Bob Rouleau

MarkSchu - I won't call myself a pro. There are occasions in racing when one does downshift in a corner, but to put it into perspective, you don't do it on a qualification lap unless you have an F1 style gear box, and maybe not even then.

Barber had it right.

Best,

ronbo56

I once got what I *think* is a good piece of advice (from an instructor who also advocated shifting about half way through the braking zone): if you somehow miss your shift point, *don't shift at the apex.* Carry the too-high gear through the corner and downshift as you accelerate and track out. If you're lucky you might make up the time, but even if not it's better than going off.

GlenL

How about a final note from the thread starter:

This discussion grew out of wanting to keep rpms lower in corners. This is due to oiling problems with rod bearings on the 928. One seized on my car, busted the rod and destroyed the block.

The next engine will have changes to the oil system....and a few more ponies, of course.

smlporsche

One more question from an amateur..

Example, Turn 1 at VIR comming off the front straight at about 130 MPH (for me) in 5th I have been doing what most here have advocated.

In talking to some of the faster S2 drivers some of them are advocating downshifting later in the braking zone and going directly from 5th to 3rd as opposed to me going from 5 to 4 then to 3.

Both of us are matching revs but the comment was that this allows him to brake perhaps a little later (by having less to do?) and therefore be a little faster.

Comments?

Also, another question at VIR; comming down into Hog Pen getting ready to enter the front straight I was in third but now find mydself runnig out of RPM's before track out. I'm taalking only about 50 feet or so. I've tried upshifting at this point but as others have said it is not a good time to be changing the balance of the car.

A fellow driver who was having the same problem tried shifting to 4th in the short straight before the righthander where the car "bottoms out" and although the car "feels slow" turning about 4000 to 4500 RPM's I'm able to shift into 5th a full 75 yards earlier so my exit speed has to be faster!

Later. a former PCA racer came for a ride with me and thought I was leaving something on the table and advocated going back to the first senario ??

Comments??

Thanks.

Larry Herman

As far as downshifting for turn 1, I prefer skipping from 5th to 3rd. It allows you to focus more on the initial application of the brakes, rather than being concerned with squeezing in 2 downshifts. Then again, there are those who advocate rowing down through each gear; more engine braking, harder to miss a gear, yada, yada, yada. I usually pass most of them under braking.

The problem in Hog Pen is more interesting. In the absence of sector times, all you really have is exit RPMs. The question is how much you are giving up by using 4th gear before the righthander. If you are getting more speed from the righthander out onto the straight, then it definitely is faster. BTW I had the same concern with using 3rd vs 4th at turn 11 at WG, and though it "felt" slower, 4th allowed me to carry more entry speed, and take a better line, yielding 300 more rpms at the S/F line.

Veloce Raptor

VIR turn 1: IMO, you do not want to super-late-brake this corner. Nor do you ever want top skip gears, IMO. There is just too much opportunity to go from 5th to 1st in your scenario (I have seen it happen). If you know your heel/toe technique, you should be able to brake at a reasonable spot, and then do a fast 5-4-3 double sownshift after 50% to 70% of your brake zone is complete....NO engine braking. And then back to power as you turn in, in order to use throttle to help rotate the car & allow you to unwind steering lock.

Hog Pen: I agree with being in a higher gear here. If nothing else, it will teach you to carry more momentum thru that entire section, which is very important.

JMHO...YMMV

Larry Herman

See, 2 totally different points of view on downshifting. I'm sure that Dave's technique works as well for him as mine does for me!

Veloce Raptor

Yup. No right or wrong here, IMO.

TD in DC

Out of all honesty, this is where data acquisition is very, very useful. It is possible to have a higher rpm at one point in a complex section but have a slower overall segment time. Of course, it might be that you sacrifice the overall segment time because it sets you up better for the next segment.

I struggle with gearing at several places at VIR. One place was entering the climbing esses. I am bouncing off the rev limiter in 4th before entry, so I can either feather the throttle in 4th all the way up or shift into 5th before entry and bog it out all the way down to the kink before oaktree. Being in 5th "felt" faster because you are in a higher gear all the way through. Turns out that the data shows that if you feather the throttle in fourth, you actually have a very slightly higher speed at the top of the esses. More importantly, though, it allows you to take Southbend faster and even gain more speed down the hill and through the kink to oaktree. Without a data logger, I would not have guessed that.

Veloce Raptor

Also, high RPM's are not always the fast way. Depends on the car & engine. Some cars make loads of torque, but rev them above their torque band & they only make noise. Sounds faster, but it's not!

Rob S

Veloce, are you suggesting clutch engagement during the drop from 5th to 4th on your way to 3rd, or simply rowing the shift lever into 4th gear momentarily so as to guide the shift lever more confidently into 3rd? I've felt that if there is need to shift down several gears in very rapid succession, there's little benefit from actually engaging the clutch in the intermediate gears. Frankly, I'm with Larry Herman on this: I think that for such situations, skipping gears is easiest on the equipment, it's faster, takes less concentration, and is less likely to unsettle the car. Of course, it must be done right to avoid some nasty consequences, like hitting the wrong gear. But then again, rapid sequential downshifting can also be done wrong and can wreak havoc on gearboxes, clutches, engines, and driving lines too. There was a very interesting video about a year and a half ago on one of these lists showing Leh Keen in a GT3 RS at Sebring, in a top qualifying lap, where he sequentially downshifted from 6th to 1st. It was an amazing display of fast and furious downshifting. All I saw was knees and elbows. But hey, I shouldn't criticize; he was very, very fast and you can't argue with success.

I showed that video to Mike Fitzgerald, who many of you may know or be aware of. He's been racing Porsches professionally in the Rolex 24 and other venues for years. He says he sometimes downshifts sequentially, and sometimes skips gears -- depending on a number of factors. He said that the German factory drivers often shift sequentially, while the Americans often skip gears. So how's that for a definitive answer to this question?

Veloce Raptor

Rob, the latter. I do not release clutch between 5 & 4. I merely blip throttle to keep internal synchro speeds aligned. I only release clutch when I get to 3rd.

Mike is right, which is why, IMHO, there is no "right" answer. FWIW, I will ONLY go sequentially....unless I really mess up!!

TD in DC

But . . . I thought that if you did not release the clutch the throttle blip would have no material effect. Am I mistaken?

Veloce Raptor

AFAIK, you still need to match speeds between wheels & internal synchros.

Rob S

I think TD is right. There is no change to the internal transmission shaft speeds when you blip without engaging the clutch. If you double clutch (i.e. engage the clutch while passing through neutral), then you'll be better matching the transmission input and output shaft speeds, which has the benefit of putting less load on the synchros. But if you never engage the clutch, then nothing happens inside the transmission in response to your blip. Or in theory, nothing happens, anyway.

I can imagine one reason for blipping, though, under the methods used by Veloce. That is: if for some reason he needed to engage an intermediate gear (say, 4th, while going 5-4-3), then he would potentially be rev matched and ready to engage the clutch in that gear. I can't think of when that might be necessary, but maybe he can.