orderedanalog

Can you explain this? I let off the gas in both conditions, so the amount of fuel being sent into the engine should be the same... I get an blank reading in the "instant fuel economy" under both conditions.... what's the science here? Now I could see that keeping it gear could reduce speed and save on brakes due to engine braking, but how exactly do you use less fuel?

LeoR604

If you leave it in gear, the injectors will shut off completely because NO fuel is needed to keep the engine spinning. If you push the clutch in, the engine has to be fed some fuel to keep it idling. So keeping it in gear when coasting saves fuel and brakes.

Eggplant Wizard

Well I imagine the tachometer on these cars is a digital device controlled by the ECU. I suspect Audi tried to get cute and put some logic in their software to anticipate where the needle should be in response to inputs rather than simply displaying a real reading from the engine. There seem to be some bugs in the logic. On the DSG cars, if you floor it and cause the transmission to skip several gears on a downshift, sometimes the tach needle gets confused and bounces around like it's having a seizure. It clearly isn't reflecting the actual engine RPM in those cases.

NWS4Guy

This might be due to the very quiet timing of the engine - when using a Gtech, it cannot pick up the RPMs from the cigarette lighter like it can in most cars - timing is very insulated.

RX Renesis

if ur coasting IN GEAR with foot off the gas pedal, fuel is not injected into the engine to keep it from stalling because the wheels will turn the engine.

if ur coasting OUT OF GEAR with foot off the gas pedal, fuel is INJECTED to keep the engine running because the wheels are no longer turning the engine.

RX Renesis

hmm cant seem to be able to find the edit post button, so i'll add this here.

i forgot to mention that in senario 1, the cluth has to be out, cause if u push the clutch IN with the gear stick IN gear, ur estentially OUT OF GEAR.

orderedanalog

Thanks for your answers guys! I never knew that, it makes sense now that you've all explained it. Guess that's a bad habit...Feel kinda stupid here.

Well, I'm not buying this car for MPG anyways. I figure I take a 3-5 mpg hit down from my A3 which I average 23-24 in on a daily basis, but that's not a bad decrease considering the extra 125 hp I'm getting!

rktskicar

dude, I think you just have a f**ed clutch. mine is fine, been driving MT's now for 39 years. Driven many clutches, this B8 S4 clutch is fine.

Bruce

BaLLZDeePNYC

No my clutch is new its just not as comfortable as others. its almost like BMWs and the Clutch delay valves they put on there cars. You would never know i hate my clutch lol cause i drive it smooth just takes more finessing on these cars than older clutches. I wonder does our car have a CDV?

And my clutch was bad before trust me it was all screwed they replaced whole clutch and flywheel under 3k miles im up to 4300k now and its much much better but still not the best clutch on the road.

Also I think clutches coupled with AWD in general take more finessing due to the more complicated drivetrain. they just feel different than lets say my 2004 350z clutch

vwong

I agree with Bruce. I think the B8 S4 clutch is perfectly fine for daily driving. I just feel that the clutch may not be up to par for more aggressive driving (like on the track, the clutch could slip a little).


That's a lot of freaking miles!!!