Der ABT

So your saying you recommend Peter,
This thread is hillarious

ProCoach

^^This^^ FIFY.

So, let's build a belief system that allows you to do just that... with knowledge, landmarks for particular benchmark throttle levels and comparing percentage full throttle over the lap, you CAN DO THIS!

ProCoach

Yes, like most things Rennlist, it got that way FAST!

AdamBrouillard

After looking at the thread again I think you are advising to not use the entire exit of 2. The thought being that being slower out of 2 gives you more angle on the approach to 3.

The only time you don't want to use the entire exit of a corner is when this would make your exit greater than 90 degrees or when you must brake for the next corner before reaching the edge. Then you have a chicane. You don't need to brake until much closer to 3 so we know we should use the entire exit of 2.

Usine the whole exit of 2 at Lime Rock however, requires a well executed trail braking spiral entry to 3. It's theoretically faster, but if you blow it you will be slow coming out of 3. Just like turning in earlier for a trail braking entry is theoretically faster, but creates a higher risk of blowing your apex. A more circular entry is easier and less risky, but ultimately slower than ideal.

Not using the entire exit of 2 allows a more circular and easier entry to 3. It gives you more track space and angle to work with. You can see how Ben in the video reaches a constant speed or even accelerates well before the apex of 3. This is a telltale sign you need an earlier turn-in. If you can handle the trail braking at the limit of course. If you drop below the limit in an attempt at trail braking but blow your apex, you are much better off with your more circular entry done at the limit.

A few things to look for in this sequence to work toward a good line:

1. -Use the entire exit of 2, but only if you are at the limit and have too. Don't just drive out there. If the limit doesn't take you out there then stay tight. You can still do a spiral entry to 3 if you have the skill, you'll just have lost some time out of 2.
   
2. -Once you leave 2 you should not be at the limit (although you will be close) until you brake for 3. Braking will be after you have already started to increase steering for 3. You should aim for a steady reduction in radius from the exit of 2 to the apex of 3.
   
3. -A good sign you are on the right track is your max speed between 2-3 will increase. Your goal is to reach the highest speed you can before having to brake for 3.
   
4. -You should have a steady decrease in speed from the braking point to the apex of 3.

All of this is in service of 3-4 of course. They are all connected and this is a very difficult sequence to get right.

Understanding the fundamentals at work behind line optimization will not only allow you to do this sequence with confidence that you know what you are trying to accomplish at every instant, but all allow you to constantly update your line based on how your corner is going so far. If you are slow out of 2, or reach 3 too early or late you'll know how to adjust for the best possible result.

ProCoach

I would never recommend NOT using all the road (and sometimes more) exiting Big Bend.

If you're not carried out, throttle application is late, pure and simple.

Never pinch the exit of so crucial a complex exit. Or pinch exit of the Right Hander.

Still don't think it's that hard (or as variable) as you make it out to be...

Have you driven or raced this track, IRL?

AdamBrouillard

Oh, I thought that's what you meant as Ben doesn't go all the way out on 2 and someone else mentioned the recommendation was staying in the right 1/3 of the track there. How exactly is your recommendation different than mine then? I thought we were giving the same advice until you said otherwise, but not sure what you are saying to do differently now. Also, what do you mean by me saying it's variable?

I haven't been to limerock in person in several years. The iRacing version is laser scanned though. Not sure why that matters however. I can analyze mistakes in someone's line from a video that shows speed, steering, throttle, and brake pressure. I don't need to drive it personally although It certainly helps to have an expert level driver's video of the track if I've never driven it for real or a laser scanned version. Especially if the person is way off.

will968

It looks like Adam made a Lime Rock instructional video for iRacing. I believe he's advocating for a diamond style turn-in. This is the fastest way on the sim track.


Here's Chris Drake doing something similar this year. I was going to try this technique and see how it worked for me - he won his race so I'll give it a shot.

Tight line example (front wheel drive car): starts at around 3:45

AdamBrouillard

Yeah, the Chris Drake video is a good example. I didn't watch the whole thing, but go to 4:50. You'll see he reaches 81 coming out of 2 and then the speed steadily drops to 62 at the apex of 3. It is a big entry so he is dropping speed from drag even while applying partial throttle as he approaches the apex of 3. He then goes hard on the throttle at 3, gains a few mph, lifts as he transitions to 4 and then hard on the throttle again at the apex of 4. If you can do it, this is the way to do it.

