I know not too many people using the Vortech S/C on here but there are even fewer on the VW websites (well that actually know what they are doing). I have a VW GTI VR6 running a vortech V1 and 11-12ish psi on 10:1 compression. Boost levels are in the intake after the intercooler. Running Haltech so I have full control over timing and fuel.

Just wondering about tuning ignition timing and also static compression ratio vs. boost. Since its a centrifugal compressor you only see max boost at max rpm. Power peaks a couple of hundred rpm before redline (7k in my case). The torque peak is much sooner though, around 5700rpm. At this point I am only making about 7psi. Obviously every motor is different but I was wondering what the general timing trends that you guys are seeing. Do you keep doing a step retard based on boost only? Keep the timing static after peak torque? I know a dyno is the best way to tune ignition and I will be going to a load dyno but the closest one I feel comfortable using is 2+ hours away.

Also since you can't just turn the boost controller up to make up for lower compression at what boost levels do you lower the compression? Since its only making max boost for a short period and well above peak torque is it even necessary? I doubt I can get more than 15psi out of the charger without major belt slip issues. If it were a turbo on the same motor I would be looking to drop the compression at 12psi or so.

I am not looking for definitive answers just your experiences so I can make my own decisions. Thanks

 

I personally use a step retard, 1-3psi, 3-6 psi, 6-9psi retarding in increments of .2*, .4*, .6*

Every set up is different. Check the timing line on your plugs also if you are worried about being too far advanced.

 

A basic step retard isn't the best idea with a Vortech, because the motor will take more timing and make more power at 7000 RPM's and 10 psi compared to 5700 RPM's and 7 psi at the torque peak, so you're giving up some power there. On my centrifugally supercharged mustang it liked 20 degrees at torque peak ramping back up to 24 degrees by redline to make the most power, but if we tried 24 degrees locked in we would get some knock around the torque peak when there was lots of load on the motor, or it was heat soaked.

 

This is my train of thought exactly. A basic step retard is nice and conservative for a turbo but might be leaving too much on the table with the S/C.

What about a/f? Notice any trends there? Right now I am running around 12.0-12.2 and I am happy with that till I get on the dyno to see if there are any gains to be had.