Oh yeah! Nitrous for the win!! :D

Quik LS said:
I always though the you should tap the fuel line before the pressure regulator - so that the regulator's attempt to keep 40psi at the injector nozzle is not interferred with by another fuel flow.
Click to expand...


It can cause a slight lean spike when the nitrous hits, the fuel solenoid opens and pressure starts dropping until the pump can catch back up with the demand.

That was the exact reason why I tee'd into the stainless steel fuel line halfways under the car so that any fuel pressure disruptions would have a much longer time to even out before getting to the fuel rail. It wasn't really necessary for me to do that but I pay pretty close attention to detail with things like that.

Tapping into the fuel rail crossover or even using a tee'd FRPT spacer block to get fuel from is widely practiced without much issue. I would not worry about the crossover being used to pull fuel for the shot. Provided that is isn't leaking then all should be well there.
 
To the OP. When you wired the TPS and RPM input did you fully solder and then use shrink tubing or other good insulating material?
 
ILLS said:
To the OP. When you wired the TPS and RPM input did you fully solder and then use shrink tubing or other good insulating material?
Click to expand...

Negative, I brought the heat shrink but didn't have soldering equip.

I used a t-tap.

But my tps is unrelated.. :rolleyes: I hope.

Oh, no RPM input on the Zex didn't buy a controller either. Maybe in the future, but we have to get there first. I got aways to go before I can enjoy the benefits of spray. :(
 
UPDATE:

So I pulled the Maf out and I was planning on blowing it out with some filtered air from a compressor.

Needless to say I started it without the MAF and it ran no different, but this time a code pulled showed the MAF sensor voltage was low.

So I am extremely confused as to what the other code means, the "Manufactuers Air/Fuel metering" one. What else meters air besides maf, and what else meters fuel besides injectors. One reading from the other.. :confused:
 
Quik LS said:
I always though the you should tap the fuel line before the pressure regulator - so that the regulator's attempt to keep 40psi at the injector nozzle is not interferred with by another fuel flow.
Click to expand...

if you do that, you will have an unknown (too high, and possibly constantly changing) amount of pressure at the fuel solenoid and flow too much gas. it would be hard to get a good nitrous/gas mixture. since the jets are determined by fuel pressure, its best (and easiest) to tap into the system either on the schrader valve or crossover tube. By having it after the regulator, the car can monitor and quickly adjust when the fuel solenoid opens. you would also still get a pressure drop (espec. on larger shots) if the solenoid was before the regulator and it may have to adjust anyway.
 
Really?

On our large shots - 250 - we ran it from a seperate fuel pump right form the tank. Not connected to the car's fuel system or car's regulator at all....
 
i think thats the best way to do it, having a dedicated pump. But i would guess you still need to know the pressure you're delivering to the solenoid. You're going to flow more or less fuel based on pressure, similar to how the nitrous bottle will deliver more or less nitrous based on bottle pressure. with the dedicated pump setup, you're unlikely to get a pressure change since you can ignore the rest of the car so you may be able to measure the pressure you get, and dyno tune the nitrous to match it.
Rob was right in that you will see a slight lean spike on the initial trigger, but i think you will see that in any setup that pulls fuel from the car's system. IMO you may as well go after the regulator so that the car can adjust its mixture.

and yes, i can't wait to see what Hotness overlooked. we all do bone headed things (like thinking its a good idea to play with the fuel pump module) :)
 
what kind of person post a thread like this and dos post the FIX..... come on man what was it...

I need to know...

I think ILLS is right about his TPS hook up... very temper mental sensors. not connected completely, will screw the system all to hell
 
In regard to the fuel for N2O system, you can get a good look at how to do the plumbing by looking at the pictures in the 'Land Speed LS' thread in the performance section. Pictures are at #11. Ask any questions you care to.
KS
 
Yes yes very bone head. doh! Smart people do stupid things sometimes.


Anybody have the part number for the NGK's handy only 1 heat range colder?
 
The nitrous solenoid not emitting fuel should have been my first clue... Now thats a duh.

In my troubleshooting conquests last night I decided to take the nitrous fuel line off the main t and crank it over. Even ran it for a moment, and to my surprise no fuel. :eek:

I removed the T and looking in the hose, I see two homemade filters. Crap. It appears by inserting the T into the plastic line hose that whenever you twist it, it jammed it further down inside. This occurred on BOTH sides of the T so a double "filter" hahaha. IF nitrous wasn't getting fuel, neither was the entire 1st bank.

So long story short, replaced the crossover line and she runs beautifully. :cool: Better than before I am pretty damn sure!

So today, new plugs and an oil change :D

02LincLS said:
i tapped the crossover line for fuel as well but i replaced the whole hose with fuel injection hose. not sure how you did that without replacing the hose- its plastic inside.
Click to expand...

:D You are the winner! :D

Thanks for the help guys.




and oh for the record, my car ran with no MAF AND no fuel to half the motor.... I am really lucky on this one!
 
l_eb1de0aeaee44b818fa0fec3d98da334.png

l_481d0cccfa4641eb8cf37f62e569ae7e.png


Here's a couple of "the" hotness hahaha
 
02LincLS said:
if you do that, you will have an unknown (too high, and possibly constantly changing) amount of pressure at the fuel solenoid and flow too much gas. it would be hard to get a good nitrous/gas mixture. since the jets are determined by fuel pressure, its best (and easiest) to tap into the system either on the schrader valve or crossover tube. By having it after the regulator, the car can monitor and quickly adjust when the fuel solenoid opens. you would also still get a pressure drop (espec. on larger shots) if the solenoid was before the regulator and it may have to adjust anyway.
Click to expand...



