My specs:
Jets: 28n / 24f (yep, that close)
Fuel Pressure: ~53.8psi
NA AFR at WOT: low 13's
Bottle: ~900psi (heater wasn't hooked up yet)
Mods: full motordyne xyz/shockwave, plenum spacer, k&n FIPK knockoff (came with the car :-P)
Nitrous Setup: Full dynotune kit, with lean cut off, window switch, innovcate LC1 wideband
Also, of note, my fogger is mounted closer to the MAF side than the TB side, if that means anything.

Alright, long story short, I seem to be running WAAAY lean when spraying. I had to throw in the 24f jet (suggested for a 75 shot) in with the 28n jet (35 shot) in order to get below 12.0 AFR. Its dipping to 11.0 near readline.

However, I'm shooting massive fireballs when I let off, making me think I'm running rich, instead.

Is this normal -- do we just need far richer setups than whats suggested? Looking at other peoples jet selections, it doesn't really seem like it.

So, I'm thinkin, either I really AM running lean, and maybe it has something to do with the amount of fuel thats being delivered with the nitrous, possibly related to my fogger being further than a lot of peoples, or maybe somethings wrong with my fuel solenoid. Or, conversely, maybe I'm not as rich as I think, and theres something up with my wideband -- I'll pull a few plugs tomorrow to check them out.

Any ideas?

 

are you datalogging with your lc-1?

The 11.0 near redline is a good safe number. Where is it going rich at? Where are you doing these runs?

Get some logs of the a/f with rpm(if you can) and we'll see what's going on. Having it further away from the intake shoudln't affect it that much. I've seen them close to the MAF before and people haven't had problems (a few members on here). Maybe you have an air leak near the nozzle or somewhere between the nozzle and throttle body.

 

Nah, not datalogging. Just watching the AFR on my gauge. Basically, it gets richer the closer I get to redline, but not alot -- its pretty consistent. Good call on the leaks, I'll double check.

Was doing the runs out on a country high way, nothing too crazy -- no cars or intersections, only topping third. I play it pretty safe, to be honest.

Another thing I considered, I have a fairly sharp bend (still curved) in my fuel line to the soilenoid... maybe its restricting flow. Kind of doubt it though.

 

Since your bottle pressure is only at 900psi, the jets are rated at 950psi, the more you go on it, the more bottle pressure you lose, more nitrous lost, yet your fuel psi would stay the same. So that could account for the constant increase in being rich consistantly. Just a thought.

 

another thing i was thinking about is the stock fuel pump not keeping up but i'm not sure that would be the case at going richer near redline. It's like you have a "hole" where it goes lean then back to rich.

what rpms and what throttle are you at when it does that?

it's best to do all the things at WOT from like 2k to redline.

 

Sorry, maybe I wasn't too clear.

My real problem is that with the suggested 35hp shot jets, I'm way too lean the entire run. Those jets are based on 45psi, as well, and 950psi... so I should have been pretty rich, but I'm WAY lean, like mid 13 AFR

It was only doing the richer-up-top thing when I was using the 75-shot fuel jet with the 35-shot nitrous jet... but using those jets was the only way I could get below 12 AFR for the entire run.

Yeah, all runs were at WOT, about 3500-redline. Essentially, with the "big" fuel jet" it was ust getting slightly richer toward redline -- could just be a property of the stock fuel tuning. The real problem, again, is that I have to run such a huge fuel jet. I assume its something I've missed -- too sharp a bend, an air leak, or something.

 

ok, so now i understand.


hm.....could be clogged injectors on the car, fuel pump dying out,a kinked fuel line, air leak in the intake, or even an air leak anywhere from the header to the o2 sensor.

If there is a pinhole in that exhaust piping on the engine side of the wideband or a hole where the o2 bung is welded to the exhaust then it would suck air and show a lean condition when in fact it's not lean.

for the nitrous system it could have a kinked fuel line so it's not actually supplying the fuel it is supposed to, the solenoid isn't opening all the way for fuel (if it even is opening at all)

 

Yeah, I've logically (not actually) ruled out the injectors, since my AFR's seem "correct" while NA. Atleast, I'm assuming so -- mid 13's at WOT, and my fuel pressure is a consistent 53.5 or so psi.

Definitely didn't think about the o2 sensor/bung/exhaust reading oxygen though, I'll definitely check that out. The weld on the o2 bung definitely is a little crappy looking, to be honest.

Wish I had time to check it all today, but it'll have to wait :-( Thanks a ton, though, definitely gave me some ideas!

 

np. if the weld on the bung isn't that great there could be a pinhole. Do you have testpipes or did you weld it into the engine side of the cats? Either way i would suggest taking it off and shining a light on the inside of the pipe and seeing if there is light coming out around the bung.

now that i'm thinking about it, the injectors shouldn't be a problem since they are good when you are NA.

what a/f ratio is it running wot to redline when you are NA?

