston design, combustion chamber size and design, valve angle, fuel type, nitrous system design, and other
factors all play a critical role as to what timing a specific engine/vehicle combination needs. When running larger amounts of
nitrous, it is critical that the proper ignition timing be run as well as the proper spark plug heat range.
There is one specific timing that is most ideal for a specific engine and nitrous tune-up. In the end the best and correct method
to determine timing in a car is to read the spark plugs.
Due to all these variables, it is difficult to recommend a generic timing for a given amount of nitrous. However the information
below is intended to provide a starting point. After this, it is best to use the spark plugs as an indicator as to what timing a
specific engine requires. The spark plugs also will help with nitrous and fuel jetting as well as fuel pressure needs.
One large variable that drives the ideal ignition timing is the “combustion efficiency”. This is a combination of the cylinder head
valve angle, combustion chamber size and burn characteristics, and piston dome design among other things. The more efficient
the overall combustion efficiency is, the less timing is needed with nitrous. Note that when running large amount of nitrous, the
old school rule of “take out two degrees per 50 HP of nitrous” is not ideal or wise."
I was reading about the new jet table that NOS just released and came across this.It is taken word for word from your beloved NOS. Basically exactly what we are all saying.
link here:http://holley.com/data/Products/Tech...061-1-SNOS.pdf
Variables such as piston design, combustion chamber size and design, valve angle, fuel type, nitrous system design, and other
factors all play a critical role as to what timing a specific engine/vehicle combination needs. When running larger amounts of
nitrous, it is critical that the proper ignition timing be run as well as the proper spark plug heat range.
There is one specific timing that is most ideal for a specific engine and nitrous tune-up. In the end the best and correct method
to determine timing in a car is to read the spark plugs.
Due to all these variables, it is difficult to recommend a generic timing for a given amount of nitrous. However the information
below is intended to provide a starting point. After this, it is best to use the spark plugs as an indicator as to what timing a
specific engine requires. The spark plugs also will help with nitrous and fuel jetting as well as fuel pressure needs.
One large variable that drives the ideal ignition timing is the “combustion efficiency”. This is a combination of the cylinder head
valve angle, combustion chamber size and burn characteristics, and piston dome design among other things. The more efficient
the overall combustion efficiency is, the less timing is needed with nitrous. Note that when running large amount of nitrous, the
old school rule of “take out two degrees per 50 HP of nitrous” is not ideal or wise."
I was reading about the new jet table that NOS just released and came across this.It is taken word for word from your beloved NOS. Basically exactly what we are all saying.
link here:http://holley.com/data/Products/Tech...061-1-SNOS.pdf
Robert
The guys here are just trying to help you. No offense, but YOU brought up timing in post #9, but got defensive when others disagreed. You're being hard headed and not listening! It won't be too funny if your car blows up going by the 2* for every 50 hp rule, even in a lt1 car on a 200 shot that you mentioned earlier.
No offense but maybe you should go back and reread the thread. I asked about jets sizes. And I wasn't asking them how much timing to take out I was stating that if the company says it's a 200shot and you pull X amount of timing for a 200shot but in reality it's a 275shot then that would mess up shxt! They got off on the whole 2 per 50hp kick!!! People keep saying yeah wait till you blow your motor lol!! Been spraying since 1994 and been doing good so far!!! And where did you get LT1 from? I haven't mentioned LT1 anywhere. Both cars I speak of are ls1 cars.
... it needs what it needs and not 1* more. LOL 
When you got away from teh q16 and went to c23, why did you do it? Were you having the same issues with the Q16 that other people I know were?
Curious... I'm looking at what to run for fuel next year, Torco's still available, sort of, but now it's called competition fuels
http://www.competitionracefuels.net/products.asp
I have a local dealer for that, and the 118nos looks like the same stuf it used to be. I am not 100% on that, but the spec's look the same, and it should be available.... so I may take that route. Or, just go to to LVD in the spring and buy a drum of C16, not sure which would be a better way to go.
NOt trying to put 400 hp of nitrous to the motor, but if I move to a fogger I'll have to toss a 30 or a 32 jet in it and see what the car does.
