z1bigtom2004

Was reading and they say the porting makes the 2.5 into the power of a .21 for under 100.00..

But isnt all that work gonna be wasted when u need to resleeve?

240.00 for the RB TM323 or 100.00 for porting....What would the power diff be? For the money spent.

fastcrash

as much as i like the 2.5R, you couldnt port it enough to make the power of the rb 323. that said, dont expect to just slap the 323 in there and forget it. i think there will be a few upgrades required to put that power down.

z1bigtom2004

Fastcrash.......Is there anything to replace asap, or just replace as u breakum?

fastcrash

u have a t-maxx or revo?

z1bigtom2004

revo........In pieces as we speak......Busted rear diff......8 teeth striped off ring gear..[&o]

fastcrash

thats a shame. i havent had any issues with the diffs, but it seems more and more ppl are. i keep going thru these http://www2.towerhobbies.com/cgi-bin...?&I=LXHGG1&P=Z but i think i finaly have the slipper set right. the only thing i would do to revo without breaking something is the FOC. all of the weak gears are removed when this is done, but you do lose reverse. one of these will help to get as much bottom end out of the 2.5R as possible. http://www2.towerhobbies.com/cgi-bin...&I=LXGBC4&P=ML

z1bigtom2004

fastcrash........check ur mail!

fastcrash

i dont see anything new inbox, what am i looking for z1bigtom2004?

z1bigtom2004

Was supposed to have been sent to ur email addy.........

Well anyway!!! I just ordered that SH .28 for my Ofna Ultra LX....Do u have any idea what pipe i should get for that motor?

And how do u be sure that it will fit correctley for that engine?

Sorry new to this nitro stuff.

fastcrash

oh.. that mailbox um... i honestly dont know very much about the sh.28. there is a sticky in the hpi mt forum where you could get the advise of ppl who have that engine. here's a link. http://www.rcuniverse.com/forum/m_27...mpage_2/tm.htm post your pipe question here, this was a very popular topic, im sure you can get some help here. you can also read the posts to see what other ppl have chose.

z1bigtom2004

Thanks man......

hotchi1

were did you get that you could do somthin for 100 dollors?

stilllost

My Feedback: (3)

thats a know brainer. you answer your own question, what's the point you will have to resleeve anyway. get the tm323. iv heard nothing but praises. as far as drive train issues, with the new slipper clutch having it set right i.e. not so tight that you can do wheelies, but loose like the book says. i heared that you have to adjust the tranny so that it shift earlier so that when it does shift you are not on your lid.

Alteramod

big tom......... to answer your port polish waste after resleave...... it would only be half and half.
Half of the job is done to the ports on your block. That part is where your getting most your power. The second step is on the sleeve which isnt as effective but does help. I already know that you wouldnt get the power of a .21 out of it because ive port and polished the pro.15 and the only diff between that and the 2.5 R engines are the port sizes. With that said I port and polished the pro .15 and it only gave me the power of the 2.5 . Im sure you would gain some power but one hint to ya is to practice it on an old block and sleeve first if you have one. And after you do it to your good engine make sure you have every little peace of metal outa that engine. Another thing is to cover your bearings with cloth or something or just take em out before your do it to so they dont get metal bits in them.

Alteramod

another thing that my friend did was narrow each side of the piston rod. This makes it cut the air easier. Not sure if traxxas does this to the 2.5's stock or not but I know ofna does and thats where we got the idea.

tommythecat

My Feedback: (2)

The 2.5's do have a knife edge on the rod but it is a bit blunt for a knife edge. I'm not 100% sure but I think that trintiy sells a preported sleeve.

Personally, I love my trx 2.5, its an incedible engine. I picked up an O.S. .18 TM to drop in, but the weather still hasn't cleared up enough here for break-in. Regardless, even after the TM goes in I will still keep my trx for beater use (winter running and when I feel like running accross streams and such) That way I will not beat my O.S., the O.S. rebuild is way more $$$ than the trx 2.5. I got a whole recip assembly (piston, sleeve, conrod, pins, clips) all for ~$65 on ebay (I think it was $65 or in that neighborhood) But when I looked into a complete rebuild for the O.S., it looks like the P/S and rod will be well over $150, so I'm planning on babying that engine. I picked up a seperate engine mount, flywheel, clutch, clutchbell, OWB and rotostart backplate for the new O.S. so that I can swap the engines out without really having to strip parts from one to use on the other, that way I can switch engines in <10 minutes.

My thoughts:
Upgrade your engine to a new one, then work on your 2.5. That way you can take your time on the porting without putting your truck out of commision, and if you botch the porting job, at least you didn't scrap your only engine. Then keep the reworked 2.5 for running in bad conditions like heavy rain and mud, cold and snow etc... or if your like me, for when you decide to go out creek crawling. That way you save your nice engine from all of the abuse that those conditions cause.

But if you decide to go this route, you will want to be careful and select an upgrade engine that will drop in without modifying the throttle linkages, so that you won't have to spend a lot of time swapping the engines.

mauth

I know this is an old post but... I have a ported and polished 2.5r from rb mods, but in the truck now is the rb 323. The 2.5 is fast and easy to control. The only thing is I don't know what the stock 2.5 is like, when I got the truck the engine came with the mod. I could never get it to pick the front wheels up. Now just finished with the breakin of the 323 and WOW! to me was night and day even with the 36 spear gear. Hard to keep the front wheels on the ground! I love it!