Hey guys,

I'm having boost issues, long story short my boost gauge (autometer) reads psi but my car feels N/A until I hit 6k rpms and then you feel a burst of power like the turbo is finally kicking in and while you're feeling that burst of power by psi drops from 8psi down to 5psi. The previous owner decided to go with 750cc low imp secondaries and wired in resistors and I'm wondering if this could be a part of the problem. I figured if I had a boost leak my gauge wouldn't read psi. Anyone have any input? I'm a complete newb (is that term still used?) when it comes to forced induction.

 

S4? Stock turbo? Stock other than the secondary injectors?

 

Check the wastegate for proper operation. Also how much in/Hg are you getting from vaccum at the boost gauge? Do you have air/fuel ratio gauge? What are the reading on acceleration?

 

To answer all questions:

S4 everything stock except secondaries.

Boost gauge reads -20 in/hg at idle

No wideband at the moment so readings are unknown.

If the issue can't be narrowed down, I'm going to install my microtech lt8s and when that's done, I will know what's going on when we tune it.

 

1. If everything is stock, there is no need, nor a way to properly manage, larger injectors.
2. Unless it's a very late model S4, there is already a resistor pack for the stock low impedance injectors integrated into the engine harness.

Unless you plan on replacing everything, and I mean everything except the core engine (turbo, gaskets, injectors, ignition, exhaust, etc), I would highly suggest sorting the car now before moving to the standalone. You're going to introduce a multitude of variables to the scenario which is going to make troubleshooting exponentially more difficult.

 

That's what my buddy said. We should get the issues sorted now before the microtech goes in. My car is a late 88. It has the square s4 offset injector plugs and no resistor box. The primaries are factory 550cc high imp injectors and the secondaries are 750cc low imp with resistors spliced in line to the injectors (which is what the previous owner did).

 

Might be picking up a set of factory high imp 550cc secondaries this weekend and removing the inline resistors.

 

Scratch the injectors, they're the oval red tops, I need the square red tops.