Things that make me wonder.

alvin l nunley

Premium User
How can people denigrate my posts without offering an explanation of where I went wrong? They just call me names and say I'm wrong!! I've been accused of being condescending, what's worse?
 
I'd like to see your example where anyone denigrated any of your post and called you names, just because someone says your wrong, or the info you gave was useless is not calling you names.
 
I appreciate your comments Al. I want to try the bathroom scale thing - I just need to find a good wall (don't have one where I live).
 
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jaymancds

Premium User
I appreciate your comments Al, they bring up good points in a lot of cases. Along with that, alot of your posts are over complicated for the weekend warrior racer.

Example: You mention air density quite often. Having been around engines and tuning I understand that air density DOES have an effect on performance. However, there are several problems with this being the go to point of everything. Number 1) I dont have the tools to measure air density, nor does anyone that I race with. 2) I don't have a dyno at the track to adjust tuning to match it. 3) Beginners read these forums ALOT more than experts. They are already confused with tires, preps, setups, weights, gears, track conditions, etc. The LAST thing they need is another variable in the mix. 4)Air density will make so small of a change, that most people will never feel the difference. At the top level, sure they know, but the rest of us wont be able to tell.

These complicated topics are fun for those of us who have been around a while, and or like me, spend every waking moment thinking of how to get faster, but only work to further confuse everybody else. In many cases it also derails a thread, and sometimes keeps everyone from answering the original question. No hate from me, but sometimes its a little too... complicated (y)
 
I appreciate your comments Al, they bring up good points in a lot of cases. Along with that, alot of your posts are over complicated for the weekend warrior racer.

Example: You mention air density quite often. Having been around engines and tuning I understand that air density DOES have an effect on performance. However, there are several problems with this being the go to point of everything. Number 1) I dont have the tools to measure air density, nor does anyone that I race with. 2) I don't have a dyno at the track to adjust tuning to match it. 3) Beginners read these forums ALOT more than experts. They are already confused with tires, preps, setups, weights, gears, track conditions, etc. The LAST thing they need is another variable in the mix. 4)Air density will make so small of a change, that most people will never feel the difference. At the top level, sure they know, but the rest of us wont be able to tell.

These complicated topics are fun for those of us who have been around a while, and or like me, spend every waking moment thinking of how to get faster, but only work to further confuse everybody else. In many cases it also derails a thread, and sometimes keeps everyone from answering the original question. No hate from me, but sometimes its a little too... complicated (y)
Ive been attending, or have been a part of (tire specialist), the top tier of karting for about the last 10 yrs or so. Not 1 major race i can think of there was a jet change for air density where it produced the winner. In those 10 yrs or so, ive seen maybe 3 changes of jets, that was with plate classes, due to too rich or lean on the spark plug readings.
Ive seen on a dyno, at the builders shop, where a jet change of 1 size, can add or detract a half HP. Hard to make a change of that magnitude at the track, without first throwing the motor on a dyno for verification.
 

Ted Hamilton

Design Drafter / Racer
Ive seen on a dyno, at the builders shop, where a jet change of 1 size, can add or detract a half HP. Hard to make a change of that magnitude at the track, without first throwing the motor on a dyno for verification.
This is why you build a table of HP for given atmo conditions and change jetting according to conditions at the track. It would be stupid to make a blind stab at it. It would be equally stupid to never know that table and always be leaving hp on the table... Of course if you haven't master driving technique, tires, and chassis balance first, it won't matter.... So, IMO the biggest factor is isolating and attacking whatever is costing you the MOST time first. Atmo conditions are pretty low on that list for weekend racers.
 

alvin l nunley

Premium User
Ive seen on a dyno, at the builders shop, where a jet change of 1 size, can add or detract a half HP. Hard to make a change of that magnitude at the track, without first throwing the motor on a dyno for verification.
Amazing!! Even with hard evidence, you deny the advantages of tuning to the conditions!! Absolutely Amazing, what can I say??'
I'm reminded of the old saying "you can lead a horse to water,..................." or "hard to teach an old dog........................"
"tuning is tough" (Al Nunley)
 

95 shaw

Premium User
I think what most are saying, is it is possible to generate reams of data, calculate everything, but, unless you can accurately interpret that information and accurately apply it with the means available, your time is likely spent doing the things you can accuarely control.

