29 replies to this topic

[prty]

Slow times in motor racing, ideal to make bizarre threads.

So, and I guess I'm not alone, a lot of us would love to drive competitively, but being a lack of time, a lack of money, or a lack of effort, rental karting is all what's left. And when talking about rental karting it's unavoidable to come upon this evil unleashed beast, the Sodi Rental Kart:



In action:




The question is - how to drive this thing fast?

Usually I've done rental karting a couple of times per year, and usually I've won, but my laptimes are still some 2-4 seconds off the lap record. I feel I won only because I'm more into motorsports than my friends so I just know the right lines, but not the right technique. So it would be good to improve on this. What I've tried (always talking about slow corners)

- Corner entry oversteer: brake and turn at the same time (when using brakes is needed), to have it pointing at the right direction as soon as possible with the help of that slide, as there are only rear wheel brakes in the kart. But it just dies mid-corner, and has no revs to pick it up from there on. On reflection, I might be doing too much coasting (no brakes nor throttle applied) after the braking slide. Any brake-throttle overlap is required? Maybe getting back to throttle earlier? Before the apex? But then there's a chance to appear for...
- Corner exit oversteer: disastrous, I guess caused by being too fast mid corner. The kart just bounces in a slide, the revs drop as if it were in painful agony, resulting in no corner-exit speed, making it slower than the case before.
- No sliding: doing the turning only with the front wheels. Slow.

In quick long corners where you don't get off the throttle, it understeers. What I do is to make a really abrupt turn in, so rear wheels break a bit of grip, but I have no clue if this is quicker. They should provide some telemetry at the rental places

So, until more experimental work is done I think the way to go is keeping corner entry oversteer, but without any coasting and with a constant steering angle.

Thoughts? Experiences? Footage?

Edited by prty, 10 December 2012 - 20:48.

[jimjimjeroo]

Last time i drove one of these I ended up in hospital

[Trust]

This is very interesting thread. I would also want some professional tips for driving. I've tried many techniques but somehow I get feeling I always get almost identical lap times. Not much improvement.

Edited by Trust, 10 December 2012 - 20:45.

[Dolph]

There are some old threads on this. I started one long time ago. Search for "karting tips"

[molive]

Forget about the brakes and don't let the kart slide too much, that's what I do anyway. I actually looked for some pointers when I first started 4 years ago, but I found it was easier to just watch and learn, following the faster drivers during the qualifying sessions.

I've been racing in this "karting friends championship", and I have won 5 races since. Ours is a very close competition. Of the 16 participants, at least 10 have a real chance of winning. We race with 8cc engines here.

My best result was 2nd in the final standings last year, but this year I wasnt very good. I even got disqualified in the second-last race! I started in the last row but in 3 laps I managed to pass everybody, I was leading comfly, but my kart broke the chain and in the rush to get back to the race I forgot to transfer the ballast to the replacement kart. Bummer! It was supposed to be my 2nd win of the season!

This year we adopted a reverse-grid rule (first on the table starts last), which meant I had to start in the last row almost every race in the first half of the season (we have a 11 race calendar). I loved the new rule when my kart was good, but hated it when it wasnt.

[prty]

There are some old threads on this. I started one long time ago. Search for "karting tips"

I know, actually posted in that one
But from what I understood, it was general karting tips, not rental karting tips. I think they probably should have different ways to be driven.

[kpchelsea]

Basically the karts have no power so will not slide and accelerate at the same time which causes them to bog, any slide under acceleration coming out of a corner even a small slide will lose you acceleration. However going into a corner a little slide helps initial turn in but if the slide is too much then you can't accelerate early because of the bogging effect.

[kosmic33]

Carrying speed is essential in the fast bits, once you've built up speed you have to try and keep it
Big swooping lines in the tight corners - being smooth is key here as oversteer kills the engine.
Sacrifice entry and apex speed for exit speed is most important

Carrying speed is essential in the fast bits, once you've built up speed you have to try and keep it.
4 wheel drifts and mild oversteer arent as bad in the fast bits - anything to keep the revs & speed up

[kosmic33]

We race with 8cc engines here.

Are you sure?
Look more like 4hp 200cc Hondas to me

[nada12]

If we're talking about the usual <10 PS rental karts that are often more than a couple of years old it's often an exercise in futility to try and squeeze the last tenth out of it, since its mostly the guy who weighs the least and/or happened to be in the kart who retained the most power over the years that's going to set the fastest time, unless it's a very tight track.

