LCP

AWE's center vent boost gauge is extremely nice. It really does look factory (I went with the black bezel that matches all of the black plastic in the area), both when lit and unlit. The vent is still functional, except it doesn't slide left and right. I put in the middle vent to center it in the vehicle. That creates a balanced look that you do not get when put in the left vent closest to the instrument cluster. If you've been on the fence about getting an A-pillar gauge or other gauge because you didn't want it to detract from your beautiful interior, this is the one to get. I've had my S4 for 28 months now, and it took me that long to find a gauge I would be happy with.

As far as the install, AWE's instructions were perfect. The time to install was accurate at 1.5 hours too. Even that 1.5 hours was with some resting, stretching, talking, tool borrowing and giving pointers to someone else during their short shifter install. I had never installed a boost gauge before and had no problems.

Here are my observations regarding how much boost my K04's were pushing, with beta software from APR. I am suspecting it's about at the limit of the injectors.

1. When does boost kick in on the low end?

For this, I did testing mostly in 4th, 5th or 6th gears. The car is simply too fast in the lower gears to observe what is happening at a specific RPM, and boost lag is less noticeable in higher gears. Starting at idle and flooring it I would see 1psi by 1100rpm, and that would linearly build to 7-8psi by 2000rpm, and reach 17psi by 2700rpm.

2. How much boost does it make once full boost is reached?

For this, testing was done in 3rd gear where 7000rpm could still be experienced without doing ludicrous speeds. 17psi would be reached before 3000rpm, as stated above, and stay there to about 5000rpm where it would slowly taper to 15psi at 7000rpm. Perhaps a pound or two less was made in 1st and 2nd gears, which go by incredibly fast (0-60 in less than 4.5 seconds).

3. What kind of boost spikes were there?

When stepping into the boost full throttle in midrange RPM's, the boost would routinely spike to 19-20psi and settle quickly to 17psi. Once, 22psi was seen.

4. How was boost affected by shifting?

Perhaps thanks in part to my Forge valves, I could routinely keep 5psi between all shifts from 2nd to 6th gears, if I shifted really fast. From 1st to 2nd gear, the most I could see between shifts was 2-3psi since it won't shift as fast as the other closer spaced gears. If I didn't shift real fast in each instance, boost would turn into vacuum.

5. How much boost was there if flooring it in neutral?

This was perhaps the most informative thing I did. I took the transmission out of gear and sat there, flooring the gas pedal for lots of free revs. Positive boost pressure of 1-2psi would start to build after 3000rpm, and by 6000rpm, a full 10psi could be seen. This is why the best launches (if the clutch can take it) happen when you floor the accelerator from a low rpm, and as it's passing through the midrange rpms, you begin to quickly release the clutch -- BOOST has built before you've even started to move. Just sitting there at 3000-4000rpm the engine is in vacuum and then has to start building boost as you're starting to move.