Rookie Q: Determining Shift Points

[search161]

SlowPoke stated in the "What I learned..." thread:

Before the driver's meeting, you should be able to recall the whole course with your eyes closed, noting shift points, braking zones...

My question is: how do you determine shifting points?

After my first lap where I didn't take it out of second after I got it there, I tried to note where the pickup was slow out of corners and work backwards from there. I take it there's a point where I'll instrinsically understand which gear I should be in simply based on the walking the course layout?

ie: The left turn after the third pass through the triple cones is tight and leads down to a tight right - I'll need to get down into 1st late into that left and keep it there until I'm coming out of the right hander...

The next question would be how to determine when a quick shift up and then down again would be better than simply running high in the lower gear.

Final questions: Does anybody use stuff like this to analyze their run? http://www.gtechpro.com/rr.html
I'm computer nerd as well, so this gets my gadget radar pinging like CRAZY!!!
Or should I just learn what my engine sounds like around / at / in the red?

[Slowpoke]

Noting shift points on the first walk throughs is something that you guess at with experience. I was wrong on Sunday, actually, Daniel was right. :o I thought I would have to go to first at the hairpin at the end of the straightaway but I didn't have to. So, I usually do the first run through in second gear the whole way. I note where I bog, where I hit the rev limiter and adjust for the second run.

One thing to keep in mind while "bogging"... on the exit of a turn, you don't have your full "friction circle" available to you anyway. So unless you WANT power oversteer (RWD /AWD) you don't need "full power" until your steering wheel is fully unwound.

As for when to shift... you probably lose at least 0.3 seconds of time off throttle while shifting. Most people will bounce off the rev limiter for a second or two rather than shift. (Or if you're Marsh, half the course.) Basically, if you can avoid shifting, it's probably a better idea. Because once you go up, you must come down. Many people can't get their full downshift done in their braking zone, risking releasing the clutch mid-turn (possibly destabilizing the car on an imprecise rev-match), and splitting the driver's focus between shifting and the proper braking start, turn in point, apex and exit. Getting the line right through a corner is worth 0.3 seconds as well, so sometimes focusing 100% on the corner is better.

You have to know your powerband as well... mine reaches it's peak at 5500 rpm, falls off quicker after 5800 (though redline carries me to 7000). On road courses It's far easier for me to shift at 5800 to manage my powerband than in AutoX courses. Although I was at the rev limiter in second at the end of that straight (~85km/h) and I COULD have upshifted halfway down the straight for max powerband, it made no sense, really.

[Maddog]

When you have peak torque of 400+ around 3500 RPM, and 300 torque from 2000 to 5000 RPM, then you usually don't have to worry about shifting in autox. 2nd gear is my best friend :D

[search161]

Thanks, Slowpoke!

I don't loose many horses in my upper rev range, and the engine seems happy there. So I think I'll make sure I run high in 1st a little more often. I'm used to thinking in straight lines (highway on ramps) and so am programmed to shift just before redline. I'll have to deprogram that for these events.

Seems like I have a much taller 2nd gear that you, I can hit 100 before shifting to 3rd. I guess it's more than just the horses and awd that cause that slingshot effect in those WRXs! I'll have to start practicing my 1-2-1 shifts some more!

[MitS]

Thanks, Slowpoke!

I don't loose many horses in my upper rev range, and the engine seems happy there. So I think I'll make sure I run high in 1st a little more often. I'm used to thinking in straight lines (highway on ramps) and so am programmed to shift just before redline. I'll have to deprogram that for these events.

Seems like I have a much taller 2nd gear that you, I can hit 100 before shifting to 3rd. I guess it's more than just the horses and awd that cause that slingshot effect in those WRXs! I'll have to start practicing my 1-2-1 shifts some more!

If you are driving a 1.8T (assumed from your wheel thread) you will want to pick your shift points carefully. If you are out of boost it will hurt your times. Some events I can tell where I have to go back to first, others I have to try both and see if my time improves one way or another. I'd prefer to stay in second as much as possible but well chosen shifts can pay big dividends. If you are bogging, first gear becomes a no brainer.

Above 5500RPM you are getting into the land of diminishing returns on the stock turbo and shifting to second early can be beneficial. At the drag strip I never shift below 7000RPM but when turns are involved it's completely different.

[search161]

I am indeed, Mits. And you're right about the boost, it's just that I still think in terms of the general ability to put power to the wheels as opposed to more exact / technical reasons. I'll get there though.

The lap where I stayed in 2nd was certainly my smoothest (in terms of ride quality), and certainly my slowest. The reason I asked about shift points was in trying to gain more time I went into second at one point but brought it in to the corner before the straight too hot and had to scrub down to close to 0. Turns out that was my fastest lap by more than a second though, so I know I'm on the right track.

I'm hoping to be out at the event on the 13th. I would be great to see another 'Dub at one of these besides the Green Monster. Can I call shotgun for your ride now, or do I have to wait until I can see the car?

[Daniel]

When I had my WRX (2.0 Litre Turbo and plenty of lag....), I almost never shifted to 1st. More often than not it paid off to focus on nailing the braking point and the line and just dealing with a bit of bog - no matter how frustrating it was. If you get the speed and line right, you'll come out the other side faster every time..... ;)

and as a bonus, your transmission will thank you.....

Mr. "Slowpoke" STi, makes an excellent point here:

"One thing to keep in mind while "bogging"... on the exit of a turn, you don't have your full "friction circle" available to you anyway. So unless you WANT power oversteer (RWD /AWD) you don't need "full power" until your steering wheel is fully unwound."

Comes in to play even more with a front wheel drive, unless you have a LSD.

[MitS]

I am indeed, Mits. And you're right about the boost, it's just that I still think in terms of the general ability to put power to the wheels as opposed to more exact / technical reasons. I'll get there though.

The lap where I stayed in 2nd was certainly my smoothest (in terms of ride quality), and certainly my slowest. The reason I asked about shift points was in trying to gain more time I went into second at one point but brought it in to the corner before the straight too hot and had to scrub down to close to 0. Turns out that was my fastest lap by more than a second though, so I know I'm on the right track.

I'm hoping to be out at the event on the 13th. I would be great to see another 'Dub at one of these besides the Green Monster. Can I call shotgun for your ride now, or do I have to wait until I can see the car?

I will be doing the PITL series but my car won't be ready for the first event of the season. I've got a few things that need attention so. H2sport couldn't get me in until the 18th so I'm a spectator for the first couple events.

It will be nice to see another VW out there. Too many of them only go to the donut shop. Passengers are always welcome in my car.

[search161]

How's H2Sport treating you??? I've been in email discussions with them for the last week or so, figuring out details for coil-overs and ECU reprogramming. Everything so far seems great, except that the Stage 1 spindles aren't in stock. :(

[miataboi]

I will be doing the PITL series but my car won't be ready for the first event of the season. I've got a few things that need attention so. H2sport couldn't get me in until the 18th so I'm a spectator for the first couple events.

It will be nice to see another VW out there. Too many of them only go to the donut shop. Passengers are always welcome in my car.

You may be in luck..

the first PITL has been shifted to the 28th.

More info to come...

[Doug Phillips]

You may be in luck..

the first PITL has been shifted to the 28th.

More info to come...

Is there an event on 13 May or not. :confused:

I just cancelled plans to go to TLMC this Sunday to attend next Saturday. I may be out of luck for both.

Doug

[MitS]

You may be in luck..

the first PITL has been shifted to the 28th.

More info to come...

Hmm, this would be perfect for me! I don't want to miss any this year. I've been working too hard and need some fun.