I recently installed a nitrous wet shot system on my car with the jets set for a 75HP hit (41/20). I took it to the dyno yesterday just to see what the numbers were and this is what I got:

Red Solid: Baseline HP
Red Dotted: Baseline TQ
Blue Solid: Nitrous HP
Blue Dotted: Nitrous TQ



I don't have much experience interpreting graphs or knowing how curves are supposed to work, but a couple things seemed odd to me about the dyno:

• Nitrous HP flattens out early in the RPM range while base HP continues to climb.
• This is not shown, but my AFR's for the base pull were low 13's all the way through the RPM range. My Nitrous AFRs started at 13, then dropped to 11.5 (and stayed) at the point where the HP flattened out

NItrous engages @ WOT between 3500 and 8000RPM (I have a 8500 redline).

Nitrous pressure was @ ~920PSI and the bottle was only at about 4lbs full (couldn't get a refill before the dyno )

My non-nitrous modifications are Intake, HFC, and Exhaust. I also have a Hondata Toda Reflash from a while back (going to get a flashpro in the future).

If anyone has any input that would help explain the behavior displayed by these graphs, i'd be greatly appreciative!

 

I like that Tq. curve. Tops out at about 210

ROD

 

N20 seemed to always be about the torque...that's why yours looks like that. Seems fine to me.
I personally wouldn't have it hit till 5k..not 3500. But I don't think youre WOT at 3500 really ever lol

 

The things that's throwing me off is that I'm getting the 70 hp gain when the nitrous starts hitting. But it tapers off at the top and ends up being like a 40hp gain by the end of the gear (hence the low peak hp). I would have thought that it would keep increasing at the same rate all the way to the top.

 

Negative. You have a flat rate of nitrous flow. In order for HP to keep increasing as RPM goes up, you need to flow more nitrous as RPM goes up.

 

It only turns on when I switch the system on. I'd only be at wot at 3500 if I was actually planning on using the nitrous lol.

I set it lower so I could get a longer spray on the initial gear that I start squeezing on. More power under the curve

 

Care to elaborate?

I think I understand the concept, but if it were an issue of applying more nitrous progressively over the rpm range, then I would have expected the HP to taper off a lot smoother. But it flattens out with an abrupt "elbow" around 6100rpm. (This is where the afr incidentally becomes rather rich @ 11.5.)

 

When I ran my nitrous set-up, I definitely started spraying at 5k wot. At this point running my 75shot it eliminated HP drop early. Power for me didn't drop til later in the rpm range. If your gonna stick with 3500 as your engagement point(I don't recommend) then you may wanna change your nitrous pill if your afr permits or opt for a progressive nitrous controller. Also try having a FULL bottle to see if that was the issue.

 

My suggestion would also to be try again with a full bottle, and I started spraying at 4.7k. I was always told much Lower than that was dangerous.

With nitrous, the more pressure you have in the bottle, the bigger the shot will be regardless of the jets in your nozzle. It should stay around 900-1100 psi. My guess is because you only had a few lbs left In the bottle, your nitrous pressure probably dropped significantly after your initial spray. So it probably started as a 75 shot but since the pressure dropped (shown by the AFRs going rich) you had less nitrous in the system than you're expecting so you made less power. When my bottle was at 3-4lbs, I always considered it empty lol

 

Like others have said you are getting a constant flow of nitrous (possibly tapering off even if pressure drops during the pull). Constant flow means you are getting less and less of a hit per engine cycle as the rpm increases. Look into a Nano system for maintaining pressure.