flatlander_14

ok, i started thinking about the 2.5 engine and how so many people have problems and yet so many people love it. i want you guys to reply to this with the following info:

1) what is your elevation?

2) about what was the temperature/humidity at the time you broke it in?

3) how has it performed? any problems with tuning or performance? think its perfect and wouldnt trade it for the world?



i suspect some of the engine problems have to do with the elevation at which people break in the engines. i remember reading somewhere(after i broke it in) that near sea level you need to richen the engine more than the factory recommends to comensate for the air density. here is what i did so far:


1) near sea level, like 20-30ft

2) i broke it in around 6, it was about 70-75degrees maybe and little humidity

3) it was great for the first gallon and a half, now i want to throw it out the window. it became VERY picky at tuning, CONSTANTLY overheated, and would love to go to traxxas corp, find whoever invented the 2.5 engine stuff, and SHOVE IT UP THEIR ARSE!!!

4) gallons of fuel through it at the time of writing this?

ok, now how about you?

Savage_Dias

Good luck dude, you're on a massive undertaking to say the least!

bubbafien

My Feedback: (1)

i am @ like 5,500 elevation and i had about 2-3 gallons before i sold it and it ran awesome it was in december when i broke it in so pretty cold. performed awesome, tune was EASY!

bubbafien

jrtoons

1) what is your elevation?

about 1500 feet

2) about what was the temperature/humidity at the time you broke it in?

90 degrees 80% humidity

3) how has it performed? any problems with tuning or performance? think its perfect and wouldnt trade it for the world?

I'm on my 15th tank and it was very temperamental for the first 10. The last 5 have been trouble free and it has gobs of power.

I broke it in over a 3 day period - temps and humidity were consistent.

yrral

1. i think i'm at 520 something feet.

2. I'm not sure about humidity nor temp. but i think it was in the 80's ...humidity...not sure.

3. only like a quart so far...lol. but so far its running great. i had a little trouble with spur gear, but that's b/c its old.

Wookie

My Feedback: (5)

I sold my T-Maxx, partially due to the engine being such a pain. But here were my statistics.

Elevation: around 80-100 feet.

Temperature/humidity: Upper 50's to low 60's and mid level humidity.

How did it run?: Well break in was a pain, tuning was a pain, keeping it running was a pain. I richened the mixture, leaned the mixture, made sacrifices to the RC Gods for the perfect mixture.

Nothing really worked. The sad part was that I had much better luck at keeping mine running through a complete tank of nitro than most of the guys I know. Part of it was that I figured out how to drive it. When ever the idle dropped quickly I would punch the throttle regardless of where I was. Kept it running most of the time, with out the throttle punch it would die 4, 5, 6 + times per tank full.

I probably had around 3/4 - 1 gallon through it, maybe before it became so frustrating that I just ran my RC10GT.

yrral

well i think break-in sucked but it was the same way when i had to break in the pro.15.

I think break-in at the end was great....mine ran great, didn't stall, no problems during break-in.

then i went to the "brickyards" and i went nuts jumping it and stuff. then the spur gear was bad...it was from the old tmaxx ( i did the 2.5 exchange. got another gear w/ 2 less teeth for better speed then that gear screwed up my truck....made it run weird. so i digged up the old gear and worked ok, but still striped.

gotta get a new stock gear...then it should run great.

if you guys are having trouble you might have to replace something inside.

Later,
Larry

bigfin

I got rid of the reverse stuff, used the fwd only gear. Truck is alot smoother, no lurch when idleing, better acceleration. I actually lowered the idle speed, whole thing seems better. Sorry don't remember any of the stuff from when I broke it in, but I definetly think the forward only is the way to go.

*~RC~*

i have never ever had a single problem with my 2.5 untill the day it died out and got replaced. it may have something to do with the fact that i live in hawaii, i heard hawaii is the ideal humidity eleveation and outside temperature to run cars. only problems ever where flooding of the engine after about 3 tanks, but that is eaisly fixed.

bigjdubb

I am at about sea level maybe a bit above. It was low to mid 90's out and typical 90% + humidity. I didnt have any problem with the break in but ran into a few problems when I started trying to tune. Most of it was because I have never had a nitro engine before. Once I got it where I felt it ran well and didnt get to hot I havent had to change anything. The only problem I have is the idle isnt always right on. Like someone stated above, I have to keep my finger on the throtle sometimes to hold the idle. I am now on my third gallon and it still runs strong.

I think most of the problem lies with the fact that this is a mass produce high performance engine. When you compare the number of TRX 2.5 engines out there compared to other similar performing .15's. When you have to make that many the tolerances open up a bit and starts to cause problems. It works the same way with real cars. If Ferrari had to put out the numbers GM did, they would be in the shop even more than they are now.

Traxxas should have just taken the easy way and added more displacement to gain the power instead of trying to squeze it out of a .15.

robin640

1) what is your elevation?

Elevation was some where around 1500 ft above sea level

2) about what was the temperature/humidity at the time you broke it in?

