Today me and my friend were talkin about our nitros, and he said you can bore out the exhaust hole in the engine, and it will give you a little bit more power and a little louder. So now is this true or is he lieing.

me and my friend also thought of doing that. but i do not know. for more power try takin a dremel or somthin with a little grinder and takin a little steel off of the header. the parts that connects to the engine. just make it a little wider. look in the myjato will fly when i get done with it. thee is a guy that has a pic of what he did to his. and it looks prety good. you do not really need louder.

yes in some engines this will help in a noticable way and in some engine's it wont help as much. You can also in some engines the exaust port in the sleeve is a little bit smaller then the exaust port is in the crank case. with the sleeve in the crank case you can take a marker and mark the excess metal on the sleeve and with a steady hand dremel it out. But i wouldnt do this if you arent good with a dreamel and if you dont have a steady hand as one slip up can cost you a lot of money.

But yes this is true

Yeah, I have traxxas 2.5R. I am just trying to get as much power out of it, as I can. Because when my local Hobby Shop gets the NEW TRAXXAS 3.3 engine in. I am going to trade my 2.5r in for it. Yeah so can i dremal out the sleve in the crank case?

no no no.. well you can. but i would nto recomend it. do the header. go to the thread my jato will fly wheni get done with it!!! and on the first page there is a picture of a header. with it dremeled out. go there and take a look. so ya know what i am talkign about.

Yes you can do the sleeve just dont do the crank case. But you have to take the sleeve out of the crank case to do it do as i said with the marker but dont over do it because you can mess it up reall quick. And make sure you have a steady hand because one slip and the sleeve is now a paper weight so be careful.

I just got done boring out my header about 20 mintues ago, and i just ran my car I can tell that i bored it out. It has more torque in midrange power. The front tires come off the ground when i punch it doing about 30+. It has never done that before, I am thinking about the sleve, But I can get a little more out of my header.

Check out this RC Driver article, it goes into header porting in some detail: http://www.rcuniverse.com/magazine/a...article_id=398

The engine used is an HPI 15-FE I believe, so it should be very similar as long as your exhaust is the oblong, rectangle shape, just like in the article. if it is a round header, there would be no material to take off, so you couldn't do it. i don't know what the manifold looks like on the 2.5R, so you'll have to read the article. Hope this helps

Yeah it helps, thanks man!!! But I am still wanting to know if anyone has tried to bore there 2.5 engine out.

I thought i saw a little while ago that some one had tried it. Now i dont know if it gave the engine any consderable hp or torque. But usually the trx engines have the sleeve port a bit smaller then the exaust port on the crank case. So if you dare to you can do the sleeve work just be careful. if you want to see how much material you could take off take the engine off the car.

Take the header off along with the head, put the piston at bottom dead center then you can put it to a light and look through the exaust port or you could take a marker and put it into the exaust port and color the parts of the sleeve that shows then take the sleeve out and you can look at how much material you can take off. But i would not do to much off the top of the exaust port if any because you could change the timing of the engine and have it not work at all. Just make sure that when your dont to make sure the inside of the sleeve has no burs on the inside of the sleeve or have the sleeve not be smooth then it will scar the piston causing compression loss.

Thanks man! I will try that and comment back on that.

i think it wont be eligable for the lifetime replacement if you port it, but yes you can put a champher on the lower edge of all the intake ports and if you raise the exhaust port by about 1/2 of a millimetre you will gte more tp end. this will get you a lot more power all up but be warned, use common sense and NEVER get the dremel near the chrome ONLY the brass, the chrome will flake off and leave u with a dead engine.

Dann

What do you mean by champher? could i bore out the intake hole were the airfliter sits on?

no... just grind as much away at the bottom of the intake ports as you can but DONT go near the chrome yet. you only want to flow it not actually port it ( not for your first time ). follow the stains on the outside of the sleeve as those are made by the fuel so it will let it flow better and have more power, and most importantly more punch.

Dann

pic

my friend is ciming over today with his rc and he has the hpi .15. I guess that is the best engine to port the exhaust. SO we r going to do his engine today and i will get back to yall on that.

Ok guys i got my sleve out and ported it and i am now just waiting to run it tommarrow. I will reply on the performace on the porting on the engine.

send a pic of the sleeve. do u know what u are doing for sure? wel will hafta see.

Dann

O I know I got it right i went to my local hobby sho and they helped me do it and they help me alos get my cooling head off, to since i striped out two screws[:@]. They told me i will see some mor epower off the line and some more top speed.

Ok if you didnt touch the exhaust port you will get no top end, you will only get more punch. probably a LOT more though. tell us how it goes.

Dann

Nope I my lhs repair man bored the exhaust port to the max he did everything.

which .15 is it? the T-15, or the 15-FE?

trx 2.5r

Ok guys i just got done running my car and i can notice some more accerleration but nothng in top speed. I think i am going to try something else. I am thinking about making my own custom exhaust really loud. For maximum power. Is there any one in hee that has made a custom exhaust before.

custom exaust's are alright but you got to remember you need the back pressure to the tank. And the less back pressure period the less acceleration. The more back pressure the faster you will accelerate now only to a certain point. If i where you i would just go get a tuned pipe that will show a increase in acceleration and in overall top speed. But if you really want more top speed try changing the spur and the bell gear.