Hairpin turn in low hp kart

Driving, Data & Fitness.
81

And to @alvinnunley point, I am not 100% sure on the noise bit. It is normal for tires to make noise when you’ve got em all stretched out like that. It just seems like he’s going at it a bit too hard.

If I had to imagine it: I would likely approach that initial turn from top left edge. I would likely brush some brake to settle kart just prior to turn in. I suspect I’d immediately at turn be back on gas however hard I can get away with. Only to very quickly have to transition back to the left. So you have to be sensitive to that. That’s the COG moment that’s really important here. Like @Matthijs_Hofman said, you could even see the first turn left as the beginning of the run out to the end. It looks like this turn and the next (which sets you up) are one continuous steering angle. Squirt down then ease it around the first corner and let it build a bit then shoot it through the X area. I think it’ll hold all the way out.

82

Maybe if we used some terms often heard at a F1 race, or at most any race for that matter. For example, the terms, “tight” and “loose”. When a driver uses the term “tight”, he’s telling you the front tires are sliding, (the car is pushing) when he says the car is “loose”, he’s telling you the rear tires are sliding (sometimes referred to as oversteer). Of course, there can be infinite degrees of both. Just saying the car is sliding, in my opinion, is not precise enough.

83

In which case, Al, which do you think the slide at entry apex is? I would assume it’s a push, basically.

84

Just to make a friendly observation. I see 2 people with different experiences trying to talk to each other in a foreign language, trying to adjust their explanations so that each can understand the other. No problem, we can get through it.

85

Well, it’s hard for me to tell, in my world, just saying sliding, gives you only a vague idea of what you’re talking about. I would understand it to mean that the whole kart was sliding, equally, front and rear. No push, no loose, just sliding. Like going to a corner and hitting a patch of ice and the whole kart just slides off the track. Not tight, not loose.

86

I suspect that’s accurate. It isn’t a lot of sliding and it’s not really specific. More front end than back. Just make it go away and see what happens. If you can understeer through there faster and still setup the next turn, go for it.

87

I would describe that as “push”. On my own kart, there would be several options to make it “go away”. lol. But on the rental kart, I doubt that any of those options are available. You might tell the track owner about the problem, he may know what to do. I’m sure he wants your experience to be as pleasant as possible.

88

Haha I meant try it without the push. Slower if necessary to see. It may be that it’s unavoidable. Admittedly make it go away isn’t specific.

89

Yes, indeed. You have very good argument about the build up speed. I should be able to build it from there, if I settle the kart a bit better through that turn to prevent sliding at the exit.

You are right, nothing to add really.

@Matthijs_Hofman It looks quite simple, but what makes it hard is that the track is narrowing all the way to the start-finish line straight. It just gets tighter and tighter, yet you accelerate all the way to the line. What comes on my mind is, that I should slow down and change the line like this:

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Yellow line refers to the current, whereas the google map dotted one could be the new line, maybe more effective for building speed towards the straight. What do you think?

About the tight and loose, kart is mostly understeers around the track, front end is very heavy and loaded, that is how it feels at least.

90

You are onto something. I resisted the temptation to draw a line and I’ll resist the temptation to comment on the ones you drew.

I’m not sure what the line is and it’s gonna depend on what actually happens on the surface as opposed to pretty lines on paper.

But yeah go with that and adjust line slightly as you figure out where your launch point is.

I think its still rounder at bottom though. More like yellow. The rubber is a nice semi circle down there. But I do like how white allows itself to go left a bit more as you head up. This white line is too much left… resistance is futile, I commented. Anyways as TJ says if you get the turn right all the footwork sorta falls into place, paraphrased. You have the idea, line less important. Feel it and try it on track. Mess around here.

91

I’ve refrained from posting in this topic because there are a lot of voices and I think most points have been covered by the others, but in this photo the white line would be my preferred line.

White line allows you to get to the power earlier by getting the kart rotated earlier in the double-rights, so will carry more speed into the final corner and down the straight. Yellow line completely compromises the exit of the first right-hander. Always prioritize the corner that will lead you onto the straight fastest. Sacrifice your exit of the first left-hander to better setup for the rights.

If you’re using the yellow line, you are experiencing understeer from simply turning into too early and too soon and asking too much of the front tires too quickly.

You almost always want the kart mostly rotated before apex, so you can get on the power earlier and it “floats” off the corner with minimal steering input. Trying to get the kart to rotate at or after apex is just going to delay your ability to apply throttle and therefore delay how quickly you can get down the straight.

92

I don’t know. The white line looks too extreme. Remember we are talking about rental karts, not two strokes. Maintaining speed is sometimes more important than an optimal exit. I feel that the white line compromises the left hander too much.

I’d go for an option between the white and the yellow line. But this is where my experience ends. I have never driven this track and that is vital for the last details.

2 Likes
93

On second look, yes good point. I think white line is chopping the exit of the left too much, so I wouldn’t go quite that extreme. Here, I’ll just draw it:

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Sorry if I missed something along the way, the topic is long. :dizzy_face:

94

And there you have it.

@tjkoyen mic drop
image

1 Like
95

@Stacker

This. Pavle, this is worth paying attention to and figuring out.

