I'm going to be mounting up a Garret GT35R running Megasquirts DIYPNP, I'm not really too sure how much power its going to make but I want some fuel to play with if possible. I already have a set of 720cc injectors for the primaries. I was curious what kind of injectors I should get for the secondaries, what fuel pump, and what FPR everyone recommends? I was thinking about doing 1600cc secondaries, a Walbro 400 fuel pump, and I hadn't really decided on an FPR(Heard good things about Aeromotive?). Just looking for some advice on as to what I should run. The motor is a stock S4 block with stock S4 internals, no porting has been done. (Will be professionally tuned)

Thanks in advance for the knowledge!

 

720/1680, walbro 400 and aeromotive A1000 FPR.

i would be more concerned with the structural integrity of the block though, even at 14psi the turbo is capable of 400-450whp, beyond where most people begin to break the casting in the event of minor hiccups.

 

KISS. When I had the GT35R on my turbo II that made 466rwhp @ 21psi, I had very simple mods:

-apexi PFC
-HKS FMIC
-walbro 255
-stock primaries
-1600cc bosch secondaries
-stock fuel rails/FPR
-basic streetport

I was running high on the injector duty cycle at that boost level, though, so a nice set of ID2000's would also be a good choice for the secondaries, and they are said to be much better injectors than old style bosch 1600/1680's.

 

the stock FPR stops raising fuel pressure after 10psi of manifold pressure, beyond that it also stresses the diaphragm inside the FPR which will eventually rip and begin pissing fuel into the rear intake runner.

so i would ditch the stock FPR on anything over roughly 300whp.

 

When does the stock fuel line / stock fuel filter become a restriction?

What is the "optimal" fuel flow? N/A FCs had the primaries receive fuel first and then flow up to the secondaries, TIIs go to the secondaries and flow down to the primaries. Or should it be run in parallel?

I'm sure I could find this info while searching but I'm being lazy

 

the stock lines are fine on gasoline until you get to like 500hp, at that point it might be worth a look to see if something larger is needed.

the filters, there are two, should be new, the replacement interval is 30,000miles or two years, if you're trying to double the stock HP, you might make the main filter annual.

 

All USDM FC engines had fuel flow through the primary rail then into the secondary, through the FPR and back to the tank. Only some JDM turbo engines had the fuel flow reversed to the secondary rail first.

Either way, it doesn't matter. If the FPR is doing it's job, both rails will see equal pressure at all times.

 

the stock fuel lines/rails/filter are good for about 600whp on pump gas.

 

And then what? Too restrictive?

 

i would think so, but why would someone build a car for more than that and keep the stock rails and hard lines?

it's too risky with a car on the rollers that can do 60mph to 145 in only a few seconds. you could find a dyno with a loading brake but then it becomes time consuming on the rollers checking various loads and accuracy.

 

Great info! I was planning on the getting the same turbo for my car. Would 1600 cc on primaries and secondaries be fine?