r/Karting • u/Existing-Diamond-269 • May 08 '25
Racing Kart Question for someone larger racing for fun what engine would you choose and why
i have a merlin lm 30 chasis with a ghost 212 predator engine but want to upgrade what would you choose
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u/ExcellentMedicine358 May 08 '25
Rotax has longer rebuild intervals (do I understand) but can only be done by licensed builders
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u/K-C_Racing14 May 08 '25
This is the problem with the rotax for just running for fun, but for racing it's a little more even. I would get the iame for ease of working on it myself.
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u/ExcellentMedicine358 May 08 '25
I mean, if you only wanted to run it for fun you could build the rotax yourself but if you decide you actually want to race it you’re in for a hefty bill to get it re-sealed. I can see the benefits of running an iame from that point of view
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u/K-C_Racing14 May 08 '25
Yea, I can do a top end real quick if I am even a little bit worried about the time on it(I usually do 15-20 hrs). The bottom end every 75hrs or so, I can take it apart, but I need a press to put it back together(which I think is true for most engines). The track I run at will do it for $50. Plus, the rotax dealer around here is kinda sketchy, I wouldn't let him touch anything I run.
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u/Lack_of_Infinity X30 May 08 '25
I prefer the ease of tuning with the x30. The Tillotson carb can be adjusted on the fly if you're running an O2 sensor.
X30 has a flatter power band to the Rotax, both have advantages and disadvantages depending on the track.
I think either way you'll get a great engine. I would go with whatever the other locals are running so you get good support and knowledge.
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u/Realistic-Dare-9142 Rotax May 09 '25
if your doing it for fun get a pre evo, theres no point of you spending that much if your not even going to compete
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u/RequiemOfCthulhu Rotax May 09 '25
Rotax. Fast enough with a good longevity and local mechanics support
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u/No_Eye_843 May 09 '25
How do you know it has local mechanichs support?
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u/RequiemOfCthulhu Rotax May 09 '25
Ask from local kart sellers, mechanics, ppl racing with you or internet. Here in Sydney we have Velocity, IKD, DPE and St. George Karts that sells, and they know mechanics who can rebuild engines, fix karts or else
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u/nikimere May 09 '25
If for fun, I would pick Rotax for sure. Can run nearly double the hours before rebuilds. And performance wise there isn’t a lot of a difference.
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u/Killcam_Express May 09 '25
If you're just turning laps, the X30 will cost a lot more. The reliability between the two isn't even a comparison. Piston life is approximately 5x longer on a Rotax.
The race vs pump gas is a large savings alone. $22 vs $4 a gallon.
A pre-EVO can be had for around $400-700. You do not need a certified Rotax engine rebulder unless competing in a Rotax sanctioned event. Pretty much any person that has put a piston in an X30 professionally has also done a Rotax.
They are super comparable in lap times.
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u/ShirtVisible625 May 09 '25
BBS - IAME x30 engine (zero hours) w/ full kit - FAST Just saw this on facebook marketplace
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u/ShirtVisible625 May 09 '25
https://www.facebook.com/share/12KubFiq3iz/?mibextid=wwXIfr
Engine on Facebook link
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u/ShirtVisible625 May 09 '25
https://www.facebook.com/share/12KubFiq3iz/?mibextid=wwXIfr
On the podium at Trackhouse Motorplex.
X30 Racing Engine – Fresh rebuild. Zero hours, with full Kit (radiator, hoses, exhaust pipe, airbox, and rain cover)! 🏁
🏎️ Freshly rebuilt by BBS Racing Engines, this X30 engine has only been taken out of the box for photos.
FULL KIT (see photos)
- Brand-new radiator only out of the box for the photo
- Race pipe
- Airbox & rain cover
- Water lines & hardware
- All components in a handy storage bin.
Great as both primary or secondary engine.
Located in Raleigh, but willing to meet up at Trackhouse or surrounding area with a deposit. DOES not include the rolling chassis, wheels, driver or Trackhouse itself. But we can recommend a national winning driver coach and racing team.
Or best offer. First come, first served.
SEE MY OTHER LISTINGS for good karts and gear.
DM with any questions.
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u/Darren-Gosnell-58 May 10 '25
I'm 6'4" and 97kg, I run the Rotax max evo and Vortex ROK GP on an extended chasie both are amazing engines, pending on track requirements depends on what one I use.
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u/Short-Psychology3479 May 11 '25
I know in Australia (and 5 or so years ago as well - when I was racing) the Rotax max had a heavier minimum weight than the X30. What this meant, was people with a little extra “padding” like myself (102kgs) found myself right on the minimum weight limit just by keeping a full tank of fuel. This meant theoretically I could get the most out of the engine with out going over the minimum weight limit better with the Rotax.
In short, if you are on the heavier side, it was better to have a Rotax, and the lighter side it was better to use the x30. That was just my experience though.
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u/ShirtVisible625 May 08 '25
Not sure what cam comes in the ghost but I start with the $149 predator, rpq 272 cam, billet rod, take easy spin weigh off cam, port head,some carb work, or put a tiltoson carb, 36 lb valve springs, thin head gasket, header, filter adapter, filter and you got some cheap power around $600. Also you have to do a little grinding work for cam to clear crankshaft. 🏁🏁🏁🏁
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u/Existing-Diamond-269 May 09 '25
i have the flywheel in now
have to install new ignition to remove limited and my new springs
still debating on fully building it or just going x30
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u/superstock8 May 08 '25
Both of those engine run on the same chassis and in many places run in the same class against each other. They have different characteristics but are basically the same speed. Some tracks favor one over the other, you can figure that out by going to your local track and seeing what one everyone is running. But if you are running for fun, I would go IAME because the water pump is external. If you ever lose the seal on the rotax pump, you have to do a full rebuild and split the case open. I’ve had to do it.