96

Thank you for all the comments so far, the more we discuss, the more it becomes clear to me what am I supposed to do to improve!
Now when I take a second look, my white line looks a bit sharper, I agree. Overall I need to correct the line a bit comparing to the one I drive now.

Oh you don´t know me. I could talk about this stuff for quite a long time, this is nothing. :sweat_smile:

Yes, but any kind of racing experience I had before karting was mainly with cars that have differential, so the karting line is quite different. Watched a lot of F1, WTCC, WEC and the racing lines used are quite familiar to me. This is something new, I will give my best to understand and use this on the racetrack. Let me clarify, rotating the kart before apex (partially at least) requires a later apex if I am correct? Wouldn´t that affect the momentum and slow down a kart down, as momentum is important in weaker karts like rentals? Just being curious.

97

Not really, at least in this case. We are sort of at the point in the conversation where the “every-corner-and-complex-requires-something-different” phrase comes into play, so at this point we splitting hairs a bit. But it’s good to ask and understand!

Let’s look at this one specific example:

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Looking at how these lines overlap, you are not killing your momentum more or less in either line. The amount of momentum lost is going to be about the same. The difference is, you are losing your momentum earlier with the white line. That allows you in turn to get the kart rotated and back to throttle earlier as well, meaning you maximize your speed down the following straight because you’re accelerating quicker. The yellow line loses the same amount of momentum as the white line, but it loses it later, because you charged the entry of the corner lower and harder. So you are losing the momentum later in the corner and therefore getting back to throttle later, and falling behind all the way down the following straight.

It isn’t necessarily just about making late apexes either. You can definitely apex too late and completely lose all your time gained on the entry of the corner by going extra wide. You also start asking the kart to do a lot of work in a small amount of time since you are waiting to turn in and then turning in abruptly and looking for quick rotation. That will upset the kart and cause understeer/oversteer.

The way I break a corner down is like this:

  1. What is the following section like? Another corner? Which direction? Long straight?
  2. Based on that, where do I think I want to apex the corner to be set up correctly for the following section?
  3. From there, I’m trying to find the smoothest and most progressive way possible to get the kart to the apex point I picked out without scrubbing too much speed or working the kart too hard. Usually this is a firm input to a nice smooth arc around the corner to hit the apex.

Of course, then you need to look at variables like tarmac type, track surface imperfections, availability of useful curbing, engine/weight/class, tire type etc. and factor those things in to see how the corner is unique and if it requires a specific input or series of inputs to drive it differently.

1 Like
98

I’ve always gone with the theory that; optimal speed is achieved with optimal entry “and” optimal exit. Still, you’ve always got to be anticipating the next turn and its optimal entry.

99

I just got back from racing the rental machines at NJMP.

First off, wow that was fun. Driving a rental kart on a racetrack I am familiar with (NJMP) was an absolute ball. The fact that the karts are relatively slow (but quick enough) adds to the experience. Its just such a different way to drive.

I really dig the idea of this series. 2 races a month. $75 per race: quali-pre-final. Done in 1.5 hrs.
What’s not to love?

What was also cool was the drivers: 12 drivers ranging from 1 supersonic young man to a middle aged guy just getting going. But, unlike the typical rental kart experience, everyone was there to race and appeared to take it reasonably seriously. While there was a very wide range of abilities the race went well and everyone had fun (from what I saw).

Nick and I had a ball and I can see myself doing as many of these as I can.

Anyhow, now that I’ve driven these a bit I can review my thoughts and say much hasn’t changed in my thinking but it likely will over time as I become more accustomed to these karts.

I got to run 2nd so I was able to observe the fast guy a bit so that was helpful.

These karts are heavy. The weight effectively makes em slower to do stuff like rotating and turning.

The tires are ok. They do warm up and there is grip. They can be leaned into.

The engine basically seems to be happiest just merrily chugging along at full throttle.

Basically everything says “drive me smooth”. True to form I did not drive smooth and got to experience @Stacker’s tire noises.

What I noticed was that everything that can be smoothed out should be smoothed out. Line. Inputs. Etc. These big karts are not happy being shocked. They are heavy and slow to react and seem to prefer being asked gently to do things. In the case of this track, by the last couple laps I had figured out that no braking at all was an option and was having fun with that. I’m not so sure that’s ideal but its interesting that the kart can be driven that way.

In general everything @Matthijs_Hofman was saying about weight transfer is important. The “shift” from side to side is slow and needs to be slow. You have to weeble-wobble these karts instead of point them.

More to come as I get quick. The fast kid will be fun to learn from.

2 Likes
100

Alright, that makes perfect sense! Very good explanation, I understand much better now, thank you!

@Bimodal_Rocket That is nice, being able to look at faster guys line, should help a lot! Everything is correct. The karts are heavy, as you said.

Only difference are tyres, as you said they are okay, but I feel NJMP is much faster track, less corners, better tyre cooling so it might be the case that these karts actually like faster tracks like yours.

Could this be a thing, like tyre overheating? I know it is 10mins for me, but it gets tight quite often, especially when you need to overtake. What do you think?