I had a similar problem and forgot to change my power enrichment from 5000rpm on my n/a tune down to 2800 or so for the dry shot. By the time I hit the spray at 3500rpm, it couldn't keep me from going lean (like 17:1 once) at 4400rpm. PE value fixed it, but I couldn't get the KR out above 5K rpm unless at 15* WOT!!!!!!!!!!

I have the LPE 100 maf and LS2Edit, which I think was the issue (bad tables, maf sensitivity, etc.). It looked OK on the dyno at 75* temp, but sprayed it once on the street under 60* and it fell on its face with detonation. Finally said screw it and sold the dry kit. Also, I had 47lb injectors and LPE Stage III heads w/ small 224 cam, and I was spraying 12" from the damn MAF with just a 75 shot at 1100psi.

Good luck.

 

My PE should have nothing to do with it. PE is tuned for a solid 13:1 AFR across the board N/A. With that being, when the spray hits, it shoudl not go to 15:1, especially with my nozzles being 3" from the MAF. I think the 12" away is why yours went so lean.

1100 is gettin up there for bottle press too!

 

Yeah, as you and 860 said, I need to go ahead and slap a FP gauge on there. That will rule out fuel supply issue. I have not changed the filter, the car has a little over 20k miles on it and I bought it recently. Could be an original filter. Although the car has little miles, it is now about 6 y/o. I might as well change the filter too. I really dont want to have to add a pump. If I do have to then the stocker must be bad because it should have no prob supplying up to 450rwhp....which I didnt even come close to when I let off at 4400rpm

 

Yep your right. Was looking at the pictures having just got back from the French Quarter in NO My eyes aint as good as they were...wait to you see the magnifing glass mod I to to the NX jet kit I got from ya!

Beer

 

Too dang far. The latest dry system for NX is IN the MAF. Most of Robert's (robert56) testing has shown that closer = richer. My own changes confirmed it. I had them 8-9 inches away mounted in the side of my K&N. Then, I moved them to inside the filter at 3-4 inches away. With a 150 shot it showed 11.8 afr. Unfortunately I don't know what the af was when they were far away but I know it wasn't hitting NEARLY as hard. It had to have been running lean. I was pretty sure my DC was at 92% however I've been trying to find my graphs (getting too old.. memory and all) and don't know where the h'll they are. The DC should have been higher than that according to some of the other threads.

 

Its not too far. That distance should work just fine. However I am sure that when you moved yours closer it probably went richer.

But heres what is likely going on with the original posters setup....especially on the larger vette and truck MAFs.


1 in 10 dry nitrous setups seems to end up like this....way too lean. Half of the dry setup are leaner than I would like to see and are in the 12.5-13.0 range.
Its all about where the center of the stream of the highest density nitrous is centered as it passes through the MAF.
Even though it may appear the dry nitrous fogs the entire path...it has a high density area as it exits the nozzle...especially when its that close to the wires in the MAF. So what can happen....is the majority of the nitrous shoots right past the MAF wires without hardly registering. Just having nitrous go through the body of the MAF is not good enough...it must come into contact with the wires.

The closer you are...the more at risk you are of having this happen. The closer you are the more critical aiming the nozzle correctly becomes because the high density stream is narrower the closer you get to the nozzles exit. It fans out with distance.

The farther away...the more foolproof it is...but the more leaner on avg you will become.

In this case...something about the direction of spray is not allowing the nitrous to hit the wires with enough density. Youll either have to turn the nozzles...or repostion them or both. If you turn them...be sure your line is not twisted....because if you turn the line and nozzle and get it working right...the line will eventually turn back to where it was at a later time and make you lean again.

I would still check out your fuel pump for sure....but generally when a dry shot is lean like this...its all about placement and spray patter across the MAF.

 

after looking at the pics again...it appears the nozzles are aimed at the top 1/3 of the MAF. They probably dont need to be turned..they need to have the angle increased so the top of the nozzle moves aft toward the back of the car. That will make it spray more toward the center. That means youll have to make new holes and tap at an angle. Its best to look down the intake with the MAF hooked up as you place the nozzle.

 

This is my biggest beef with a dry system.Dry systems can be finiky... Adjusting airfuel by nozzle placement is a band aid. The correct way of adjusting air fuel should be from computer tunning. My main concern with adjusting airfuel by nozzle placement is that it is a posibility for nozzle position to sometimes move from engine torque over. If this happens and the system goes lean it can be a huge problem.
Dave

 

just throwing an idea out there i ran a dry kit on an 04 gto make sure your throttle position sensor is reading 100% if it doesnt it wont give the correct amount of fuel as it revs up. i had several tps's that jumped around different precentages on the scanner and ran fine it went lean on the bottle though.

