dedicated fuel suply for NX; questions

[otter1363]

dedicated fuel suply for NX, running lean....

So I am considering a dedicated fuel supply for my nitrous set up and have a few questions maybe some can answer. I currently run a nitrous express wet set up (150 shot) into a taped T/B spacer. I currently pull fuel from my supply line before it hits the rail.

I assume by adding a dedicated system to my wet set up (using race fuel) I could add a bit more spark - right?

considering building a set up as opposed to buying one off the shelf. While I have never really put a fuel system togeather before I think it should be pretty straight forward. 1gal tank, in line pump, filter and regulator. What PSI pump would I need and what PSI would I regulate it to?

A -6AN line would be sufficent for my set up?

I dont know if I would need a return line or not?

Any input is appreciated...

Click to read more...

 

[madscientist]

you can check out the kits on the nitrous outlet website to see what all is included, also i have ran bigger shots than that with only an upgraded pump

 

[otter1363]

Not so much a concern about being able to supply the fuel, rather looking to add more spark to my nitrous tune.

 

[CrunkMaro]

Not so much a concern about being able to supply the fuel, rather looking to add more spark to my nitrous tune.

stand alone will let you run a higher octane in the dedicated fuel supply which will allow you to get some of your timing back and open up more options for tuning.


as far as pressure, use high pressure, less chance of lean spikes.

as far as the system, i would use an inline pump, nothing outrageous, a normal walbro inline pump should suffice, use a fuel filter/regulator off of the 03+ vettes (the regulator is built into the filter) and then you can run the return right back off of the unit into the tank.

might want to put in a relief valve at some point just so you can get fuel out of the line if you don't use it all.


thats just my .02

 

[otter1363]

Well, finally got all the parts for the system and messed around this weekend putting it in.

Gutted fenderwell and bent some aluminum, reinforced with a small amount of steel

Pump installed

Bracketing for the washer tank, overflow and the fuel cell.

Aluminum Cover

Finished with a top bezel plate

Ran some lines

Finished...

 

[Runtz52]

thats a clean set up, i like it alot. been thinking about doing something similar with my pacer, so i can have a separate tank for race gas

 

[CrunkMaro]

the things i could do i had that much room in my engine bay...

i'm always thinking in terms of 4th gen fbody, everything has to mount in the rear :-/


clean setup. should be a killer. are you going to use 110 for the dedicated fuel system?

do you have a methanol system as well?

 

[otter1363]

Thanks guys - Yeah pretty nice having a boat load of space for installs. Gonna run race fuel and see if I can get away with adding a degree or two of spark back in. No Meth...

 

[otter1363]

Been to the track a couple times with this new set up. Keeps runnign lean. I have a safety feature in my controller (thank goodness) so it cuts it off when leaning out. I bumped the fuel jet two sizes and tested it with a small 35 shot. A/F was fine (11s) so I dialed up a 75 shot this weekend at the track and back to lean again. Put another fatter fuel pill in - still too lean. Dont have any more jets so I started adding fuel via my tuner, like anothert 8% and still too lean. Gotta pull some lines I guess and see if I have a blockage.

Just didnt think I would have this much diffrence. Using a 60PSI pump...

 

[Yaj Yak]

very cool set up tho

 

[otter1363]

Just seems odd that I jump 3 jets with a 60 PSI system and its still too lean.

 

[Sinister Drag Designs]

Also might want to check that your fuel solenoid is working. On a 35 shot it didnt go super lean because of the size most likely. Did your AFR get any richer with the larger fuel jets? Sounds like its dead or not getting power.

 

[otter1363]

Ok, so I pulled the fuel line, fashioned up a fixture to hold my #38 fuel jet and put the pump to it. It measured 50 PSI. I pulled my fuel solenoid and ran the test through the fuel solenoid as well. Pump/filter/regulator/solenoid/gauge/#38 jet. Pumps at 50 PSI. I dont know what the volume shoudl look like but heres a quick vid of the flow through the soleniod and jet

http://s40.photobucket.com/albums/e224/0tter1363/?action=view&current=fuelflow.mp4

I pulled the lined from the solenoid to the nozzel, all clear, pulled the spray nozzel, all clear. I am gonna put it back the way I ran it last year - fuel tap from the rail to the solenoid and see what happens. Kinda driving me batty now...

 

[otter1363]

Also might want to check that your fuel solenoid is working. On a 35 shot it didnt go super lean because of the size most likely. Did your AFR get any richer with the larger fuel jets? Sounds like its dead or not getting power.

Its getting power, I can hear them fire till it cuts out. Also pulled it and tested it tonight. I really couldnt tell if it was getting richer because it would fail safe in a second, not enough time to see if it was rising or falling.

