So I took the $1000 kart racing this weekend. Made a bunch of improvements and fixed broken ***t on it but ultimately was about 2s off the leaders and 1s off the middle of the pack, which is freakin’ huge.
The main thing I’m trying to solve for is how much of that deficit is driving and how much is chassis\tires (Looks like engine is close enough).
I asked a faster driver for data to compare with during the exact same session (final). I’m curious what others think, there’s some big differences here from entry to apex… which makes me wonder… is the kart possibly bound up on entry or am I just not rolling as much speed into the turn?
Here’s a GPS speed trace (Driver name removed unless they decide otherwise :D)
Yep double fast left and it’s pushing all the way from that second apex out to the exit. It’s hard to tell from the video though… which annoys me
I was able to cure a fairly wicked push/kick/slide with a front track adjustment earlier in the day, however the push on the faster turns has been harder to solve. That said I’m at 55” on the rear, which I never imagined would be a thing with a 206 on MG reds, but I ended up with that due to some pretty severe hopping.
Even if the kart is bound up, apex speeds should be similar. Exit is where you would see the deficit if it were really bound up. Red is overslowing the kart.
Look at the braking traces; Red holds high brake pressure for longer on entry and then immediately is back to full throttle. A lot more point and shoot/on and off. Blue rolls the transition between braking and throttle more progressively and is balancing the kart on the traction limit better. Red holds the brakes until they reach a minimum speed that allows them to go immediately to full throttle. Blue starts rolling off the brakes sooner and getting into throttle sooner while being progressive with that input.
Both drivers have similarly strong braking traces, with sharp initial input and a steep deceleration curve. Red just hold the brakes too long and doesn’t trust the kart.
It’s very possible it’s bound up too, but the brake input says there is plenty of time to be found on entry too.
What is the kart doing in the middle 1/3 of the turn? After point in, does it hold the line you want or are you putting more input in to get it to where you want it to go? Which tires are not gripping? Front? Rear? All 4?
James, if I’m reading that correctly it would appear to be braking. You are hitting lower minimum speed. But, it seems you both are stepping on the brakes at same time, but you seem to be holding it longer?
It sure looks like I’m overslowing, but it doesn’t feel like it. I “think” I’m doing a very short stab on the brakes and then turning.
It varies, but in the tighter turns it’s did seem to finally hold its line at the apex in this session.
Once the tires came in, it did seem to hold its line much better on entry than any of the prior sessions of the weekend.
Before the final (data is from final) I noticed that I was having to work on my initial turn in inputs, it seemed like they were too late and abrupt and unsettling the rear.
During the final I was working on those inputs.
All four over the course of a lap. Fast sweepers I’m getting a little hopping on entry, oversteer, then a push on exit. Lots of corrections during the turn. Setup changes helped, but the symptom is still there.
That’s where I’m a bit confused because it feels like that continued deceleration on my part is not from braking. But the data doesn’t lie either
Yeah bound up on entry is not something I’ve come across before…. But this kart is a bit whackadoodle and I’m relearning how to drive too.
I agree with TJ. From data and video clip, the kart has been over slowed for the turn. Especially T6/S4, you will use the uphill and turn to bleed some speed off instead of brake. That corner is also slightly banked, so you can carry more speed than you think.
At the sweeper, you entry might be a bit too narrow.
TJ nailed it. You’re good on the brakes, but just carrying too much brake too long.
Usually when I see traces like that in lower HP classes, where a driver is losing in the first 1/3 of the corner, he/she is often too smooth on the wheel and not inducing enough yaw early enough in the corner. Tough to tell from the video if that is the case.
Seems like it’s mostly driving, but from the sound of it the setup isn’t doing you any favors. Do you have room to move the seat forward?
One thing to remember in 206 is that the brake zones end up being really short, so there may be some time to be gained by being a little less aggressive on the brakes. Even if you give up a little in the braking zone by doing this, you might gain more at turn-in/apex by being able to just naturally have higher apex speed.
You also may find that you can get on throttle earlier than you expect because there’s no power. I noted this before in other posts, but when I drive 206 it always takes my brain some time to adjust, even just coming from KA, because I’m expecting some throttle-driven rotation when I get to the gas, and the 206 is just so low HP that when you hit the gas, there is no throttle-driven rotation. So you have to reprogram your brain a bit to just jump on throttle that much earlier and be confident the kart won’t kick or oversteer on you.
If you look at the traces, you will see the other driver transitions to trail-braking where as you maintain the same brake pressure. You can tell by the change in slope of the trace. both of your initial brake inputs are parallel through the first half of the brake zone then diverge as the other driver begins to release brake pressure in the second half of the brake zone. He is also turning in later than you in most cases. This could be a setup thing given the issues you were facing. Maybe the other driver is trying keep the front end loaded for turn in and help with rotation.
This is most evident in the big LRL complex at the bottom of the track trace and last right hander before the short straight. In the long straight the other driver looks nearly flat out, where as you have a moment of braking/binding where you are losing time. In the last corner the other driver is rolling the corner more and you hold the brake longer almost until apex. He is back to throttle slight later in the corner, but is carrying more speed through and out of the corner.
Edit: Didn’t watch the video this morning before posting about the data… Counter-Clockwise…oops! Easiest way to compare data is area between the curves. If I read this correctly you are losing the most time in T1, T3 and last turn before Start/Finish. Just a stab here, but seems like you need to free up the rear of the kart and push your apexes a little deeper. You are both turning in at nearly the same points, but his troughs are softer and yours are pointy. That could be from trying to get the kart rotated too quickly and not keeping it loaded up. How else is he pulling 2 - 4 mph on you out of the corners?
I am no expert, but do love a good graph…and Math. I think TJ hit the nail on the head with the Point & Shoot reference. Where is @speedcraft with his energy cycle philosophy application?
This seems very plausible, I noticed my inputs were irratic at times and I was working on making them smoother, with constant planned pressure, less abrupt turn in and also less unwinding of steering once I get to the apex.
The size of the gap could be down to kart and or tires I guess, but the difference surprised me, especially on entry to turn 3 (uphill banked left) and through the first turn. Although for sure the kart was scrubbing off speed through oversteer at the point the speed was lost in t1.
My thought was that the slowing in entry want trail braking, but something else.
At least the exit seems on par, because that was something I was chasing up to that point too. I had to roll into the throttle and even then the rear was sliding and I was chasing it. I had a carb issue that was exacerbating it too. Never thought that would be a thing with a 206
By the final though I could basically go straight to the ped stop and the chassis/tires would stick.
In T3 and T8, I’m guessing is the other driver is trail braking while James uses straight line braking? This would explains why red’s longitudinal acceleration slope decreases in the middle of braking in T3 and T8. More fundamentally, it appears that James is over slowing the kart.
