I'm looking at a Supplemental Fuel System but not sure is Utec capable of controlling one. I know buying a bigger injector is the easier route but I'm curious if I can go this route so I dont have to worry about the hotstart problem with bigger injector and Utec. I know AEM or Emanage is capable of doing it.

 

You then have to worry about equal dispersion between cylinders. I ran additional injectors years ago, and wouldn't do it again.

 

/\ is it that bad? I know one with a g35 with built motor that run them and he seem to be fine.

 

I agree with Hal, it was a band-aid solution to getting more fuel into cars back in the day....and I don't think you can do it with a UTEC.

one solution that no one has seemed to use would be to use a fuel pressure regulator with a pressure multiplier in it. it makes tuning a bit more challenging but it would allow you to use smaller injectors for better drivability. With the arrival of the new dual and triple pump fuel systems available, the increased fuel pressure from the special regulator wouldn't be an issue. On a typical single pump setup, you would really be taxing a single walbro if pressures were up to 80-100 psi. with such a setup, you could run a 700 HP (flywheel HP) motor on 600 cc injectors ( assuming a max of 80% duty cycle and a BSFC of .60) at about 85 psi max fuel pressure ( roughly 100 psi when you take in account the pressure to overcome the head pressure of 15 psi fo boost.)

 

like quad says, higher FP might be your answer. just turning it up from 3.5 BAR (stock) to 4.0 BAR would be a world of difference. the stock injectors flow 290 at 3.0 and 330 at 3.5 IIRC, so thats another 40CC (13.8%) on a small injector, i dont know what size youve got right now, but 440's are pretty common, so using them, if you turned it up the extra 0.5 youd be turning them into 500CC injectors (850's turn into 967's ). im sure its not a direct relationship, but i would bet its close and certainly worth a try

 

Supposedly I have a 440cc but I doubt I have that because I'm only pushing 370whp at 8psi and my IDC is already on the low 90's. I was tuned around mid 70's and when temp goes below 50's, forget it!! I don't have a fuel pressure gauge so I'm not sure what my FP is..

 

if its running on stock pressure it should be 3.5 BAR which i believe is 51 PSI, so at WOT youre probly hanging around 48-50 PSI, possibly lower with the 440's. are you running stock or A/M rails?

 

I have stock fuel fuel rails.. The only thing upgraded on my fuel system is the injector deatschwerks 440cc and Walbro 255 fuel pump... I don't have a FP gauge so I don't know what pressure i'm getting at WOT

 

you should be able to log that, im under the impression that it is something that can be logged with a utec or other logging equipment. since youre on stock rails, getting an AFPR and turning up the walbro would def make your 440's act bigger

 

I think the problom is in the tune and NOT the UTEC.I've contacted plenty of people and its split SOME have no probloms some have minor.ITS your tune man.

 

ahhhhh..the early deatschwerks injectors (the 440s and 550s) were rated by DW at the stock nissan fuel pressure of 3.5 bar. these injectors (rated at the 3 bar standard) are really 400 and 500 cc.min injectors. take a look at the flow sheets that came with your injectors. I have the DW 550s (really 500s when compared to a denso or RC)

 

ahhhhh..the early deatschwerks injectors (the 440s and 550s) were rated by DW at the stock nissan fuel pressure of 3.5 bar. these injectors (rated at the 3 bar standard) are really 400 and 500 cc.min injectors. take a look at the flow sheets that came with your injectors. I have the DW 550s (really 500s)

I forgot to add that since you don't have a return fuel system with a boost referenced regulator (to compensate for boost pressure in the manifold), your effective fuel pressure is dropping 1psi for every 1psi of boost in your manifold.

 

I don't have hotstart problem, I'm concern I might get it if I upgrade to a bigger injector.

My A/F is in the mid 11's so how is it the tune? I can reduce pulse width in the higher rpm but that will decrease fuel and I'll end up leaner.. I'm running a meth kit so that allow me to subtract a little fuel but still not enough. I think I really need a FP gauge so I can see if Im loosing pressure at the higher rpm or get my injector flow rate check. The injector came with the STS kit so I'm not sure if they actually send me a true 440cc injector, I have the paper that came with it and it does say 440cc...

 

what is the cheapest way to increase my fuel pressure without getting a retun fuel system? i'm only pushing 370whp so i don't want to get a return fuel system...

 

you can't......unless someone makes a different regulator that fits inside your fuel canister. Nismo might make one, but you are better off saving the money and doing a CJM return system.

 

Sorry to jump on your thread AthensG but since we talking fuel pressure I thought I would ask.
I have had my APS TT kit on my car for awhile already.
I thought they came with 440 injectors but I'm seeing on their site 500.
I also see that they added a fuel pressure regulator and say they upped it to 4bar pressure.

So how much pressure am I really pushing? and does anyone know if the new APS TT kit changed specs?

http://www.airpowersystems.com/350z/fuel/fuel.htm

I'm also running a Meth kit same as AthensG
Snow Performance Stage2 Boost n MAF dependent

I had a electronic Fuel pressure gauge with the AAM adapter.
Can I use that adapter to use a mini mechanical fuel pressure gauge that will connect directly to it?

http://www.alteredatmosphere.com/mm5...y_Code=350Z_FS

 

people have been looking into modifying the stock FPR, but as far as i know nobody has done it, so as of now you cant really up the FP without doing extra modifications to stock above and beyond an AFPR

 

Yes, that is just a 1/8NPT thread port, and 1/8npt is the standard for the mini mechanical fp gauges.

 

I know this is an old thread but a vortech FMU would work fine to up the fuel pressure without a return style fuel system. I have been debating on running the vortech FMU with a 2:1 disc with my new fuel return system. The FMU will work on either system.