 

As long as you have good fuel supply, here's what I see. Your nozzle location may be the source of your issues. Below is the Known good location for the BlackWing. possibly what's happening is once you get some air flow moving through the intake the bottom area of your spray pattern is being lifted enough to miss the maf wires. I have never seen this spot used before. Coming in on the sides allow a nice even mix with air and keeps cold spray on the wires where it's needed for a good reading to increase your pulse width. This is often the issue with dry, nozzle mis placement, and the resulting dry bashing (please don't take this personaly as I know it's frustrating).

Robert

 

Very good insight. Yes this is often over looked. Set your PE Enable a little bit lower than your bottom rpm activation. I also have my PE Enable set at 2800rpm and activate system at 3200rpm. This also helps with lean spikes on activation.
Robert

 

But what rpm is your PE Enable set to? It prob is not your full issue but rather a contributer and needs to be set correctly if not allready done.
Robert

 

this happened to me on the wet shot, i hit 14.1afr new fuel filter and it was great. thing that pissed me off was the dealer told me they did all of the reguar maintainance before i bought it, but that, plugs and eerything else was all factory...bastards

 

Sent as a PM, but in case other Black Wing users have questions on were nozzles can go.






Hoses are all -4 from the Noid to nozzles (-3 ends on the hoses, custom from HSW)

Be interesting to see if Nozzle postion is the culprit, although I am sure you don't want to make your Blackwing a pincushion

 

Okay this is what I was waiting for...this I believe. And this is exactly why I went ahead and bought Nitro Daves plate conversion kit and am going wet. Honestly, even if I got the nozzle pointed in exactly the right stream to hit the resistor wire inside the MAF just perfectly...I still wouldnt want to live with the possibility of that nozzle becoming slightly turned the next time I change jets, or the next time I take the intake off to clean it, etc, etc. If it is that finicky, then forget it.

Fuel pressure may be the culprit, but these cars can usually support 450rwhp+ stock pump, and from what Ive read, the 01 Z06 (my car) has a better fuel system than the 02-04...i read this somewhere, but im not sure how true it is.

I didnt want to have to monitor AFR and FP at all times with this setup. My goal was a 100 dry shot with the car otherwise stock. My new setup will be wet 100 shot with a FPSS...so I wont need to monitor afr and fp with that.

The one thing I was looking forward to is the ability to tune timing with the dry shot, but oh well, maybe I will do the IAT trick mod and reduce timing with that

 

Again, I believe this. And I had thought about it but I was waiting for someone to confirm it. But again, I think the wet system will be much more reliable.

 

My thoughts exactly. Although I am disappointed, I thought the maf would react a little better than this...I am anxious to receive that plate!

 

FPSS FTW!

 

Keep us up-to-date with the conversion. Hopefully your problem will be solved. Unfortunately, if it is a fuel delivery problem, you could be sending a grenade into the motor. Although 383LQ4SS made a very good/technical case, I highly doubt your concerns of "slightly turned injectors" is going to make the difference between running fat and running EXTREMELY lean. There's gotta be something else wrong.

 

This thing about the nozzles turning somewhere down the line is absolute nonsense. Never heard of this happening. If the nozzles were in the correct postion you have quite a variable before you would be missing the MAF, this has been shown and proven with mucho testing. I have well over 200 hard azz passes and 4 nozzles with no movement what so ever.
It's really to bad you threw in the towel so easily. Similar conditions and problems with a/f can happen to a wet hit also, however, changing jets for a/f can be easier than relocating nozzles to a correct position.
We recently did a dyno of my new dry kit, and a buddy did a dyno of his new plate kit. Well my dry was in the ball park and adjustable that day. My bud's wet went way lean, mid 13's all the way through. He/we did not have the right jets to get it into line. So moral of story, he will be paying for another dyno trip with a hand full of jets. So which is more easy/cheaper to set up, this day it was the dry that was non problematic whereas the wet gave us issues. Also, the wet hit had a nice intitial lean spike (fuel system), and the dry did not.
As for 1 in ten set-ups not working correctly, or going lean. Well I certainly respect Al's input, but this time I totally disagree. What we have been finding is nozzle placement is key, and I have not seen one yet that couldn't be set with proper nozzle location. If the MAF is working for your n/a needs, then it will certainly work for your dry spray needs. Remember guys, 3 to 4 inches has proven to be the location, with nozzles in the neck.
Good luck to ya though, and hope things work out. Keep us updated.
Robert