Priorities for finding more speed in Supercan classes

[Len Cockman]

Our son races in the ManCup supercan classes. His mechanic (me) is struggling with tuning to help him close the gap between P1 and the tail end of the field. We struggled more than usual at the ManCup Norway race earlier this month and, to top it off, I fell after the Saturday storm, broke a thumb and tore ligaments.

So now I have more time to do research as wrench turning requires two opposable thumbs.

If there were a flow chart of sorts/priority outline what would be the top five things you would do that make the most obvious drops in lap times?

See you in Daytona, hopefully with the cast off my left arm and rehab completed.
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The challenge of the "thrash" between runs makes it all worth while.

[Walt Gifford]

There is really only one thing that will give you speed in supercan and that's driver skill.

Gif
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FAA certified jet engine and aircraft technician
Nicholson Speedway class champion 2001
Yamaha KT100 Service Center
40 years karting experience

[John Wehrheim]

Well you might not like what I have to say, but being 2 1/2 seconds off the fast time is huge. I agree driving is very important, but Chassis setup is just as important. Here is how I would rank them
1. Chassis Tuning
2. Proper Driving technique
3. Motor
4. Race Craft.

Now as it pertains to your son, I think being off this much time is both driving and chassis. There are a lot of questions.

Looks like your son is racing a Birel, if that is correct, is your setup close to the recommended setup.
How old is the chassis?
Is the model of Birel you using proper for low HP kart

Does you son give you good feedback on what the kart needs or is doing?
Do you know where he is losing time?
Have you done split times between your son and the top drivers to see where he is losing time?
Is there anyone you know that races in the class that you can overlay MyChron laps to see where he is losing time.

Recommendation:
Hire a driving coach and a tuner for a test weekend that knows their stuff for a day.
FYI - Practice will not help you if you are practicing bad habits.

[al nunley]

You ask the impossible, you know that right?
I could list about 20-30 questios just to start off.
First question is how long have you and your son been at this? I know it looks easy, but it isn’t, as you’re finding out.
Books have been writen on this stuff, have you read any of them?
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If the data does not support the theory, get a new theory. (Al Nunley)
All else being equal; Compression is the Holy Grail.
45 years, in and around karting

[Len Cockman]

John:

No offense taken. Andy has just about completed his second season of running most of the ManCup races in each of these seasons. Given my profession is about as far from engineering as possible (Fine Arts) kart racing is an amazing and fun challenge.

I have noticed that in cold or inclement weather our driver is closer to the front than during summer weather/nice days. We have agreed that due to my lack of years as a tuner that he is most likely over-driving the kart (over-reaching to keep from falling behind) and losing lots of momentum on corner exit.

We have run a 2002 chassis during the 2010-11 season. I realize this is nuts but we have a great time with a very limited budget and are in the process of hunting down a lightly used, less than 3 year old chassis for Daytona. We had the frame checked at the MRP ManCup race and found that it is straight (surprising).

Several other questions that I have are...how frequently do the Yamaha class racers have their engines rebuilt based on running WKA national events, changes to new axle bearings, etc.

Overall, we have found most of the racers and teams to be very helpful. The folks at Adkins, Franklin, MRP, Comet have all been friendly in sharing suggestions and information.

In closing, I feel that coaching from an exerienced racer will pay huge dividends and it will last much longer than a set of tires.

Thanks.
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The challenge of the "thrash" between runs makes it all worth while.

[John Wehrheim]

Len,
Several things that caught my attention from your comments
1. Your statement "I have noticed that in cold or inclement weather our driver is closer to the front than during summer weather/nice days. "
This tells me that your kart is too bound up(too much grip)
2. "We have agreed that due to my lack of years as a tuner that he is most likely over-driving the kart (over-reaching to keep from falling behind) and losing lots of momentum on corner exit.".
When my son got into karting I tried to emphasize it is better to go slow in, fast out. This will allow you to get on the gas at the right time. This is even more important in the low HP karts.
3. Running a 2002 Birel is most likely very tired, chassis is soft, therefore changes you're making to the chassis are having no effect. I would recommend getting a 1 year old chassis with limited races. I am sure Jamie at Franklin, Mark at Comet, Mike at Grand Products and other major shops know some of their customers that are looking to get new chassis for Daytona. Just make sure you get a chassis that has a fairly large sweet spot for tuning. Some chassis are easier to tune than others.
4. In Yamaha Can, the top guys are rebuilding top ends every 2-3 races, but at your level, I would not worry about that right now.
Like you said, money will be more well spent on a driver coach and tuner. I would buy that new used chassis first, then do the coaching and tuning.

