Let's say I'm doing 55mph in 6th gear and I get the sudden urge to race up to 90mph. What is the proper way to downshift into 3rd?

This is how I have been doing it: press the clutch, blip the throttle to 4,000 rpm as I downshift into third, then let go of the clutch, floor it.

Should I be double-clutching instead?

 

Try 4th, it's a little less harsh and still fast

 

No way, down to 2nd at 30-35, down to 3rd at 60, down to 4th at 80.

Blipping is not really necessary. If you are trying to do it quick, because it's "go time", just go straight to 3rd and let it loose. If you are setting up to make a fast pass or something, yeah, blip and run down through the gears to 3rd, or just blip. The tranny seems to hate to go from 6th to 4th, but 6th to 3rd is easy. It has some guides in there to keep you from accidentally going down to 4th when you were in 6th it feels like.

 

Bliping actually helps the tranny, but it is not absolutely necessary; unless you want the tranny to go to 100K mi. and you do this type of surges often.

Double de-clutching is not necessary at all, we have had syncrhomesh in cars for a decade now

 

So depressing the clutch then releasing it halfway thru the shift (while you are blipping the throttle) and then pressing it again and engaging the gear then releasing it again.......
This is "unncessary"????
You guys just go 6th to third no blipping and hit it???? Doesn't the car lurch like mad??
ZZ

 

I've done this twice when I was learning stick shift. I chirpped the tires downshifting from 6th to 3rd without blipping. Quite fun, feels like I get hit by a mack truck from behind. But I want my car to last a long time, so no more for me, which is why I posed this question.

 

Practice THIS and you will have no problem.

Drive in the gear that you would want if you must accelerate. (I.E. 3rd gear at 55MPH) and note the RPM (for a number, maybe 5000 RPM?)
_____________fill in the blank

Now if you are in 6th gear cruisin’ at 55MPH (maybe 1800 RPM?) and you want a clean down shift, you’ll need to have the engine RPM’s at about 100 (one hundred) more than the number you have put in the above blank. (5100 RPM in this example).

With practice, you’ll know (about) what RPM you need to match engine speed with car speed for any given gear.

IMO, double clutching is not a bad idea if one is “skipping” gears. I.E. 6th to 3rd.

Double clutching in this example is…..press clutch down, shift to neutral, let the clutch all the way up,(while in neutral) then press down again, shift into the gear of your choice (THAT CAN BE RPM MATCHED with out redlining !!!) and let clutch out with engine RPM a ”little” higher (50-100 RPM) for the given speed.

Hope this helps.
Scott

 

You all have to think about what RPM to downshift? I guess I didn't follow because I don't even think about that, it's all natural. Matching engine speed for each gear happens by sound and feel in a split second, I don't look at my tach.

 

"You all have to think about what RPM to downshift? I guess I didn't follow because I don't even think about that, it's all natural. Matching engine speed for each gear happens by sound and feel in a split second, I don't look at my tach. "


Rob, you're correct!

I do not recomend that someone "stare" at the tachometer while down shifting, but the little "exercise" was meant to give afr0puff and idea of where to start to develop a new skill.

All I pointed out was what experienced drivers do without thinking.....Matching revs to car speed takes practice, and more practice!

Scott

 

I am not sure of what technique this one is honestly

You are not supposed to slip the clutch in the middle the way you are describing. The purpose of bliping is to bring input and output shafts of the gears to same or close to same speed.

Double declutching was in the days of when we did not have synchromesh in our transmissions, it was an absolute necessity (God, I feel old) Without the synchromesh, it should be done as the Professor explained it, except that you can (on upshifts) and need to (during downshifts) blip the throttle when you let the clutch out with gear in nuetral.

With syncrhomesh, you depress clutch, [put gear in neutral, blip throttle, select new gear], let go of the clutch. The activities in brackets are done in overlap mode. Synchromesh is quite effective without bliping throttle on upshifts, but this needs to be done on downshifts unless you have dogleg transmission.

The actual purpose of matching input/output shafts speeds in the tranny is not to upset the car's balance during hard breaking (especially trailing oversteer breaking) while downshifting. If you let the tranny match input/output shafts' speeds, you will get a big lurch on the rear tires and you will loose control in this extreme stituation.

In daily driving, not necessary at all, unless as I mentioned earlier, you want to keep the car with this tranny for over 100K miles.

 

He meant "release the clutch when you are halfway through the process of shifting" not "halfway release the clutch while you are shifting."

-- Mark

 

Yes to the above!
I meant exactly what professor said-- just didn't put it the right way
I think I'm doing it right-- the car doesn't usually lurch at all.... I just wanted to make sure the double clutching is the right way to down shift... not just press the clutch, rev-match, then re-engage the clutch
Thanks
ZZ

 

Sorry for my misunderstanding, my fault

At the end my point is that you do not need to double-declutch due to the syncrhomesh, but of course no one will critisize you for doing it, no harm as long as the rev match is done

 

Thanks for the info, I was was wondering if double clutching was necessary, since I can never move fast enough to do it. Just one question, when did car transmissions start coming equipped with syncromesh? Is this something recent, or has it been used for the last decade or so?

 

The synchromesh has been around for quite a while (at least from my point of view). My mom's '79 Volvo Wagon had synchro's and so I learned how to drive a stick without needing to double clutch. I think that car was on it's original clutch when I learned how to drive (it would have been about 10 years old at that time).

Anyhow, my girlfriend's mom used to have a Fiat X19 (I think that's what it was - the little roadster) and it didn't have syncro's (or if it did, they were all worn out), so double clutching was the name of the game in that car. Not sure what year it was, but probably mid 70's.

-D'oh!

 

My '73 914 has synchros, and I'm pretty sure the beetles and the 60's american cars had synchros too.

d'oh - any chance you still have that volvo wagon around?