I can understand what you're talking about, 'cause been thru close to a dozen motors myself.... I haven't been through any of these overhead cammers, but all of the pushrod motors had one thing in common. That was tollerances so loose, you could see them. The amount of slop in a crank (the lateral travel) was just reduculous. That was the advantage all of the Japanese manufacturers had on us dumb ol' round eyes.... they had engineered things so that they wouldn't beat themselves to death. That's exactly what all of the Windsors I had been through had done, or were doing. I know these mod motors are a lot tighter, and a lot less prone to self destruct.
All in all.... I'd rather have fun in mine. I certainly don't abuse it. I'm **** about speed bumps, and I feel like a door ding would devalue the car like a full on wreck.... but I didn't spend all this money on it to keep it in my museum. It's kinda like health nuts.... they're gonna feel really stupid when they're laying in their death bed... dying of NOTHING.

 

ok I am going to throw my 2 cents in.

In the State of California according to the DMV you must be in the right gear for the speed at which you are traveling.

Thus if you were to try your little clutch in and hold while rolling to a stop you would get points marked off on your driving test for failure to engage the proper gear while coming to a stop.

That said I have been driving for more then 18 years, all manuals etc the manu-sport Mazda 6 I had for a brief time.

ALWAYS ALWAYS downshift when slowing down.

Your trans is designed to do this, not only is it better for the motor, by using positive ring pressure to keep your cylinders working right but better for the clutch pressure plate and brake system.

When you engage the clutch by pressing it in you are withdrawing the clutch pressure plate causing the clutch pak to disengage from the fly wheel at speed say 40 or 50 mph as you approach a stop your rpms might be say 2,500 (lets just say). Now you press in the clutch causing the clutch pak to spin on the input shaft at high speed. Sometimes due to friction loss etc the clutch pak is no longer perfectly balanced, so this off balanced rotational inertia causes unequal stress on the throw out bearing, usually resulting in pre-mature failure when using this process over a long period of time.

Now lets look at the brakes, when you are at speed and you disengage the clutch, you remove the drivetrain from the system in regards to slowing the momentum of the vehicle down. The total weight transfer is now almost 90% or more to the front, since you have taken out the drag friction of the rear wheels/rear end since they are in free rotation now. So you will be replacing front brakes twice as fast typically.

Now lets say you are "free wheeling" it to the stop infront of you and some moron darts right in front of you. Your first reaction is going to be hit the brakes. BUT you left foot is holding the clutch in, so one of two things is going to happen you will hit the break with your right (like you should) while holding the clutch in (this method increases your stopping distance traveled, since you do not have the added benefit of engine breaking) this will 90% of the time cause you to rear end the moron in front of you.. still your fault by the way.

OR since the sudden action of the moron in front of you might take you by surprise some people will release the clutch and hit the break with their left, usually while their hand is hovering over 1 or 2nd gear. Now 50mph in first usually does not engage so that added split second distraction usually means, little or no braking, no engine engagement and big accident.

Your engine and trans was designed to be accelerated and decelerated. So if you are not using engine breaking you are really just breaking your engine (sooner then someone would ever ruin their drive train from downshifting to a stop)

 

Nosferatu... you are the man.

 

Good Gawd! I've grown three new chest hairs just reading this post...

 

What he said.

 

I've pulled 3 out reading some of these answers! Got black stripes on that car yet pitpup???

 

Ok so question to you guys....

If I am rev matching to downshift ....
Clutch in, shifter to N + blip throttle + in gear, release clutch...

Let's say I can't nail the EXACT RPM for a match... close..
If you are too low, you feel the rpms rise a bit
If you are too high, you fee the rpms drop quickly as they make the connection... (i'm talking +/- 300-700RPM)

Is this hard on the parts? or is it a built in tolerance
As between each gear, I am kinda near the right RPM when downshifting, but its not dead on all the time.

Advice guys

 

Quote:

Originally Posted by Boomer

Ok so question to you guys....

If I am rev matching to downshift ....
Clutch in, shifter to N + blip throttle + in gear, release clutch...

Let's say I can't nail the EXACT RPM for a match... close..
If you are too low, you feel the rpms rise a bit
If you are too high, you fee the rpms drop quickly as they make the connection... (i'm talking +/- 300-700RPM)

Is this hard on the parts? or is it a built in tolerance
As between each gear, I am kinda near the right RPM when downshifting, but its not dead on all the time.

Advice guys

Actually you don't need to stall your shift at N while blipping the throttle. (a lot of the older crash boxes required a double clutch to downshift)
Modern transmissions are very forgiving in this manner, as you no longer have to double clutch to select a lower gear.

