T-maxx 2.5

[Zachary]

Well I just bought a New Traxxas Tmaxx 2.5 the other day and just wondering what you all know about it. Hows the engine as far as reliability and tuning and such. How long does the engine run for (gallon wise)? Should I upgrade the drive train? just what ever you know please tell me.

Also The engine really doesn't like to ideal. Is that just the engine or plug or broken in bad or tuning? any help appreciated. Thanks

 

[CharliesTheMan]

Would you be interested in selling your old truck? The 2.5 is a pretty strong engine when it's tuned correctly, my 2.5 will pull wheelstands all day long if you want and it's got decent top end. Keep in mind this is with stock gearing, so I could go either way with the gears to adjust to my liking. If I were you, I would run the 2.5 for a while and then when you wear it out you could consider upgrading. The engine not idling sounds like a tuning issue, but I'm still kinda new so I think you need to wait and see what a veteran says. When you decide to upgrade, you could go with a 3.3 from traxxas, and OS makes an OS 18 tm that will drop in, and an OS 21 tm that will also drop in. The 21 tm has big block power, and you will have to replace the entire drivetrain to handle that much power. The OS 18 tm is a much better option in my idea because It's got about the same amount of power as the 3.3 but most people say they are much easier to tune and last longer. The only problem is that OS just cut production on the OS 18 tm because of the os 21 tm, but I would think that someone will come out with something similar to catch that part of the market, and you will still be able to find them on ebay. Another option would be to send your 2.5 engine to someone like ABMods once it gets some wear on it. You will have to wait and see what the veterans say about how much power can be gained from a mod engine. If I were you, I would put RPM A-Arms on my truck ASAP. They have been great, ist amazing how strong they are, and they really make the truck a lot more dependable, and they also drastically improved my handling. It made it drive and handle like a different truck, and that was just using the stock settings, no telling how good it will handle once I tune the suspension. I think two of the most important mods are a good screw kit (because the traxxas stock screw heads strip out quickly) and the RPM A-Arms. I hope this helps some, I've only been running my T-Maxx for about 3 months, and I'm no veteran, this is just what I've learned from my experience in driving and upgrading my truck.

 

[marauder]

I'm new to nitro so I can't fully answer your question yet, but I do recommend the flow chart for troubleshooting. My T-Maxx was bought used but like new condition, maybe a few tanks of gas through it. I still treat it like it is in the break in stage because it looked straight out of the box new. I ran my first tank through it at idle, the entire time and it did not hesitate or quit. I would imagine the engine is either running too rich or lean causing it to fail. Maybe my engine is a fluke, but it will idle until the tank is empty if I let it.

I hope one of the experts chime in and help you out with your truck. I have the TRX 2.5 in my T-Maxx and it is more than quick enough and I have the remote set at 1/2 throttle for now. Can't wait to open it up on some dirt, it doesn't like my pavement well but that is what I'm running it on for now until it is broken in properly. I need one of those infrared thermometers so I can monitor my temps. Be sure your engine is up to temp before you begin to tune it as well.

 

[CharliesTheMan]

Yea, I forgot to mention that, you definitely need to think about getting a temp guage, and its always best to let the engine warm up before you start fine tuning it. If you tune it when it's cold, chances are you will have to tune it all over again once it reaches operating temps. Good Luck!

 

[gravdigr]

The main traxxas site has pdf files of the instruction manual which covers tuning. Outside temp and humidity can have an effect on your tune so if either of these change you should retune. I think the tuning procedure for the 2.5 and the 3.3 are the same but not positive. I know for the 3.3 stock settings are 4 turn out for the hsn and the lsn screw should be flush with the housing. Always tune the hsn first. Do a couple passes to warm the motor up then do a high speed pass or 2. if you are blowing blue smoke during your high speed pass lean the hsn (turn it clockwise) 1/16-1/8 turn and make another pass. Keep doing this until power does not increase or the smoke stops then richen up the needle 1/16 or so. You always want to see smoke coming out the exhaust and you want to keep temps between 200-240f, 270 and beyond pretty much guarantees you damaged your motor. After the hsn is set you tune the lsn. To do this have your truck running at idle and pinch the fuel line 1-2" away from the carb and count the seconds until the motor dies. Under 3 seconds richen the lsn (turn it counterclockwiseclockwise)1/16 turn at a time, 3-4 seconds is tuned, above 4 seconds lean the lsn 1/16 turn. After the lsn is set then you can adjust the idle screw until the rpms sound right, not too fast and not stalling. After you set the idle you should retest the lsn with the pinch test as it may need reset after changing the idle.

You should be able to find more detailed tuning instructions at the traxxas site.

 

[marauder]

It also never hurts to look over on YouTube at some of the instructional videos as well. Me being the type of person that learns more by seeing and doing than by reading, and a manual to me is really hard to take in at first. Once I know what I'm doing it is easy to refer back to a manual, but until I fully grasp a concept reading about it just confuses me more. I am simply amazed by the amount of content that you can get with YouTube, heck I even get instructional videos on how to service our 1:1 vehicles on there. Always worth looking at because you can see and hear desired results using their techniques. I have even seen people upload a video of the problem they are having and it was solved rather quickly which I also like to see in the event that I find myself in their shoes I will already know the answer to my problem.

Hope this helps, and again, good luck and enjoy the hobby.

 

[Zachary]

Okay thanks guys.

Just one thing to add is I am no noob at this at all. I know the whole tuning procedure and letting it get to temp. The thing runs fast but needs a new clutch, (broken spring screwed the shoes up) and so far has been really strong with me beating the hell out of it.

And CharliesTheMan what do you mean will I sell my old one?

 

[CharliesTheMan]

When you said that you bought a new T-Maxx 2.5 I thought you meant that you bought a whole new truck, and I was thinking that you had an older .15 T-Maxx truck. But from your last post I'm guessing that you meant you just bought the new 2.5 engine, not the whole truck. Sorry about that

 

[Zachary]

No I did buy the whole new truck. no worries CharliesTheMan.
I had a older 1.5 maxx supped up with alum. everywhere and I think thats what you tough. and that truck got stolen. Thats why I bought a new one.

 

[Bryson]

If you dont mind me asking, why dont you just buy a new 3.3 T-maxx and save yourself the hastle of upgrading things. It just dosent make sence to me. Oh and what happen to your savage? Why dont you run that sucker anymore.

Bryson

 

[Zachary]

well i got the tmaxx for a really great deal. 275 brand new. The savage I had I traded. Thats how I got my maxx before this one that just got stolen. My buddy traded me for his and thats why you hear nothing about the savage anymore.

 

[CHRIZDIZLE]

How the hell the poop get stolen? Man I would be looking for blood if my stuff got stolen/messed with..

 

[Zachary]

Our garage got broken into and of course the ONE night i left it in there.......