MK8 PCV Retrofit: Track Testing Results are In!
If you read through all of the Trip Reports, you probably already saw this video going over the results from Fastivus 2023. I wanted to be sure to post it here with the other tech articles as a basic update for those interested in following the progress. In case you missed the original post about the MK7 vs MK8 PCV systems, follow this link to be brought up to speed.
To sum up the video and results above in a nut shell:
MK8 PCV retrofit was used as shown in the original video detailing the function of it. This means the Tiguan PCV hose is used to adapt to the MK7, but the “extra” hose of the Tiguan part is capped off.
Zero oil-ingestion related problems noted through sessions 1 and 2.
Session 3 had one blip of knock retard on all cylinders towards the end - Initially I was worried this might be the same old problem, but viewing the data overlaid on video found that it occured simultaneously with hitting a curb HARD while getting back on throttle. I’m cautiously optimistic this is not PCV-related, but will be getting confirmation in ~3 weeks at VIR.
The tune I was running was a bit spicier than before, running approx 26psi tapered to 19psi at redline. The idea was to do what I could with “stress testing” the PCV valve as much as I reasonably could with an IS20.
I forgot to mention in the video: ZERO perceptible oil consumption all day. At VIR I used 1.5qts over (3) 20 minute sessions for reference. The car has used zero oil since the last oil change about 2500mi ago, which includes (2) autocross events and this (1) track day at Summit Point on the Shenandoah Circuit.
Next steps for this MK8 PCV experiment include:
Gathering some baseline logs for wastegate duty cycle, spool, etc as-is.
Install the 034 TMD (which DID finally show up last week), plumbed to the currently-unused Tiguan PCV hose. This will be considered a “full retrofit” that utilizes the venturi built into the hose to generate a vacuum on the crankcase during the transition period from intake vacuum to before the turbo fully spools.
Gather more logs to see the effects on wastegate duty cycle, spool, and crankcase pressures to evaluate if this form of retrofit:
1. is doable without major ECU tune changes.
2. requires ECU tune changes - and if so, how much (to the wastegate tables).
3. has any noticeable/positive effect on crankcase pressures.
4. worth doing at all.
Track test it again at VIR in ~3 weeks. Since I had no issues at Fastivus with running the PCV valve as-is, chances are that’s how I’ll run it at VIR unless the testing above shows tons of promise with little downside. I’ll absolutely be bringing the stuff with me to install/test if I find the need, plus have a tune ready to go if necessary (or worst case scenario: my laptop with me to edit as needed).
