ZEX 82011 Questions

[bby_evo]

I have a dry kit (82011) and I am interested in knowing what the fuel pressure increase is supposed to be. I have 36f and 32n2o jets, a 55 shot. How much will the NMU increase pressure. Stock is around 43psi. I know a competitors kit will jump to 60-70psi when n2o is activated. I just want to make sure the increase is great enough so I don't run lean. n/a I run a tad rich with 275cc injectors. If the NMU can increase the pressure as high as 70 psi then my flow should reach a peak of approximately 350cc/min which would be adequete. Any help would be great. (inj. rating of 275cc/min is at 43.5psi; approx. increase found utilizing inj calc. on rc fuel inj. web site)

[amick]

Well there is not an exact answer to your question. Fuel pressure increase will depend very much on what engine and fuel system the kit is attached too and how much pressure is in the bottle. Our kit will adjust the fuel pressure depending on what the PSI is on the bottle. To give you an idea it could increase any where from 15-40psi depending on the setup. Our jetting is designed around stock injectors, fuels system, and fuel pressure with the dry kits. If you have changed any of these then really you should tune with a wide band to customize the jetting to your individual setup. This will be the most accurate way of tuning in your combo. I hope this helps.

[turtleman]

Does the bottle referencing factor change fuel pressure differently with different jets? In other words, if you have 75hp jet pair, is the bottle pressure going to be able to make a potentially bigger difference in the actual result fuel pressure than if you are running a 55hp jet pair (because the fuel jet is smaller)?

To help understand my issue, here's what I'm trying to do.
I'm running the 82011 dry kit but I have a maf controller to add fuel. (I feel it's more accurate and my fuel pump is already pretty high on PSI stock - not a ton of room for increased pressure) So with this, I could just leave the NMU completely out of the fueling part but I really want to use the bottle pressure referencing feature. So what i was thinking was to use the most neutral fuel jet I can (maybe a 38?) and basically tune the maf signal editor to take over on the fueling beyond that. At that point, I'd use only the maf controller to tune or change my shot size.

[amick]

If I am understanding your question correctly you are asking if you can run the samller fuel jet and the use the MAF to adjust for the rest of the needed fuel. If that is corrcet then yes sir you could.

[turtleman]

It's tricky to explain and I'm bad at explaining things so sorry.

Let's say I'm running a 75shot or perhaps bigger nitrous jet. Of course I can tune for that completely independently of the NMU's adjustment but here's the thing. If I use a fuel jet that makes a very small change relative to the nitrous jet, will that make the bottle referencing feature less effective because I'm reducing the metering affect of the NMU?

Here's the scenario I want to avoid. I tune it perfectly at a certain bottle pressure. Then bottle temp changes and my tune is way off because the majority of my fuel compensation is happening over the NMU's head by the maf signal editor that does not reference bottle pressure.

[amick]

No sir it will not lessen the metering effect of the nitrous system.

[turtleman]

What would be the proper way to disable the fuel pressure adjustment side of the NMU so it's effectively just a nitrous solenoid? I have a maf calibrator for the nitrous and apparently the 80+psi the NMU creates is blowing up my fuel regulator diaphragm.

Originally I was thinking just leave the two vacuum fittings disconnected but then that would make a huge nitrous leak at the NMU every time I sprayed, no?

[amick]

You could simply pull the fittings out and put pipe plugs in the ends to close it off. This would completely do away with the NMU fuel pressure adjustment and cause no adverse affects. Of course you would have to have some other way to get your fuel enrichment.