boostedv6

I'm starting my turbo project next weekend and I have a few questions about the fuel delivery. I am going to buy a walbro 255 fuel pump but i'm not sure about injector size, the fmu ratio, or the fuel pressure regulator. I am hoping to make 230-250whp @ 7psi with 19lb injectors with a 4:1 fmu. However, according to this link that firstfirebird sent me, http://www.rceng.com/technical.htm I am going to need larger injectors and an fmu with a much higher ratio. So my question is what combination of injectors, fmu and afpr do I need? Oh, and what afpr's will bolt onto the v6 fuel rail?
Summit sells this one for the tuned port motors and it looks like it will fit, but I'm assuming I will need one that can go lower than 35psi.

firstfirebird

iTrader: (3)

Can you post a link for the regulator you were looking at?

boostedv6

oops, here's the link: http://store.summitracing.com/partde...5&autoview=sku

RBob

iTrader: (1)

An FYI, the stock V6 MPFI system runs at 43.5 psi fuel pressure.

RBob.

TON*LOC

if your using a fmu you need to run the stock injectors. the reason is becouse the the fmu wont controll the injector pulse, the ecu does, so if you were to put bigger injectors in there then your car would run rich *** hell becouse your ecu still thinks it has the stockie in there. the best fmu from my experience is the 12 to 1 that means for every psi of boost it will raise you fuel pressure by 12 psi. if you are running a fmu you will not need a afpr becouse your car will run off your stock fpr till you hit boost then it will run off the fmu so it is not needed

boostedv6

If I use stock injectors and a 12:1 fmu then at 7psi I will have about 126 lb of fuel pressure which can't be safe. The reason I need larger injectors is so that I can run lower fuel pressure and not max the injectors out. I am going to install a fuel pressure regulator so that I can lower the base fuel pressure to compensate for the larger injectors.

TON*LOC

you'll be fine people have been using fmu's on forced induction motors since god knows when. jackson racing, vortec, comptech. your saying all those companies have been doing it wrong all these years and your going to be the ones who does it right and proves them all wrong ?? just go with what works and has been working for years

firstfirebird

iTrader: (3)

126psi is unsafe, especially since the stock pressure is 43.5 (the ammount the lines are intended to handle).
And no, the car won't run rich if you lower base pressure (which gets raised by the FMU). Either way if you have been building cars for years you would know both situations are not the proper way to do it, and would be suggesting to get a computer tune. Both using the AFPR and RRFPR (FMU) or one without the other is still not going to atomize the fuel properly.
MegaSquirt FTW!

boostedv6

Have you built your megasquirt yet? I was thinking about getting one but my camaro is my dd so I can't afford to have it down for a while while I try to figure out how to make the megasquirt work.

firstfirebird

iTrader: (3)

From what I understand it can be done in a weekend. If you build it, another day. I'll let you know, I should have it any day now. Yesterday I got the Vac/Boost guage, AFR guage, and the wideband o2 all hooked up.

TON*LOC

how come in every forum on earth when you talk about using fmu's, it never fails some one will come in and tell you to use electronic tunning of some sort. he is asking how to make what he already has work! not completely change the set up he already wants to use....i stand by what i have been using and will continue to use and that is 12 to 1 fmu. if you want me to dig up all the build i've done using them fine i will but i dont see the need to do it.

boostedv6

look, we're not saying that a 12:1 fmu is never a good option, it just isn't in this case because my fuel pressure would be way too high and my injectors would be maxed out.

Anyways, I guess I've decided on the injectors and fmu, so does anyone know if this afpr will bolt onto the v6 fuel rail?

http://store.summitracing.com/partde...5&autoview=sku

firstfirebird

iTrader: (3)

I believe that is the correct one (TPI AFPR's fit). If you look at your current FPR, you will notce the tamper-resistant screws (torx heads). You have to have the special torx bit to be able to get the stock FPR out.