Chonda Engine Tuning

[Robert Schneider]

My name is Robert Schneider and I am one of your fellow Chonda class racers. I currently hold the fast lap time at GCKI. I also hold the lap records at NTK in Denton for both the long and short track configuration in the Chonda Heavy class. I purchased my engine from ARC as a "build it yourself" package. This package costs $155 dollars and I assembled the engine myself. I measured a few dimensions and cleaned all the components very thoroughly before torquing all fasteners to the correct values.
I’d like to help everyone that wants assistance with getting the most power out of their engine as the rules will allow. If anyone is interested in getting the same performance from their engine as I do, I propose meeting at the track on a non-race weekend to go through all the steps necessary to get everyone's engine running in tip top shape. I will first test how well your engine is sealing up on the compression stroke and the result of this test will determine if the engine needs to be repaired or if we can go straight into the tuning of the engine. Some of you may have noticed that I take notes at the track every time I drive my kart. These notes detail how the engine and chassis are tuned for each session of laps I run along with the weather conditions during the track time. Each time I go to the track, I tend to have at least 5 entries in my notebook, one for each time I take my kart on the track. From these entries I have determined what settings work best for the Chonda engine under a range of weather conditions. (I have found that the settings for our engines that yield the lowest lap times are very different from what is recommended by the main 'tuners/engine builders' of the Chonda engine.) I will use the records in my notebook to setup everyone's engine for maximum safe power output. If I see a lot of interest in this proposal I'll even create a set of instructions to tune the Chonda engines.
By helping everyone improve their engine performance I hope to create a more friendly environment amongst the Chonda racers where everyone is willing to share ideas so we all run the lowest lap times that we are capable of.
Tuning the engine properly is only one piece of the puzzle to running fast times. The next element is tuning the chassis for maximum performance. The final element of the equation is driving style.
Also a side note about the LO206 engine rules: I read over the LO206 rules and they allow enough room for tuning of air/fuel ratio and ignition timing to make the engine perform very well or very poorly base on how these two elements are set. This means that an LO206 engine will only perform well if the air/fuel ratio and the ignition timing is set correctly just like in the Chonda engines.
If anybody is interested in a chonda tuning workshop please respond to this post. And if anyone wants to know more about my background with engine tuning beyond Chondas just ask me.

[Ted Dziedzic]

I'm always open to learning something new. Count me In!

[Stacey Lewis]

Hey Rob... I am very interested in this as well. I know two others that would be interested as well. Aubrey Ellis and Barry Peel I know for sure would love to learn more. Count us three!! Let us know when so we can make this happen.

[Rob Brown]

Im in! Just say when….

[Robert Schneider]

Awesome! I can come out next Saturday or Sunday, the 23rd or 24th. Some preliminary things to do before coming out is have 15/55 as your gearing combo installed or ready to install. Have .038", .039", .040" and .041" jets with you. Also it is very important that you have a temp sensor installed UNDER THE SPARKPLUG. If you have an extra head gasket bring it with you in case the head needs to be pulled off for repairs.
The 15/55 gears ratio works well with the timing of 26 degrees that shifts the peak power output to lower in the rpms. I'll post more as I think of it.

Robert

[Ted Dziedzic]

Robert,

Quick question on the timing. Do you use an offset key or set it manually and torque the flywheel to let the taper retain it with no key?
I believe many of us use the 2014 ARC 6619 flywheel with built in 32 degrees of advance and ARC recommends lapping the flywheel to the crank as part of the install procedure.

[Robert Schneider]

I have the first version of the 6619 flywheel so I just put in an uncut key which results in 26 degrees. Since yours has 32 degrees in it already, you'll need to install a 6 degree key backwards to retard the timing. Lapping the flywheel is a good practice to improve the fit between the flywheel and the crank shaft. I always use a key to align the flywheel since it's easier to get it right than when not using it. Some people including myself have had trouble using the keys because if the key is not sitting at the right angle it will keep the taper in the flywheel from meeting up with the taper on the crank. To avoid this interference with the key install it so the flat portion is horizontal and parallel with straight part of the crank shaft. And if anybody is having issues with getting their timing set to 26 degs, don't sweat it because I'll have the tools with me at the track to set it correctly.

[Robert Schneider]

I also recommend bringing a new spark plug with you. Its always a good idea to run a new plug when setting air fuel ratios. I'll be bringing a few new plugs and a few head gaskets with me just in case you guys don't have these parts with you. I'm leaning towards being at the track on Saturday morning and staying there most of the day. Does this work for you guys?

[Ted Dziedzic]

I'm good either day. My problem is the 6 degree key. Not sure if I can get it delivered before Saturday unless paying triple shipping on the value of the key. Looks like only shipping option available from ARC was priority mail for such a small item.
Hope it gets here by Friday evening. I ordered three of them in case someone needs one also.

[Robert Schneider]

Does everyone interested in attending the tuning session on Saturday have the new version of the 6619 arc flywheel? If you purchased the flywheel this year from Arc then it is the new version. I am asking this question for two reasons, one so that I know what the base timing is for the flywheel and two I need to know if the flywheel has holes drilled in it to remove it with a puller. If anyone does not have a 6 degree key with them, I can make a few to bring with me. Also, does everyone have a 15 and a 55 gear?

Right now it looks like the following people are going to attend the tuning session on Saturday:

Ted Dziedzic
Stacy Lewis
Aubrey Ellis
Barry Peel
Rob Brown

Everyone is welcome, and if anyone misses our tuning session I will post the results of the session in this thread along with explanations of why things were changed.

Robert

[Barry Peel]

I will be there. I do have 15/55 gearing and new spark plug. I don't have any 6 degree key or head gaskets. Can I purchase from you guys?

[Charles Borsos]

Robert, this is a great initiative. Wish we could make it out but have a family commitment. Hope to see you all at the track on the Sept 7! Charles

[Scott Lytle]

Rob, this sounds like a great learning opportunity that I will make time for. What time does it start on Saturday?

[Ted Dziedzic]

I have all in hand or mounted on kart except the 6 degree key at this time.

[Rob Brown]

I can't make it that quickly. I still need change my main seal and figure out if its my valve seals that are leaking causing smoking. Plus I don't have all those jets nor could I get them soon enough. Oh well guess I miss out...