Lowering Cross is the only way to find speed...

[Lily Smith Racing]

2018 Prodigy Cadet
Purple Plate Predator/Clone classes
10yr old little girl (been racing since 5)
As a high-cross kart, we'd prefer to be near the manufacturers recommendation62%-65%, but instead need to be at around 57% to find speed. Not sure what why this is the case.
Had conflicting responses to this as to whether it has to much bite, or not enough bite. Usually run yellow vegas in the 45 point range at our local track, prepped from a well known tire guy that knows and races at this track himself occasionally. Daytime Racing - track changes and variates due to watering as per sunny/overcast/etc.
Generally speaking, am I locking her down and bandaiding the lockdown by decreasing cross? We seem to run much better at night with same setup.
Only other thing other than cross that is an issue is I'm short about 1.5%-2% left side as she only weighs 55# and all weight is bolted to left side.
She's fast out... Very fast. Entry-no, Apex-Okay, Fast down straight... it's an entry problem and I'm not sure the weight is transferring properly... too much bite? need more rear weight? Tires over-prepped?
Please help... Thanks in advance
Smitty

 

[racing promotor]

Confirmation your running same tires as night racing for day racing ? What does entry no mean ? Is most all her experience night racing ?

 

["J'-remy]

what tire pressures are you running? you can free up a kart and increase speed with upping pressure. lower will help lock it down. knowing your pressure game is in someways as valuable as the the prep

 

[flattop1]

add more weight if the left is low . and you want to stay with factory numbers .

 

["J'-remy]

Nall told me he's on 72% cross so even he doesn't follow the factory numbers which are 68%

 

[paulkish]

little girl

Big to Little size and where weight is located on the drivers body matters.

Generally a smaller person/youngster needs to be elevated or raised up to get a kart chassis to work.
It takes effort to transfer weight and the effort will come from weight being used to leverage the chassis into working.
If too much weight is located low when g forces act they will cause the weight to leverage in a more straight out to the right direction then being pivoted down and to the right.
Raising up a young small driver or putting weight high up on the seat can help get weight to do some work for you to operate the chassis.
Another option is to lower cross which directly puts more weight on the right rear to do work for you engaging the tire and on the left front which puts weight where it is easier to get to the right front.

Biggest tell of a chassis not working well enough for you is an entry problem.
Once the driver gets it into the corner and needs to exit it's easy for them because weight which would normally be available to put back in place for exit and the straight is already there.

... and maybe because this is all IMHO and ain't necessairly right anyway. ...

 

[flattop1]

Nall told me he's on 72% cross so even he doesn't follow the factory numbers which are 68%

I rarely follow any advice .
Still if you were to setup initally with factory numbers .
The left side needs to be in the range selected for them too work .
Being 5 lbs over , so you can do that is well worth it .
Especially if its faster .

 

[JPMKarting]

"factory numbers" are just a recommendation of a range...they arent gospel.

Feed the kart what it wants, regardless of what the manufacturer says. Heck, I hardly even pay attention to numbers anymore.

 

[flattop1]

Something to try would be move the left front out one spacer .
What is the actual entry problem or issue ?

 

[OVALTECH1]

At that particular track I’ve never found it ever gripped up enough to benefit from higher cross numbers… I always had better luck with a low cross setup and sometimes reverse air to get me by.

 

[XXX#40]

Don't get hung up on a "suggested" baseline set of numbers.
Those numbers change dramatically from driver to driver, track ro track.
We won 2 championships on a nemesis at 52% cross
We are like JP, don't pay a bunch of attention to numbers, make adjustments and let the stop watch be the decider

 

[flattop1]

take you a 6 foot 4 driver at 225#'s . The only real adjustments are what shoe horn your using to fit them in .
Never was lucky enough to have a light weight where adjustments affected much ,
% wise.

 

[XXX#40]

take you a 6 foot 4 driver at 225#'s . The only real adjustments are what shoe horn your using to fit them in .
Never was lucky enough to have a light weight where adjustments affected much ,
% wise.

My 6' 3" cousin wanted to be a fighter pilot, nope too tall.
Sometimes your a victim of your own choices, and because you want to do something doesn't mean you should, or can.

