I am one of those guys who downshifts to slow a car down...I rarely coast to a stop..using only my brakes. The result : low gas mileage and maybe some excessive engine wear. I also blip the throttle on downshifts. My question is should I be coasting more...using up my brakes and letting my engine get a break. One of the reasons why I downshift is that the car stays in, or closer to, its power curve. I am curious what other people think. I know the argument that brake shoes are cheaper than clutches...ok I understand that one...but what else?...AND, if I did change my driving habits, how much increase in MPG could I see? I have averaged only 18.5 mpg on my 2.8 12V car since I bought it in July 97.<p>TIA<p>Steve S.<br>97 2.8QM

Brake pads are cheap compared to clutches and transmission work. Every time you shift, you change gears which wears gears, input shaft, clutch, flywheel , syncros etc etc.

In heavy traffic, it pays to downshift. That's because every time you touch your brakes, the guy behind you will by force of habit automatically get on his brakes a little harder, and so on, and so on. Slowing down by engine braking leads directly to a smoother traffic flow. (I take a certain amount of pride in not touching my brakes except for dead stops all the way home from work -- eastbound on the Schuykill from Conshohocken to 676 at 6PM!) <p>In any case, it shouldn't affect the life of your clutch significantly. If anyone is *that* worried about "wear and tear" on their transmission, they should just stay in 1st all day....

I have driven two manual cars past 90,000 miles without any clutch problems, and I downshift all the time. If you can properly 'blip' the accelerator, there shouldn't be any appreciable problems. I'm not sure about downshifting being a reason for better traffic flow, but I am sure that instant acceleration and emergency manuevers are pretty hard to pull off in neutral. When I was taught to drive stick, that is why I was told to stay in gear, so I always had an out. Now, in addition to that, it's just plain more fun to drive that way!

I never downshift unless there is a reason. If I am coming to a stop sign, esp if there is no traffic, I'll just take it out of gear and drift, and I'll drift as far as I can to save fuel. Otoh, in heavy traffic, I also attempt to use the brakes minimally, using engine speed and downshifting to control the car. I'll also downshift for fun, too, like when cornering for fun. It's great to go through a tight curve passing some moron in a truck or exploitation on the outside at double or triple their speed with no brake application whatsoever <G><G><G>! However, basically I avoid downshifting as a matter of habit to save fuel and wear and tear - I look for a reason to keep in gear rather that look for a reason to put it in neutral (as it seems most people on this board do - I just have yet to be convinced of the logic).<p>Having said all that, I think you know more about performance driving than I do, Steve, from knowing you on this board, and you may not _want_ my opinion :-)! But, you did ask!<p>Darryl<br>98.5 1.8T qms<br>95 Outback m<br>81 280ZX GL m

I understand your point of avoiding the brakes to help keep the traffic running smoothly. But with the idiots out on the 'Sure-kill" expressway that tend to tailgate, your brake lights will help to keep them out of your backseat. If they don't see the brake light they may not realize you are slowing and will have less time to react. <p>Just a word of caution to prevent any unnecessary collisions. I wouldn't want any harm done to any A4s out there or their owners.<p>Dave<br>

Whenever i see a red light far in the distance, and just want to "coast" to the light, i usualy pop my car out of gear without using the clutch. I just tap the gas and apply a little pressure on the shifter and the car will smoothly pop out of gear. <p>Does anyone think this is bad? I know NOT to do this when the cruise control is on!<p>Christian J. Long

There's a certain amount of "false alarm" brake lights seen when driving in heavy traffic. Many people press their brake pedals several times a minute, even when they're not really slowing down at all. <p>This causes the driver behind to eventually ignore or devalue the "warning -- I'm slowing down" information provided by the brake lights (otherwise known as the "boy who cried wolf" syndrome).<p>So I would argue that you're better off saving your brake lights for those times when you're *dramatically* slowing. The drivers behind you will know that your red lights *really* mean SLOW DOWN!! <p>My 2 cents.

Trannys are VERY expensive...so I would not make that a regular habit if I were you. Coasting probably is fine...but depress the clutch to get it out of gear.<p>I use to have an MGB with no synchro first gear....the previous owner made sure<br>to jam it into gear before the car was fully stopped...hence he took out first gear.<br>You ever try to own and operate a car without first gear? Try doing it for 9 months.<br>Blaaaaaaaaaaaa....can you say bogggggg.<p>Steve S.<br>97 2.8QM<br>

I notice my German and Italian friends and co-workers who learned driving in their country downshift to slow down. <p>Taking the foot off the gas pedal before a curve<br>to use engine brake and downshift to slow down was necessary to pass the driving test in my country.<br>I usually downshift.<br>I'm aware of the clutch wear vs.the brake wear debates, but I personally think downshifting is<br>one of fun parts of driving a stick shift.<p>Nozomi

