Do I need to run two fuel systems? I guess I could run nitrous only through my nozzles. Would that mess up the nitrous atomization process since I didn't mix with fuel? If I need to run two different fuel systems, do I just need another regulator?

 

That I am aware of, don't you just run the nitrous through the jets and add additional fuel with a larger disk or injectors? Sorry to ask that question on top of yours, but I thought that this is what was always done....

 

Direct port kits are always wet kits. So they have two lines running to them, one for fuel and one for nitrous. The fuel and nitrous are mixed and atomized in the nozzle and sprayed.

The problem with a wet kit is that since they are spraying fuel, they need a constant fuel pressure. With the rising rate FMU, there is almost no way to tune the fuel pressure going into the nozzles. As fuel pressure goes up, so will the amount of fuel being sprayed by the nitrous nozzles. But the nitrous flow won't go up. Obviously this means that A/F will totally get screwed up.

Tony, I've seen people spray just nitrous with their wet kit nozzles. Haven't heard of any problems with it. I think Jime did a dual fuel setup though. He had a separate mini fuel cell to hold race gas. and he bought another fuel pump and factory FPR to control it. I guess you could go that route.

If you plan to get a turbo, it's not such a big deal because the fuel pressure with a turbo is much more consistent. As soon as they hit full boost, 3-4K, the fuel pressure will level off since the FMU is boost dependent. With the SC, the fuel pressure will keep going up until full boost at redline.

 

Thanks for the info Jeff. If I go FI, I don't plan on using that much nitrous. I guess I could just treat it as a dry kit.

 

It is very very simple.

In order to run a wet setup that requires constant fuel pressure, either
A. move the stock fpr AFTER the fmu...
B. add an additional stock fpr AFTER the fmu.

I chose option B, and it's perfect. It works either way, just easier for me to throw an extra factory fpr in there than to make the flange on the end of my rail, and move that.

Here is a diagram I chopped up and recreated, for a wet nitrous on FI car from my website:


Enjoy

 

Thanks Hal...it make sense now from looking at the diagram.

 

It really may not be necessary to run a dual fuel pressure setup for a wet nitrous kit and forced induction. Remember that once the manifold pressure goes positive the fuel pressure HAS to increase by the same amount of pressure in order to flow the correct amount of fuel. This is one reason why the FI setups need boost dependent fuel regulators. Although fuel injection maps can be adjusted to change the pulse width of the injectors to overcome a fuel shortage, the same can't be done on a nitrous system that stays wide open during operation.

In simple terms, your nitrous system needs to see a fuel pressure increase to match the air pressure increase of the intake manifold.