gspot35

I am currently running a vortech s/c and the split second piggy back. I would like to upgrade my fuel system to something more suitable for 9psi. I have been having problems with the fuel system. Every once in a while after driving spiritedly my a:f goes way rich (13:1) at idle then way lean (16:1) when I apply gas. I turned the car off for a few minutes then everything is back to normal. I think running the stock injectors at 100+ psi may be taking it's toll. What are my steps in picking out new injectors, adding a fuel pump with a return, and tuning the new injectors. I know Booger has had some experience with this as well as DFWG35. If anyone could shed some light on this I would appreciate it.

BTW I'm not afraid of diving into the R4 software to tweak this thing, but I want to get something more efficient than what I have now.

Thanks

booger

iTrader: (6)

I think if I had it to do over..I would have gone with 440's [ still may ] John Isbell suggest taking 2 degree's of timing advance out , He think that may solve my lean start and idle problem . We'll see ....How much HP will 440's handle ?

Carlitos

iTrader: (1)

BTW
I have the six 440cc inj from my Greddy TT kit for sale and they are brand new, never been used.
$400

zbicklin

Hey gspot,

I am actually installing PE 380cc injectors with AAM's V2 return fuel system and Walbro 255lph pump. I already have the injectors but am still waiting on a fuel kit to be completed by AAM. I got the PE 380's for 2 reasons:
- Only 22% (or so) larger than stock injectors so tuning idle and vacuum should be easier with the R4.
- The PE injectors are a direct drop in replacement for the stock injectors. No soldering or splicing new clips.
Once I finally get everything I will post some pics of the install and my R4 settings.

Steve

booger

iTrader: (6)

I took out the 2 degree's of timing out in the Split Second box . 2 degree's across the whole vacuum and boost timing map . It helped alot . The car seems to start and idle much better . Going to the Dealer Friday to do another air / idle learning procedure and have them take the 2 degree's out in the ECU . If every thing works out , I can finally start to tune this thing for boost

dfw350z

Booger – I am glad John’s info helped.. Keep us posted on the progress.

gspot35

Thank you guys for the response. I like Zbicklin's idea of going with a swap in injector. From what I remember the PE's were very expensive and took a while to get.

Boog, do you think I'd have to pull timing across the board with the 380cc's?

Z-Bicklin, I'm in No Va, I'd like to meet up with you and check your car out sometime. Are you going to MIR on the 5th of March?

booger

iTrader: (6)

I really dont think you will . I dont think your making that big of a jump and the ECU should be able to control them . You'll just have to lower the numbers slightly on the vacuum side of your fuel map ...and retune . Are you going to do cams ? If so....you may have to.... because of lower vacuum and idle

zbicklin

I'll be out of town the weekend of the 5th, but maybe we can meet up some other time. The PE's were $870 for the 6 and took 3 weeks to get but I think there of a very high quality. I've been waiting on the AAM return fuel sytem even longer, but it should all hopefully be a good setup.

Steve

gspot35

So, do you remove the Vortech supplied aux pump? Do you connect the Walbro the same as the stock fuel pump? Do you need to modify the filter? Are you doing this work yourself? If so I would volunteer to hand you tools...I need to know more about this. Have you seen this set-up before first hand?

booger

iTrader: (6)

Yes...you ditch the aux fuel pump and the FMU . The Walbro goes in the tank in place of the stock fuel pump [ with a little alteration ] . The kit comes with a FPR that you install on the fire wall , and the return line is hooked to it to control fuel preasure in the rails . No more worrying about aux. fuel pump settings being right before you write to the piggyback ECU .

gspot35

So what controls the FPR, strictly boost? And the R4 settings control the duty cycle of the injectors? I'm trying to avoid running 100+ psi throught the injectors. Is this going to solve that problem?

booger

iTrader: (6)

Oh...forgot that part....Yes...With the FPR...fuel preasure rises 1psi for every 1psi of boost . The vacuum line you ran to the FMU , will now run to the FPR . It adjusts alot like the BOV . Bolt on top with retainer nut . Adjust to 48 to 52 psi at idle

zbicklin

Yes... Exactly what Boog said. And I will be doing the install myself and I plan to take pics of the install. I'll let you know how it all turns out once I get it installed.
Basically Boog has the whole thing going except between the larger injectors and cams he's having a rougher time with the tuning then I expect to have.

gspot35

So will roughly 70 psi be enough fuel pressure to maintain a 12:1 or richer a:f under boost?

booger

iTrader: (6)

If your going with 380 injectors or better ...Yes . I think it would be ok on the stocks to . You would just have to retune your fuel map . In the Split S box .remember [ 10 ] means no change to the stock injector pulse . I believe you can go up to [20] or down to [0]