Wizz Kid

whats the difference between the 2.5 and 2.5r?

carlbellybutton10

2.5r is made for racing

Wizz Kid

how so.

Art91

The only difference between the 2.5 and the 2.5r is the blue power tuned engine head. There may be a difference in timing and port configuration but im not sure.

DaveG55

It depends on how old the 2.5 is. It used to have some differences in timing but on the newest ones the only difference is the cooling heads. The silver heads are cast aluminum and the blue ones are machined. The machined ones are susposed to give a bit superior cooling compared to the cast head. I've got one of each and cannot really tell any difference. Other than that, there is no difference in the two engines. You cannot even find 2.5 replacement parts anymore, you have to buy 2.5r parts.

Traxxas_Tech

My Feedback: (22)

Correct. There was a very short run of 2.5's that had internal differences. The odds of you having an engine with those differences are slim to none. Even with those differences there was no difference in power output. For all current 2.5 and 2.5R engines the only difference is the Blue Power Tuned cooling head. [8D]

Wizz Kid

thanks a lot... that clears things up!

twomanytoys

Traxxas says the difference between the 2 are the cooling head, timing and more agressive porting.

Traxxas_Tech

My Feedback: (22)

Refer to post #6. There are no differences in porting or timing. Only the cooling head.

keepontruckin

when i traded my 2.5 for a 2.5R i went on the traxxas web-site, and read that the 2.5R has a different sleeve

"TRX 2.5R PowerTuneâ„¢ Head
The Powertune machined aluminum cooling head promotes even heat distribution for stable engine temps and rock-solid tuning consistency. Other mods include a new sleeve for improved engine efficiency and better power."

and [link=http://www.traxxas.com/products/nitro/trx25/trx_trx25.htm]here[/link] is the link

Traxxas_Tech

My Feedback: (22)

Yes, and as stated in post 6, those differences were only seen in a short run. In current 2.5 and 2.5R's there are no differences in the engine's internals. Only the head.

keepontruckin

so there is false advertising on their website

correct??

Traxxas_Tech

My Feedback: (22)

No false advertising, because there is a difference between the original 2.5's and the current 2.5 and 2.5R's. Is there a difference in your 2.5 vs 2.5R? Probably not unless yours is getting quite old. If we didn't make it known that there was (at least at one time) a difference between the two, someone would be upset about that. We have not removed that from the website because there are still a number of older 2.5's out in circulation. We simply do not publicize every running change we make to our product line.

DaveG55

What's the point of your argument?

If a manufacturer changes something to make it better what's there to complain about?
And since they are no longer selling a plain 'ol 2.5 it makes little difference anyway.

Personally, I think that you are just arguing to give TraxxasTech a hard time which, I think, sucks. There are precious few factory people that are willing to help on fourms and to argue with one just to argue seems petty and counterproductive.

Wizz Kid

another q...... are the 2.5's ending production? i noticed some sites with back orders and limited quantities and out of stocks? im sure a lot of people are buying 3.3s and dealers are stuck with 2.5's they cant sell.

Traxxas_Tech

My Feedback: (22)

2.5's are not ending production. They are still OE engines in the 5109 S-Maxx, 4910 T-Maxx, and the 4409 Rustler. They are just not sold by themselves. 2.5R's are almost as popular as the 3.3 in regards to the engine replacement program, dealers should not have a problem with moving their 2.5R stock.

Wizz Kid

thank goodness... our series that im racing in allows any .12's or .15's only in the RTR variety. the TRX is the best for torque and exit speed and will most likely be the motor of choice. i'll keep looking around. thanks for your help!

christoptt

Wait... how do I know if I have the only difference 2.5 head thing? Im getting a T-MAXX 2.5 without the R and I want to have replacement parts.

Traxxas_Tech

My Feedback: (22)

Guys, it's really not that difficult. Parts are interchangeable even if you have one with the internal differences, which is not likely. You'll have parts support with any Traxxas product.

Here is a link to the 2.5/2.5R exploded view drawing: [link=http://www.traxxas.com/products/nitro/trx25/blueprints/050119_TRX25REXP.pdf]2.5R [/link]

You can take any part from that exploded view and put it in any 2.5. Again, now the only difference is the blue cooling head.

cmaxx25r

2.5 and 2.5R arent different  in size so buy a piston and sleeve and drop it in , do think the ports are machined out at a different angle for a more racing throaty feel, but not to sure , I traded in a 2.5 for a new 2.5r and if fires right up everytime I prime it ..I bought tmaxx off ebay not knowing the condition of the motor guy I bought it from said it ran great, yeah well when i got it the freewheel spin freely with out force so i knew it was shot,, i could replace the sleeve and pist for 60 or replace it with new motor for 96 bucks through the replacement warrantee.. 96 dollars isnt nothing when you have a headache thinking of breaking the motor apart.. On my 5th tank at stock settings and still screams ... who cares about neighbors when your having fun,, besides most of the older people getting a kick out of seeing trucks like tmaxx..

t-maxxdriver

is there a difference in an old 2.5 and a new 2.5

1QwkSport2.5r

No difference.