But other than that, in those very limited power karts, always maximise acceleration out of corners. Brake early and softly as to not drop the revs too much, go back on throttle on turn-in and floor it as soon as you can without sliding too much. You'll always more than make up the time lost by braking early.

[kpchelsea]

Are you sure?
Look more like 4hp 200cc Hondas to me

200cc Hondas have 6.5hp

[prty]

Carrying speed is essential in the fast bits, once you've built up speed you have to try and keep it
Big swooping lines in the tight corners - being smooth is key here as oversteer kills the engine.
Sacrifice entry and apex speed for exit speed is most important

Carrying speed is essential in the fast bits, once you've built up speed you have to try and keep it.
4 wheel drifts and mild oversteer arent as bad in the fast bits - anything to keep the revs & speed up

I don't feel I'm losing time in the fast bits, probably because I'm doing that.

So in the slow bits, in this video, at this time:
https://www.youtube....NgZttk#t=12m34s
A guy with a Mansell helmet passes the other guy. It seems that he's pulling away easily so I assume he's good.
As soon as he gets in front, he throws the car in with entry oversteer for the slow left hander, but it doesn't seem to affect him after.
How would you rate the guy in that video by the way? I think I drive similarly, but have no GoPro to show it Is that the right amount of sliding or too much?

Edited by prty, 10 December 2012 - 21:29.

[kosmic33]

This is surprisingly informative

[rage2]

Lose weight lol.

Seriously, I weigh 200lbs, and I run these karts whenever I travel to India to visit my staff. Half these guys have never driven before, but they weigh 120-130lbs, come out of the corners completely sideways, taking totally wrong lines, and lap a second faster than me. I'm no slouch either, I'm running against another co-worker who weighs the same, used to actually kart professionally with Karthikeyan, and we're pulling laptimes within a few tenths of each other.

If you don't weigh the same as a skinny 12 year old, you're not going to come close to the track record. Back when I was in my late teens and skinny, I would be the one setting the lap records. And if you ARE skinny and light, make sure you do it at the end of the day when the track is hot, the line is dust free, and your kart is as light as possible. I used to kart all day long, and there would be a 1-2 second lap time difference from first thing in the morning, till 5pm in the afternoon on an indoor 50 second track.

Edited by rage2, 10 December 2012 - 21:42.

[rsaca]

As a kart driver myself (125cc Shifter), my advise would be that any time you're "drifting", you're losing time. Fast hands in the slow corners and slow hands in the fast ones.

Look at your braking points and try to brake a little later without losing mid-corner speed and not compromising the exit. Follow the racing line, learn where the apex is in each corner and always take them. That's the fastest way around the track.

Good luck.

[Zava]

This is surprisingly informative

lol. never thought of the 'weight distribution' idea, but quite like it!

OP: I've been to a kart centre this year (and planning on going next month as well) and had the luck to see the lap record holder guy do some laps at the end of the day, on the hairpin at the bottom of this video he was doing the corner entry oversteer lap in lap out, and was doing constantly 25.6-25.7 laps (record was 25.5? maybe .4) so I think that works.

[thegforcemaybewithyou]

In my opinion the most important is not to enter the curve with to much speed, as that will only lead to drifting through the whole corner from entry to exit.
Better brake a bit earlier or only lift the throttle and try to avoid any drifting/oversteer. The only point where a liitle bit of drifting is allowed is the very beginning of the corner, but at the apex and the exit the car should feel neutral with a very small amount of understeering. If the speed at the apex is correct, the kart will not oversteer but "bounce" a little.
I'll try to find a video of this bouncing.

Thats how i achieve the fastest times in rental karts.

[kosmic33]

Then again, maybe he's fast round the rest of the track but not that corner and since its an indoor kart track, theres been noone else quick enough round the rest of the lap to punish him for being slow in that corner?

Heres a video of some 11 year olds racing karts with a similar power output to a hire kart.

Yes I realise that is where the comparison ends but it also shows how smooth they are to be fast

Edited by kosmic33, 10 December 2012 - 22:06.

