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2.5 motor specs

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C

chris73

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What does the 2.5 stand for...I've read i before but for the life of me I can't remember where. Other motors such as Sirio and Picco have numbers such as .18, .23 , and .21 so what are the Traxxas numbers?
 
The 2.5 means 2.5 cubic centimeters, whereas the .18, .23 ect stands for cubic inch. Just another way to measure the size of the engine.
Heres a little chart relating CC to CI that i believe Olds posted a while back:

0.12 cubic inch = 1.9664477 cubic centimeter
0.15 cubic inch = 2.4580596 cubic centimeter
0.18 cubic inch = 2.9496715 cubic centimeter
0.21 cubic inch = 3.4412835 cubic centimeter
0.25 cubic inch = 4.096766 cubic centimeter
0.26 cubic inch = 4.2606367 cubic centimeter
0.27 cubic inch = 4.4245073 cubic centimeter
0.28 cubic inch = 4.5883779 cubic centimeter
 
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OK, then, dumb question.

The Revo has a 2.5 'R' engine and the new T-Maxx hs a 2.5 'RACING' engine. Is this the same engine except for the blue anodized head on the Revo?!?!
 
I still haven't found out what's different about it, but it sounds like it turns a higher RPM than the stock 2.5, and seems to hold it's tune to a T, where the Tmaxx 2.5 is usually very pesky when it comes to holding it's tune.
The stock 2.5 is MUCH more cooperative when a larger and more efficient cooling head is added.
 
rolex, I think you may be right. The Revo 2.5 needs no babysitting in most cases, if broken in properly. I have heard many people complain their 2.5 T-Maxx is always out of adjustment. Time will tell as I have both now and the T-Maxx is brand new and yet to be broken in.
 
Revo Rancher said:
rolex, I think you may be right. The Revo 2.5 needs no babysitting in most cases, if broken in properly. I have heard many people complain their 2.5 T-Maxx is always out of adjustment. Time will tell as I have both now and the T-Maxx is brand new and yet to be broken in.
Click to expand...

If you have a brand new Tmaxx, before you even start the break in, put a good cooling head on it. I'm using the ACNCM head, and I have no more tuning issues with it. Seriously, dump the stock head right away.
 
I found the same head, and i'm glad i did. It made the engine so much more easy to tune and easy to start and keep running. Rolex, are you using the giant or enormous head? I was using the enormous one and it worked soo good, till i sold the engine for the sirio .27...lol
 
Think u got it mixed up. The enormous one is smaller than the giant. The giant came out last.
 
Okay, it just seems to me that enormous would be bigger than giant. I don't have the ridiculously huge, tremendous, behemoth, monstrous overwhelming one. I have the one that came before it.
Thanks for clearing that up.
 
Yeah, i don't know why anyone would need to go bigger than the enormous head. Just overkill in my opinion.
 

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