Track Tac

Chassis info/setup help

B

BRE

Member
As some of you know I started my own chassis last year this year changed it up a little. been working real good issue were having is rear of kart being loose in center and out of corner an its a pavement track. Pretty good with setups but this one is being a pain lol. We are about 2 tenths off one night we had the mini cups with the Hoosier tires an they put more rubber down an we where at a 12.8 right now we are at a 13.0 for past few weeks. My son is around 10 lbs over for class that maybe a tenth slower. But winner every week running 12.8 12.7. I have thrown everything at it, we are running yellow vegas. I'm just looking for anything to try PM me with any info I greatly appreciate it.
Here is setup
cross 62-64
left 55.5
nose 45.6
castor R11 L9
Camber R -21/2 23/4 L- +5/8 +1
rear thread width 371/2 - 38-1/2
air R 15-10 L 12-8
This is what i have tried I do, have 10 lbs on left to get left side weight up thats why he is little heavy. i have tried prepping outsides with hotlap 2. Oh yea this is a gold plate animal an have tried 4 motors all the same times except that one night , have tried anywhere from 6500 to 6800 rpm. I can say cause of the slide in corners at rear causes him to stay off gas little more then other guy. sorry I wrote a book lol Thanks Jason @ BRE
 
BRE said:
As some of you know I started my own chassis last year this year changed it up a little. been working real good issue were having is rear of kart being loose in center and out of corner an its a pavement track. Pretty good with setups but this one is being a pain lol. We are about 2 tenths off one night we had the mini cups with the Hoosier tires an they put more rubber down an we where at a 12.8 right now we are at a 13.0 for past few weeks. My son is around 10 lbs over for class that maybe a tenth slower. But winner every week running 12.8 12.7. I have thrown everything at it, we are running yellow vegas. I'm just looking for anything to try PM me with any info I greatly appreciate it.
Here is setup
cross 62-64
left 55.5
nose 45.6
castor R11 L9
Camber R -21/2 23/4 L- +5/8 +1
rear thread width 371/2 - 38-1/2
air R 15-10 L 12-8
This is what i have tried I do, have 10 lbs on left to get left side weight up thats why he is little heavy. i have tried prepping outsides with hotlap 2. Oh yea this is a gold plate animal an have tried 4 motors all the same times except that one night , have tried anywhere from 6500 to 6800 rpm. I can say cause of the slide in corners at rear causes him to stay off gas little more then other guy. sorry I wrote a book lol Thanks Jason @ BRE
Click to expand...
I'll bet if you gave the name of the track where you're racing you would get more responses. I'll bet people could help more if they had your stagger numbers.

Are you sure your clutch is stalling at peak torque? How about air density, do you keep track of it?

From the desk of Al Nunley
Comments compliments criticisms and questions always welcome.
If the data does not support the theory, get a new theory. (Al Nunley)
 
Sorry forgot about stagger
front have tried 11/4 to 11/2 rear from 1/2 to 1
King George Speedway 1/5 mile tight corners very little lift in center but when kart is right no lift
Checking air no i have several other karts winning at track or running top 3 every week without any issues. But yes I have tried to lean motor out still same its to do with chassis I mean if you cant get threw the corners without being loose an have to stay off the throttle more then you cant get the straight away speed either correct..
 
Im not farmiliar with the track. But 1/2 inch to 1 inch of rear stagger on a tight turn 1/5th mile doesnt sound like enough. And 38 1/2 rtw is still about an inch to narrow. Left side sounds a little low, to much lf caster, not enough rf camber, to much lf camber, and still a little low on cross. Nor enough nose. So, Im curious to what kind of kart this is, bc on anything I have running asphalt, my kart would be so RR dependent, that it would be so tight before the apex, that it would slide the rear (mainly being the RR) and be loose because its to tight on entry. I am curious as if you ever check the track temp, and tire temp. I use the track temp to select the tires Im running, and tire temps can really tell you what the kart is actually doing. I could be wrong, but I bett the RR, and maybe the RF a little, is smoldering hot compared to the others. It sounds RR dependent from the setup, and if you were back down on the LR driving off the corner like its supposed to be, you then would be tight bc you dont have enough rear stagger, and RTW... And oh by the way, rolling vegas from the inside for asphalt, is the ticket... But not with anything hot lap... :confused: If you want anything explained in more detail, pm me... But this is all just how I see it, and is only an opinion... A friend of mine is using my setup info on asphalt, and walking the dog everywhere.
 
