I'm a new (and happy!) A4 Quattro owner so sorry if this question sounds very basic for this forum:

When using the engine to brake by downshifting, how is the braking power delivered to the wheels? Is it delivered equally to all wheels?

If I happen to be downshifing and by chance hit a slippery area on the road, will the engine braking be uniform on all tires or ? I remember once I had this situation come up on a rear wheel drive and since a RWD transmission only applies power to one wheel, I had a very close call (did a 360 going at 50 mph on a freeway...I think my heart stopped for a few seconds!).

Quattro drives all 4 wheels all the time, power distribution is adjusted based on wheel slippage. This should hold true for when you are using the engine to brake as well. It certainly feels like that's what happens.

Regards,
Rodney

'99 A4 1.8tqms

I was reading one of the car mags (R&D or Motor Trend.. can't remember) that said you should only downshift when you need to accelerate and that you shouldn't downshift to slow down. What's everyone's view on this?

Mike D.
99.5 2.8qms

I read the article and agree. Break pads are much cheaper than a clutch and some engine work.

Torsen actually only works when loaded by torque. This is how ABS works in our car without driveline locking up under braking (4x4's lose ABS when on). But, there is still the driveline connection under engine braking, which "in effect" allows for 4 wheel engine braking.

Engine braking is actually a really important Q advantage for braking on snow and ice. It has saved me dozens of times when I couldn't brakes safely, but still wanted to slow down on glare ice. Downshifting just for grins is a lot of wear on the gears. Save it for emergencies and the track.

I down shift pretty much all the time (usually only to 3rd when coming to a stop.) Definitely downshift if you're driving an old country road! That's half the fun. It helps to match revs of course. I haven't run into any trouble with clutches yet.

Mario said it best...
Brake pads are a lot cheaper and easier to fix than clutches and transmissions... but those u-shift-ums are soooo much fun!

I really don't care what any article says, I bought a standard transmission not because I like to upshift but because i like to downshift. Into 3rd on a country road goes without saying. But how about a 90 degree turn, the light is with you, and you're in 3rd or 4th....you brake as you approach, and then....are you guys telling me you aren't downshifting into 2nd, making the most of that quattro and pulling yourselves thru that turn and feeling like you just came out of a slingshot? You're braking all the way through the turn instead? Because you want to save your precious clutch wear and tear?? My A4 is new, but I've got 111,000 miles on a Saab 900 with an original clutch that says this kind of driving won't wreck your car. And if you're leasing, well, what are you worrying about anyway. So fine, brake with the brakes when you're approaching that stop sign or stop light...there's no joy or excitement to be had in straight-line braking anyway, unless you like playing chicken. But through the turns? Friends, this is where it's AT.

Rick

I do it all the time (on both of my previous cars), especially when I approach a 90-degree right-hand turn. I like to have that power available when I accelerate out of the turn.

Now, only if I knew how to heel-and-toe properly...!! :)

It is terrible to leave the car in a gear that is too low!

If the engine has plenty of braking power it also has plenty of acceleration power and that is where you want to be. Forget about the clutch and transmission, worry about the idiot you have to pull away from, NOW.

I've always heard the brake pad vs. clutch discussion in the past, but have enjoyed downshifting most of my driving life (over 20 years). The only clutch I've ever repaired was on a manual Cherokee (no big surprise!). Has anyone actually had to replace a clutch on an Audi under 100K miles? If so, how did you drive it. Aren't we only talking about $3-400 for a replacement. Even if it is harder on the clutch, isn't it worth the driving satisfaction? I'd be interested in other's thoughts on the subject.

Will Rogers
99.5 A4 2.8QM

The A4 has wonderful brakes why not use those to slow down? I can see downshifting on hills to keep from accelerating or prior to a corner to be in the correct gear to exit the corner. There is no reason to down shift just to slow down.

There is a difference between downshifting and engine braking. Sounds like your doing it right. What the article was probably saying is use the brakes to slow down not the engine.

yup.. brakes are cheap,.. save the engine and transmission, clutch, linkage,.. use the brakes.

nt

The Torsen (torque-sensing) center differntial redistributes power from wheel that has minimal grip to others on acceleration;this generally means that wheel that is spinning fastest because it's slipping will get minimal power. Now, on engine braking, I would expect that the Torsen can sense that the wheel on slippery surface is not receiving traction, so it "disconnects" that wheel from the power delivery (engine). However, I am unsure!

Frome personal experience drivng FWD cars since 1970 and Quattros since 1991 in hilly Steelertown area, using engine braking invariably gives me better control in snow/ice than braking. I have been able to stop smoother and with better control by slowing down via downshift than brakes. Also, on driving, I try to use the highest gear in which the car will pull without lugging to minimize wheelspin.

Another scenario where engine braking is handy is when going down a very steep and slippery hill. Using the engine's braking power to slowly bring you down the hill gives you more control and therefore is much safer than using just the brakes. Plus, if you start off in a low gear (which you would in this situation) there's no problem of possible wear on the clutch due to downshifting.

Going back to the original question of this thread...does the Quattro system work the same when it's used in an engine braking manner?

The reason the auto downshifts is so you will be in the proper gear to accelerate! It does not do this to help you slow down.