Post by
C-Kwik »
https://forums.nicoclub.com/c-kwik-u426.html
Sun Jul 06, 2003 5:43 pm
8 psi is getting a bit hairy. Ultimately, its going to depend on two things. 1st, the pressure the pump can provide at the needed fuel flow rate. 2nd, the ability of the injector to overcome the high fuel pressure. If you keep adding pressure, at some point you won't be able to open the injectors. As far as 12:1, being way too much fuel, it depends. Even with an 8:1 FMU, I doubt you will see a full 8:1 rise at 7 psi as RPM's rise. It will probably level out at some fuel pressure. And from that point on, the pump will provide the same amount of fuel regardless since it can't supply any more pressure. The 12:1 will just get to that point earlier. And being that even an 8:1 FMU will run mostly rich, the 12:1 will just be overkill.
I would try to keep that ECU and injector set-up you have even if you go to the NSport kit.
And I have a couple of recommendations if you get the Nsport kit. See if you can get a hold of a T04E-50 trim compressor section instead, especially if you are looking to increase the boost in the future. May cost a bit more, but will be more efficient at higher boost levels.
Second, before you install the NSport/Revhard Manifold, do some major prep work on it. The ports will not match the ports on the head. You will need to do a little bit of port matching. If you have an air powered dremel, it will go quickly. An electric dremel may take some time. Also, remove the cast flashings(Seams right where the two halves of the outer mold meet) and any sharp edges, particularly in the structural areas. These are places where cracking is most likely to start. Enlarge the holes where the studs from the head fit. The outer ones should be widened a little more than the inside ones. I actually had to do this just to get it to fit in the first place. Cut the mani to head flange so each port has it's own manifold(similar to the way the FMax mani is cut). And lastly, inspect inside each port carefully. I recently replaced my RevHard due to a major crack along a prior repair weld. I found some kind of a strange rod inside one of the ports of the new mani and had to remove it. I didn't prep the first one completely due to some other concerns, and I would have had it repaired except the crack went all the way through the wastegate flange. I would have taken pictures to show details of what I mean, but I had to get all the prep work done and the system assembled in less than a day. I did all that I mentioned above, and I'm sure it should go a long way in preventing any cracking in the future.
Or you could wait 2 more weeks, and I can give you my result on accurate A/F ratio on 12:1@4-5psi. 
