foaxaca

My son's 94 FD now has completed exhaust/intake mods - HKS dual intake, down and mid pipes (no pre or main cat) and HKS catback. We also just had boost and temp gauges installed so we can track boost level and engine temp. I've read on several posts that the wide open exhaust is very susceptible to "leaning out" which has been happening. One recommendation has been to install a boost controller to prevent boost creep above 10 psi which we are going to do. Another recommendation that we have seen is to upgrade our fuel delivery system. What type of upgrade should we do? Is an upgraded fuel pump enough? If so, what type would any of you recommend?

Trexthe3rd

It depends on what if any future performance upgrades you plan to do. But just based on what you have right now, the two most popular upgrade would be either the walboro 255 or the supra fp. The real benefit would only be realized if you also install a fuel pressure regulator to raise the stock fuel pressure. This in essence increases the fuel delivery across the board.
A true fuel upgrade would include at lease the following:
Fuel pump
Fuel regulator
EMS
Larger injectors
(optional)
Fuel line
Fuel rail
Fuel filter
Pulsation damper

matty

supra fuel pump and 1300 cc injectors.

Improved FD

agreed....but the pulsation dampner is likely not needed if you have an aftermarket regulator, I haven't had any problems without it

you can also get away with using the stock rails, but the aftermarket rails look cool!

grimple1

iTrader: (1)

Walbro 255lph and 1300cc secondaries. You'd be set for a while.

Have a look at this guide. It might help you figure it out.

http://www.stealth316.com/2-fuelpumpguide.htm

GoodfellaFD3S

iTrader: (213)

Also note that a boost controller *will not* help you when it comes to boost creep. this is a condition caused by the mechanical wastegate being of insufficient size to vent the required exhaust gases away from the turbines, thus leading to uncontrollable boost that rises with load/gear/rpm.

Your only alternatives are to introduct exhaust restriction in the form of a high flow cat or restrictor plates, or pull the turbos off to port the wastegate (not a fun job). Each FD experiences boost creep to a certain degree, some worse than others.

Also, while I'm on the subject: the amount you creep will vary as I stated above by load/gear/rpm as well as temperature, but in each situation the amount you creep to is irregardless of the boost you are trying to run. Meaning: my FD typically creeps to 12-14 psi right now with my BNRs and ported wastegate, but that doesnt bother me because I want to run that much boost anyway. If I was trying run 10 psi, then it would be a problem. Some people think it creeps x psi on top of what boost you 'should' running, but this is incorrect.

hope this helps---

Improved FD

I'm surprised you are getting creep with your bored out WG Rich

GoodfellaFD3S

iTrader: (213)

more efficient turbos, keep in mind these new 3's have completely new/bigger rotating assys, to include all four wheels and both shafts

foaxaca

Does a blow off valve help in venting those excess gases? Does that help deal with boost creep?

GoodfellaFD3S

iTrader: (213)

no, the blow off valve is located on the intake side of the turbo and helps to prevent compressor surge when the throttle plate is closed, it has nothing to do with the wastegate and the exhaust side of the equation.

rynberg

Ugh, your son's motor is on borrowed time! Full exhaust on the stock ecu and fuel system =

My strong advice is to put the main cat back on the car until the car is ready for a midpipe. This would include an aftermarket ecu (Apexi PFC), larger injectors/fuel pump, and porting the wastegate or running restrictor plates. Also, for boost levels above stock, a larger intercooler is strongly recommended, especially since an open hot air intake is being used.

A midpipe is a serious mod on an FD, one that is taken far too lightly by the majority of owners. It is probably responsible for more blown motors than any other mod....