SierraBravo

On an S6, do you lose the 4 cyl mode with this system?

Also, for the high-flow cats it says it requires a stage 2 ECU remap. Does this stage 2 remap even exist for our cars?

DeerHunter

Can't answer the second part, but 4-cylinder mode is not at all dependent upon your exhaust set-up. Nothing will change in that respect.

Vijay

So far as I know there is no stage 2 remap at present. It basically disables the input from the post-cat O2 sensors so you don't throw a CEL due to the high flow cats. This can mess with emission testing protocols in some states causing you to fail if cat "readiness" is part of your OBD based emissions check. Best check before you do this.

SierraBravo

So the 4 cyl mode is not dependent on the valve actuation. Got it, thanks.

It looks like the high-flow cats are for some time in the future. Now just to get some ceramic brake pads.

mikec7s6

for 99% of my driving, it never even goes into 4 cylinder mode. you literally have be feathering the gas and coasting on a flat road under 70mph for it to even work. any slight throttle input and it goes back to 8 cyl. kind of pointless feature if you ask me.

SierraBravo

Maybe because the car is suppose to be left in cruise control for it to work. Just know that I have been able to get some impressive mileage on the highway and would like to keep it that way.

mikec7s6

it works even without cruise control, you can switch to the efficiency meter and see the gauge turn green every time it switches back and forth. I don't really monitor my mpg but if I wanted an a6 that gets good gas mileage I would have got a diesel or 2.0t. ive had both of those as loaners and the mpg those cars return is quite impressive.

Dr Chill

My car is not nearly that sensitive. It switches to 4 cylinder mode even at 50 mph when I keep the throttle pretty steady. It's seemless.

tenspeed

From the A6/S6 Product info book (page 6)

" V4 mode uses cylinders 1, 4, 6 & 7 & is accomplished by an electromagnetically controlled camshaft which rotates into a zero lift camshaft profile; the other cylinders are shut down & fuel injection/ignition halted after first taking in air to act as an air spring for reduced power loss.

V4 transition will occur in a fraction of a second under these conditions (coolant temperature of 86 degrees, 3rd gear or higher & between 960 & 3,500 rpm). V4 mode can last for up to seven minutes at which point all cylinders are engaged to prevent excessive heat loss & efficiency."

http://www.datarunners.net/AUDI/docs...20a6%20PIB.pdf

SierraBravo

Hmm, didn't know it would only last up to 7 minutes. When I think about for just a bit it does stand to reason. The heat loss could cause problems.

I just like the good mileage during road trips. Keeps the wife happy.