This is an interesting article I found on the internet, describing the diffferences between lappin and testing and going through how they runs tests with the chassis, engine, and tires. Might not apply to the regular budget driver who cannot afford different axles, torsion bars, etc, but there are some details that I thought would be interesting to try once I run at consistent pace.
Tire testing can get very expensive too 
I like this article a lot. I donāt know that Iād have the patience for testing but he does break it down well. He emphasizes that most should be ālappingā.
āFor a lapping day, the toolbox should be simple and light. Bring an air pressure gauge, chain lube, and fuel. While that might be bit of an exaggeration, itās not far off. The setup on the chassis should be the ābaselineā setup the factory advises you to begin with, and the engine should be ran a bit on the conservative side (for example, a bit richer and/or lower RPM than race-recommended). The idea is to pound 100+ consistent laps ~not caring about the lap times, just the fact the driver can hit his/her marks every time. This is not testing. This is learning to drive a kart near its limit of control as consistently as possible.ā
I agreed with that part too. You canāt do testing and make changes to the kart in setup until you are able to consistently drive your kart at the limit with the baseline setup. Once you do that, then you can start making changes and see if that improves times. Iām sure that doesnāt just apply to karting, but car racing as well
The only kart Iāve ever had that could go 100 laps with just an air pressure gauge, chain lube, and fuel was an Arrow / TM shifter kart. Everything else Iāve ever had needed the full toolbox plus a tub of chassis parts, a tub of powertrain parts, and an electronics box including oscilloscope and soldering irons.
In the past year I stuck to rentals. It was pretty interesting trying to race and win on karts that not only couldnt you tune, but each was different, each time. Some of the flaws were pretty extreme, too since stuff was busted.
I learned a lot about driving things by driving bad things.
KT2 youāll be able to. Last summer I was doing around 100 laps each session weekly, that too in 40-50 degree heat. The kart just lapped it up.
Youāre buying the wrong karts 
longest ive ever been out was around 30 minutes on a newly paved track. couldnt even lift the kart back on the stand, (it does weigh 220 pounds). Im still nowhere near consistent enough to bang tons of laps out at the same pace, I seem to improve a lot every time. What time difference would be considered consistent? (50 second lap time)
If you are within a few tenths Iād think thatās consistent.
ohā¦ well at the end of the race day when im doing well all my laps are within a tenth or less. but I generally qualify around a second slower than my fastest lap. Any advice on how to find and keep pace at the start of a day with only 10 minutes of practice before quali?
Practice and seat time so youāre able to get to the limit on your first hot lap, rather than having to build up to it over the full day. Just takes time.
Pretty common for newer drivers to go quicker when they have someone to chase too. Lots easier to spot your marks when you have someone in front of you to reference. Can be harder to go fast without that rabbit to chase, when youāre on your own. Might need to work a bit more on nailing down your braking, turn-in, and throttle points in your head if youāre struggling to go quickly without following someone.
Go out in practice and overdrive it a little if you have to, just to see where the limit is.
This is really true. first year I found pace I thought didnt exist when I followed someone. Dont know how but it happened. I think what ive been doing wrong in practice is building up speed, with only 5-10 minutes I should overdrive and find the limits quickly so I can turn it down in quali and get faster early on. Suck that I dont get practice days but Iāll use this advice. Iāll try and make the lockups and mistakes in practice so I dont have to during the race
I found that doing paved oval taught me so much about qualifying. In oval, you get two laps, thatās it. And, the laps are sub 15s. There is no āwarm upā. You have to put a good lap up, pronto.
I canāt articulate clearly why I found quali in oval so useful in regards to how we do it normally. Thereās something about how short the laps are and how little time you have. I was able to qualify much better in oval than normal.
If you ever get a sim, try oval.
sims are expensive, cars are expensive, karts are expensive. Im lucky enough to have 2 of those but I dont think I can fit it in my budget unless a wii wheel counts
Doesnāt even have to be a real sim to practice that sort of mental exercise. Jump on Xbox and Forza or whatever you have, and run practice there and see how quickly you can get up to speed.
Obviously the more realistic, the better it is to train the muscle memory, but even just using a controller, you can learn how to build up some of those mental skills.
you have to prioritize not having any waste. If you gonna pin it into the corner, make sure you can do it with quiet tires. You shouldnāt be scritching or hopping or anything. Your turns should be unhurried into the turn so that you can maximize grip on way out. Feel the relevant gripping front tire as you go into and out of the turn. Is it stable and quiet? Are you getting all of its grip
It is not sliding or popping at any point?
So basically in quali I want to be a smooth guy. I want to feel the acceleration early, smooth, and long.
If you only have 30s you have to pay attention and produce instantly. Somehow being forced to do it fast made me calm down and be much less wasteful of energy.
This may explain some of my quick reaction time when it comes to avoiding incidents ahead of me on track. 
In my experience, the best way to āturn onā your driving performance, is to NEVER turn it off.
Give Race Walking a try:
http://www.intuitivespeed.com/training-techniques/training-techniques/race-walking/
I know it sounds crazy, but so are the results. I took a financially imposed 11 year break from racing. Then I came back to a track, car, & tires that were new to me; 125 laps later (Friday practice and two races on the weekend) I was within 0.18 of the lap record, which was set in my race. How? I ādroveā all 4015+ days of that 11 years. 
I sometimes actually walk around as if I am on a circuit, like when I reach a 90 degree turn on the side walk, Iāll go to the outside, turn in at the apex, and make one foot is still on the sidewalk to avoid a corner cutting penalty
Iām about to find out - never had a chassis less than 2 full seasons old before this year.
Most of the problems I have are with drivetrains - the shifters suffer a lot less wear to the chain, sprockets, and clutch than the TaGs or the 206. A 219 chain is meant for 9 horsepower but we feed it 30.