theiceman

this .... sometime it wont go when it is super cold and starting out .. so back to first

such is life in a classic 911

Scott997

This is an interesting 915 thread. It seems everyone's box has its own unique quirks based on its life.
I have gotten to know mine pretty well, but once in a while it protests and I just delicately acknowledge its request without getting mad and forcing it.

Something my 915 wants is what I call "breathing the clutch" whenever going back to first or into reverse. Letting the clutch all the way out and slowly, slowly going back into first or reverse.
Going from modern boxes I use to get so frustrated and try to force it, but then I realized what it took.

I use to think the 915 was not tolerable until I stopped fighting it and worked with it. Now since I had my pedals adjusted I can throttle roll and heal/toe downshift the car. First gear is just about the only thing that annoys me!

Replacing the transmission fluid, coupling, bushing, and adding the rennshift has made it so much better. I drive the car pretty much daily now.

JCP911S

The upshift is just a slight pause in neutral during the shift... no need to do anything else... the reciprocating mass of the engine will naturally drop to match the rotation speed of the drive-train.

Downshifts are another matter entirely... the reciprocating mass of the engine must be Accellerated to match the rotational speed of the drive-train.

Generally, this required "rev-matching" to do it properly. In neutral, the throttle is blipped before the shift to the lower gear completed. The better way to do it is to "double clutch"... in neutral, the clutch is engaged, the throttle blipped, the clutch disengaged, and the downshift completed... this requires two blips of the throttle, but provides much better matching of the engine mass and rear wheel speed.

When done while braking, the requires 'heel and toe" technique to match revs.

In street driving, most people just slip the clutch on downshifts, but in a racing situation, this technique is crucial.

ADias

How high do you rev when starting cold on your 1st 1-2 shift of the day?

I imagine you do not recommend shifting at 5kRPM when starting cold.

Scott997

On my 86 with over 70 degree ambient temps I can shift immediately without any negative feedback. Before my mechanic worked on fine tuning the shifter adjustments it was a rough pull.

pmax

I'm surprised how many do not know the 915 reverse gear, unlike any of the others, is not synchronized. Manual says to pause a few seconds before shifting to reverse.

theiceman

i'm sure more than a few of us have had the "ratatatatatat " reminder

Scott997

It takes long enough to get there from first!

gerry100

I found it helpful to think of the shift as "two beats" = out of one gear and into the next.

Hold the shift **** gently the 915 will tell you when its ready.

quick enough when you get the hang of it.

Involving and adds to the enjoyment of driving

GTgears

Start car.
Idle 2-3 minutes.
Drive. 1st 1-2 shift of the day at 4000rpms.

John H

'When executing the 1-2 shift, say "check" when pulling it out of first and then "book" when sliding it into second. It is not a one syllable move.