my 95 Z is a completely forged 355, has wider ring gaps and a 224/230 on a 114lsa, with 10.8:1 compression so its nitrous friendly, i currently have a dual stage nitrous setup, 125 a piece. i wanted to up the shot a bit for next year, but whats a safe level? this may sound like a lot but can i do 175 per stage? or its this just ludacris? im more worried about the motor than the drivetrain as i have a fuilly built 700r4 with a manual valve body, 9 clutch packs per gear ect... and i have a 9 inch vigilante with baloon plates. thoughts?

 

although you did not mention the type of head or portwork you are using or the rear end you have to handle the added stage, i would say the amount of spray will be fine you should be happy with the performance for sure,TAlt1 in louisiana has a 175 and has gone in the 9s on a stock rear but i am sure it is only a matter of time

 

175 perstage really depends on how the bottom end is built? It deffently goping to come down to the tune up. Make sure you have enough fuel delivery.
Dave

 

My 2 big worries would be main caps (you didn't mention them) and your fuel system.

 

Another thing to worry about is the 9 disk clutch pack you are planning on using...

The idea is OK, more clutches = more holding power.. But to get them in there they have to make them very thin, thin metal + high temps = warping quickly under the power/tq you are looking to throw at it. I would advise looking through the drivetrain section about this...

 

Some things that will be important to think about:

How much timing are you running?
What spark plugs?
How far apart are the two stages spaced? How high in the power band?
What ignition are you runing?
Where are your nozzles placed? A 350 shot worth of fuel is a lot to take through the throttle body. You may also end up with lean cylinders.
What does your fuel system look like? Pump, lines etc?
What octane gas are you running?
What size primary line are you running to the solenoids? 4 or 6an?
What size bottle? 10 or 15?

You need to consider all of these things. Sorry if they are basic, but you never know what someone else is thinking.

 

sorry its a walbro 255 pump, both jets spray through the throttle body, the tranny is already done and in the car. i run a malory digital ignition, i forget how much timing im giving it off the top of my head, but i do plan on having it tuned out. the crank, rods and pistons are all forged, i do believe its still a 2 bolt but has ARP bolts. the heads are stock except for some ferra valves. i am getting new heads for it in a few weeks, and a matched cam. im not worried about streetability, this is my "race car" i have my SS to cruise on the weekends forgot to add its a 10 lb bottle but i cary 4 bottles with me. fuel lines are stock but are being upgraded.

 

2 bolts will start to be a concern at these power levels....
A single 255 pump is not going to support this big of a shot. Esp through the throttle body. I am surprised you were running 250 off that 1 pump. I wouln't go much bigger than 200 wet on a single 255 pump.

 

how is a 255lph pump not big enough? i figured a 255 was plenty because you can run a 255 in a DSM push 30 psi on a 1:1 ratio, but if i need a bigger pump ill run a bigger pump

 

255s max at around 650ish hp. A 300+ shot had better put you in this range. A 255 on stock fuel lines will make for a BIG lean spike on a 300+ shot. I personally would not run a 300+ shot on just a 255 intank.

You may also be looking at problems trying to run a 300+ shot through the intake. I have personally seen many LT1 and even some LS1 cars puddle and pop on just 150-175 shots. Nearly doubling the amount of fuel compared to those shots is just asking for a backfire.

Another problem you will likely run into is distribution problems. Right around 225shots LT1s start to lean out the rear or front cylindars. Breaking spark plugs and then ring lands are a good possibility.

As far as your motor:
2 bolt mains aren't the best for a nitrous motor. I would look into spacing your stages apart and higher in the power band. Maybe 3500 and 4500 to keep the stress down on the motor. More space between stages will also help compensate for lean spikes. Timing and spark plug choice should also be looked at. To much timing and or to warm of a plug will lead to detonation. Run race gas too.

 

I'd be suprised if the 700r4 makes it a year even with occasional nitrous use at that hp level. You'll be hitting it with some serious torque. I went through 2 supposed bullet proof 700r4 rebuilds from a reputable builder, before switching to a TH400. I ran a 200 shot, then 250, then 300 (two stage system) through the TB over the course of 6 years in a 10:1 pump gas 383. The majority of the time I used 2 nx nozzles and a seperate fuel system for the nitrous. I never had a problem with fuel puddling or backfires with the nx setup, but I ran either a 3200 or 4000 stall during that time. I did have lean conditions in the front and rich conditions in the back cylinders though. On my current build, I'm switching to a progressive direct port, to solve this issue. I suggest you look into a DP system as well, or aleast switch 1 of the 2 systems to DP. Talk to some of the supporting nitrous vendors, I'm sure they can give you some advise and direction.