Saleen series VI and Fuel Pump and pressure

[cheftjpeck]

alrighty then techies. I just had a Saleen series VI installed, changed pullies etc etc....at what point is it wise for me to change the fuel pump, when should I have to....right now..with my saleen i changed to the 39lb injectors, FRRP cold plugs, 90mm lightning MAF, kooks L/T with catted x pipe, that Intake boot is the saleen extreme one....and I have a C&L Conical filter and heat shroud on the end....it is an Automatic GT with stock gears: so with that out of the way....I was going to switch to the 3.4 pulley but was concerned that 9.5-10PSI was too much with stock fuel pump so I got the 3.6 with 7.5-8psi.
will there be any gains to switch the fuel pumps or is it simpley peace of mind and safety factors. am I okay with my stock pump and 7.5-8psi boost....what should my fuel pressure maintain at (so I know when I am looking at the gaugewhen am i running into danger) sorry for the NOOB questions....just wanting to see some STRAIGHT ANSWERS that are not SALES driven as if you ask a vendor them...
TJ

 

[Cali HP Addict]

You are perfectly fine with the 3.6" pulley. Most likely you will be fine with the 3.4. However, some indications of maxing out capacity above 6k rpm with the 3.4" have been seen. This is most likely someone with an 8rib belt setup or someone who has been lucky enough to have no belt slip. This is not to scare you from going with the 3.4" if you are running JDM tunes. There are literally hundreds of guys running the 3.4" and stock fuel pumps without a single problem.
As far as fuel pressure goes, your car is set up to run a fuel pressure of 39" at 0 vac. and 0 boost. Meaning 39# at current atmospheric pressure. You should see a pound for pound increase in pressure -vs- boost. Meaning you should see 49# fuel pressure at 10# boost. The same is true for vacuum. You will lose 1# pressure for 1# vacuum, however, your car will never drop below 29# fuel pressure no matter what the vacuum is.
So, if you wish to push your car a little, have plans to build the bottom end in the future, or just want total piece of mind then a fuel pump upgrade is worth every penny and should be done sooner than later IMO.

 

[cheftjpeck]

thx...well that sux, so i would have been ok with the 3.4 damn I am a chicken....I just got worried....even Jim at JDM said I would be fine....but others warned me...so I did not want to go the 3.4 then have to install the fuel pump after the fact...maybeI will send the 3.6 back and exchange for the 3.4...I dont know I have murphys law when it comes to decisions I make..thats why I tend to go conservative....oh well. I guess the 3.6 will be ok.....7.5 -8 psi will still be fun for a daily driver//thx allot...

 

[Slofoot]

Get the 3.4 and upgrade your fuel system with a GT supercar fuel pump and a BAP and you'll have plenty of fuel for the 3.4" pulley. The GT500 twin pump setup is better but it's more cash.

 

[ZmanM3]

The 3.6 pully isn't so bad either. I am making as much power with it as some are with the 3.4 pully. I would go with the twin fuel pump system though for the piece of mind even with the 3.6 pully. PMP sells a kit!

 

[ZmanM3]

Dang, Slofoot it is good to see you here!!

 

[Hawgman]

Don't even get me started about fuel pressure

 

[don_w]

Upgrading the fuel system is on my shortlist of things to do... but I've had excellent results so far with just the stock fuel pump and a BAP up to 12psi boost. I won't increase the boost until a new pump and 60# injectors go in there.