Maximum Downshift Question
 

Over the weekend I pulled out my stock 85 MPH Speedometer (pretty crazy!), and am going to ship it out to Helmut at North Hollywood tomorrow to update to 160 MPH. I am also going to have him indicate Maximum Downshift point on the speedo as well. My factory manual indicated the following:

o 1st Gear 36 MPH
o 2nd Gear 63 MPH
o 3rd Gear 95 MPH
o 4th Gear 118 MPH

Ok, now I know I never will downshift into 1st at anywhere near 36, in fact I don't know if I could even shift into first at 5. But has anyone actually downshifted from 3rd into 2nd at 63 MPH!!. Is this safe, and commonly done without worry? I am sure I wouldn't make this a habit, but those are some damn tall numbers!

Looks pretty good to me, seems those speeds coincide with my rev limiter. :D I wouldn't bother with first gear, if your down shifting into first at 36mph, you probable won't be doing it for long.

downshifting to a gear where you will be at the redline does not make any sense, you should be in the power band in the gear you are in. If you are down shifting on the track, and expect to still slow down more before you need the power, just don't let the clutch out until you are at corner entry speed, ideally you should be in a gear that will allow you to be at you best possible position in your power band.

not really an answer to your question,

Jim

You may want to double check your manual. I think the manual says the maximum speed in a gear corresponds to those numbers, but will then probably specify different numbers for maximum downshift speeds.

I know those nembers look like the numbers in my manual, but not for downshift points.

I can't think of any situation where you'd want to downshift into a gear at a speed that close to redline.

Maybe some of the guys who drive track events can be of better help but I would think shift points on a speedo would be distracting (+ I dont think your a looking at your speedo when driving track events). From what I understand (and what I do when I drive) the sound of your exhaust note is the indicator of shift points both up and down. Maybe marks on your tach with bottom and top of power band would be better or a shift light instead of a clock. Just some thoughts from a rookie.



Only if you wanted a new engine.;)

I never watch my speedometer when downshifting. In fact, my last track car didn't have a speedometer, and I never missed it.

Harkens back to the days of VW Beetle and 356 speedos with I, II, III, and IV red marks!

One situation where it might be useful ... coming down Pike's Peak without brakes!

"I never watch my speedometer when downshifting. In fact, my last track car didn't have a speedometer, and I never missed it."

Heck, I never look at the tack on my track car (no speedo) just look for the shift light and listen to the exhaust note.

Jason

So that "would" be coming down Pikes Peak in a VW Beetle.

Regards

Hayden

there's a reason why real sports cars have the Tach in the center of the dash and not the speedo like most common cars....

Yes, who needs the speedometer anyway? Replace it whith something useful like this: :D

http://forums.pelicanparts.com/uploa...1064965274.jpg

yeah, and a jato rocket , to get that dial all the way round to 12G!!!

I agree that speeds can be a distraction and the rev-counter is central for good reasons.
As a generalisation I think those speeds are all about 15-20mph too high as changedown points. I do a lot of 911 driving on roads similar to Pikes Peak including the untarmaced sections (Good practice for hillclimbs as well as fun) and I find there is little point in changing down a gear unless you have at least 2000 rpm left to accelerate in the lower gear.
Exceptions might be to aid braking (no lectures on the pointlessness of engine braking, I've heard it already and I'm too old to change the way I drive) or for greater control in a bend or going down hill - this last I include with reservations: I think, as mentioned by Warren, driving down Pikes Peak with no brakes otherwise you need some revs left for it to be worthwhile changing down.

Post scriptum: I've seen Milu waking up before a hairpin that has to be completed in 2nd and dropping from 5th to 2nd to be at around 6000 in 2nd and go round at a constant 6000rpm, could that be a justifiable usage? - the swine also matches speeds so well that you hear it but don't feel it.
-Isa

Thats the sign of a perfect downshift, heel toed to perfection

I know. He also double declutches and also completes sustained changes like that. I hope Milu misses this thread as I had something nice to say about him;)

i don't see the point to this H&T thing :confused: i guess it's an American thing
i've done car handling courses and none of those even mentioned it..
i do know that double clutching is redundant and doesn't gives any edge over normal clutching with working synchro's

Which car handling courses have you completed?
I believe it is still: part of the UK Police class 1 driver tuition; taught by instructors of the HPC and by some Porsche approved instructors.
Try talking to your instructors, they may tell you they are superfluous, advanced or track only techniques. Master them anyway and then make up your own informed mind:)

slipcourse , handling under rain conditions FWD
then a 2 day racing course at Spa , FWD
and the last one was a drifting course with RWD

Use the brakes to slow the car not the engine.
The car does not care what gear you are in (as long as engine braking is not a factor) during the turn in.

At the end of the straight my attention is aware of my braking and turn in referance points, traffic around me, track condition and preparing to either threshold or trail brake along with car control. It is a critical time to expect to divert my attention to speedo downshift points.

The greatest fear in down shifting is mechanically over reving the engine or locking the rear tires (not good in a corner), perhaps that is what your marks hope to avoid?