Hey guys i Was just curious if it was bad to down shift from lets say 5th to 4th to 3rd and 2nd too slow down or if driving in mild traffic. I know i have great breaks and i do use them.I been doing this for some time now on my previous cars and my p-car 32k miles no problems thank god. Also someone once told me idk how true it is or if its a bunch of crap but to down **** creates combustion or somthing. Thanks

 

Depends on how you're downshifting. I love a good downshift, and almost always do it as part of slowing down. But I blip the throttle, and heel-and-toe if I'm braking, which doesn't cause much wear on the clutch, and allows you to practice techniques for the track during your everyday driving.

BUT, if you're just downshifting and slipping the clutch to engage the next gear without matching rev's, then you're essentially using the clutch to slow the car. Clutches are much more expensive than brake pads, so I wouldn't use this technique...

 

As rye said, you want to blip the throttle to rev match to keep clutch wear to a minimum. If you don't do this you will be accelerating clutch wear and as rye said, brake pads are cheaper than a clutch.

Dave

 

Thanks guys i was meaning down shifting to kinda slow down i guess its a bad habbit, but also i tried the rev matching with the blip its not easy matching the revs i guess practice makes perfect.

 

IMO its not good to.

You downshift to have the car ready to accelerate out of a turn in the proper gear.

You brake to slow down the car.


The sequence is brake…then shift…then turn.

If you coming to a stop and want to go from 5 to 4 to 3 to 2 you can rev match as the others say but what’s the point unless you are practicing heel/toe. Might as well slow the car and go from 5 to 2 and heel toe once, which IMO is actually better to practice.

 

Ok so no more downshifting like that unless your heel/toe use. If your in third gear coming to a light just use the breaks. How do i figure out the rev matchs lets say from 3rd to 2nd

 

Downshifting to brake isn't the best, downshift to get more power to accelerate.

 

yep. gears to go, brakes to slow. nuff said.

 

I don't totally agree. There are times that using your gears are much preferred versus using your brakes, like controlling speed coming down long grades or slowing gradually when road conditions are really slick due to rain or snow. Using your brakes on long grades will wear the brakes out prematurely. Even with ABS, using brakes under certain slick conditions will increase the chances of a skid or loss of directional control.

Under normal dry, flat driving conditions, lets say you are approaching a red light at 45 mph in the city and the light is several hundred yards ahead to allow a gradual stop. You let off of the gas and do a normal downshift from 6 to 5 or 5 to 4, you then begin a slow but consistent decelleration. As the cars speed continues to drop, there is no problem with downshifting to the next lower gear, without the "throttle blip" as long as you choose to downshift when the engine rpm's are matched to the cars speed and gear selection. You are not creating any premature wear on the clutch as long as the down shifts are crisp and quick and you aren't "slipping" the clutch. I normally get down to 2nd or 3rd this way and then just flip it in to neutral as you roll up the last 100 feet or so to the light.

I do agree it is not good to downshift from a high speed by pushing the clutch in, letting the engine rpm drop significantly, then let the clutch out unless it is an emergency stop situation and you are grabbing gears and full binders.

The heel-toe throttle blip is actually best used in a racing/performance driving situation where you are downshifting as you approach a curve. You want to keep the rpm up in the power band for your engine for the acceleration out of the curve, but also to not have the weight transfer too much to the front by using a lot brake. This helps keep the rear end hooked up especially with a rear engine vehicle.

Using the heel-toe throttle blip in normal driving is a great place to practice it so it becomes second nature, it's fune and in a Porsche it sounds great, but it isn't really neccesary in my opinion.

 

I once attended a Porsche Track Day with Derek Bell. if you don't know who he is, you probably have no business in a Porsche. The school was held at Road America, a track with three long high speed straights ending with 90 deg turns. On one of them you approach in 5th gear at 120-160 mph depending upon the car. I asked his advice about downshifting through the box to 3rd or 2nd gear for acceleration out of the turn. He pointed out that it would require 2 or 3 rapid downshifts in the braking zone requiring good heal and toe technique for matching the revs. While simultaneously concentrating on using the proper line. He called it three opportunities to miss a shift and possibly over rev the engine. He said you have some of the most powerful brakes currently sold in the world. Use them. It's much easier and cheaper to replace worn brake pads and rotors than clutches, pressure plates or the possible catastrophic money shift. Only in real competition is it necessary to add in the engine braking afforded by going down through the box. In competition, wear and tear on the power train components is an accepted cost to win. It's not necessary otherwise.

If that advice was good on the track, it applies even more on the street. Just use your brakes and drop into the proper gear when the car as slowed and you rev matched to it. You can go down through the box for the heck of it, but it's not necessary.

 

fred,

nice article on Derek Bell in December Panorama

 

Thanks for the great advice guys im no pro race car driver i may pretend to be haha but i know heel/toe is not easy i watched a race car driver on youtube just looks wayyy to difficult to much going on

 

I guess nobody over fifty has read this thread yet or they would have pointed out that years ago, the brakes on cars were not all that effective and they wore out more easily. It was recommended to all manual shift drivers at that time that they should learn to slow the car down by downshifting in combination with the brakes. The requirement for this is long gone and the prevailing thinking is more along the lines of use your brakes to slow down and your gears to speed up.

 

Just my two cents, if I am traveling on the highway and the traffic is slowing in front of me I brake and then blip the throttle to down shift a gear so that when I am letting the clutch out I am back in the 3-4K rpm range and not lugging the car down low when I need to accelerate again. So it is more like matching revs for the lower gear should traffic pick up again.

 

Does anybody know if the pdk has the same concerns re: wear? Isn't the tranny supposed to make shifts seamless? If I downshift say from 3rd at 4K to 2nd at 5K, does the pdk rev match and minimize clutch wear?