GeorgeKelp

My Feedback: (1)

What do you guys think? thank you in advance.

GeorgeKelp

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help me decide which one i should get between the two.

caseyddr

My Feedback: (13)

i personally think the TRX 2.5 is one of the best .15 engines available... Rumor has it that it can rev up to 50,000 RPM!

jswinkos

i would make sure it can fit. a guy at my lhs tried to put one in a xxx-nt and it wouldn't fit in there. it would hit the transmission brace.

caseyddr

My Feedback: (13)

yah thas what is wierd bout the TRX, ya gotta do some modding to get it in.

grampi

I have one of each engine. One seems as powerful as the other, but because the 2.5 is a bit more finicky than the Fantom, I'd recommend the Fantom.

GeorgeKelp

My Feedback: (1)

but wouldn't the nearly 50,000 rpm make it go way faster?

Wallrat

50k sounds like just a rumor. I think traxxas states that it'll turn 39k, and companies usually exagerate. I've heard that the Fantom and the 2.5 are very comparable. The 2.5 does have the engine exchange program going for it though.

caseyddr

My Feedback: (13)

nope, traxxas has never lied about there vehicles and they claim themselves it is a 50,000 RPM engine. now whether or not you can tune it that well to get it there is up to you, but if anything the engine is most definatley a 40000 RPM no doubt. Come on, the nitro 4tec stock goes 60+ mph, while the rustler goes 50+ mph. Traxxas underrates there vehicles if anything.

grampi

Traxxas does underrate their vehicles, but there's no way the 2.5 turns 50K. It turns about the same as the Fantom which is in the low 40's.

GeorgeKelp

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"The TRX 2.5 uses only top-grade, ultra-high performance, large diameter ball bearings. Top quality bearings improve power by reducing parasitic friction. The rear engine bearing uses a high-tech composite cage for reliable operation at engine speeds that approach 50,000 RPM"-- Direct Quote off of Traxxas's website. Im just stating that this is not a rumer.

solo racer

You need to be careful when reading advertisements. It is by no means saying that the motor will do 50,000 rpms, rather it is saying it does something in the vicinity of 50,000rpms (such as 40,000 rpms maybe?). They do not make any specific claims as to how high the motor revs.

Wookie

My Feedback: (5)

"The rear engine bearing uses a high-tech composite cage for reliable operation at engine speeds that approach 50,000 RPM"


You must read the quote carefully. The make no mention of what their engine is capable of reaching, only that the rear bearing is "reliable" with engine speeds approaching 50,000 RPM. It gives the illusion of their engine reaching speeds of 50,000 RPM when in reality it's more like 39,000 - 40,000.

On a fundamental level they are telling the truth, just not the whole truth.

GeorgeKelp

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good point, but its worth calling them and finding out.

packfan88

My Feedback: (2)

a search on any engine
take the os .15 cv-rx
and you will find about 5 different rpm and bhp ratings.

who knows what to believe, but someone has to be right.

GeorgeKelp

My Feedback: (1)

HAH i got the answer!!! i called traxxas and "mike" was the guys name, lol i felt like putting that, and i asked, " what is the maximum rpm for the trx 2.5 engine?" he responded, " ITs gonna be in the upper 30's to 40's". so that means it is about 37 or 38, not much.!

nitroman88

My Feedback: (5)

good find!!! 37-38 is still respectable. but not as good as the fantom numbers. But does the traxxas new .15 have more tourque then the fantom?

GeorgeKelp

My Feedback: (1)

maybe, because it says that it has high acceleratino and high top end.

grampi

I'll tell you what, just from everything I've read in the past 2 days about the 2.5, I'd definitely say go with the Fantom. A lot of people are having a lot of problems with the 2.5.