Not quite in a PWM returnless fuel system. The absolute fuel pressure is changing all the time yes but that is not what the engine is seeing. The engine is seeing the desired injector delta or real close. The reason for this is because the fuel pressure has to be in relation to manifold pressure (or vacuum). In relation to manifold pressure the computer attempts to seek a set pressure drop across the injectors (injector delta). It does this by comparing the manifold pressure against fuel rail pressure which is why it has the FRPT (fuel rail pressure transducer) which compares the two by sensing direct rail pressure and then having the vacuum nipple that connects to the intake manifold sensing MAP. This sends a signal to the PCM which then interprets that into a duty cycle. Then it looks up what flow and pressure it will need to meet that. The PCM cross references those values in the fuel pump voltage table and comes up with a voltage to send to the pump to get the desired injector delta. This happens many many times a second. What that means is that when the fuel solenoid on the nitrous system opens and starts releasing fuel into the intake via another path besides the injectors then the injector delta will drop for a split second. Then once the FRPT see's this it will recover and then remain stable again.

In an electronic returnless fuel system there is no "after" the pressure regulator. There is only before. How far before the FRPT and injectors you tap into the fuel line will determine what your lean spike will look like. The farther away from those items and the smaller and more gradual the spike will be because the momentary pressure drop will get absorbed by the surrounding higher pressure and tend to even out.

Allot of technobabble, trust me I know. But it is sort of necessary to explain how the fuel system seeks a given pressure drop to understand what works and doesn't work when tapping fuel for nitrous. Knowing why it does it that way is also important too. Sorry for the fuel system dissertation guys.
 
The Hotness said:
I removed the T and looking in the hose, I see two homemade filters. Crap. It appears by inserting the T into the plastic line hose that whenever you twist it, it jammed it further down inside. This occurred on BOTH sides of the T so a double "filter" hahaha. IF nitrous wasn't getting fuel, neither was the entire 1st bank.
Click to expand...



Darn, and I had my vote about to be cast for replacing the MAF sensor in backwards. If you have a CAI with the filter adapter bolted on the flange of the MAF then it is not hard to do if in a hurry. Don't ask me how I know about this. a "friend" had it happen to him one night when he was tired and in a hurry to button a vehicle up so that he could tune it. ;)
 
ILLS said:
Not quite in a PWM returnless fuel system. The absolute fuel pressure is changing all the time yes but that is not what the engine is seeing. The engine is seeing the desired injector delta or real close. The reason for this is because the fuel pressure has to be in relation to manifold pressure (or vacuum). In relation to manifold pressure the computer attempts to seek a set pressure drop across the injectors (injector delta). It does this by comparing the manifold pressure against fuel rail pressure which is why it has the FRPT (fuel rail pressure transducer) which compares the two by sensing direct rail pressure and then having the vacuum nipple that connects to the intake manifold sensing MAP. This sends a signal to the PCM which then interprets that into a duty cycle. Then it looks up what flow and pressure it will need to meet that. The PCM cross references those values in the fuel pump voltage table and comes up with a voltage to send to the pump to get the desired injector delta. This happens many many times a second. What that means is that when the fuel solenoid on the nitrous system opens and starts releasing fuel into the intake via another path besides the injectors then the injector delta will drop for a split second. Then once the FRPT see's this it will recover and then remain stable again.

In an electronic returnless fuel system there is no "after" the pressure regulator. There is only before. How far before the FRPT and injectors you tap into the fuel line will determine what your lean spike will look like. The farther away from those items and the smaller and more gradual the spike will be because the momentary pressure drop will get absorbed by the surrounding higher pressure and tend to even out.

Allot of technobabble, trust me I know. But it is sort of necessary to explain how the fuel system seeks a given pressure drop to understand what works and doesn't work when tapping fuel for nitrous. Knowing why it does it that way is also important too. Sorry for the fuel system dissertation guys.
Click to expand...

Quik sent me an article someone wrote on the returnless system and I didn't quite get it but that makes sense now after reading your explanation. I guess the car adjusts quick enough for these shot sizes though. So if I wanted to log a couple runs to look for the length of time it takes to correct, what values would i capture? fuel rail pressure, fuel pump duty cycle...
 
on fuel I usually log:
Long_term_fuel_trim_bank_1
Long_term_fuel_trim_bank_2
Short_term_fuel_trim_bank_1
Short_term_fuel_trim_bank_2
pressure_drop_across_fuel_injector
fuel_pressure
fuel_pump_dutycycle (i think it's called)
 
the returnless fuel system basically drives the fuel into the end of the far (passenger) side of the fuel rail and then build up pressure, adding fuel as the injectors let it out.

so my worry about tapping into the line between the rail (for the fuel feed of the wet system) is that you can draw back some fuel from the far injector (cylinder #4) since all the fuel getting to is going past the regulator and then past the fuel tap off, what's left is then making it to the passenger side rail.

Tapping the fuel line before the regulator seems to allow less disruption of the flow across to all the injectors.
 
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