Lonestar

iTrader: (14)

Howdy y'all

I can somewhat wheel a car, but I can't for the life of me set one up. I think the more years you've driven your RC cars "as is", the less able you are to analyze where you could gain time with some smart setup changes...

We run on VERY slippery surfaces in the morning. Later in the day the grip comes up (barely) and this is usually costing me dearly: Usually between the reseeding/first quali, and the mains, I lose about 20% in my ranking as the grip comes up, and the other guys are then able to leverage the EXTRA grip and become faster and turn sharper, while I watch them helplessly take the inside line while I drive a car which is now too safe to be fast, as opposed to being safely fast in the morning.

Hence my question to the experts, ideally track experts rather than keyboard engineers please: What setup changes do you do as the grip comes up (be it carpet, or asphalt) from nothing to "something" during the day to leverage the extra lateral G's while not losing the plot? The only two I feel truly confident with are (1) stiffer rear diff (2) stiffer rear springs (for instance from 2.6 to 2.7 on the Slovaquian luxurypremium machines). And even then...

I am NOT ASKING HOW TO NOT TRACTION ROLL. Traction rolling does NOT exist where I race... we go from zero grip to "some" grip

What about you? Please don't just quote Xray's setup helper, tell me what you really believe in

Cheers,
Paul

(edited to further explain the issue after trilerian 's answer)

Marcos.J

iTrader: (239)

usually just droop and camber change are my changes for the day.

trilerian

iTrader: (51)

To be honest it sounds like you may need to make changes to your base line setup. Generally speaking, at club races (where there are not hundreds of cars running), as traction comes up your car should get faster.

With that said, as traction comes up I try to make my car less responsive. Add more droop, stiffer front springs not rear. Stiffer rear springs, in my opinion, make the front more responsive and can lead to traction roll. Less front caster, more glue on the front tires, lower ride height, or lower center of gravity (ulcg battery vs lcg). Other things, try a body with less front down force, or mounted less aggressively. I know I am always surprised how different my car handles going from a Racer body to one of the more down force bodies like the dbx.

Lonestar

iTrader: (14)

trilerian - interesting. Thanks. I understand my question was unclear.

What I want is the car to be MORE responsive as the day progresses. Where I race, in the morning the grip is low (like, REALLY LOW) and you need a forgiving car that has some naturally built understeer to not like you are ice-skating, which you actually are. Typically the stock setup sheet is perfect in such conditions. In the afternoon, grip comes up to a level that is probably deemed as "standard" by US standards. We don't know what traction rolling is, and you can still spin if you apply too much throttle - still, you can start driving a bit more aggressively and make it rotate a bit more, you want more front-end, not less.

Let me amend the opening post to explain that I want to be able to use the extra grip as the day progresses... not tame the car down at all!

Cheers,
Paul

Darren Stoner

I find even at black crc carpet tracks with a sub floor permanently set up still get faster as the day progresses.. for club level racing I try to have the car set up to be optimized for 3rd qual and mains..

Easy changes to make for low traction is to lay the shocks all the way down and add shims under the inner camber links. let the car roll as much as possible. if you do traction roll start by taking shims back out then stand the shocks back up.. It's a simple easy change that can be done quickly.

Darren Stoner

^^ sorry, didn't proof read. do the opposite of what i said to do with the shims. raise the outside and lower the inside.

trilerian

iTrader: (51)

That's just too funny!
In your case then, I would try a higher roll centers before stiffer springs in the rear, and maybe a lower diff in the rear, I prefer to use roll center to limit the lateral transfer of weight as opposed to springs because they also affect front/rear weight transfer. If you are on the edge of washing out when giving throttle, I definitely would not want stiffer rear springs, but a lower rear diff will help the rear of the car ride higher while on throttle, keeping more weight on the front. You can try a higher diff in the front too, which on black carpet for me causes traction rolling. Also try the higher down force body, or more aggressively mounted body. I always liked the Type-S for lower traction but gives steering. I will generally run that body on a fresh layout until traction comes up just a bit. And for me, I would try to get more flex in the front of the car. This isn't universal for everyone I talk to, but my cars generally steer more on point with more front end flex. The rear though, sometimes more flex helps, sometimes it doesn't, I have had inconsistent results there. You can also try more negative camber in the front, but it is generally better to have a set of tires with less glue on them.

Also I want to say, these are things that work for me, and I am still new to experimenting with setups. I used to just ask every time I needed my car to do something different, but I am now trying to understand weight transfer a little more and make guesses as to what is needed. Most of the time I notice an improvement, but it is usually pretty subtle.

Billy Kelly

iTrader: (9)

Lonestar.

have you tried having one of the faster drivers runs some laps with your car?

Lonestar

iTrader: (14)

Billy, unfortunately we don't run on a permanent track - and there is no practice. Get there in the morning, layout is new for everyone, reseed, 3 qual, 3 mains, done, disassemble track - no opportunity to exchange wheels, no warmup laps, no practice, nada.

now before this gets off topic as it often does I am really not asking you guys for advice on how to troubleshoot my car, which, honestly is not doing bad at all I am asking how you guys setup YOUR cars when the grip goes up to acceptable levels and you're trying to get more front end.

Thanks!
Paul

Zerodefect

Generally my car gains rear grip as the day goes on, I run the same setup mostly. Just drive around a slightly loose car in Q1.

I can mitigate most changing track conditions with tire dope. Full dope early in the day. Way less rear for the mains.

sosidge

I normally race on non-permanent tracks and you expect the track to be very "green" at the start of the day. I have a couple of rules of thumb:

1. If the car is handling well in the first round, I know the setup is too safe and I will struggle as the day goes on.
2. I avoid making any changes after the first round because I know that the track will change a lot.

So basically, I'm looking for a car with a "loose" rear end when the grip is low at the start of the day. I avoid changing setup as part of my routine during the day - I only change setup if the car is bad after the second round.

As far as setup goes, don't underestimate the importance of having full steering lock available, and the two main changes I would be making is a stiffer rear spring, or a reduction in rear toe. Spring rates are so similar now, and chassis are so soft, that springs don't make the difference they once did. Toe is a powerful setting though.

Airwave

iTrader: (1)

I believe in you buddy!

From a more usable point of view, I can remember I always used a steering monster on carpet (TCXX rulez) and reduce the steering travel in the morning to have an easier car, but you know, it was years ago :-(

Lonestar

iTrader: (14)

I love you too my friend!

I think you're making a lot of good points, as I was hoping you would when I saw you posted here I am probably too focused on making sure the car is driveable early in the day to not blow the qualifiers, and then as the day passes by need to play (and lose) catch-up the, instead of learning to drive an edgy car early on and then getting faster as the grip level goes up... this is my risk-adverse inner nature I guess.

do run full steering lock all the time though (I'm a firm believer in having the fingers doing EPA's job...). Stiffer rear spring is my go-to trick too, but as you are pointing out, these days they don't make "much of" a difference anymore, like us old-schoolers used to be accustomed to 20 years ago - it's more like a third or fourth order thing nowadays.

Rear toe is very powerful indeed, and every time I have tried going below 3deg, the car was very edgy, even with more grip. How low do YOU go on lo-grip, temporarty UK-style carpet tracks?

Any comments on steering geometry (be it toe-intake or ackermann), or even flex?

Thanks!
Paul

gigaplex

iTrader: (2)

I never change setup, I just adjust my driving to the conditions

Lonestar

iTrader: (14)

Well, this used to work for me to, up to a point where with the modern, ultra-grippy and front-end-biased cars, it unfortunately doesn't work any more