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How Many People Knew It!?

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Willthethrill

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I wanted to know how many people knew that the t-maxx 2.5 is a .18 sized engine, and the 2.5 stands for 2.5cc's. my LHS told me that lately and it blew me away. i thought the trx was powerfull, but how will it go with a sirio 21!!
 
The 2.5 IS NOT an .18 sized engine. It is a .15 sized engine.
The Sirio .18 will smoke I SAID SMOKE the 2.5.
 
okay boys here is how it goes

2.5cc= .15
3.0cc= .18
3.5cc= .21

Please make sure your facts are straight before posting. the 2.5 being only a .15 is old news.
 
Originally posted by Willthethrill
I wanted to know how many people knew that the t-maxx 2.5 is a .18 sized engine, and the 2.5 stands for 2.5cc's. my LHS told me that lately and it blew me away. i thought the trx was powerfull, but how will it go with a sirio 21!!
Click to expand...

If your LHS is a HobbyTown USA, then you just got tagged by another not so bright hobbyshop worker. Regardless, their information is wrong.

As mentioned by several of my colleagues above, the 2.5 does stand for 2.5cc which translates to a .15ci engine.
 
LMAO....

No dis to will but the fact that the Trx 2.5 "racing engine" is a .15 is common knowledge to most RC peeps and if your work for a hobby shop and are telling people that it's a .18 then you definitely need to seek a different line of employment. I'm sure Traxxas named it the 2.5 as it has much more general market appeal then .15 in a world of larger engines.

Yes, the Trx 2.5 is definitely a screaming "power house" for a .15 and will smoke the arse off many .15 engines on the market. The 2.5 is what I'd regard as a factory mod'd engine as it's much more aggresively ported then any past engine offering from Traxxass. Like most engines, even more power can be derived from the 2.5 with proper professional moding. Sirio makes a piston & sleeve specifically for the porting on the 2.5 and it adds even more power through the entire power band.

The problem/s with the 2.5 is that it doesn't have nearly enough displacement to power a 10-15 pound monster truck. It's a mean machine in the lighter Nitro Rustler and 4-tec. It can be a tuning nightmare, that's often very difficult to tune and it doesn't ever seem to hold a proper tune.

I have like 3 2.5 mills now (one with Sirio piston and sleeve that's a kick ass "sleeper"). I plan on holding onto the engines for various future projects.

As for the Sirio .18 in a T-maxx, yeah (I have one)...it's a nice mill and will SMOKE the 2.5 but it's not a HUGE difference in overall power coming from the 2.5. If you want a big steup in power you need to get a true bigbore and $1000 for driveline upgrades..lol. The Sirio .18 is easier to tune holds a tune better then the 2.5 but it's still not on par with an O.S. engine as far as overall quality.

Peace
 
Hey I got a question for you all? On my .25 HPI Nitro Star engine, it says 3.5 on the side. But, I thought the .25 was indeed a 4.1cc?? I mean I'm still learning, but correct me if I'm wrong. I can't beleive the guys LHS told him the TRX 2.5 was a .18. Maybe he misunderstood the guy when he should have said it has the power of most .18's. But, altogether it is a fast engine, that I have replaced with a big bore finally. Let me know guys about my question!

Woody
 
Hey woody, Yeah dude..that's NitroStar is a 3.5cc. I don't think HPI even makes a nitro engine with 4.1 displacement or do they??
 
Hey Nitro!
Good to hear from you. Well, the engine that comes in the Savage 25, is a .25, but on the side of the mill it states 3.5 So, I'm at at loss for what to actually call it. All I can say, is that I love it. Yeah, Nitro you know what truck I put this thing in. Talk about a blast. I have to rebuild two shock Friday night, so I can bash this weekend once again.

Woody
 
.25 use the same block as a .21 which is a 3.5cc which is not to be confused with the size (diameter) of the piston sleeve or at least that's the way I understand it. Hope that helps.
 
Yeah Humbold,
I was thinking that, especially when they came out with the .21 drop in engine for the T-Maxx. Engine block size is different than what is inside the engine. So, do I actually have a 4.1cc?? I imagine so!

Woody
 
Block size is way different than displacement. .12 and .15 share the same block size, same crank, and same conrod. The diff is the piston/sleeve size.
 
So, I must ask! Why do they call a .15 a BB?? I really do not think that it is any where near a BB. Just my .02

Woody
 
Re: Re: How Many People Knew It!?

Originally posted by SkyMaxx


If your LHS is a HobbyTown USA, then you just got tagged by another not so bright hobbyshop worker. Regardless, their information is wrong.
Click to expand...
Hey Hobbytown advise is as good as you can throw it...
 
Big Block in 1:1 means the piston and throw are the same size, or the piston is wider or equal in width in comparison to the distance it travels up and down.

By putting a .15 piston in a .12 engine, it may make the movement the same distance as the size. Which would technically make it a big block.
 

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