[al nunley]

A lot of good stuff here.
Three things I would get first are an air density gauge, an EGT gauge and a “good” compression gauge.
Cold air is denser than hot air, mostly. If your carb is set too rich, cold air can lean it out, letting you go faster, hot air can richen it up. Thus the need for an air density gauge.
I like the EGT gauge. It will tell you, very accurately, if you’re too rich or too lean. It’s so much better than a CHT. Your going to get differences of opinion on that, but I am 100% correct on that point.
Compression is important. Test it often. Every race day after the racing is over. A “good” KT will pump right at 160psi. Much below that and the engine makes less HP.
A good driving couch is a good idea. Tell your son that every corner on the track has a limit to how fast he can drive it. Getting thru the corners smoothly is real important. I learned early that braking into, and thru, a corner is bad, You brake straight, start to turn when it’s right, get back on the gas as soon as possible without getting out of shape. If I got on it too early, and it looked like I was going to drop a wheel, I would touch the brake. Never let off if at all possible. If you let off, the fire cools and the power drops. Let him understand that flapping the throttle thru a turn, while it may seem neat, it’s not, you loose HP and speed.
_________________
If the data does not support the theory, get a new theory. (Al Nunley)
All else being equal; Compression is the Holy Grail.
45 years, in and around karting

[al nunley]

Forgot.
The clutch, if it's an oil bath type, should be, coming off the tight corners, right near 9,300 RPM.
Take your engine to someone that is good and make sure the crank has as near to .000 runout as you can get. Check the CC's in the head. Have them make sure the Exhaust port is near the limit of the rules. With in .005". No less.
Don't cheap out, new main bearing every time youi have the engine apart...
_________________
If the data does not support the theory, get a new theory. (Al Nunley)
All else being equal; Compression is the Holy Grail.
45 years, in and around karting

[al nunley]

Something else, if he's flapping the gas going into a turn, he didn't go in deep enough. If he goes in deep enough, there is no time to flap the gas pedal.
_________________
If the data does not support the theory, get a new theory. (Al Nunley)
All else being equal; Compression is the Holy Grail.
45 years, in and around karting

[John Wehrheim]

[al nunley]

[Len Cockman]

Jim, Al;

Sincerest thanks for insightful information. You have suggested a number of things that I will be doing in the near future. Texts by Memo Gidley and Stevie Smith have been helpful but tend to reiterate what I learned during season 1. NKN informational videos and periodical articles have helped quite a bit as well.

Given a race weekend involves practice, race, race...does that equal three races days?

We have three blueprinted engines, two Laukaitis and one Comet. We have Horstman HDC5B clutches that are rebuilt and installed at the shop(s) to their specs. Very specific times are kept and our plan is to do rebuilds after 4.5 hrs. run time.

We aim for a stall speed of 8700 with 14,200 on the top RPM. We lazer align the front to the factory specs and then slightly alter based on driver feel and lap times.

Our current plan is to go with one set of tires and "switch" them for Sunday racing until we are within one second of P1.

Given MRP is our home track I am in the market for Birel equipment based on that fact that I raced one before our son started in Supercan and feeling comortable and familiar reduces stress between runs.

Again, thanks for being so helpful.

Len
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The challenge of the "thrash" between runs makes it all worth while.

[Kent Metcalf]

Got to ask this because as these guys know I have been fighting the same battle as you BUT Mine is without question in our class. My driver is around 50 pounds too heavy for a 310 class so a second or a second and a 1/2 is not bad for us. How much dose your kart and driver weigh going over the scales on race day? anything much over the min. you are a stuck duck. That brings me to a new post coming Walt and Al if you can help me on weight for classes. Good luck Len
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St. louis Mo.

[Len Cockman]

I keep records of how much extra weight and where it is located so we are usually within 4 lbs. at the first Friday morning practice. I mark the tank after he crosses the scale and aim to be three lbs. or less after each run.

Although our local track does not suggest it we have taken to "scaling" the kart via the track scales. This seems to have balanced the kart.

I have found that we burn about 1lb. fuel during each practice session, .75 lb. during time trials and anywhere from 1 to 2 lbs. during the pre and final.

Andy is a type1 diabetic and tests his glucose before each run. He makes certain that his number is a tad high before each run as going too low could be dangerous for he and possibly his competitors. Andy has a routine of chugging a full bottle of water just before heading to the grid. This one lb. of extra insurance keeps a decent run from being D.Q.ed.
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The challenge of the "thrash" between runs makes it all worth while.

[Tim Doll]

Others have already mentioned this, but I'll repeat it anyway:

Handling/setup is critical in low power karts - any extra speed you carry through a corner will show itself all the way to the next braking zone.

Driver skill and technique is obviously important in this regard, but if the kart isn't right it's hard for even the best driver to compensate.

Tim
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Standard disclaimer - I'm FREE - No longer affiliated with any organization, I can say whatever I darn well please!.

Everett, Washington