Hey guys, I am in the process of building out my NX kit for my C6 ls3.

I have been reading a lot about the lean spike caused at the initial hit.

I see that NX has 2 kits that will work with my car - one with solenoids mounted at the intake manifold & hardlines to the plate, and one that was made for camaros where the solenoids are mounted on the plate.

Should I be opting for the solenoids on the plate? Will that get rid of any lean spike?

I have a standalone at 55psi for the fuel delivery - not tapping the rail, which should help if the noids were up on the intake mani..

Curious to hear your thoughts.

 

I'm curious as well. I run a standalone 150 shot at ~55 PSI (noids on the manifold) and am seeing a lean spike on the hit. Many combat this by shortening the fuel line from the standalone. Others are triggering the fuel noid 100 RPM sooner than the nitrous (with a 2 stage controller). That is what I thinking about doing since my controller has 2 stages.

 

How bad of a lean spike are you getting?

 

It'll bounce up to 13.5 then settle down to 11.8-12.2-ish. My runs have been quite inconsistent lately. Sometimes rich, sometimes lean...

Does the stand alone fuel press drop much when spraying?

 

It shouldn't drop at all. Do you have a way to data log the fuel pressure?

 

Not currently. I've just been trusting that it works as intended... Sorry to hijack this thread but I do have another question that may be relevant: When I energize the standalone, is it safe to assume that there would be a pocket of air in the fuel line between the fuel and the solenoid? There is no return fuel line so it seems unavoidable. Would this contribute to the lean spike?

 

Did you flow the fuel side? The pressure needs set while the fuel solenoid is open and flowing through the jet you are using.

 

I have not. I'll set that tonight. Going to do some testing on Sat ahead of Street Car Takeover next weekend.

 

I tested the standalone and see a 3-4psi dip when the solenoid is opened. I run the standalone at 55psi. I have since bumped it up to 60psi and I am seeing a more stable AFR. It appears that the AFR steadily richens as the rpms increase.

 

How are you controlling the timing?

 

Lingenfelter LNC-2000.

 

If you're running a progressive that has 2 stages, or fuel and nitrous control separate - you need to play with having a higher fuel percentage vs nitrous on the hit. You also hit on something often overlooked - every time I go to the track, before the first run, always crack the fuel line at the fuel solenoid inlet - vapor/air in that line has had me chasing my tail more than a few times

 

Don't worry about a quick lean spike.
it happens during converter flash and won't hurt anything.
Hard to get around it anyway.... nitrous is at 950psi your fuel is at 60ish or less with low pressure set up,, the nitrous will get there 1st always.. but like i said it wont hurt anything dont waste time or effort trying try"fix" it.... it ain't broke.

 

As long as there is proper timing removed from the tune, going lean like that isn't going to hurt anything. If the tune up is correct, then you can lose fuel during a run and the motor will be fine.

 

Wont hurt anything other than 60' and ET.

When youre in a jet limited class, tune has to be clean hit to stripe. Cleaning the lean spike up or leaving it alone can be a powerful tuning aid on a killer track versus a marginal track. Ive also learned you can over fuel, and it will start pinching the 2nd ring.