sautan

Hello. Not sure if someone asked before but I could not find anything. I understand the racing line can have many factors such as elevation change, camber, and actual racing condition. I understand best way is to drive the line and test it out. However, is there a standard method to compute ideal racing line just based on map?

I am using circle and straight line to connect each other. No clue if this is correct or not. Please advise.

ProCoach

wanna911

Race line, de line or qualifying line......

Race line is very dynamic.

ProCoach

Very?

Shouldn't be...

This is my favorite "simple" explanation. http://speedsecretsweekly.com/wp-con...s-Weekly-1.pdf

IF the car is driven to the limits of it's adhesion, AS MUCH OF THE TIME AS POSSIBLE, the line is defined BY physics, FOR the particular driver/car combination.

Not the other way around...

Twenty pages...

jscott82

This is a great question. Circle and straight line, is a common misconception, and one that I see some instructors propagating by oversimplifying the discussion.

In a perfect world its actually 2 parabolic curves (corner entry and corner exit are separate curves) and a straight line. That part you could probably compute.... Real world you have to throw in things like camber changes, bumps and pavement changes that will complicate the prototypical line.

996AE

Many novice drivers need to understand exit speed is critical as is what is the next corner all about.

Glen

I like to look at the track from google maps or earth satellite view....

ProCoach

Bingo. Start with the end in mind and work back.

Bingo. First step, period.

Yes.

LuigiVampa

Following someone who knows the line is usually the best way for me. If I am at a new track I find a "local" and latch onto their bumper.

wanna911

I agree that the ideal line is the same. However how it's presented depends on the drivers level of experience. A beginner may not apex turn 11 at Road Atlanta like pro's and advanced level drivers do. Maybe not even a new to Road Atlanta driver. It takes a little time to know where you are. Also the turn 3 complex. Lines will vary as you learn the track. I still see advanced level drivers going way too far right for 2. But it's safe, and sets up easier braking for 3 so acceptable imo.

As for the racing line I was moreso referring to defensive vs open laps and maybe slightly more tire wear friendly line when doing laps 2-3 seconds off max pace.

9114609048

The only book I ever read about racing and finding the correct line was written by Ritchie Ginther. It was a good read, but my real education at a new track came by following other drivers. After four SCCA stock sedan races, I bought a used 911 and entered the '73 IMSA Daytona Paul Revere 250. I had never been to Daytona before and every time I got passed, I'd try and follow for as long as I could. I'd go on and DNF in that race, but a few years later I finished 2nd to Holbert, then I won it overall in '77, after a good race with Haywood.

"find a "local" and latch onto their bumper". Great advice!

sautan

Thanks for all the input. I totally understand actual ideal racing line can be different during actual driving. However, I am just trying to find out how I can properly (mathematical formula / method) draw out the ideal racing by just looking at map and put away all other possible factors of camber, bump, elevation change, and etc.Simply looking at the google satellite map.

ProCoach

A good guide is that unless there is a compelling reason not to, ALWAYS use the FULL width of the track in these calculations.

The exceptions are well known by folks that study them. The aforementioned Road Atlanta T2 and T11, VIR T4A and T4B, Summit Point Turn 4-Turn 5... The list goes on, but I think Glen's comment (the perusal and study of the Google Earth maps) is the best starting point.

George's recommendation is SUPERB. It was actually Alan Johnson who was the author (and a successful Porsche dealer and multi-time National Champion) with Richie's input, who wrote "Driving in Competition," here:

What Alan did before anyone else was to study similarities in the most efficacious way through particular corners, then classify them one of three different ways, Type 1, Type 2 and Type 3, in order to standardize the approach, prioritize and optimize performance through each of them.

You should get this book as well, because it's still a reference for folks who are trying to do this 42 years later. I think a new version was scheduled to come out

ProCoach

What did the driver DO? THAT is the question...

Scooby921

This is a major part of my approach. I spent several years running 15-20 autocrosses a year. You have to learn a new course and new line at every event. It's always a balance between conserving speed and shortening the distance between corners. Every third or fourth corner I'd look back and see if the planned line was still going to be effective, or if a new course element required me to place the car elsewhere for a better exit from the next corner. Knowing where you want to end up makes it much easier to see the path leading up to it. You can't look at every corner as an individual event and rely on starting wide, clipping the apex, and tracking back out to result in the fastest lap time.

As was mentioned by another, the physical track surface and topography will have an impact on your racing line as well. You can look at satellite views and plan ahead for when you arrive, but you'll have to adjust your line if there are bumps which impact braking, cornering, or accelerating. During an event you may find yourself adjusting your line as people start dropping wheels off track and drag dust and debris back on. Your entire line can change when it rains as the normal racing line might be slick with oil that inevitably drips off cars, or the rubber embedded into the racing surface is now slippery. Then you add in the up or down hill nature of a corner and it changes things again.