[thegforcemaybewithyou]

Another point that came to my mind: Don't try to lean into the corner, better stay upright in the seat or let the cornering acceleration let your upper body lean slightly to the outer side of the corner. That should give in theory the tyres better grip on the outside.

[Tenmantaylor]

Keep your minimum speed up even if the line doesn't feel ideal, especially onto the straight. Rental karts are poor at acceleration.

Turn in sharply to provoke the rear and get the kart into a balanced slide as soon as possible and get back on the power as soon as you can. This is when the tyres have most grip.

Karts are balanced on a knife edge as they dont have suspension, the difference between understeer and oversteer is minute and being able to exploit that will see you waltz away from people It's tough work though, if you don't do much upper body exercise you might struggle over a long race.

[kosmic33]

Turn in sharply to provoke the rear and get the kart into a balanced slide as soon as possible and get back on the power as soon as you can. This is when the tyres have most grip.

So the tyres have their most grip when they are not actually gripping????

[rsaca]

So the tyres have their most grip when they are not actually gripping????

When you drift, you're losing time!

[schumimercamg]

With indoor karting you must use the rear brakes to get the kart turned otherwise you will just understeer wide- these can't be driven like other racing cars.

[Tenmantaylor]

So the tyres have their most grip when they are not actually gripping????

All tyres do, it's called optimal slip angle. Go forth and learn young padawan http://en.wikipedia....wiki/Slip_angle Go watch any racing car, even F1 cars, in slow motion. At peak grip all tyres are sliding.

Edited by Tenmantaylor, 10 December 2012 - 23:58.

[kosmic33]

All tyres do, it's called optimal slip angle. Go forth and learn young padawan http://en.wikipedia....wiki/Slip_angle Go watch any racing car, even F1 cars, in slow motion. At peak grip all tyres are sliding.

But you were talking about sliding the back of the kart around not trying to find the optimum slip angle......

[prty]

Yeah, because I knew that tyres have its grip peak at a small slip angle, I was trying to slide all the time. Guess it was being overdone, especially with this little power.

at the apex and the exit the car should feel neutral with a very small amount of understeering.

Didn't feel like this at all, so I will give it a try next time, and see how it goes.

Thanks everyone for all the advice by the way!

[Tenmantaylor]

But you were talking about sliding the back of the kart around not trying to find the optimum slip angle......

The quickest way to reach the optimum slip angle is to provoke the rear Especially on sharper corners.

[rhukkas]

Ask the marshals very nicely (aka with a £20) which is the best kart... simples.

The karts get bashed around so much that no kart is the same. Some you have to drive aggressively and some you have to drive smooth. Just try and find out which is the fastest kart

Edited by rhukkas, 11 December 2012 - 10:27.

[kingofspa]

Lose weight lol.

Seriously, I weigh 200lbs, and I run these karts whenever I travel to India to visit my staff. Half these guys have never driven before, but they weigh 120-130lbs, come out of the corners completely sideways, taking totally wrong lines, and lap a second faster than me. I'm no slouch either, I'm running against another co-worker who weighs the same, used to actually kart professionally with Karthikeyan, and we're pulling laptimes within a few tenths of each other.

If you don't weigh the same as a skinny 12 year old, you're not going to come close to the track record. Back when I was in my late teens and skinny, I would be the one setting the lap records. And if you ARE skinny and light, make sure you do it at the end of the day when the track is hot, the line is dust free, and your kart is as light as possible. I used to kart all day long, and there would be a 1-2 second lap time difference from first thing in the morning, till 5pm in the afternoon on an indoor 50 second track.

this...
i used to kart a lot last year..i dont have a track where i am now.my friends were slower than me in the corners,even 4s slow in lap time but if somehow they manage to be on my tail going into the main straight they would pass me half way down the straight and i am on full throttle.its frustrating.i close on them dramatically at the next corner but....the straight kills me

[Haribo]

Yeah lose weight and keep momentum - those are the most important things to do

Seriosuly, in my local indoor karting track, there's a steep ramp, which is so steep that you're not supposed to stop on it or just below it in case of a red flag as you'll never get going again. The skinny waifs who weigh 8 stone just simply pull away from me up the ramp and there's nothing I can do about it!

But as other people have mentioned, the rental karts are so underpowered that you need to keep the revs up at all cost. Even if driving round the outside of a tight corner might seem slower, once you straighten up you'll have more speed on the following straight