Steve,<p>I was just thinking about this (ABS vs. Torsen) the other day as the streets got wet and cold. If you are in a slippery condition, which will be better in slowing down the car - use brakes (ABS), or down shift with Quattro (Torsen).<p>Will the Torsen work in reverse? That is - while downshifting, if one of the wheel started slipping, will the Q shift the braking force to other three wheels?<p>If that is the case, then downshifting seems like a better way to go in most cases. ABS will not come in to play until the wheel is completely locked up.<p>CSR - 97QM

ABS is supposed to control slip during the application of brakes (and attempts to reduce speed).<p>The TorSen is supposed to distribute power to reduce wheel slip during the application of power (in attempts to accelerate or at least, not in a braking situation).<p>If you are using engine braking, and not pushing the gas pedal, then the TorSen should have no effect. There is no torque being generated for it to distribute.<p>Anyone disagree?<p>

If you look at the diagram of the Torsen system and also read the patents on it, you will find that the torsen system applies in only one direction, and if you use engine to brake, then the torque applied on the system is effectively 0 in the forward direction, therefore the system is not of any use when it comes to braking. My personal 2 cents, I engine brake when the road conditions are less than ideal and the rest of the time I use brakes because brake pads and new rotors are cheaper than a new engine and or a new tranny.<p>Albert

Steve, Do you have any throttle body mods? Air filter? I get 23 mpg on my 12v. I should say that as much as half of my mileage is highway. I had an 80 Accord that I always coasted to a stop in. Warped rotors and new brakes at about 40,000. <br>From then on, double-clutching through every gear along the way, as follows:<p>Toyota truck- 40,000 to 140,000 replaced factory brakes. No clutch,no engine,no transmission.<p>Accord-new to 165,000 one set of brakes, No clutch,no engine,no transmission.<p>A4- almost lost my wheel when the nimrods that mounted my new tires didn't tighten my lug nuts well. Noticed that my brake pads at 50,000 miles are more than 1/4 inch wide. No clutch,no engine,no transmission.<p>I think that downshifting possibly could cause a higher wear rate,but I'll bet on average it is only slightly worse. Doesn't it just feel right to always be in gear. Another thing is that I rarely come to a full stop except at a traffic light.<p>Bill Shaffer<p>

Ok, lets see if I can make some sense here. When you accelerate the engine is moving the wheels and when you downshift to deaccelerate, then the wheels are moving the engine. This causes and increase in engine vacum. Excessive backpressure can cause many things mainly leaking valve guides wich by the way is the leading cause of oil consumption, not the rings. Another con is oil blowing by the rings. When the engine is off power, the rings are not forced into the top part of the ring grove and more blow by is the result. I'm not going to sit here and tell you that engine braking will cause your car to use oil and your oil will get over contaminated, but from one friend to many as and engine builder I would never recommend it. Use those Rofens Steve! :)<p>Corey

nt<br>

I'm no expert, but according to Bob Bondurant's book on performance driving, downshifting is not needed to slow the car with todays 4 wheel disk brakes. Rather, he explains the downshift (done heel-toe of course)is used to keep the car in balance. So it not only keeps the car in the powerband but also keeps the proper weight distribution when you accelerate out of the turn.<p>29 mpg 97 1.8T Quattro (highway miles, 53,400!)

At my last track session, an EURO-Spec M3 (1 of 44 brought to North America - all yellow - all imported to Canada) had a piston thrown through the block when the shifter bound and the driver shifted from 5th to 2nd entering a corner. Ouch. Many of us cried in sympathy.<p>I never use engine braking on the track. My car is in 1 of 3 states:<br>- speeding up (hard on accelerator)<br>- constant speed (balance through corner)<br>- slowing down (hard on brakes)<p>At track speeds, where my engine is usually sitting at close to redline anyway, engine braking would be asking for trouble.<p><br>DC<br>94 S4

Hello Steve<p>Here in Switzerland if you push hard down<br>a mountain road without using the engine<br>brake there is a lot of chance that you run<br>out of brakes after 15 curves... now by saying<br>that I mean it is absolutely not a problem to<br>use engine brake providing the fact that you<br>DO NOT downshift WITHOUT keeping the rpm in<br>an appropriate range otherwise you'll kill<br>your clutch and even worth your engine. Engines<br>hate radical rpm changes when you downshift.<br>Now regarding fuel saving, engine wear, etc...no <br>mysteries, this way of driving is more expensive <br>but I would say forget it, heel/toe and enjoy !<p>Greetings Laurent