onebentvalve

iTrader: (1)

The title says it all when i run the 42n24f fuel jetting I am getting AFRs from 15-17. I do not have a fuel pressure gauge but I didn't think a 75 shot would tax the fuel system to where I would need a fuel pump. I have a walbro 255 in a housing already modified for our cars off my old z, but I do not feel like installing it unless I need to. I'm thinking of throwing a larger fuel jet in to see how much if any my AFRs change.

Has anybody else had issues like this?

BluestreamDE

You need a tune as in Uprev flash custom to your setup. Installing a larger fuel pump won't make your Injectors spray more fuel and I hope you didn't think that was a possibility. You need to run alot richer with nitrous and that can only be done with a tune.

CK_32

iTrader: (1)

Nitrous is like a turbo in a bottle.

You need to tune your ECU just like any FI set up. Larger pump might be needed if they are maxing out but it sounds like you just haven't tuned your fuel settings yet. Larger pump will add more fuel due to higher pressure. But not in a good way.

That was my problem when I put my 320 walbro, it was pssing fuel but it wasn't able to be tuned until I modified my fuel pump and collector to allow the tuner to control the fuel volume properly.

Also a wet shot will help with lean AFR if you're running dry.

onebentvalve

iTrader: (1)

I am running a wet shot, I listed my nitrous jet size 42 and fuel jet size 42. I was running a wet shot when I got high AFRs. I had a 42 nitrous jet and a 24 fuel jet which should be a well tuned 75 shot for our fuel pressure. My issue was high bottle pressure surging the nitrous into and pooling in the manifold. I got a zex automatic heater to replace the pronitrous one that was cooking my bottle unreasonably. Now I'm getting 11s and 12s on the afr and I'm running a 50 nitrous jet and 30 fuel jet (100 shot). Definitely not new to power adders I had a turbo Miata I seat tuned on megasquirt and rb25det 240 on nistune. Still learning the nitty gritty of nitrous but have a full understanding of the more oxygen/ chemical supercharger concept. My walbro pump has also been modified according to cjmotorsports guide. I have alot of leftovers from my 350z build (g35 is current).

CK_32

iTrader: (1)

I figured you had a wet shot but I just figured I'd cover that if you weren't.

Have you looked for vac leaks? Is your pump with the mod pushing out the proper PSI to the fuel rails? You SURE those are the proper jets? I know very little about nitrous to be honest. But I'm just going to go down the possability list on what could lean out your AFR during a hit.

This AFR reading is this off of a AEM gauge type unit? Or are you actually full logging this while it's happening? New gauges are really accurate but logging a the full data can show you a lot more of what you need to see beyond your AFR's.

Has someone tuned your set up for the hit? Or did you just bolt on and go?

onebentvalve

iTrader: (1)

This setup is very basic. Aem wideband I'm watching during pulls ( I actually have closed road to test on). My issue was overheating/over pressurizing my bottle and getting a n2o surge. It was a combination of an overpowered bottle heater (nitrous outlet) and me pushing the limits of the green zone on my gauge. I got a zex temperature controlled heater that sits the needle exactly on 900 psi which is optimal pressure (living less than an hour from summit racing rocks!) Now my AFRs are perfect 1:12s. I stepped up to the 100 shot 50n jet and 30f jet and it's jamming. As far as wet kits go 100 is in the realm of safety, but I'm addicted and going dry shot on large injectors this summer. I recommend using the dynotune nitrous kit I have. They're very helpful when you call. I will definitely be using them for future setups and will post a full review of my kit expierence. I have right at 600 invested and price point was my goal for my first nitrous install.

I do not have my fuel pump in this car yet and doubt I'll need it until the dry shot. I ran it in my 350z I had before this car.

CK_32

iTrader: (1)

Nice man glad you got it figured out. That would make sense tho.

Why would you run dry shot over wet? I always thought wet was always the better choice.

onebentvalve

iTrader: (1)

By tuning the car's ecu to spray more gas through the injectors when the nitrous is spraying, either by running the injector longer or more open or both and probably through bigger injectors. This is compensating for the fuel that you would otherwise mix with the nitrous at the nozzle. This provides a more even distribution of the mixture.

I am definitely considering going with a dry shot as of right now.

CK_32

iTrader: (1)

Huh always thought wet was more accurate and better distributed.

Learn something new every day. GL with your build man! Seems like you're on the right track already.

Dhoffman

I just installed my Zex wet system 2 months ago and it’s working great. instead of going from a 55 shot to a 75 shot I purchased jets to go to a 65 shot. I would rather creep up in hp then make a big jump. Has anyone experimented with different size jets other than what the kit comes with? Right now I’m running a .021fuel and .036 nitrous. I’m going to Change the nitrous to a .038 to get to 70hp. I know I’m probably being to conservative but I have not got a tune yet. Any educational comments are welcome.

onevq35de

You mentioned a review?

Dhoffman

Ok here is the review finally. After creeping up the ladder of hp with different size jets so far i went from the the 55 shot to 85 shot with nx jets. running a .043 nitrous and a .025 fuel
My Z can’t get enough. I also in stalled an AEM wide band and the a/f ratio are consistant
around low to mid 11’s when spraying. I know im risking damage without a tune.