I have tried all types of stagger, castor, camber and cross setups. The kart enters fine. Yes will agree on left but kart is 10 lbs over weight now. If I move tread width out more will free it up more off corner. if I had more nose rear will be looser. This is a kart I designed and had godfather build. I have another kart phantom running same setup but less nose and on a rail winning ever week. To me the kart dont have enough rear weight thinking of moving seat back some to get more rear weight. Now if you like could you send me some prep info threw pm never used anything but hotlap2 on vegas. Now i have never went below 11 and 9 on castor someone told me run like 6 and 4 ???? No the right side tires are not hot they are warm but not hot also the LF hardly warm at all like hardly on track not sure if that means anything or can help.. thanks for reply's
 
10 pounds over doesnt bother me, i run 380 in mediums, and still have no problem winning... So with that, id play with the left, and the nose... And 4 and 6 caster, isnt what id be running, 4-6 lf yes, and then pending on tje track on how much rf i have... I do know, i started jacking with the caster, and kart went from winning, to dominating. Shared my information with a friend, and he wins everything he enters his kart in... And hes well over super heavy weight. I still think, that often times people think the kart is entering fine, but thats the root of their problem... And i have found most people are too tight on entry, especially on asphalt, and it translates into what your experiencing. Im not saying you dont know what your doing, or if any of this will even help, or if thats even your problem. But if it was me, id try and get the kart loose on entry, and then see what i have from there... Just to make absolutely sure it wasnt affecting my exit...
 
I understand what your saying its hard for me to tell my son just keeps saying its loose in rear I was thinking it was tight and sliding, but every time I had cross it gets better but still loose in rear Im just lost can you send me some numbers to try ill try anything at this point. Thanks for your help
 
Some karts like the high cross set up ,some like the low cross set up. Your high cross set up could be making the kart very loose and you're crippling the rest of the setup to try to compensate for that. Even when they are right, Hi cross set ups can be touchy for young drivers to get comfortable with.

Practically everything about your set up keeps too much weight away from your RR

Lower cross allows more weight to transfer to the RR wheel, especially on exit.
I would try a low 53-55% cross.

As much left side weight as you can get, can you move the seat over any more? I wouldn't worry about the 10lbs extra, I run 30 lbs extra with a gold and go faster than we did without it

I'd drop the RF air press back to around 10, the 15 could be making you loose.
I'd drop the LF air pressure closer to 8, the 12 could make you loose

Get the rear tread width back to the normal 39 1/4

You'll probably want more rear stagger once the RR starts working

I wouldn't prep tires yet, you'll only make a slow set up feel more comfortable, but still be slow

Let us know what you find
 
After reading CT's post, although I dont think that practically everything is keeping it off the rr, I would have to agree with 90% of what hes saying... I didnt even think about it being a junior driver, nor have I really wrenched on any juniors on asphalt, and weve been running mega cross setups forever. So thats what I am used to running, and they really arent that easy to keep rolling... Almost kind of violent at times. So i would go with what he suggested. And we didnt start prepping, till we had our karts running up front and winning... If you ever do want to try my high cross stuff, shoot me a pm. Same with the tire info...
 
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Most of our competitors run the hi cross set up, we've tried it a few times and my kid just doesn't like it. We can get almost as fast, but we fight wheel hop when the sun is shining and the speed goes away on long runs. I find the low cross setup is more comfortable for the driver, more forgiving for my setup and the kart gets better on long runs. We might be giving up a little on the first few laps, but it seems worth it.
 
AP way too high. We used to run L-8 and R-9 or L-9 and R-10 at the most. you know what kind of times we were running.

Robert
 
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