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I think this will work out great. But I’m unlcear on a few things.
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RMax dates will be run in conjunction with the series races with separate Rotax classes.
<<#1. Does this mean that the dates with RMax will have BOTH RMax races and club races on the same day?
#2. If both are run on the same day will Tag Masters and RMax Tag Masters run separately or at the same time?
#3. If both RMax TM and TM run at the same time are there two different sets of tires / oil running at the same time?
#4. What Oils and tires for the club series (MG Yellows? Mojos?)
#5. Will there be any sort of registration for numbers for the club series?
If so I’d like to keep #12 that I had last year at the Track. My concern is that there may be more number conflicts with more drivers. But having more drivers is good.Perhaps the easiest way to do this is to list out the dates / specs for each class / series separately.
Mile HI Series, Front Range Series, both sound good to me. Could even do something like TTIMI or NECO series (N.E. Colrado).
As someone with only a few months of experience and no Rotax engine I’m very pumped about this series. Not sure I’m ready for CSC quite yet so this provides a good growth / learning series while being able to run against some people from CSC who might use this for a practice series.
Thanks
I meant to say a second set of wheels, not hubs. You can just get two sets of tires, but then you need to keep changing them. If you get a second set of wheels (about $130-200) you can have a practice set of tires and save your newer set for quallifying/racing.
Yes, practice time is key. I know, and I need more of it.
My oint was that you shouldn’t even worry about a “new” set of tires until you are within a couple of seconds. Up till then you can keep running the same set of Yellows.
However, I practiced on the YHCs and then switched to the Yellows right before my race. Big mistake. The kart setup was so different that I had a tough time learning to drive the higher grip tires. Afterward I figured out how to adjust the kart for the yellows and now can really appreciate them. What I was trying to say was get your kart set up and practice on the same type of tire otherwise you’ll be toast on race day.
Well I started last July and only got two club races in at the Track at Centennial (MG Yellows).
I ran two races and some practice time and the tires still have plenty left to them.
I’m sure they will have lost a little bit of grip, but until you start getting within 3 or 4 seconds a lap of the leaders I doubt that you will notice much difference at all. In that last 3 or 4 seconds there is paobably a lot of difference, but just learning to drive well will take a good number of laps.
Having said that for new or used tires what I can comment on is different tires. I’ve practiced with Bridgestone YHCs that are stiff whereas the MG Yellows are a lot softer and stickier. I made a big mistake in saving that first lap for qualifying with the new MG Yellows. They were Sooo different from the YHCs that I could barely drive them and had poor qualifying times. The MG Yellows are great but they are soo different that you will want to get your kart setup and get used to them prior to a race.
I suggest getting a spare set of hubs and running two sets of tires. Use the older set for practice and the newer set for a race. I doubt that you will need a new set for club level racing until you start getting fast. For a relative newby a set of MG Yellows should probably last for two or three races and practice in between. I’ve heard you can stretch the life out a bit by rotating the tires from side to side as the insides or outsides tend to wear more and rotating balances out the wear pattern
Makes sense the Motori would do better as it womps on both the Leopard and rotax on both HP and Torque according to the graphs.
It appears that in 06 the Motir ran at the same weights but now for 07 they’ve added 10 pounds for the Motori to equalize things a bit.
Understand.
Of course gearing makes a big difference so it seems that on a tight course with a lot of sharp turns the broader low band of the Leopard works better while the Rotax gets bogged down with that bump at the low end where the exhaust valve kicks in. More open course and the Rotax HP gets the advantage.
Now the rpm answer is really confusing from an engineering perspective.
If you look at the “power band” of both engines, the rotax has a nice broad power band and since it is at lower rpms it can be geared to take advantage of this.
If rpm were more important than HP, then those low rpm 4 cycles that produce around 34 HP would be getting trounced by Leopards which is not the case. If these graph were run at sea level at 29.92 inches of mercury (barometric pressue) then at 17,000 rpm you would only have 14 HP or less in Colorado due to density altitude factors. Temps above 60 degrees would provide even less HP.
It does seem that the gearing is a bit more critical with the rotax, especially on courses that have a big mix of technical turns and long straights. It also seems that the HP loss near the exhaust valve transition causes a problem.
