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The range of usable power is whats important. At some track, the range required is not that critical. For example, at IMI, we only need about 3 to 4,000 rpm range. We turn our Rotax no more than 12,500 and do not go below 8,000. In that range, the rotax is hard to beat. However, at a track like Bandimere, we are at 6,000 off the slow corners and yet we top out long before the end of the straight. Those motors that have a wider power band, can easily beat the snot out of the Rotax there.
At Grand Junction, its just about a draw. At the current weights and power band demands, its about a dead heat. No engine has a clear advantage that I can see. I’m not sure about The Track. At first glance, I thought it would be all Leopard, again due to power band requirements. Now I’m not so sure. It may turn out that up hill, advantage Rotax, down hill, advantage Leopard.
I just received an email from Marty Casey with TagUSA. The Rotax weights will be back to ’06 weights as soon as the web mistress gets it done.
Brad is right about it being a tech issue. There are some oils that do contain performance enhancers. There are also some that while they do not contain enhancers, they mimick enhancers and again, make tech very difficult. Open oil, like open fuel, makes a mockery of tech. Why control anything if you can’t control fuel.
If we are serious about tech, first we have to spec fuel. The nice thing about VP is that it’s just gas, not oxygenaters of any kind. It is also very consistant. No matter where you buy it, it will pass tech if properly stored. Limiting oil to 2 types (castor and sythetic) covers the needs of most engines and makes fuel tech possible.
The Maxima 927 is a very good caster oil. It works fine in shifter engines and many Tag engines. However, it is not recommended for Rotax. Rotax very strongly recommends the use of synthetic oil and the Motul after extensive testing has proven to be the best. I have run both oils in our Rotax and the Motul builds far less carbon on the piston than the castor oil. While I have not gotten a difinitive answer yet, there is strong concern that Rotax will not honor the warranty if the customer uses castor oils.
VP changed suppliers on it and there were bottom end failures as a result. Rotax used to recommend it but no longer. Now Rotax recommends Motul 800. Its a very good oil. Burns clean and stays in suspension.
I can’t argue with you that $1,500 is a bit steep when compared to the Honda package you are offering. If they are indeed as equal as you claim, that may be a good deal for our customers. I am just pointing out that the K80 is not near as bad as some would make it out to be and it does give very good racing. As we saw from the TV of the Stars New Castle race.
ComerJet.com should be banned from karting IMHO. They feed on the “Motor is the reason you win” mentality.
K80 engines can be had from several sources for less than $1,500 blueprinted and brand new that will and can run in the front of a Stars cadet race.
The outside pole sitter was Nick Neri in one of our karts. I did not see the end as the wife called us for diner. But I tell people over and over, K80 racing can be the best racing on the planet. It is by far the best racing Stars has to offer and it is some of the best racing I’ve ever seen. The motors are so even that it really comes down to driver.
After watching racing like that, how can anyone trash the K80? I know for a fact what Nick’s motors are, how much they paid and how often they maintain them.
And it ain’t $4,000 like some will claim you have to spend.
As we all know, jetting is critical on getting the best from a Rotax. Surprise, that’s not one bit different from any other engine on the market. We all use MaxJet software to set our jetting but I was interested in finding out just how accurate it was for my motor. Now I could have spent a couple of days at the track burning up tires but never really knowing for sure if I had it right or not.
So I spent a couple of bucks with a dyno to check out where my MaxJet numbers were. In less than 1 hour, I found the answer. It is off by two jet sizes. The motor ran fine at the recommended settings but I did find that if we went 2 jets sizes smaller, we found a slight boost in power. I only suggested using the dyno because you can get accurate answers quickly and economically.
What happened in Florida was entirely different. There we had a dealer who sorting cylinders and selling the “best” for thousands of dollars. What I suggested some racers may want to do would make me exactly zero dollars, none, nada, zippo. If you followed my suggestion, all it would have done is made YOU faster. I have had people come to me and ask for a different cylinder and my answer is why? There’s nothing there. Its a waste of money to try and sort parts. Better to spend the time at the track working on driving.
My whole goal is to make every racer in this state as fast as I can whether you bought your kart from me or not. To that I’m offering a FREE seminar on prepping your kart and learning how to maintain it. Part of it will be what a guy should do to prepare for a national level event. If that makes us an “Outlaw”, well then call the sheriff. we’re guilty.
I’ve only setup karts at 35 different tracks around the country. I don’t know everything but I do know a bit. If you don’t want access to that info for FREE, then I guess you can do what ever you want.
@Mike Jansen wrote:
Wow, and i’ve got a freshly rebuilt rotax (top and bottom) kart for sale. Glad it’s got a seal on it… 8)
Hey Mike, you may want to hang on to that thing and come and do the Grands. 😯 Oppps, I’m sorry I forgot. At the Grands they do a lot of racing. 3 heat races, an LCQ, a pre-final and a 25 lap main.
Just kidding Mike
Dane hit it exactly on the head. No question the 50 is faster. But the driver has to be better to take advantage of it or he/she/it will actually be slower. The 40 is better for newer drivers as it has a wider tuning window and is more forgiving to mistakes.
The compound was changed a bit last year. This is the tire we will be using this year. We used it last summer at the Miller Shootout. I do not know if its possible to tell the difference visually but I do know that only the revised compound is available. There maybe some old tires still around but I don’t know were you could find them. (or why) I would not be concerned about getting old style tires, they have been out of circulation for almost a year.
The Mojo is the spec tire of the RMC. That is 100% certain. It is our intention to run the Mile High challenge to full RMC spec and that would include using Mojos.
Now before you guys go slashing wrists and punching up the reply key for a flame job, investigate the Mojo a bit further. It actually is a very good tire. It does not have more grip than the MG Yellow, it has less. It also wears much longer. But more importantly, it does not fall off over time. (Once a rock, always a rock, right?) In fact, some claim it gets a bit better after a couple of heat cycles.
It does require two things.
First, the setup of the kart is different. What works for the MG will not work for the Mojo. So the simple thing to do is test and find out what works.
Second, the driver has to be much better. You can not go out and slide the Mojo around like you can with MG’s or B’stones. It over heats quickly and the grip goes away. The good thing is that once it cools down, the grip comes back. Our weaker drivers will hate the tire. The good drivers will get smoother and get better. You have turn in earlier, gentler and unwind sooner. You have to learn to let the kart rotate under you, not force it.
If a driver does not get some extensive experience with the Mojo, he/she/it will be at a huge disadvantage compared to the guys who do. In the MinMax class last year, 7 of the top 10 including all the top 5 were from Florida. Why do you think that is. Do they all cheat? Is the water better? The reason is simple, they run the Mojo year round. That is why Andy S. and the Gatorz series switched to Mojos for this coming year. To better prepare his customers for the Grand National.
I would guess that for most drivers, you could buy just two sets of Mojo’s to run all of the Mile High Challenge and do all the testing you need getting ready for the Nationals. I know that I couldn’t get that much racing out of Yellows.