The n2o system shouldn't do anything with the EMS or fuel injectors. It just adds fuel into the intake to decrease the a/f ratio (maintain a normal a/f with the nitrous actually). the injectors would be pooping out on you NA or with nitrous since they aren't actually used to bump up the fuel.

 

I have non-resonated testpipes -- its welded just in front of the stock o2 sensor, at a slightly different angle.

Yeah, I'm thinkin my fuel is good -- mid 13's to redline at WOT. I assume thats about right, anyway. Maybe someone can correct me?

Anyway, will dig into it a bit tonight! Really want to get that 75 shot going! I was actually suprised how noticeable the 35 shot was (well, with a window starting at 4000, anyway -- lowering it later)

 

i'm not sure what the stock a/f is up to redline without boost. I didn't start doing logs until i had boost so i'm not sure what the stock ecu does.

well, first things first. check the power at the fuel solenoid. See if it's actually opening. Then see if it's actually pushing fuel through it when it opens (possible kink in the line). The fact that you are mid 13's stock and also mid 13's with a 35 shot of nitrous makes me wonder if there is any nitrous going in either.

then once you make sure that is working i would check to see if the welds on the o2 bung are correct. It should be welded all the way around the bung with no air holes. A bad seal at the test pipe/header connection would cause a weird o2 reading also.

keep us updated.

 

I'm pretty sure the fuel is being delivered. When I had the jets for the 35 shot in, I was running upper 13's, but with the bigger fuel jet, and not changing the nitrous jet, I could get it down to 11's, but other people aren't having to do it -- but I think that means the fuel jet is working fine (plus, I pulled the line off the fogger and I could smell fuel in it, after a run.

I might try to screw my wideband into the other side, into the stock O2 bung temporarily and see if that changes the reading -- that would tell me if its the bung or not, I think, and that way I dont have to pull any exhaust parts off.

 

have you put in colder plugs?

 

Yep, using the NGK's that everyone uses.

 

I would suggest checking your fuel filter then your niod filter they maybe old or clogged

If your filters are fine and not clogged, I think your fuel tee may have a restriction or just too small. I am using a 3/8th tee and lines.

Also just how long is your fuel line to the niod, when you have a long fuel line to the niod it causes a lean condition when yout first activate the system. The reason is nitrous is under 900-1200psi and fuel only 45-55psi so nitrous gets there 1st. To help solve this problem you want to make the fuel line short as you can or tune your car to run alittle richer the 1st couple hundred rpms

hope this helps

 

Yeah, I do question if theres too much restriction at my adapter. I may just connect the fuel line that goes to the solenoid straight to my rail adaptor, and leave the fuel pressure gauge sender disconnected, and see if that makes a different.

And yeah, I still mean to pull apart my solenoid... just haven't had any time lately :-(

My lines from the solenoids are the same lenght -- I always wonderd about that, because of the pressure difference, but never really heard anyone talk about it, so I assumed it was one of those little things that while technically true, you're only going lean for one revolution, etc. I did have to add a .1 second delay on my lean cut-off to get it to not freak out the very instant I hit the nitrous.

Thanks! Hopefully I have time to jump into it this week.

 

keep us updated

 

Any updates yet?

 

Nope, not yet. My front tires were completely toast (showing belts on the inside edges), so I was waiting to sell off another project before throwing down on some wheels and tires, and was damn busy for a few weeks there, as well.

So, the cars now sitting on 4 jack stands, because I pulled all the wheels and tires off, so I could send my TPMS's to WheelDude.com, so they could install them in my new Rota P45R's. They should be here in 5 business days or so.

So, tune in next week for an update on AbsurdParadox's Lean Car! *credit music*

 

Hey guys, a quick update for ya. I went ahead and moved up to the 75 shot. The dynotune manual suggests: 42n, 24f. As usual, I have to run a larger fuel jet to stay under 13:1 afr -- running 42n 34f. I'm still shooting GIANT fireballs out the exhaust, and letting off after a fourth gear pull and stabbing the clutch will sometimes cause the car to die, actually (too much fuel, I assume). So, as expected, going up in size didn't change much. It still seems like I'm running too rich and too lean, lol.

I pulled the nozzle out, and it all looked fine -- a bit hard to tell if something was lodged way down in it. I haven't had a chance to pull the solenoid off and take it apart -- might here in a few hours.

I got video of a 3rd gear NA pull. Can someone tell me if my AFRs look fine? To my knowledge, this is roughly what they should be: http://www.youtube.com/watch?v=zlSnHC_KEEI (if you're reading this quickly after I posted, the video is still processing, sorry)

Also, I notice a lot of people have their nozzle quite a bit closer to the TB than I do... perhaps that could have something to do with it (see pics)?

Here are some pics of some highlights of my setup, and maybe you might notice something wack that could be causing me to lean out.