Curious... I'm looking at what to run for fuel next year, Torco's still available, sort of, but now it's called competition fuels
http://www.competitionracefuels.net/products.asp
I have a local dealer for that, and the 118nos looks like the same stuf it used to be. I am not 100% on that, but the spec's look the same, and it should be available.... so I may take that route. Or, just go to to LVD in the spring and buy a drum of C16, not sure which would be a better way to go.
NOt trying to put 400 hp of nitrous to the motor, but if I move to a fogger I'll have to toss a 30 or a 32 jet in it and see what the car does.
When you got away from teh q16 and went to c23, why did you do it? Were you having the same issues with the Q16 that other people I know were?
Curious... I'm looking at what to run for fuel next year, Torco's still available, sort of, but now it's called competition fuels
http://www.competitionracefuels.net/products.asp
I have a local dealer for that, and the 118nos looks like the same stuf it used to be. I am not 100% on that, but the spec's look the same, and it should be available.... so I may take that route. Or, just go to to LVD in the spring and buy a drum of C16, not sure which would be a better way to go.
NOt trying to put 400 hp of nitrous to the motor, but if I move to a fogger I'll have to toss a 30 or a 32 jet in it and see what the car does.
Curious... I'm looking at what to run for fuel next year, Torco's still available, sort of, but now it's called competition fuels
http://www.competitionracefuels.net/products.asp
I have a local dealer for that, and the 118nos looks like the same stuf it used to be. I am not 100% on that, but the spec's look the same, and it should be available.... so I may take that route. Or, just go to to LVD in the spring and buy a drum of C16, not sure which would be a better way to go.
NOt trying to put 400 hp of nitrous to the motor, but if I move to a fogger I'll have to toss a 30 or a 32 jet in it and see what the car does.
The Q runs pretty hot and since N20 already has all the oxygen it needs the Q is not a great benifit. C-16 and N02 are both good nitrous fuels.
32 in the fogger is pretty good sized jet.
C-16 would probably be OK, maybe try the N02 from VP for a little more room in the tune up.
+1.. Clean94z, I reread the thread, but my statement still stands. As far me mentioning the lt1, I was going by your screen name, so my mistake. Good luck with your setup.
C-23 has a MUCH larger tuning window than the Q16.
The Q runs pretty hot and since N20 already has all the oxygen it needs the Q is not a great benifit. C-16 and N02 are both good nitrous fuels.
32 in the fogger is pretty good sized jet.
C-16 would probably be OK, maybe try the N02 from VP for a little more room in the tune up.
The Q runs pretty hot and since N20 already has all the oxygen it needs the Q is not a great benifit. C-16 and N02 are both good nitrous fuels.
32 in the fogger is pretty good sized jet.
C-16 would probably be OK, maybe try the N02 from VP for a little more room in the tune up.
Fuel wise, I'm just looking at the options right now, I'm definitely staying away from the Q, too many people have had issues with that ****. If I end up with VP, I'll either get a drum of the C23 or the NO2, but I may try that competition fuel, being that it's supposed to be the same as what I've been running, and I'm used to reading a plug with that.
32 jet is pretty healthy. I'm looking into just going with a fogger and being done with it.
Might just freshen my motor up, see if I can get oen of cary's CNC'd intakes for a cathedral port head, and since that should match up about perfect, just do it once and be done with it. Have him put a set of bungs in the intake for a DP right off, and then toss a fogger in the car. Someone also told me about a super victor that someone's cutting up and putting a 4500 flange on, as well as porting and doing a bunch of work too, supposedly they were on display @ PRI. I'm going to look into that. I even considered just putting one on the fast, but it's gonna be more of a pita to do the jet changes on, and whatnot. Probably still do what I want, but I'd rather try to do it right the first time, save a little $ down the road.
32 jet off the brake should liven the car up a good bit I'd think, if it stays together. I'm thinking.. 32/28 jet spread and start with about 5.5 psi of fuel, #10 plug and about 8 degrees of timing for the first run, see what it looks like.
