Can You Really Analyze Data in the Wet? An Honest Answer

You've probably felt this. You're driving in the wet, on your own, no teammates to compare against, hardly anyone else on track. And you notice you're not really improving. You're not learning much from your telemetry, not getting much feedback from the MyChron.

And you start thinking: what's even the point of charging it? It feels useless in the rain.

Why wet data feels pointless

The complaint is legitimate, so let's state it properly. The track changes every single session. There are no real reference laps to compare against, and no teammates. The grip changes, the standing water level changes, everything comes down to the conditions on that particular run.

So even if you did notice something in one session, the next session is either wetter or drier. It's never the same. That's genuinely how I used to feel about it too.

What changed my mind isn't that the problem went away. It's that I realized I'd been asking the data the wrong question. You're not going to get a clean like-for-like comparison in the wet. You're going to get something else, and it turns out that something else is worth quite a lot.

1. The lines, which is the big one

Here's the thing about a wet session: across fifteen laps you will have tried several different lines, whether you meant to or not. That's a free experiment, and normally you throw the results away.

A section heatmap fixes that. It shows you, for every lap, the gap from each of your mini-sectors to your best time in that mini-sector. So you can literally see which lap produced your best result in each part of the track. Then you go and look at what you actually did there.

In that lap I went really wide, and it worked. The delta says I gained a tenth.

And crucially, it isn't binary. It's not "wide or tight, on the kerb or off it". There are corners where the answer is somewhere between full wide and full tight, and you need to find that middle. Working out where your time went in each section is what section analysis is for.

2. Speed is only half the equation

This matters everywhere, but in the wet it's decisive, because wet lines differ from dry lines much more than people expect.

Time is distance divided by speed. Speed is fifty percent of the equation. The rest is distance.

You want the least distance while carrying the most speed. A tool that tells you "you carried more speed here" without telling you that you also travelled much further is giving you false information, and some software genuinely does that. It's too important to neglect.

I tell my drivers at Babyrace the same thing constantly. Speed alone is a trap.

3. Grip, and what your tire pressures did

Make a reasonably large tire pressure change, up or down, and then look at the grip indicators: the friction circle and the grip load index. You'll see how the grip behaved differently, whether you genuinely had more or less.

You also get the shape over the session. Did grip build as you went, suggesting the pressures started too low? Or did you keep losing it, suggesting they started too high? That's a real answer to a real question, and it doesn't need a reference lap from anyone else. Finding your optimum pressure with data works the same way in the dry.

4. Your braking, which is where the wet is won

Everybody assumes you don't have to brake hard in the wet, that you have to be careful. It's the opposite.

You almost have to be a much better braker in the wet than in the dry. I really believe that.

The logic is simple once you see it. In the dry, especially on the high-grip Italian tracks, there's so much grip that the kart partly slows itself, in the braking zone and in the mid-corner. In the wet, yes, you arrive at a lower speed down the straight, so in theory you need less braking. But your minimum speed is so much lower, because it's slippery and you can't carry speed, that you have to genuinely stop the kart. And stopping requires the brakes.

So braking efficiency becomes the thing to study. How efficient is your deceleration, and how much do you combine braking with turning? In the dry you combine a lot. In the wet it depends on where you are: if you're hooking the kerbs, you brake hard in a straight line and come off as you get to the kerb, which looks almost like straight-line braking. Everywhere else, you combine plenty. The full technique is in braking in the wet, which is the companion to this piece.

Lines by class matter here too. In a 60 Mini you'll often open the lines up, because the torque is so low that the RPM and momentum have to stay up. In juniors and seniors there's a lot more torque, so tighter lines that cover less distance pay off, and you use the brakes and the exit speed that a 60 Mini simply doesn't have with ten horsepower.

5. RPM, sprockets and your final drive

Look at the RPM traces and you get real intelligence about gearing. Your final drive ratio, the sprocket and pinion combination, shows up clearly.

It won't tell you what to do. What it does is show you what happened in other sessions with different sprockets, and the difference is usually obvious. You might find that going shorter for more acceleration isn't needed, because you already have plenty of wheelspin. Or you might see you're controlling the wheelspin well, your bottom end is weak and your top end is too strong, in which case a shorter gear is the right call. Gear ratio basics cover the mechanics.

6. Water temperature and carburetion

Two engine channels earn their keep in the rain.

Water temperature. It gets very cold in the wet and won't hold temperature on its own. So you close off the radiator to keep it at the target, and the data tells you whether you closed off enough. Water temperature has its own guide.

Exhaust gas temperature. Watch how it behaves through the lap. If it's dropping too much, you're almost certainly too rich.

You can never run the same carburetion between the wet and the dry. You have to lean it out massively.

The reason is mechanical: every time you brake and wait before getting back on the gas, the engine fills with fuel that doesn't get burnt. So it goes rich. You lose performance in the mid-range, and the response at the bottom feels dirty, delayed, laggy. Then you go and change it, which means having jets to hand, or on an X30 simply closing the carburetion with the two screws. EGT and jetting both go deeper.

What you actually walk away with

Yes, the next session's conditions will be different. It might be drier, so you brake later and carry more speed. It might be wetter, so you brake earlier and carry less.

But you'll arrive knowing that in those conditions, at that lap time, those lines worked. And that's a memory you can index against.

This session the track was quite wet and I was doing a 1:11.0. Those lines worked well. Next time I see similar conditions, that's my starting point.

With a MyChron alone, or with Race Studio 3, you couldn't really do this. Or rather, you'd need a detective's patience or an engineering degree to unpick it. That's the actual change, and it's why the logger stopped feeling like dead weight on a wet day. Once you've got the lines sorted, analyzing wet session data channel by channel is the next layer, and Senndit's weight transfer in the wet covers the technique side.

So remember: in the wet you can still get a ton of value out of your MyChron, or your Unipro, your Alfano, whatever you're running. You just need the right tools to read it with. Keep pushing, start using the data you're already recording, and you'll see the lap times and the race results follow.

Sign up to PURPL, let me know how it goes, text me on Instagram, and keep sending it. Ciao.