I recommend using this pattern at a moderate shift speed. (almost a shy 2 seconds)

Clutch in, blip throttle + Select lower gear, clutch out, gas.


Actually there are several variations to to this pattern but the above is the most common. I have about four different variations to "rev match" downshifting I use at the track, but stick with that one for now.

Higher revs are better as you are not jolting the engine to get up to speed to match the tranny RPMs. It's far easier for your engine to stay in it's power band if you over rev while downshifting. Taking a downshift while not being in the right RPM range can cost you valuable seconds on the track.

Hard on parts... well, that's subjective. Lets say you need to be at 5200 RPM to down shift smoothly. If you are close to the Exact RPM but a little low, say 5000 or 5100 it won't really hurt anything. But, if you are no where near the correct RPM, say around 2500, then yes you will begin to mess up your syncros.

 

This is exactly the way I downshift if I am slowing down in a higher gear and want to get up to speed again quickly. I have seen a number of people who downshift to slow not doing the rev matching, getting the drivetrain to lurch, then continue on down. In my opinion, this is the cause of wear.


Bingo! The rev matching is crucial.

If am traveling at highway speeds (55+ mph) in 5th gear and then slow down to exit, I leave it there until the speed is somwhere around 30 mph, perform the above downshift, then travel in 3rd gear. If I needed to slow to a stop, I would shift out of gear at about 20 mph, take my foot off the clutch, and then use only the brakes to stop.

Based on what people have posted here about downshifting to slow down, moving from 5-4-3-2-1 seems like more work than necessary in this scenario. I suppose it depends on the stopping distance you have to cover.

This has been an interesting discussion so far.

 

Yeah its in the near range..nothing like a 2000 hop or anything.

But I do notice that if I overshoot by a bit, theres a slight movement (as the engine slows to match the wheels ... rather than being COMPLETELY seemless... does that hurt anything? like is it excessive clutch wear or anything? or nothing to be worried about.
IE: Like having to shoot for say 3000 and hitting 3300-3500

 

I don't understand why so many think the engine is more effective at slowing the rear wheels than the rear brakes?

Your argument seems to argue that brakes alone will cause a longer stopping distance because the rear wheels will be free wheeling as you put it. But in my car when I step on the brakes, the rears are no longer free wheeling because my brakes are slowing them down.

If engine braking truly shortened stopping distances, automatic transmissions would be more dangerous, since they upshift on braking (according to a previous post.)

 

i always downshift through all the gears while stopping too.

 

Just to play devil's advocate here...

1. We don't all live in California
2. Once you have your license, there's no law that says you must be in the proper gear.
3. You can downshift while coming to a stop without letting the clutch out for each downshift, thus, you can be in the correct gear without engine braking.

I personally have done PLENTY of downshifting and engine braking over the years, and never wrecked a clutch because of it (that I know of). But it's common sense that it does cause more wear and stress on the driveline than simply letting the brakes do their job, so now, for stop signs at least, I never downshift through the gears. If that's considered babying my car, so be it...

 

I downshift, engine brake, and powershift whenever I get the urge. I have always driven like that. My first car, the original clutch started slipping and the engine would not hold compression at around 170K miles, second car same deal at 200K miles. Of course this car has more HP than the other two put together. I hope the drivetrain is up to it, but I did not get this car to drive it like a grandmother.

 

Most cars equipped with automatics will replace their brakes at a faster rate then a properly driven manual. 100% fact

The quote you are refering to about automatics upshifting has to do with driving downhill in an automatic, wheel speed and throttle input in this case tells the trans computer to go to a higher gear for fuel efficency, since most trans logic do not include an inclinmeter in the shift logic. Some higher end vehicles such as the 2005 - newer Toyota 4-runner Limited and sports have this feature and will not only automatically downshift but also through automatic ABS and TCS over-ride apply up to 10% braking pressure without driver input.

 

With regards to driving/braking with the engine off: because a majority of the cars on the road have power brakes, braking with the engine off is not a good idea. After each brake pedal depression with the engine off, the pedal gets harder and harder to depress.

Also, with the engine off, you lose your power steering... who would do that, anyway?

 

only weinies don't downshift while braking. WTF did u buy a mustang for? lol get a honda. cant figure out heel to downshifting lol?

 

Only weinies bring back a thread that's been dead for almost a year.

 

We can argue it until the cows and pigs and chickens and bison and wildebeests and mooses and elephants and albino tigers and chipmunks and prairie dogs come home. . .

But heel-and-toe is fun. Learn it for that, if for no other reason.