zimbo

iTrader: (4)

I currently have the Vortech supercharger which comes with an 8:1 FMU and the SS box to control fuel. With that setup and the stock injectors, the kit is able to deliver enough fuel even with the 9lb pulley and a raised rev limiter.

As some of you know, I'm tinkering around with the idea of going to a custom turbo setup instead. If I use the SS box and the FMU from the Vortech kit, it's possible that I might be able to deliver enough fuel with a TT @ 8psi. But even so, I'm concerned about the longevity of such a solution with the stock injectors and the stock fuel pump.

My thought is to use 440cc injectors and the Walbro pump in place of the stock pump and then use the SS box to control the FMU (i.e. when it comes on and at what pressure).

Any ideas from the experts? Am I going to be able to reduce the pressure low enough that the car isn't overly rich at idle?

I know that some degree of modification is required to get the Walbro to fit. Is it fairly obvious? Is the Walbro pump really loud as some have surmised?

Thanks,

--Steve

esemes

steve--

im NO expert at all... thas for sure... but i have (on my list) the walbro 190l pump (should fit in easily) instead of the 250l version (that needs to be modded to fit)

i would also think about injectors, as the oem may not last the duration (even if they work for now).....

enuf from me.....
(back under my rock)

zimbo

iTrader: (4)

To clarify, the Vortech kit comes with an auxiliary inline fuel pump (which houses a Walbro 190l as I recall) which is controlled via the SS box. It also comes with an 8:1 boost-based FMU.

Here's a schematic:



If I keep the with stock injectors the concern is that I'll be over-stressing them and/or may not be able to deliver enough fuel for the TT. If I upgrade to 440cc injectors, the concern is that I won't be able to dial back the fuel enough at idle.

My understanding is that I can replace the 8:1 FMU washer with a 6:1 washer, which might help.

Any thoughts?

--Steve

t32gzz

iTrader: (1)

I am using 440 injectors, a DFMU and an auxillary inline pump for on boost fuel delivery. The one thing I have that you have not mentioned is an SAFC II. The SAFC does 2 things for me.

1. Decel air feature allows me to run the BOV
2. The Lo Throttle Map allows me to trim back the injectors under 3500 rpm's to avoid running too rich at low rpms.

When I first got the car back, tuned for boost, but not for a Lo Throttle map, I was getting the code for too rich and triggered CEL lights all the time. Adjusting the Lo Throttle map on the SAFC has cured this.

Skidazzle is using stock injectors, a Walbro pump, an inline pump, DFMU and SAFC. He is taking out the Walbro this weekend to see what happens to his fuel pressure. He runs 8psi daily and has been on stock injectors for over 6 months. I am sure he can offer some insight into this as well.

zimbo

iTrader: (4)

t32gzz, thanks for the feedback.

I actually bought an SAFC-II (in case the SS box was not sufficiently tunable with the R4 software) but I have not needed it thus far.

Based on Skidazzle's experience it may be that all I need is a Walbro pump (to replace the stock Nissan fuel pump), but I'll wait to hear from him to see if it is even needed.

--Steve

ravaz

iTrader: (1)

Steve, if you were just going to go with the SAFC-II ontop of the SS box, I'd just ditch both and get an e-manage which can do all of that (based on what Tim wrote above). I'm sure the tuning of both are similar.

-Bill

zimbo

iTrader: (4)

Bill, no current plans to use the SAFC-II. I'm pretty sure that the SS box can do what I need it to do. If not, eManage is always an option

--Steve

t32gzz

iTrader: (1)

Steve - I have a brand new e-Manage possibly for sale if you decide to go that route.

mprowe350

[QUOTE]Originally posted by zimbo
[B]I currently have the Vortech supercharger which comes with an 8:1 FMU and the SS box to control fuel. With that setup and the stock injectors, the kit is able to deliver enough fuel even with the 9lb pulley and a raised rev limiter.

As some of you know, I'm tinkering around with the idea of going to a custom turbo setup instead. If I use the SS box and the FMU from the Vortech kit, it's possible that I might be able to deliver enough fuel with a TT @ 8psi. But even so, I'm concerned about the longevity of such a solution with the stock injectors and the stock fuel pump.

My thought is to use 440cc injectors and the Walbro pump in place of the stock pump and then use the SS box to control the FMU (i.e. when it comes on and at what pressure).

Any ideas from the experts? Am I going to be able to reduce the pressure low enough that the car isn't overly rich at idle?

I know that some degree of modification is required to get the Walbro to fit. Is it fairly obvious? Is the Walbro pump really loud as some have surmised?

Thanks,

--Steve

Steve,
I wouldn't use both the Walbro and in-line pump/fmu. The pressure from a Walbro 255 is plenty for the set-up you're thinking of. But, you will need the aeromotive pressure regulator or the SARD type R which I use. That is required to lower idle pressure and increase fuel pressure w/boost. I can let you see mine now that it is done and show how easy it was to do. This is only true if your running 380cc injectors since I haven't seen how the Walbro reacts to the 440cc injectors. Otherwise just keep the set-up you currently use and remap the A/F I'm sure it will work.

As far as the loudness from the Walbro, it is louder but not noticable if you put the insulation back like it was from the factory. Again you can check mine out for your self to get a better feel. Let me know if you want to check it out this weekend I'll be around Cary/Raleigh for the most part. I also have a spare fuel pump assembly if you haven't seen it yet. It will help you see what has to be done for the Walbro to fit.

MIKE

zimbo

iTrader: (4)

Thanks, Mike. I'd like to see your setup sometime.

--Steve

basam350z

iTrader: (1)

Looking at the diagram I'm totally confused. I know that the SS Box turns the fuel pump on after 1000 rpm. But the fuel pump just goes around the FMU. What he heck is the FMU doing then?

It can't actaully be raising pressure.

mprowe350

basam350z,
I believe the FMU sends the voltage, based on its vac/boost input, to the pump which pumps the fuel.

MIKE

basam350z

iTrader: (1)

The FMU is not an electrical component. Unless you mean the Splitsecond box, which does turn on the fuel pump at a sent RPM point.

Can someone explain how this system works?