 

[flattop1]

2018 Prodigy Cadet
Purple Plate Predator/Clone classes
10yr old little girl (been racing since 5)
As a high-cross kart, we'd prefer to be near the manufacturers recommendation62%-65%, but instead need to be at around 57% to find speed. Not sure what why this is the case.
Had conflicting responses to this as to whether it has to much bite, or not enough bite. Usually run yellow vegas in the 45 point range at our local track, prepped from a well known tire guy that knows and races at this track himself occasionally. Daytime Racing - track changes and variates due to watering as per sunny/overcast/etc.
Generally speaking, am I locking her down and bandaiding the lockdown by decreasing cross? We seem to run much better at night with same setup.
Only other thing other than cross that is an issue is I'm short about 1.5%-2% left side as she only weighs 55# and all weight is bolted to left side.
She's fast out... Very fast. Entry-no, Apex-Okay, Fast down straight... it's an entry problem and I'm not sure the weight is transferring properly... too much bite? need more rear weight? Tires over-prepped?
Please help... Thanks in advance
Smitty

Back too the original issue . Night time tires wont work too good in the day time .
Eexclusions apply .
A balanced setup may work well 46/54/54 . Tune from there.
Tires; obviously could be off, even with some experienced help .
Entry issues are typically front end related .
Raising the weight and or driver combo will alter the weight transfer ability .

 

[Bumpy]

Keep adding RF caster til she slows down.
Could most likely add Cross back with
more caster.

 

[XXX#40]

I'd raise the seat before I done anything else.
Too many times I have seen small children way to low in the kart.
They lack upper mass to aid in transfer

 

["J'-remy]

You've gotten a lot of good advise but try one thing at a time. Changing too many things at once and your head will spin. Take notes so you can always go back to a baseline. Set up sheets from the internet are very helpful (attachment link). once you get the kart where you like it becomes more of a tire choice and less fiddling with the chassis IMO.

http://www.stoutracingengines.com/setup/KARTSETUP.jpg

 

[bomber315]

What tach do you run? What rpm is she turning? How much is she letting off? Are you sure she is running it as hard as she can?

 

[CarlsonMotorsports]

OP, You say that she's good from center off, but not on entry.
To me, that suggests that this may not be a chassis problem, but rather gearing (or possibly roll speed.)
Being fast @ exit and slow on entry (assuming she's running it in without lifting) tells me you may need to drop a tooth or two of rear gear. You could also go up 1 tooth on driver and up 2 on rear gear and see if that helps on the big end some.
Going up on air will fix the roll speed issue (if it's that or she'd locked down.)




-----
Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
33 years of service to the karting industry ~ 1Cor 9:24
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com

 

[Lily Smith Racing]

Wow,
Lemme start by saying thank you to everyone for the responses. My question all started because we've actually got another kart to run our clone motors without re-scaling weekly from what we usually run up here (predator with stock gas tank in place due to local rules). We now have the '18 and a '21. The 18 will be the clone chassis and the 21 our clone. Apparently the only real change that matters between the two is that more cross was built into the 2020+ chassis.
We are going to re-set the seats to the point of touching the body on the left side and have seriously considered moving them up physically higher to help with weight transfer as I believe this is a good starting point. I too do not want to throw 10 changes at the karts and then not know what has worked/not worked. I do know that she has gained 6# so we're just over 60# consistently. My 1st goal is to get the L side corrected. 2nd is to get her slightly higher. Was planning to start the season on the LOW side of mfg recommended cross and send it... See where we are.
My daughter is not an aggressive driver so to answer questions about letting off and such, not anymore than she has to to make the corner when she has an open or gapped space, however she's also not going to show another driver her nose, or even push the envelope in a white flag situation... That said, we're actually quite fast... just give up space on entry and have to get it back everywhere else. Driver development and sticking her nose in when necessary is something to work towards as a goal after I get the chassis working correctly/consistently. I want to find that entry speed so that we can just gap the field (as I'm sure everyone else does) and check out from there.
Tires - have we tried our night time tires at the day race, yes. I've also had another tire guy do up a set specifically for that track - they suck for us yet another (very good blue plate racer) has the same exact tire for that track and practically laps the field.
I'm wondering if I'm locking her down and thus requiring me to neutralize the numbers to account for too much tire bite? I'm not trying to chase the numbers so much as I don't want to fight the chassis which should be inherently free from its design. The last thing I want to do is put a band-aid on what should already be a good piece of equipment. If it's as simple as I'm over-prepping that'd be helpful.