How are you guys wiring up your FPSS? Where is it place in the scheme of things?

 

i havent used a fpss in 6 years,got tired of the surging/not working because of them.

 

I wired per NX instructions. I did have some surging issues. NX instructs that it be wired in a manner to cut out the relay which in effect will shut BOTH solenoids down in a wet kit.

In theory if it was wired to ONLY cut the nitrous noid and not the fuel noid it would work with less surging due to the fact that a pressure build/drop loop would be avoided which is the cause of surge.

However, for whatever reason NX engineers want it wired to cut out the relay per their included wiring diagram(either the ground on the relay or wired in series with the WOT switch)

IMO, i ditched mine it was more problems then help in my experience. I haven't looked back.

 

I've searched a few threads and it looks like a lot of n20 users are ditching the fpss.

 

Maybe it is just the NX FPSS...

 

I ditched mine.. I am using NX too.

 

A friend of mine uses the nos fpss on a carb plate setup running a 180 shot with no surging issues. Maybe more people have fuel delivery issues than they think...

 

To summarize, this is a very rough guess but the NX FPSS seems to not be ideal while the NOS FPSS seems to be problem free. Perhaps someone should start a poll?

Also, I'm wondering what types of pumps people are running (both with surge issues and those running smooth).

 

Walbro 255lph intake pump new fuel filter too.Plus the car never goes lean from the O'2' readdings.

 

How is your fuel regulated or is it a dry kit?

 

i wouldnt trust the air fuel gauge if it's hooked to the narrow band O2's,they get ignored at WOT anyway.

i read my plugs,and my car hasnt gone lean. never used a fpss,all they are is Hobbs switches,i have seen the NOS and NX 1's,and they are identicle.

 

Ditched the FPSS.

 

My switch is installed just upstream of the fuel solenoid, and only shuts off the nitrous solenoid. No problems with it. It's a NOS branded FPSS - if that makes a difference.

Dave

 

Interesting... so there are three possibilities for surging.

1) Brand (NX vs. NOS) - NX seems to surge more
2) Fuel System Upgrades - Improved fuel pumps and/or injectors
3) Location of the FPSS - on the fuel rail or near the fuel solenoid

This is based off of our few inputs but perhaps we can find a solution for this to make it work as intended.

 

This might help...

1)Surging occurs when your FPSS is set to high back it off and you will most likely fix the problem.

2)Surging can also occur if you ground your solenoid through the FPSS, this happens because the FPSS is not designed to handle the amperage a solenoid puts out. Ground the relay through the fpss. This could also fix your problem.

3)If im not mistaken all FPSS are manufactured by someone else and NOS and NX put there name on it.