One note. Last year I had it dialed in pretty good pulling fuel from the fuel rail. I didnt run the safe guard for lean out conditions then. Since I put a new system on I activated the lean safety feature. I know from experience it may shoot lean for a split second till the fuel hits. I have (in the past) had issues with the fail safe in this regard. I deactivated the feature last year and found as quick as it leaned it richens back up. I ran the new fuel supply set up last month and set my A/F safety cut at like 15:1 and it shut down. It shot dope well into the 60' mark. I dont recall it going that lean before, even momentairly.

 

[otter1363]

OK, after talking to folks who are smarter than me at setting these up, the general thought is I am trapping air in the line prior to the solenoid. I have received two thoughts on how to better set up my lines. Not really sure which would be better (not a pro at plumbing) so looking for input...

Proposed 2 moves my return point to the input side of the fuel solenoid and regulates all flow to that point, proposed 1 is essentially the same but moves the regulator to the return line. The intent here is to regulate the return pressure to a point where I keep 50 PSI at the solenoid.

 

[Eagle]

fuel purge solenoid!

Seriously though, seems like there should be enough fuel pressure to keep air out once its purged initially. Just be sure to keep enough fuel in the tank to keep your pickup submerged?

 

[otter1363]

I draw fuel from the bottom of the fuel cell as opposed to a submerged pick up. I'm gonna run it like proposed #1 - see what happens I guess.

 

[Eagle]

That's how it should be... So good call.

 

[otter1363]

Ok - changed up to proposed #1, fuel pressure dropped to 40 PSI at the jet. Bumped up to a 48 jet (10 over), still lean. Something is very wrong here...

 

[Eagle]

I'm confused. Perhaps your regulator isn't set to make 50psi? Where are you measuring PSI "@ the jet" from? When you say that its lean, what are you considering lean? Does the motor on nuts run at the intended AFR - and what AFR is that? What does it run @ with the nitrous on? Finally (for now) what nitrous jet are you running?

 

[otter1363]

fuel pump is a mallory 4060FI, rated @ 60GPH@55PSI, regulator is an aeromotive 13301 rated to 65 PSI (have the big spring in it). I measured the pressure after the solenoid and before a #40 jet (made a fixture to hold the jet). My A/F read ~10.5 with the fuel pulling from the fuel rail (last year) with a #38 fuel jet and a 62 NX jet, run a 12.2 A/F on motor. I put a #38 fuel jet in to start with on the new fuel set up and the system shut down when it leaned to 13.0 A/F (per controller safety set up).

The first plumbing set up with the dedicated system was as shown as "current set up". I measured 50 PSI with the test fixture (stuck the #40 jet as it would normally be seen, after the solenoid) and ran lean - shut down when it hit 13.0 A/F, pretty much imeadeatly. Talked to nitrous express and was told I may be trapping air in the line from the reg. to the solenoid (~3' line) so I switched to proposed #1. My PSI dropped to ~40 with this set up (as measured in my fixture after the solenoid, before the jet) and jumped to a #48 jet on the fuel. It still leaned out to over 13.0 A/F and shut down.

Hard to believe the pump aint puttin out enough to put fuel through a .048" jet but starting to wonder...

 

[Eagle]

P#2 won't work because there's no restriction going into the fuel tank, so the fuel will flow that direction before it chooses to go to the solenoid. (path of least resistance)

A .048" fuel jet is enough fuel for over 250HP... you've got something else going on here.

Are you sure the fuel solenoid is opening fully? Are you sure your nitrous pressure isn't too high?

 

[Eagle]

does the fuel solenoid have a "through" port? (scratch that P1 comment)

Finally, why return it at all? Just run the pump straight into the FPR and a line to the solenoid?

 

[otter1363]

NX pressure is around 800 throughout all the testing. While I am not positive the Fuel solenoid is fully opening I and pretty sure. Heres a vid of the flow through a #40 jet,

http://s765.photobucket.com/albums/xx295/otter1363/?action=view&current=VID-20110829-00002.mp4

I run a return because the pump requires one. I'm gonna go back to tapping off the fuel rail this morning. If it works fine, I will come to the conclusion I have the wrong pump for this application.

 

[otter1363]

Put it back to the fuel rail tap with a #38 jet. Kicked the safety again. I disabled the safety and worked perfectly. So I'm an idiot, I guess it was just seeing the initial lean spike because I plumbed it back to the dedicated set up with a #44 jet - no safety and ran good. The 44 will take it to ~ 75 shot, A/F read 11.8 so I would need to keep going with the jet size to run a 150 shot.

I'm pullin it out and just going to run the fuel rail tap set up. I know it works perfect and I dont need to keep playing around trying to find the right jet size.



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