car surges when using NOS

I recently filled my bottle and went for a ride. I haven’t used nitrous for about 6 months. When I squeezed my car surged on and off with power. I haven’t done anything to my car during the 6 months of not using NOS.

I have also noticed a low RPM miss when I bog the car down that has recently surfaced. If I short shift from one gear to the next and floor it my car misses under 2500 rpm (off the bottle).

Here’s my setup:

Crower 62403 dual springs/ti-retainers
milled head (10:1 comp)
Cam gears/pullies
Clutch specialties stage II clutch
NOS dry EFI kit (jetted at 60hp)

I dynoed 149hp to the wheels 3 months ago (off the bottle), but recently dynoed 139 so in the last 3 months I have lost 10 hp and my car misses at low RPM. Any ideas, I have changed plugs, checked wired, changed oil, and that’s about it.


have u done a Compression or Leak Down test?

Make sure your jets are CLEAN. When you haven’t used a nitrous system for a while the chances of something getting in there are better.

You may want to check your compresion/leakdown

Even though i don’t have NOS I have always been told to nevr use it under 2500 rpm. Can do bad things to your engine. Too much nos per stroke. Maybe that is what did it.

Check your plugs, if they are not melted or have little tiny grey specs on there, then you are fine. Even if your car was running on three cylinders, nitrous would not cause the car to surge unless there was a problem with fuel or nitrous delivery. (more likely your nitrous line or jet is clogged.) Purge your nitrous line really good. You want to also make sure the bottle pressure was good, aprox. 900-1100 PSI. If the bottle is cold, then you’re not going to get good pressure and your going to get surges in pressure from your nitrous feed.