Yamaha KT100: Pipe vs. Can

[Joey Kowaleski]

Next year I will be moving into Sr. Yamaha and have to go from the can to the pipe. I was wondering why some organizations run the pipe in the Sr. classes. Also what is the difference in performance and lap time? thanks.

[Daniel White]

At our .25 mile, 7-turn track, where you are only on the brakes twice per lap, the difference is about .7-.8.  It’s a significant difference, and I feel it throughout the rev range. Moreover, in my opinion, the pipe makes setting up the go kart even more critical / difficult. With the can all I had to do was point the kart and I was near the front. Pretty boring really.

I love the SR-Y pipe compared to the can.

[Jay Sinon]

We just switched to Yamaha Sr. this year and so far we haven’t noticed much change in the lap times. Our Jr. engine made about 19 hp at 320 lbs. Now we our making about 22hp but weigh 360 lbs.  My Daughter said she likes running the pipe more midrange in the turns but I think the extra weight we are caring balances out the extra power we make.  Not much time on the pipe yet to really come up with conclusive results but this is what I’ve seen so far. Is everybody else seeing the same thing? Or do I not have it figured out yet?

PS: We are running a 11 turn 7/10ths mile track

TaG Sr.

[Will McDonough]

As to changing from can to pipe you will pick up lap times.  With a pipe you have 3 things you can do to just change your times and rpm. Header Pipe and flex.  Don’t get these right and you’ll still be running the same times.  Remember kts make power in the 9500-14500 rpm range. Gear for the bottom pipe for the top

[Jay Sinon]

In our case there is not much we can change, we basically use WKA rules and have to use the RLV9110 header with an Sr-Y pipe with at least 9.5″ of flex/connecter tube from the piston. We can go longer but I have not played with the lengths yet. Everybody locally seems to want to stay as close as possible to that minimum length.

TaG Sr.

[mike clements]

On my Dyno my best KT-100 shows 17 BHP with my best pipe. Since it was blueprinted by Pete @ Superdyne I have to believe it is as close to being the best as we can get. With that in mind, what difference do you see between the best pipe and the 3 hole can or the 4 hole can ?

[Jay Sinon]

Mike said ” what difference do you see between the best pipe and the 3 hole can or the 4 hole can ?”

When Daniel Woltjer sent back my engine it came with a Dyno sheet that read just about 19hp when it was built for a 4hole can(Yamaha Jr.) When he sent the Dyno sheet for a engine he rebuilt for me with a WKA Sr.Y pipe(Yamaha Sr.) it came back with a Dyno Sheet reading just over 22hp. So what I found was roughly 3.5hp advantage but I had to add 40lbs (Jr=320 Sr=360) of weight so although my daughter liked driving it better then the 4 hole can it was a wash time wise on a 7/10 mile 11 turn track. There are however pipes/Headers that make a lot more power then the Sr. Y pipe. A friend of mine put on a illegal pipe that picked up almost 2 seconds over the Sr. Y pipe.

I have no experience with a 3hole can

TaG Sr.

[FREDDY SANDOVAL]

Don’t forget about tuning the carb

If you’re not changing anything when swapping from can to pipe, then it’s really hard to judge

How many turns are you running on the T handle needle for Can?

How many turns on the T handle for the Pipe?

You should have a noticeable amount of difference in performance, so much that if you had 2 karts identically set up, same kind of driver, the one withe the can would have a hard time catching up to the guy with the pipe. FastFreddy.

[Jay Sinon]

There’s no question that the engine with a pipe is faster and has more power when tuned correctly . I agree that if they both weighed 320lbs there would be no catching the kart set up for the pipe however my dyno sheets read that there is a 3.5hp difference between the 4 hole can and the Sr.Y pipe and that’s not much more power to make up for the 40 pounds of weight that you have to add to run the WKA pipe. How many of these forums complain about weight and how they cant catch the little guy because there heavy. It would be interesting to know how much horse power it takes to push every additional 10 pounds.

TaG Sr.

[Greg Wright]

No offense to the Woltjers but the dyno numbers that they publish are way optimistic compared to any others that I have seen. Pipe is much quicker regardless of the dyno numbers.

Greg Wright
Rapid Racing Inc.
Vintage B-Stock Pilot
"When in doubt Gas it, It won't help but it ends the suspense."

[FREDDY SANDOVAL]

Have you guys noticed this topic or question was posted Dec 26th 20014?

It may not even be important to the guy that initially asked the question, as he never even replied with any more feedback.

Just a thought.

[mike clements]

I posted yesterday because I have renewed interest in running a kart again for myself. I’m old, fat, ugly and have survived 13 open heart surgeries. Also have a pacemaker. So, If a 4 hole can will pull me around the Phoenix sprint track, I might go play with one. Just wanted to know the difference between the can and a pipe.

[Walt Gifford]

It’s a different kind of drive. With the 4 hole it’s smooth steady just hold the gas down and steer. With the pipe it’s a jerky ride on and off the power where the kart wants to jump out from under you.

Gif

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

[Joey Kowaleski]

Just stumbled back upon this, completely forgot I posted it. Enjoyed running the pipe much last year much more than running the can the year before in Jrs. That seems to be the consensus, WKA should have stuck with the pipe at the national level.

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