Things like maintenance, safety, maybe even watching changing track conditions to anticipate needed changes for your next race.
Dirt racers spend alot of time on tires. It has been shown that the right set of tires can and will overcome a silght deficiency in power.

If you even are actually down on power.
 

jaymancds

Premium User
I think what most are saying, is it is possible to generate reams of data, calculate everything, but, unless you can accurately interpret that information and accurately apply it with the means available, your time is likely spent doing the things you can accuarely control.

Things like maintenance, safety, maybe even watching changing track conditions to anticipate needed changes for your next race.
Dirt racers spend alot of time on tires. It has been shown that the right set of tires can and will overcome a silght deficiency in power.

If you even are actually down on power.
Usually about an hour and a half between a heat and the feature for my track. I spend 15 minutes cleaning and inspecting the kart. Then the rest of that time is spent on tires. Cleaning, prepping, etc. I keep an eye on the track for gearing but that doesnt really take any time.
 

OVALTECH1

Premium User
I agree that jet changes “could” be beneficial especially on hot humid dank air summer days or late fall in the chill. But in order to use that to your benefit you would have to have real time data from your egt and cht and fuel consumption to be able to read and adjust from. That’s a lot of info for a mychron to record and feedback when things could change in the next hour or even half our for that matter. Not tomention that locking the kart down or having a chassis to tight will raise your temps and lead you to believe fuel needs trimmed up. All for something that will provide less benefit than the right set of tires for the day. If your pocket is bottomless go for it but for the average team it’s not feasible to chase it. Not in my mind anyhow.
 

Ted Hamilton

Design Drafter / Racer
I agree that jet changes “could” be beneficial especially on hot humid dank air summer days or late fall in the chill. But in order to use that to your benefit you would have to have real time data from your egt and cht and fuel consumption to be able to read and adjust from.
Not really.... you just look at the current atmo conditions (buy a weather station like the top asphalt sprint racers do) and then jet according to the chart your dyno guy already gave you... It's plug and play once you have the right tools.

And a heckuva' lot simpler than tires on the back end.
 
Amazing!! Even with hard evidence, you deny the advantages of tuning to the conditions!! Absolutely Amazing, what can I say??'
I'm reminded of the old saying "you can lead a horse to water,..................." or "hard to teach an old dog........................"
"tuning is tough" (Al Nunley)
Just like a radical leftist, taking a snidbit of what i said to try and make yourself look good.
 
This is why you build a table of HP for given atmo conditions and change jetting according to conditions at the track. It would be stupid to make a blind stab at it. It would be equally stupid to never know that table and always be leaving hp on the table... Of course if you haven't master driving technique, tires, and chassis balance first, it won't matter.... So, IMO the biggest factor is isolating and attacking whatever is costing you the MOST time first. Atmo conditions are pretty low on that list for weekend racers.
Time on a dyno costs the builder money, and also the racer. Plus, how long does the builder need the motor to cover all the differences in atmospheric conditions in order to build a table?
I guess im asking if you are calling some of the best motor builders in the country stupid also?
 

Ted Hamilton

Design Drafter / Racer
I didn't call anyone anything. Such tables exist, and could probably be extrapolated closely for our application. Air density can be predicted based on elevation and temperature, so expensive dyno time might not need to be spent. If I was a dyno owner (I'm contemplating it), I'd be testing. And instead of waiting around for the right weather, I'd use a humidifier and a thermostat on the wall...

Alternatively, you could use a flow bench and measure different output rates based on the temp / humid. The goal, of course, is to preserve the "perfect" 14.7 stoichiometric ratio.
 
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