First off I've run nitrous on cars before so I'm not COMPLETELY a beginner...

Anyways, I'll give a short run down of my car quick and then what its doing.

Cam only (MS4 cam) ls1 Camaro w/ th400, regular bolt ons, 2 step, NX EFI nozzle kit with the big solenoids, twin in-tank walbro 255 pumps, TSI convertor (stalls at ~4000 with nitrous)...

So had the car together earlier this year, ran 11.9 on motor but wouldn't hold any sort of a shot before it blew through the convertor (stalled at 4000 on motor then). Pulled that convertor out and sent it back to TSI and had them set it up to stall at ~4000 on the nitrous hit... Took the car back to the track last week, car slowed down to a 12.3 @ 113on motor. Went to make a nitrous pass and the car went 11.6 @ 119 on a 150 shot... Meanwhile my buddy with almost the identical car picked up 12 mph in the 1/4 vs. my 6 mph.... The next pass my car only went 117 on the bottle... BTW I was spraying outta the hole with the car.. The car did not seem to run through the convertor, or outta gear or anything, still had room left on the big end.

I'm running a 62 n20 jet and a 33 fuel jet per NX recommendation... Pulled the nitrous line off the nozzle and I'm getting nitrous, and I know I'm getting fuel. Should be a simple setup that should go 125 or 126 on the 150 gun but obviously is not working.

So my question is does anyone have any suggestions, is it a convertor problem or? (a tight convertor shouldn't lose mph, and I don't know what the problem with the nitrous could be causing a loss of mph).

Any suggestions would be great...

 

sounds like the nitrous isnt doing you much good, has your A/F been verified?

 

What were your changes between the two times?

Nick

 

For one keep in mind the weather is not near as nice as it was the first of the year. Did you 60 ft change any?

What is your tune up?

 

Double check your lines, noids, and jets to make sure there aren't any obstructions anywhere.

It may sound stupid but was your bottle full? Nozzle pointed in the right direction? Bottle pressure up around 900psi or better? Double check all the simple stuff first. 9 times out of 10 it's something stupid like that.

 

I'm getting a wideband on the car as we speak, as well as a gauge on my bottle... I guess you can't refine what you can't measure... I will have more info to go off of then. checked for all of the stupids and haven't found any thus far.

Got a fuel pressure gauge on it, and it reads 62 psi, I know thats 3 or 4 high for an ls1 probably due to my dual walbros... Is that big enough out of range to cause a huge problem?

 

i know the jets my kit came with were rated for 55psi... my car runs at 64psi with my walbro setup. So obviously that'll throw things off a bit. But i wouldn't mess with the tune up until you get a wideband and read some plugs!

good luck!