In the fall I had the following mods done to my car - catback, hi flow cat, and down pipe and PFC. I drove for a while and never saw injector duties get past 85%.

I have boost set to max at 13 psi on the PFC

In December I had a cold air intake installed. Occasionally since the cold air intake went it on cold days I have noticed that injector duty hits 98% under WOT.

I still have a medium ASP intercooler to install.

I assume I am looking at a fuel system upgrade. What would I need to do to get injector duties back to 85%? I was hoping to avoid this cost, would it be cheaper just to set boost back to 10 PSI? Would that fix it? Will these issues go away once it gets warmer, we’ve had some brutally cold days here in D.C.

 

You need larger injectors to lower you duty cycle and still run 13 psi. Either 850 primaries or 1200/1300 secondaries. A higher capacity fuel pumps such as Walbro or Nippendo upgrade is also needed.

Turning the boost back to 10 psi would also lower duty cycle.

Jack

 

Is your PFC tuned or are you running a base map?

 

Yes, just lower your boost. You should be able to run 12 psi just fine. And as Mahjik brought up, you need that PFC tuned....

 

you really need to turn it back to 12psi and consider an upgrade on your fuel system. It's pretty much NEEDED at this point if you want to safely run more boost.

And of course a tune never hurt

 

Would just an upgraded fuel pump help while staying with stock injectors???

 

It's a mail order tune from SR motorsports. I do realize I need to fine tune it. I was just waiting to get the intercooler installed before doing so. From what I have read and heard those mail order tunes are not the best beacuse they tend to be too rich, which now that I am thinking about might cause the injector dutties to be higher than needed?

 

not really, mostly because you're maxing the amount of fuel your injectors can push.

 

Nope, the injectors and fuel pressure regulator are still sending the same amount of fuel independent of the fuel pump.

When/If you are losing fuel "pressure" is when you need to upgrade your fuel pump.

 

Exactly.

 

Well my Mail-Order tune from SR was 100% the base (mod) map. I'd bet that's what you got too.. Of course that was 2-3 years ago.

 

what can the stock fuel pump handle up to? 320ish?

 

If you're talking about whp then I'd say yea, but I'd still be looking for a fuel pump even at that level. The stock pump really is inadequate for anything other than very minor bolt-ons.

 

You said you had the PowerFC tuned for 13 psi, but how much does your boost gauge say you are running? You do have a boost gauge, don't you?

I wondering if you aren't spiking/creeping and pushing the injector duty over the limits.

Also, when was the last time you changed your fuel filter? If it was a while ago, you might want to change it and run some injector cleaner b4 you go buying stuff or maybe getting the PFC properly tuned.

 

I do have a boost gage and it shows 13 psi, honestly thought I don't look at it every time I mash the pettal to the floor so it's possible that it has spiked passed it. My PFC has shown max boost readings at around .93ish. My car has 65k on it, as far as I know the fuel filter is original. I definately need to change that out.

 

The fuel filter should be changed every 30k, at MOST. Change it today!

On the other hand, a clogged fuel filter has nothing to do with injector duty, but the higher injector duty you run, the more important that your fuel system be in tip-top shape.