So are the weight difference established at sea level, as this relative differences in HP are more pronounced at altitude?
the article is focused on ultralight/experimental aircraft engines. I use Pensoil in my experimental aircraft engine, a Rotax 503 DCDI, but I would not recommend that oil for karting. This is a larger, air cooled engine and max rpms are only about 6,500. Besides, it is a bit smokey. Just for reference though, I regularly run my cylinder head temps at 350 degrees, and reliability of my airplane engine is a Lot more important to me than a kart engine.
However, as the article states, a blend generally offers the best of both worlds. I know that Klotz offers a synthetic / castor blend and I am amazed that more people in karting don’t demand use of an 80/20 blend of synthetic / castor blend. The syn does a much better job of lubricating while the 20% castor both protects while the kart is sitting idle and it also has an extremely high flash point so it helps reduce damage during an overly lean run. The lower percentage of castor also reduces varnish.
The graphs are pretty clear that the Rotax not only has more than a 1 hp advantage, but it also has more than an extra foot pound of torque and a much broader HP / torque curve. From the data it has a good 5-8% advantage over a Leopard so why does it get to race at the same weight? :idn:
I’m sure lots of companies can make a good synthetic, or synthetic blends. The best fuels for R/C pylon racing are a blend of syn and castor, just in case you get too lean. Castor works great too, but it foams and does tend to varnish more which can reduce engine life unless you like to tear down and clean your engine often (which I’m sure some people do).
Can the folks who had problems confirm that this was 3+years ago as Blink states. If so then this could very well have been a one time problem.
Again, I’d really like to know what Synthetic or Syn Blend I can run and stay in spec. It sounds like RS7 is the current spec, but if the Rotax owners need to run Motul to maintain their warranties then I think we should take that into consideration.
So is the spec synthetic Motul or the VP RS-7 that is known to cause problems?
If the latter then effectively we don’t have a synthetic oil spec’d.
that is a shame as there is no reason not to run synthetic in our eninges. they simply don’t get hot enough to require castor as compared to synthetics. I have decades of 2 cycle esperience with engines that turn 20-25,000 rpm and run much hotter than kart engines. A blend of 80% syn with 20% castor is perfectt. but it seems only Klotz offers this.
Castor is gummy and will varnish more than synthetic by its very chemical composition.
I’d really like to have a synthetic oil to run but if I can only pick RS7, with known problems then I am forced to gumm up my engine. 😥
It seems strange to me that the Leopard is rated around 23hp while Rotax claims 27 hp, yet peole want to let the Rotax run at the same weight. ???
the whole point of having weight differences is to make up for differences in BHP and either Rotax is not putting out what they claim, or they should have a weight penalty to even things out. this should be easy to check on a dyno.Well, since Rotax developed many of its 2 cycle engines for snowmobiles I guess you could check out racing Rotax at the Track today.
While draining is probably a good idea, it is less of an issue on gasoline issues than for R/C cars. The reason to run out an R/C car is that the fuel is alcholol and consequently it attracks moisture, causing rusty bearings. Gas does not attrack moisture and we live in a dry area, but the gas can get stale and gummy so make sure to put some “Sta-Bil” or other fuel stabilier in the gas before the last run of the engine. However since 2 strokes rely on the oil mixed in the fuel for lubrication, running the engine completely dry with continued cranking can score the cylinder. Consider pulling the plug, putting some oil in the cylinder and then having it crank a few times to disburse the oil. (then seal it up)
3.75 per lap sounds pretty well calibrated to what e-470 costs.
Has anyone tried them on a track?
The technology is likely the same and if the AMB systems can read them why not! :loony:
Again, I saw some posts talking about tracks needing to replace their units, but are they listing the txprds for sale on the classifieds section?
As someone wtih LOTS of experience on care and feeding of NiCad, NiMH and LiPo batteries (lots of R/C car and electric R/C airplane experience) I can provide a few tips.
If these are NiCads then they may be salvageable but are probably toast. NiCads should NOT be left for periods of time with a near full charge. NiCads get “memory” and start losing capacity. They need to be carefully discharged for storage and then peaked prior to use. Some times you can use special pulse charges that fix the degradation to some degree, but it sounds like these may be beyond revival. If a track is ordering a whole bunch for replacement I suggest they work out a trade-in deal with AMB as the electronics are probably 100% re-useable.
Hopefully the new units use Nickle Metal Hydride cells which don’t develop memory and have a higher capacity per weight.
Anyone around here selling used for $100 or less?
If so I might be willing to risk cutting it apart with a dremel and replacing the batteries. For more than that it probably isn’t worth risking it.
