rotax or leopard at Mooresville?

[Justin Mitchell]

I'm getting ready to buy a motor to run in MMX's TaG series. They allow Rotax and Leopard in the series. Has anyone done any testing, or compared lap times between the two?

Justin

[JIM SILVERHEELS]

Justin, git a Leopard so we can plenty of them in our class,, pleez !
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Don't get stuck in someone else's discarded chewing gum with your thought process.

[Justin Mitchell]

If it weren't for the apparent reliability issues with Leopards, I'd be leaning in that direction. But as many hours as I plan on putting on the kart this year, I'm not so sure about that. Hence the dilemma. If the performance different at MMX is significant, then I'd go for a Leopard. But if there's not much of a difference, then a Rotax might be in my future.

[TJ Koyen]

Leopards are pretty reliable if you take care of them.

Keep the revs closer to 16k instead of at the limiter (17k) and you'll make it last significantly longer.

We have very few engine issues, even with running up to the limiter regularly.
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T.J. Koyen
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DB Motorsports
Exprit/Leopard

[Justin Mitchell]

That's good to hear. How many hours do you go between a full rebuild on a leopard?

[Dan Schlosser]

Justin, we spent two days on a Rotax there and will be going back with a Leopard in two weeks on the exact same kart so we should have some good comparisons. C'mon out and we'll gladly share whatever data we gather.

When we were there I think we were on par with about any of the legal Rotax karts by the end of the weekend. There was one Leopard that was easily the fastest TAG on track though. The other Leopards were on pace with most of the rotax karts.

One thing to consider there though is weight - there were 40+ Rotax/TAG, etc the Saturday we were there and very few were actually running at weight. So if you are there observing lap times, take it with a grain of salt until you see the kart and driver up close to see if they are even close to weight. Some of the fast guys were running a solid 40 pounds underweight. With as much of a dog as the Rotax is in the lower RPM range, that much weight is easily worth a second plus.

[Justin Mitchell]

Thanks! Let me know what days you'll be there. I have a race at Road Atlanta in two weeks, but I'll join you if my schedule works out.

[Dan Haynes]

Have to second TJ's comments. We have been running Leopards for about 4 years now with no issues at all. We use the key start every time and have only had 2 starter failures in that time. We have 2 motors. The only issue we have had is when I improperly installed the clutch and ruined the crank. Luckily the motor had about 12 races on it so it went back for a rebuild.

We rev ours to about 16,200-16,400 and make sure the water temp is at least 105-110* before running it hard.

I must disclose that we only ran 1 race last year and 4 the year before that but about 8-10 each of the first 2 years in TaG.
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Blaise Haynes
#3 Arrow X1-CIK
TaG
Cook Racing Engines Parilla Leopard

[Mark Tayler]

Dan,
We're going to run the Gear-up Challenge out here in the NJ area. Great series by the way if your ever up North.

http://www.f1series.com/

This series also allows Leopards and Rotax. My son is 13 and will be running in the Formula J (Jr.) category. As I don't have the funding to plunk down for two engines would be interested in your results.

One question what size exhaust header are you running for the Leopard?
Last year they were running a 25mm, this year they are allowing a 28mm.

Thanks for any data you share,
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The Tayler Family
Mark & Kristen
Jack #5 - Jr Yamaha, Jr Rotax?
Eric - Pit Crew
Jensen - soon.......

[Justin Mitchell]

I went to the inaugural race at MMX tonight. Most of the front runners had Rotax karts.

That said, most of the front runners were NASCAR or F1 drivers, sooo that may have skewed the results a bit

[Dan Haynes]

^^names?
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Blaise Haynes
#3 Arrow X1-CIK
TaG
Cook Racing Engines Parilla Leopard

[Jerry Hudson]

GGo to the MMX website, you can view all the results and names.

I believe in any of MMX's track series (club races or Racersites cup) the Rotax is going to have an immediate advantage because the WKA Leopard (whose specs we know most Leopards East of the Mississippi are built to) has to run 10 pounds heavier than a Rotax. I believe this was done for the sole reason of giving the Rotax an advantage. Let's face it, the shop at MMX is a Rotax dealer, not IAME. They WANT the Rotax to win and look good ....

I believe when any other sanctioning body runs a race there, with most having the Leopard and Rotax at the same weight, the results will differ. Only time will tell.

I also believe most of the Nascar guys are running Rotaxes because they are supported at the track, money is no object (they don't work on the same racing budget most karters do), and they can (hopefully) put a lot of time on it without doing anything to it, maintenance wise, internally. Most of them just want to jump in and drive them.

[Ihor Bilyy]

Where did you see 10 lb plus for Leopard? (ops I found it...)

BTW, Danny Hamlin was always practicing on non-Rotax. Maybe he changed to Rotax for the race...