80 to 90 degrees with low humidity

3) how has it performed? any problems with tuning or performance? think its perfect and wouldnt trade it for the world?

Break-in went very smooth ( only vapor locked it twice, no stalling reported ). As far as tuning goes, I have not really had to touch any of the carb. setting since getting it broken in. It has stalled a couple of times and I upped the idle a bit. Only ran 1/2 gallon through it so far and I am not running it really hard.

So far I am happy with the truck.

Razoo

My Feedback: (2)

I'm about 1500' above sea level. It was around 85 degrees and very humid when I broke it in. The 2nd week I had it, I put on a Crazynut head and its never been above 230 degrees. So far I have over 2 gallons thru it and hardly ever touch the needles and it never stalls. As far as I'm concerned Traxxas has produced a great engine.

bigjdubb

IU also have the crazy nut head on mine. Maybe the fact that the factory head is tiny is why so many people have overheating problems. The Traxxas head compared to the crazy nut head is silly, it's like half the size.

hose man

My Feedback: (9)

Ironic how life is I stuck up for the 2.5 same reasoning as the 1st post and then the motor frooze up temp was 180-190 it was running great and never had one problem until now.
humidity 90% temp 85 degrees slow break in took my time and only 3/4 of a gallon thru it ,after run oil every time .I have many other nitro things this is the first time I had problems .Does the traxxas 2.5 have issues probly, are they going to do anything ,probly not .
Just curiuos how many people emailed traxxas about it ,I did


Hosed

Ushbar

My elevation is about 750 feet and it was about 70-75 out, not too bad for humidity. It ran perfect for the break-in but, now it is fussy to tune. It bogs, runs hot, no power. I used to run it slightly rich but, since I had to rebuild it, it is crappy. I have maybe 15 tanks thru it since rebuild. I want the fantom engine now definetely.

flatlander_14

im picking up the fantom .18 later today!

anyways, ive noticed that the people at lower elevations for the most part have had worse luck...

also, not too many people with 5+ gallons through it

Yacoltster

200 Feet above sea level
Temperature 65 degrees
75% humidity

Ran the first 2 tanks at the factory settings.
3rd tank leaned out low-end 1/8 turn
4th tank leaned out top-end 1/8 turn
5th tank no changes.
6th, 7th and 8th tank no changes. Wheelies on demand with a operating temperature of 198-206 degrees.(still haven't put the body on)

As you can see I still have plenty of leaning room to go......but why!

ToMorrow44

I'm at about 2,800ft and when i broke mine in it was probably 80 degrees w/ very low humidity. I didn't have too much of a problem tuning it but when i started to lean it out for better performance, it ran like crap. it will run fien for a while then when i let off the gas then it just quits. then it won't start. i don't get what's wrong with it. i haven't run it for a while...i'm getting into planes. i've flown a friends plane with a OS 46 and my dad has a heli witha OS 30 and they never stall, always starts, and you can go from idle and gas it and those engines run forever. i don't know about the OS 15s and stuff that they make for cars if they're as reliable as the plane engines, but only if the cars ran like the planes. i think the trx2.5 is being pushed a little hard. i think traxxas tried to get every .00001hp out of it that they could and maybe thats why its so picky. my friend put the sirio in his maxx and i'll see how he does with that and maybe i'll do that. also, my maxx never wheelied, even now when i have some smaller gears on it to make it accelerate faster, or right out of the box.
-Tom

j-maxx

r i just couldnt take that engine anymore it was terrible thats y i got rid of it and boutght a fantom .18 instead i have no probs now with anything

CGi_Rogue

1) Elevation = 5280

2) Temp = not sure exact but upper 90's with very low humidity maybe 10-15% at best.

3) Overall Performance = For the most part it has performed well and have had little problems with it, This was my first nitro engine so tuning was more user error I think then the engine. I have had over heating problems as it seems many have but I think much of that has to do with the outside temps while running it and my lack of tuning ability. It has never been able to wheelie like some claim but all the Sirios at the track that I race at can not either. (I think living in Denver has a big part to do with that.) As far a racing against them I have done fairly well and beaten them a few times. I have not seen a Fantom run but would like to get one soon. I have almost 4 gallons through my 2.5 and it has been a good engine but I have nothing really to base it from since it was my first. I think that too many people get to impatient and start to blame other things then them selves. There have been many of times that I thought what a piece of crap, but after taking my time and working through the problem it has performed well and have had a great time doing it.

rcmtdriver2000

I'am at 3 feet above sea level and the engine goes fine some days and others I'am ready to throw it into the sea.Humidity 100% and outside temp at 75-80.Florida.

rc_boy_12

My Feedback: (2)

I brok my maxx in at sea level. Temperature was probably 85-90 degrees. The problem im having is i am overheating everytime i run and am as rich as i can get w/o it dieing, so i am going to order a new head either from crazynut racing, or nova something... anyone useing a modified head here?