type of turbos
more info needed.
Assuming you're talking the twin turbos? If so, I believe they do work together to increase air intake at a faster rate than a single turbo.
i'm assuming you have the 2.7 liter v6 biturbo....so i'm working from that based on my knowledge of mine...the first turbo spools up at the lower rpm range to cut the usual turbo lag, then the other kicks in near the upper range of the first and continues to the higher rpms....so the big upside is that you have a constant turbo powerband whereas most single turbo configurations have no power gain until a certainpev range
Evan ... both of your turbos operate in parallel. They are equal in size and they respond in the same way at the equivalent RPM. What you are describing when one spools first and then the other occurs in only a select number of cars ... and the 2.7T V6 is not one of them. The last generation Toyota Supra had a small and larger turbo in series and would do just what you described. The smaller one would spool first at lower RPM and the larger one would come on later in the RPM range to provide more boost pressure. The 3rd Gen Twin-Turbo RX-7 used a series of vacuum tubes that would control which of their equally sized turbo would respond when. In the RX7 one turbo would spool at lower RPM and then have the second one spool after around 4000 RPM or so. And, I believe the latest BMW 335 also has a twin turbo system that operates in a similar (though be it more advances) manner to that of the Supra. Your 2.7T V6 is plenty powerful but it is just a plain twin-turbo set-up with both operating in parallel. You'll also notice that if it's chipped and you've openned up the intake and exhaust a little, this set-up is very 'peaky' ... meaning that the turbos are very strong in the mid-range when they are in full song but run out of breath after 6000 RPM or so. This is very characteristic of just a straight single turbo set-up. To get around this you need to upgrade the turbo's to flow more air (ie go to Stage III w/ K04 turbos and supporting hardware).
They work concurrently. They are not "sequential."
Looking for a Used S4 in your area?
CarGurus has 888 nationwide S4 listings starting at $3,450.
Search Audi S4 Questions
Audi S4 Experts