Hello guys,

I'm new to nitrous and need some help with a small 100hp dry shot.

318ci on E100. Runs 0.85 lambda NA with 32 degrees of total timing.

My EFI has progressive controller for the dry nitrous so want to go 30%@3000 rpm > 100%@6000rpm.

Know this is just a small shot but I'm concerned with my 12:1 hypereutetic pistons. Can pull some extra timing to avoid detonaton if this is the case.


Should I pull lets say 10 degrees of timing to start the tune and them adding some timing back? Something about 0.75 lambda should be in the ballpark?

What about spark plug? I have AP5 AP7 and AP9. Using AP5 on NA.


Car is 3500lbs, 3 speed stick, 4.88 gears, 240/248@.50 cam. 280hp@5500 331ft torque.

Best 1/8 so far is 9.2s with 1.90 60". Want to go low 8's with the shot.

If your efi will add the extra fuel i wouldnt worry about the timing if your at 32, im running 35 total and spraying 150hp no problems, motors been running 10 yrs. Hit a quick shot pull over and check the plugs.

as crlush stated. you're running such a small shot that you shouldn't have to worry about your current setup. just check things after the pass to be sure.

Should I pull lets say 10 degrees of timing to start the tune and them adding some timing back? Something about 0.75 lambda should be in the ballpark?

I'm no N02 guru but I think you've got it wrong way around, @30% N02 hit you pull a bit out, @100% you pull a lot out not put more back in. The more efficient the motor is as in you add all the shot the more timing you pull out, thats what kills N02 motors Timing, not lean. On a small 100 shot its not quite so important than say a 250+ shot. Timing does not make power, its your combo that does. If your too rich on the tune it'll take more timing but you won't make the power you could with a "clean" tune and timing out. You could try something like 2 out @30% and 8 out @100 note your mph and put a little back in and see you if you mph better, if not pull more out, trial/error with each set up to get the sweet spot.

Sorry, I wasn't clear in my explanation. My EFI does progressive on nitrou s solenoids. Not timing. Timing will be pulled just once. As nitrous engage timing is retarded.

So to be very conservative... I was thinking in pulling 10 degrees... but rethinking now... maybe it´s too much for such a small shot. I think to pull 6 degrees is ok them I´ll check everything spark plugs, WB O2 sensor and all the logs.

I already tryed today without the juice on and cn see the engine doing the enrichment getting very rich (due to lack of nitrous), timing being retarded once nitrous is on and solenoids engagement ramping up. Everything set. Just need to buy a refill.

Just want to know how much would be too rich? And what about spark plugs heat range?

Br,

10 is a lot of timing to pull for a 100 shot. I'd think something in the 4 range might be better and closer. Better to be safe and sneak up than sorry, especially with hypers.

Running them rich KILLS them too. Generally, wherever the engine runs best at WOT, you want the same basic A/F when on the N2O.

This is what happened to a friend piston hitting 150hp. What do you think went wrong here?

You don't spray KB hyper utectics(sp)

I sprayed 150 shot on my demon with KB hyper pistons 100's of passes and never had a issue. I even tried 175 a few times. I always turned my timing down to *28 on pump gas and make sure you read the directions about ring gap.

Repeat after me 10 times: "make sure you read the directions about ring gap"

Been spraying my kb hyperutectics with 150 shot for years, never had a problem, freshened it up around 8 yrs ago and they looked great. What motor is the cracked piston out of?

How much of total timing, fuel and AFR?

Br,

35 degrees, 6psi on nitrous pump, no afr just read plugs, 340ci

Hello guys, just used my first bottle. Using a #51 nitrous jet and the dry setup on E100. Everything went fine. My tune still on the rich side. 0.74 lambda at 100% nitrous @WOT. i'm looking for 0.78-0.8 range. So will increase jetting to a #62. I'm retarding 5° and total timing is coming from 32>27°. How do I know that I can add some time back? I can't see much difference on spark plugs. Everthing looks fine. Also as I´m using it progressively.. I couldn't feel a big improvement in horsepower on the street. Next tune I'´ll do it on the strip. Br,