n2ocamaro

I went to the Dyno Fri. afternoon to see what I have on nitrous and only picked up 20hp on a 100 shot. Everything on the Datamaster log looks good except RPM which looks pretty jagged. I noticed on the pull that the engine seemed to studder briefly in the 4500-5000 RPM range. Almost like the nitrous was turning on and off. I have checked all the lines to make sure there is no blockage. I test fired the nitrous through the foggers into the open air and everything looks good. I had previously tested the complete system to make sure everything was functioning correctly. I am running NGK BR7EF plugs gapped at .034., pulling 4 degrees of timing and 975 psi bottle pressure. The AFR went from 11.1 to 12.4. The set-up is as follows:

TNT Dual fogger kit (no plate-foggers are in the intake elbow)
NOS nitrous filter
FPSS
Dynotune lean shutdown (w/ wideband O2)
MSD digital window switch
Twin intank Walbros

This is on my 12.8:1 comp. 383 LT1 with LE heads and custom grind nitrous cam that made 406hp NA. Click on the link on my sig for pics.
The only thing I can come up with is maybe voltage (or amps) related as my alternator is the original one (129,000 miles) and I am running several extra electrical items (i.e gauges, fan on my tranny cooler, electric water pump, 2 fuel pumps, etc...) Are solinoids voltage sensitive? How many amps do they pull? Anybody have any other ideas?

Jditlfm

iTrader: (26)

i would look into the fpss not being adjusted properly

fstphx

iTrader: (5)

Thats the first thing I was going to ask about as well...
With the lean shutdown... I wouldnt run a FPSS

860 Performance

iTrader: (1)

If your RPM gets messed up on a dyno graph, then thats a good signal that you are loosing spark. (common on high hp LT1's) Probably too much cyl pressure for your ign system.
Close the spark plug gap down to .025 and try it again.

n2ocamaro

Thanks for the tips. I will check both things mentioned. I adjusted my FPSS with a test light awhile back, but I will check it again.

n2ocamaro

Well I finally got a chance to do some troubleshooting. The system is not firing at all. My FPSS is set correct (tested with test light and bypassed), I bypassed the WOT switch... nothing! I hot wired the solinoids to see if they click and they do. When I installed the lean shutdown and wired in the transbrake awhile back, I tested the system and everthing worked fine. So something has failed somwhere. Tomorrow, I am going to replace both relay's.

slomarao

iTrader: (6)

you tried re gapping the plugs?

n2ocamaro

I need to get the nitrous working first. Its not working at all. When I said system I meant the nitrous. Sorry.

n2ocamaro

Well, it was one of the relays. Everything is working now. I will have to do some highway testing with Datamaster and see how everything looks. If everythiing is ok I am heading back to the dyno.