Review: Street Tuned Motorsports RS3 (8V) Intercooler

This little adventure started when I took my 2018 Audi RS3 to Virginia International Raceway in Southern Virginia. I noticed that after a few laps, I was no longer getting the same level of power, and that it was becoming quite inconsistent. Since then I did an install and review of the STM Cat-less mid-exhaust pipes, and have continued my relationship with them by purchasing their RS3 intercooler. It is also worth noting that they have actually taken the time to provide dyno charts, which most other vendors had not at the time of my purchase.

Initial observations:

Based on a 1000hp rated Garrett core, the build quality and finish is fantastic. The shipping box is rather large, and includes plastic over the tube inlet/exit, plus cardboard over the grates for protection. With a 100% stock fit, no modifications were required to work with the factory crash bar or sensors. The only adjustment required was to relocate the Audi Cruise Control (radar) sensor a bit forward of it’s factory location, and they included a bracket for this, so I’d hardly call it a “modification”…

Installation:

I couldn’t find a really well put together installation guide, so I built my own (coming in another post). Now that I’ve done it once, I’m confident that I could do the full install in about a half a day, working alone. With an extra set of hands, probably 2-3 hours or so.

Fit and Finish:

Factory quality. Only thing I’ve noticed is that some other aftermarket installs are painted black – this one remains silver. There is also an STM badge welded to the top which is slightly visible if you look through the front grill of the car. The top of the crash bar fits quite close, but since the crash bar is more open underneath, you’ll still get air-flow through the intercooler.

Performance:

Initially, there’s a *bit* more turbo lag while it’s compressing the extra area (but you have to look for it). The 2.5L 5 cylinder from Audi has impeccable low-end torque, and it’s a fairly small turbo to spool, which really helps with getting over any feelings of “Lag”. On top, it’s a rocket! The biggest upside is the continued consistency. Heat soak from underperforming intercooler begins to show itself in the higher gears after long runs, and this intercooler diminishes that to the point that it feels completely gone. That said – After a few laps, I fully expect to see diminished losses in power (aka – by laps 2 or 3, I could be down 30-40hp…). With this installed, I don’t feel that happening.

Update From Dominion Raceway:

Short Version – This is a night and day difference. Pulling through the gears into the low 100’s, high rev in 4th and 5th gear pulls extremely strong, as though the wind resistance is simply gone from the car. The temperatures I’m seeing on the engine also seem a bit lower, despite now running in warmer air temperatures. I spoke to some of the team at STM and asked about recording temperatures and doing before/after, however they said that so many factors can play into that, that it almost becomes not worth it.

Final Thoughts

Here’s the break down:

Pro:

Diminished performance loss due to heat soak
Increase in power across the rev band
Straight forward installation that doesn’t require specialized tools or a lift
The car is set up for any future power-adding modifications, and I’ll never need a different intercooler
(Personal preference): the silver peeking through underneath… a bit of a sleeper, but not, look…!
+ a bit of MPG – I’m truly not sure how this worked out, but I’m noticing that my range has increased during my city driving – maybe the cooler air is helping or it’s a bit easier to breath? I’ll take it, though!
Support from STM: This is a great crew, and they have literally wanted to help me since day one. They recognize the platform that this vehicle is capable of and were nothing but encouraging as I started the installation process. I simply cannot say enough about everybody I spoke to.

Con:

Slight bit of turbo lag – to be honest after about 1k miles with it installed, I don’t notice it at all anymore
Audi Warranty – Some SA’s may not look favorably on this. Mine is fine with it, though.

Overall, I’m *extremely* happy with what this has done to the cars performance, and providing cooler air to the engine should actually be beneficial to the longevity of the entire turbo and intake system, despite being driven a bit harder.