ProCoach

Adam, this discussion started with the OP stating (and providing supporting data), that his ROC entry into the Left Hander (which, BTW, is significantly and favorably cambered, at least for awhile) was proven to have contributed to an improvement of .25 seconds (not an insignificant amount in over one of the shortest laps in North America) over a more accomplished, experienced and professional driving the line YOU advocate.

Why you've attempted to divert the discussion to an unrelated element, which has no or little bearing to the OP's original premise and observation is unknown and irrelevant to the OP's discussion or my presentation of data and video supporting this ROC entry into the Left Hander, one you described as "The problem many people have with the left hander is the natural instinct to want to go out wide to set up for it."

Yes, that's a "natural instinct," and by the data, the results and thirty-five years of driving (both IRL and in iRacing as early as March of 2008), instructing and professionally coaching amateur and professional drivers there, a GOOD one. One to be followed.

That is all. Again, IF you ARE NOT CARRIED across the full width of the road to the exit of Big Bend, to the point of nibbling, touching or RUNNING OVER THE CURB, your exit and MOST importantly, acceleration and speed to GET you to the entry of the Left Hander, is NOT what it SHOULD be.

I'm packing up after a busy year so far, one more event at Chin at VIR this weekend, and then headed to an island off the coast of Maine, where there are NO cars. Perhaps visit Nizer and examine Club Motorsports in Tamworth two hours to the west of me, perhaps coming back through Lime Rock for the Drivers Club event in the beginning of August. Will be back to race on Labor Day myself, as I have since 1988, at one of the best historic racing events in North America and in front of 25,000 spectators. Really fun to come out of Big Bend and see that hillside FULL of folks!

When I am at Lime Rock Park, I may take a look at your variable and multiplicity of approaches, adjustments and geometry, and test them. As we all know, data doesn't lie...

ProCoach

Chris is a great driver, for sure, however the bolded is what you're trying to avoid.

Your last sentence tells it all.

Drivers form particular belief systems that allow them to fully commit to whatever "plan" or path they have built this belief system around.

If they are able to more fully commit to THAT plan, then they go faster, period.

This does NOT mean, however, that this IS the fastest possible way through the corner or corners...

AdamBrouillard

Watched some more of the Chris Drake vid. Now go to 5:50. This time he turns in a bit late for 3. He only reaches 79 before having to brake as his entry is now too circular. He drops to 61 a good bit before the apex and has to carry constant speed for awhile on the approach.

AdamBrouillard

Why do you think you shouldn't lift after the transition in a chicane?

I'm not trying to divert the subject, I think I just misunderstood what was being recommended. What is a ROC entry?

AdamBrouillard

I didn't mean he had a belief system to do it, I meant he had the trail braking skills to do it. A novice would most likely be faster with a more circular approach to 3.

dizzy8085

I recently noticed some things comparing iRacing to real life. I practiced COTA a bunch on my budget iRacing rig pre track day. Ton of bumps at COTA in real life that weren't in the sim. I guess they weren't there when the track was scanned. Couple slight variations in lines that work.

That being said. Loved that I had iRacing as a preparation tool. I was right on my pace for my current skill level set, first session out.

ProCoach

What would be far more informative, objective and telling would be a serious analysis of the gSum, sector times, grip analysis, brake pressure and throttle position absolute values, as well as their relationship to one another on Chris' laps.

Only then can one even begin to say that what Chris did was "at the limit." More likely, it might (and probably would) show opportunities for improvement, which is in the end is what we ALL want.

There is NO car that CANNOT be driven faster, period.

Lastly, the idea of different lines for different experience levels is fundamentally incorrect, in order to achieve the most optimum results.

Teaching conflicting geometries and variable approaches and techniques sews confusion and prevents optimal formulation, development and execution of fundamental skills, all of which contribute to the optimal performance by any driver, in any car, on any track.

Apologies to Joe. This thread has well and truly left the paved surface...