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-   -   late apex or carry speed in 79 12a? (https://www.rx7club.com/race-car-tech-103/late-apex-carry-speed-79-12a-1022730/)

rithsleeper 01-09-13 08:14 PM

late apex or carry speed in 79 12a?
 
Ive been anylizing my track day videos and im convinced I should be trying to carry as much speed through turns as possible and not hitting late apexes so I can start accelerating earlier.... all the instructors ive been with keep telling me to brake hard, enter slower and get on accelerator earlier. Thing is, my main car has been my 89 modded corvette. And all my instuctors have driven c5 zo6.... my theory is if I have power over nimbleness then yes, take a late apex and use the power. However having only 100 hp I think any line that maintains a higher mph throughout the turn will make for faster lap times.

Am I on the right track or should I just trust the more experienced drivers? Seems like comparing apples to oranges.

eage8 01-09-13 09:08 PM

do both and compare your speed at the end of the straight afterwards. That's the easiest way to tell :)

Or you can record video and compare the time it took you to cover certain sections while trying both.

wlfpkrcn 01-09-13 11:14 PM

In like a Lamb, out like a lion.

A high HP car masks your mistakes/bad habits.

Proper lines and apexes is key to a fast lap. Start early apexing and you will drive off track or need to lift to keep it on track. Always drive the proper line and work on it from there.

jgrewe 01-09-13 11:39 PM

Slow in, fast out. You need to get the car rotated and start the next straight earlier. You still need to carry speed at the apex but earlier braking and getting the car pointed where you want to go pays off at the end of the next section.

I've looked at data between two identical World Challenge cars; one pro driver, one team owner's son. The owner's son had only done a few Skippy Schools and had only driven what we call the "pointy cars"/open wheel. He was driving hard into the corners, all elbos and arm pits through the turn and then hard down the next straight.

The paid driver was on the brakes harder, earlier, got the car rotated and he was at full throttle a full 100' earlier than the other driver. It kept him consistantly 3 seconds faster per lap at Sebring.

Kentetsu 01-10-13 03:46 PM

It really depends on what the next corner is like. Here's an example:

1. Corner is followed by a straight section = late apex (get's you started on the straight with power down sooner, which results in higher top speeds on straight).

2. Corner is followed immediately by another corner = sometimes better to make an early apex and carry some speed deep into the corner, since you have to go slow for the next one anyway.

:)



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rithsleeper 01-11-13 05:50 AM

Thanks for the advice. My whole thought was my car is super weak power wise and countering wind resistance in a straight is really tough. So my thought is if I can average 5 mph faster through a long turn and sacfice a few mph by end of next straight it would be worth it. I always feel like if I take the entrance slower and am able to start my accelerating earlier im full throttle before the exit, where my vette I would have huge understeer at full throttle that early in the same turn... im finding that my mph by end of the straight afterwards translates to only about 3 mph sacrifice but I carry about 5 mph more into the turn and through the first half. Ill really have to do some comparison.

The main turn in question is at cmp turn 567. Its a longer sweep and there are like 3 different lines people take. Also roebling turn 12 and 78 I believe....

jgrewe 01-11-13 07:42 AM

If you are having under steer problems at full throttle, you shouldn't be at full throttle yet. The tires will only give you 100% of the grip they have, you're asking for 105% from the fronts.

cord4530 01-16-13 04:51 PM

I don't know how much you have to spend, but the best money I spent to improve my driving (apart from track days and instruction) was a little GPS data logger. I bought a GPX Pro from XT Racing, but virtually any of them do a great job. I record RPM and throttle position, along with the GPS speed and position data the unit automatically records.

This has helped me a ton because I can analyze all the different laps and lines taken to see which is working better. The software makes it really easy to compare sectors that you set up yourself.

Also, I use the Dashware software to overlay data (RPM, TPS, and track position) over video that I take as well. This doesn't help me much while I'm at the track, but it helps a ton in the weeks between track days.

I don't have a 1st gen, but considering it's definitely a momentum car I would certainly favor carrying more corner speed. In my MKIV TT Supra it was definitely a point and shoot car. Brake hard, make the turn, and get on the throttle. That car rewarded late apexing.

Another thing to consider is the type of corner. One of my instructors told me there are only three kinds of corners. 1) Corners leading on to a straight. 2) Corners at the end of a straight. 3) All the others. No matter what car you have, you want to maximize your exit speed for any corner leading on to a straight. For corners at the end of a straight you want to lengthen the straight as much as possible, so you may choose a less than optimal line depending on what is after the corner.

The rule of thumb of slow in, fast out is great for people learning to track their cars. It's safer, and keeps them more in control and less likely to spin off the track under braking. But as you learn your car and your own abilities you will probably start trail braking more and carrying a loit more mid-corner speed.
-Dan

Adam12A 01-23-13 10:03 PM

Bump..I agree with this theory. Thanks

Originally Posted by Kentetsu (Post 11340988)
It really depends on what the next corner is like. Here's an example:

1. Corner is followed by a straight section = late apex (get's you started on the straight with power down sooner, which results in higher top speeds on straight).

2. Corner is followed immediately by another corner = sometimes better to make an early apex and carry some speed deep into the corner, since you have to go slow for the next one anyway.

:)



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