Analyze my nitrous setup and performance so far

Just sprayed the car tonight. ran good but not as fast as i hoped and i think its cuz its pig rich at 10.5 to 1. I want to get to 12.0 or so.


My setup is 383 sbc with AFR 195's. peak power was found using 34 degrees total timing up top. I've tied 34-39 and 34 made most power/trq. More on that later.
Stealth Ram intake with 58mm TB. Cam is a custom grind 230/245 on a 109lsa, just over .600 lift :)

made 400whp on motor alone and run 11.47 at 118.5 so far best ET. 119.1 best mph in hot air

Tonight i finished up my HSW nitrous kit install. threw in the 150hp jets. Single nozzle system with 900-950 psi bottle pressure like recommended. Jets were .062 nitrous, .035 fuel. Was rich so i went to .032 fuel which is the 125hp shot fuel size. STILL rich at 10.5 to 1. Spraying at 4800 rpm, just before end of 60 foot marker to save that 10 bolt rear :) Baby off the line then traction issues, i managed a 1.65 60 and 10.92 at 125. I was thinking trap speed should be closer to 128-130 in this cooold air tonight.


Timing is at 30 degrees total and i have 2 steps colder plugs with .035" gap.

So does that timing and plug gap look good? I figure i can expect good gains with 12 to 1 air fuel but since the motor has handled alot of timing with NO detonation problems before, i was thinking i could run 32 degreees without problems. I just wanna maximize this nitrous setup


Most ppl run 36-38 n/a anyway, i figure 32 may not be that much. pistons have slightly wider ring gap than normal n/a motor specs, i know the motor can take a shot of nitrous.

I just surprised it was so rich. How far down in jetting can i go on fuel to get it in the 11.8-12.0 safe zone? .035 to .032 didnt do much. I have .028 and .026. those are teh 100 and 75 shot sizes.

ANy thoughts and opinions would be nice :)
http://www.youtube.com/watch?v=ELP88CPWBCM

Post up the whole timeslip!! :) Seeing all of the incrementals helps to see where it's lacking in powaaah.

I run 30 degrees with a .063 nitrous jet...similar cold plug and .028" gap. I consider it conservative because max N/A performance has been 35-38 degrees but it had gains slightly better than your mph. I gained 10-11mph. You could try adding a degree or two as 1 first change and see what happens. It would allow more time to burn fuel and might show as leaner on the O2. Never make more than 1 change at a time. Checking the spark plugs is the only real way to see what's happening in the engine. Even if you only have time to do this...do it...

In the staging lanes, pull an easily accesible spark plug and repace it with a new one..Make the pass, shut the car off once you've slowed down, turn off of the track and pull that plug out...put the old one back in a drive back to the pits. Examine the plug!:) A timing mark should be identifiable on the ground strap...The porcelin should be very clean. The fuel ring down inside at the base of the porcelin should be a faint grey line. Doing this properly should be with all 8 new plugs, etc but do what you can.

Any of my 150 jet passes were all 11.5:1 A/F from start to finish and experienced eyes said the plug looked good and might make more power with more fuel. The bigger the shot, the richer you'll want to see on the O2's from what I've seen.

I like to leave the fuel settings where they are and figure out how to burn it better. More timing, more bottle pressure, more nitrous jet...all of these will burn more fuel(and pistons). Removing fuel should only make more power when you're not burning it correctly.:D hehe

Goodluck!

Thanks. I would think its burning good, as these kits i hear are designed to be extra rich anyway. I'm not sure throwing in a degree or two timing will help much. I guess i could try but i think if i keep the jetting down on the fuel, it will help, its just a little bit surprising to see 150 hp nitrous pill with a smaller fuel jet like that.

i'm near 12.8-13.3 to 1 n/a. So being that rich means alot of fuel is in there. I was gonna try the .028 jet to see what happens but i guess i can try more timing to see if the car takes it.

Was this thing designed to run at your specific fuel pressure? Maybe the kit was designed for 40-45psi and you're running 60+?

You won't see 62/62 square jetting unless you're at 5.5-6psi fuel pressure.

62/35 should be 40-45psi roughly
62/33 would be a 55-60psi tune.

These are close to what NX reccomends and they are considered safe but they should definately find more than 6-7 mph on a 150 jetting.

Timeslip incrementals will let us see MPH gains, etc and maybe driveline issues...converter slippage or trans slippage..

ok i'll post the slip info but i can tell you for sure first gear spun when it hit, and second started to hook and my 60 foot i walked it off the line, you can see in the vid. I wasnt sure how the rear would react to it, its still a stock 10 bolt :(

i am running 40 psi idle, 46 psi WOT. kit is rated 150hp at the wheels for 45psi fuel pressure, 950psi bottle pressure. thats where my heater shuts off, around 950. So i have the right stuff for the kits rating

Its a Harris Speed Works kit.

im now at 62/32 and about 31.5 degrees timing, only pulling 2.5 now and it works. around 11 to 1 air fuel, so its getting a touch better. I may try full timing and see whats up. I dont think it will hurt.

I just want to maximize this shot. right now it seems as if i'm only getting a 100shot out of this.
I have heard of ppl running 75 shot fuel jets for 150 shot nitrous jets so i was thinking it may want that
Timeslips

Keep in mind the right lane run is not correct mph wise, its 4 low in the 1/4. not sure why

run 1

1.65 60 foot
4.58 330
7.03 at 100.47 mph 1/8th
9.138 1000 foot
10.92 at 121.5 mph 1/4...should be more like 125 since the other runs the same way

next run, i shifted and hit limiter and spun worse. car got squirrelly

1.656 60 foot
4.72
7.21 at 99.2
9.34 1000
11.14 at 125.35 1/4

last run
1.61 60 foot
4.56
7.03 at 99.65
9.16
10.96 at 124.97

I'm not an expert by no means but I will throw this out there.. Try a little higher bottle pressure its propbaly droping pretty good on the big end causing your rich condition.. Just a thought ..