timing for 125 hp fogger

[John_Heard]

Those are N/F ratios out of Dave Koehlers Nitrous Master software which is based on orifice size, pressure, etc. Of course verifying the flow rates in lbs per hr is more accurate, but assuming everything is up to snuff in the system then I've found it's reasonably accurate.

I've flowed my own stuff and got the lbs per hr and worked backward into the program to get a N/F ratio and what it says the jets are is close as long as you don't have a restriction that's limiting flow significantly in the system somewhere - like when you're reaching the flow potential of your solenoid/s for example.

[John_Heard]

so your saying to set the fuel pressure at 8psi is that because its a fogger , does a plate system require less fuel pressure with staggered jets at 125 -150 hp range,

As far as I know it doesn't really matter if it's coming out of a plate or a fogger, lbs per hr of nitrous and fuel are the same either way. Foggers hit softer generally, and are adjustable per cyl in most cases, but lbs per hr is lbs per hr bottom line.

At the low flow rates we're talking about here, I don't believe there is any significant difference. If we were close to maxing something out, then yes a 4 solenoid fogger is going to have a lot more flow potential than say a 2 solenoid plate and pressures may change to get to where you need to be.

[roadrunner451]

thanks john.

[71Hellride]

Those are N/F ratios out of Dave Koehlers Nitrous Master software which is based on orifice size, pressure, etc. Of course verifying the flow rates in lbs per hr is more accurate, but assuming everything is up to snuff in the system then I've found it's reasonably accurate.

I've flowed my own stuff and got the lbs per hr and worked backward into the program to get a N/F ratio and what it says the jets are is close as long as you don't have a restriction that's limiting flow significantly in the system somewhere - like when you're reaching the flow potential of your solenoid/s for example.

I've had my stuff flowed but never got a n/f ratio from him. Have you flowed a lot of systems? I ask this because I wonder how different two systems can be. If both were say a brand new nos pro race fogger, how different could they be. I know everything is going to be a little different, but some would have you think having a nitrous system flowed is as important as having a crank balanced.

[John_Heard]

You paid someone to flow your system and you didn't get any flow rates? Or do you mean the info was in lbs pr hr and not N/F Ratio? If the latter is the case it's not hard to come up with the ratios. If you didn't get any data back from flowing your system, well frankly that was a waste of money.

I haven't really flowed a lot of different systems, just my own stuff and I've found all kinds of things. However you might say some of the things I've played with are a bit odd lol. You're right, one pro race fogger ought to flow the same as another - but the whole purpose is to find out IF it will flow what it should, and if not why. I would compare flow testing more to checking your journal sizes on your crank to make sure the machinist did it right than balancing a crank.

[71Hellride]

Well why would I need to know the n/f ratio? He gave me a couple of tune ups. Both jet numbers, timing, and fuel pressure. I've even called him on saturday night with a question. Turned out to be an electrical though. Think I got the electrical fixed so maybe I can finally make a good nitrous pass.

[John_Heard]

Who are we talking about here that flowed your kit? Did he actually flow test it or just give you a baseline tuneup for your system? Just out of curiosity, how much did you pay and what did you receive?

I guess it all depends on what you're looking for. If I was paying someone to do this for me, I would want lbs per hr fuel and nitrous based on the same jets I'll be using in the system for the hp settings I request. Specifically, I would want to know what happens when you start to reach the flow potential of the solenoids. You do reach a spot where a given jet size increase doesn't flow what it should because other parts of the system start to become a more of a restriction, like the solenoid orifice for instance.

I've never had a system flowed so I don't really know what all these guys do, or how much they charge for it.

Guess I didn't answer you about why you need N/F ratio - that's to know where you are in the tune up in regards to rich or lean. It's a just a reference number that describes the tuneup. Your data should tell you that if you change lower the fuel pressure by 1 psi, the N/F ratio will go up to X. Correspondingly, if you reduce the fuel jet by X number, what will it do in lbs per hr. Having that info can save time and passes when optimizing your tune up is the bottom line.

[71Hellride]

Monte Smith did mine. I really don't know exactly how much it cost,it's been awhile, but I already had the system and he replumbed it and flowed it. I want to say it was $500 just to flow it. A whole system from him is around $1500. Like yoiu said I just wanted to make sure everything was working right. I think yoiu pay a lot his experience also with timing and n/f ratios. I got two tune ups. 32n 24f at 5lbs and and 40n 30f at 5 lbs. I was running 6 jet spreads and the plugs still showed color and I sent it in to have him flow it and check it out. I'm sure he'd tell me the ratios if I wanted them. You said 7.75/1 ratio was not a good place to start, and I think mine is leaner than that. Monte is big into not starting one off lean or rich(like most people) the only safe tune up is the correct one. Taking in regard that every motor will want something a little different.

[John_Heard]

Monte is a pretty sharp cookie, no doubt he knows what he's doing. I am a bit surprised that you didn't really get any flow data for $500 other than a tune up chart, but like I said I've never had that done.

Yes, I would hesitate starting someone out at 7.75:1 N/F ratio as I would not start my own stuff that lean, part of that is taking a bit more timing out than what the engine might want but if that's what your engine wants to make it happy and runs the best numbers then that's cool.

I don't profess to be any hot shot nitrous tuner, all I'm trying to do his help people with something I'm pretty darn sure will get down the track without hurting anything with a place to get started. I understand totally Monte's approach to what he does with his tune ups, personally I prefer to approach it a bit different not quite so lean.

If you look at some of Steve Johnson's tune ups he sends out, they are in a whole different ball park from what Monte does, but his customers seem to really like his service and tune ups so that's cool too.

[71Hellride]

Steve is obviously a really smart guy, because he has a lot fast cars. The main reason I chose Monte is because he was so helpful even before he flowed my stuff. Telling me why stuff happened and what to do to fix it. Then he throws out numbers to prove it. He never once tried to get my business or throw a sales pitch on me. I agree that a little rich especially on small tunes will take forever to hurt something if it ever does. I sprayed around 450hp on a bbc with a fogger and a plate one time. 32n 32f in fogger and I don’t remember the plate numbers or timing. Seemed to run fine but would lose ring seal and start to smoke after some time. With a 32n and 24f jet in my new set up and no plate it’s a totally different animal. More power and ring seal is much better. Makes me wonder how good my other combo would have run with a good tune. Although I would never recommend someone start with an 8 jet spread without having your system flowed.

[roadrunner451]

OK , JOHN the 24 nos jets , 20 fuel jet works great , lots of power, ive got 8 degrees coming out , with 5. 75 fuel pressure , way better then the 20/20 out of the box,, what would this calculate to john ? sound safe ?......... plugs look fine

[John_Heard]

Good to hear you had some success with your tune up! That one is somewhere in the neighborhood of 140-150 shot based on how much fuel is in it. You can mess around with some ET Calculators and compared your N/A passes and your bottle pass to get a idea how much rear wheel HP it gained.

Safe? Probably so, what do your plugs show you? 8 degrees should be plenty safe on the timing, but only the plugs and time slip can answer that question for sure.