aip_tuner

Hey.

Thinkin of converting my T-maxx to a 4 stroker!

Is there a engine what has the power of the 2.5?

Is there a engine what will bolt in (not much modifacation)?

Do the 4 stroke engines last longer than the 2 stroke?

Is it worth it to covert it?

Please list what engines that will work?

Im wanting to save money in the long run, dont want to rebuild or buy a new engine every 2 to 10 gallons of fuel, plus i like 4 strokers better (in some cases).

Let me know what you all think about it!!!

3maxxman

My Feedback: (2)

In short, No. Have the power yes, but nowhere near the speed. 21,000 rpm's max! You will smoke clutches before you get the speed of a 2.5 Tmaxx.

You could fit a .26 by moving 1 rear shock, but that is comparable to the old Pro .15, the .40 would have to be mounted with a .21 conversion.

Yes, 10 gallons easily and even if it loses compression you just need to replace the piston ring and your good as new.

Well that's up to you. I would say if the 2.5 is your only truck, No. If you have others then, yes you might want to look at something different.
Engines that will work: (click the pic)
O.S. FS-40S-CX

O.S. FS-26S-CX

Then you will need to add things like an exhaust system and gearing.
Use the search feature at the top of this page for "Fourstroke" or "Twin 40's" and you will find lots more info, Pics and videos.

nitroman88

My Feedback: (5)

4 strokes sound cool and have alot of tourque but they tend to lack alot in rpm.

aip_tuner

Thanks 3maxxman. I was just readiing your post on your twin 4 stroker and dl'ed the video. that thing is wicked, and looks like you have lots of time and money invested in it! I found it by doing a search for four stroke stuff hehe.

I also found a kit for the conversion and went to tower hobbies and was lookin at the engines. seems a little pricy just to convert to a four stroke, unless the four stroke will run longer than the 2 stroke ( will it run longer as in more gallons of fuel befor rebuild)??

That is mostly the reason is to save money on rebuilding or buying a new engine every 2 months or so! I plan on putting a lot of time on this new toy! I will prob just buy another used one to convert, seems more logical to do.

aip_tuner

oops didnt read the answer for te question of, ( will it last longer as in more fuel befor rebuild) I got it now though.

So what is a good average # of gallons for the fs-40s-cx?

3maxxman

My Feedback: (2)

Buy a cheap old one on ebay and get an XTM 21 conversion, or get a truck that's already converted to a .21 and put the 4 stroke in it. I have many trucks that I run, if one doesn't feel like playing that day I just put it away and get another. It's much better than beating the h*ll out of it for being a problem on occasion.

3maxxman

My Feedback: (2)

BTW, don't buy the New Era Models FS conversion. Any 21 conversion will work and many come with more and are cheaper.

3maxxman

My Feedback: (2)

10 to 15 easily with temps under 300 degrees. Then a new piston ring and you could that again and again until you wear through the piston sleeve.

aip_tuner

kinda lost hehe! what is the .21 conversion for?? I thought the 2.5 was a .21 setup?

where else can i get the .21 conversion for a good price??

Thanks!

BUGGIES_R_US

ehh I dont know about 4 strokers.. theyre great dont get me wrong the technology is far superior to 2 strokers..

BUT

the thing that bothers me is that 2 strokers literally have TWICE the power cycles as a 4 stroke..

twin 4 strokes gives you a HUGE amount of torque but unless you can gear ir right, you will have a hard time getting it to go fast.. a 2-3 speed tranny will be perfect!!

But if your doing it for the fun of it, I'd rather go for 2 twin strokers.. then maybe graduate to fooling with the 4s!!

3maxxman.. please note I'm not dissing your ride in a any way!! 2 and 4 stroke are completely different and also, you know a lot about MT construction so your different lol

-ram

aip_tuner

Hey, Ok i got what a .21 conversion kit is now, hehehe.

Does onyone know where i can get a good Kit, for a good price??

Post links if ya can!

3maxxman

My Feedback: (2)

www.nwhobbies.com has the XTM conversion kits for $139, the only things you would not use with a fourstroke would be the header, muffler and the airfilter. Here's a picture of the kit everything pictured is included.

aip_tuner

sweet. Think I will get it!!

aip_tuner

Hey 3maxxman.

have you run a new 2.5?

how soes it compare to the os .40?

Basicly which has better of line, topend and what not?

3maxxman

My Feedback: (2)

The 2.5 is much faster off the line, wheelies better and has more top speed. The fourstroke will do things that NO 2 stroke can, climb inclines at idle that a 2stroke couldn't at any speed, also can drag the 2 stroke all over the place. Nose it up to a curb and blip the throttle and it will skywheelie and land on top of the curb. The throttle response is much more realistic and very smooth, it's not just WOT and brake. On most tracks the 4stroke will keep up with any truck easily. Remember you don't have enough room to use all the speed the 2 strokes can make, the straights just aren't long enough.

aip_tuner

Yeah Ive noticed that it wont even begin to reach top speed on the straight away, befor i have to shut it down, I like the speed (quick response and power)of the 2.5 but it seems to much for the truck, on loose dirt the truck will get crazy and want to go all over the place of course im still using the stock tires.

I live on 40 acers and have lots of long and tall hills that i would like to climb and play on. today i built some ramps and was jumping them ok, I plan on building a couple of tracks aswell.

Thanks for the info, when i get ready to do the conversion, Ill haller at you for some help if that is cool.

Bonefrost

My Feedback: (6)

kinda lost hehe! what is the .21 conversion for?? I thought the 2.5 was a .21 setup?

The 2.5 is actually just a .15.They maketed it 2.5 because thats the displacement,not the size.
A .21 conversion has a longer chassis.Something you will need if you put that monster 4 stroker on it.

Hey 3maxx,did you ever run yours w/ just 1 FS on it?How was it?

3maxxman

My Feedback: (2)

Yes, I ran it as a single for many gallons. It was first in a 21 conversion with a Tmaxx tranny. Then it became a Hybrid on a stock Tmaxx chassis with the MP tranny, and now the Twin 40's.
It all started with this.

Then it became this.

And now...

aip_tuner

hey 3maxxman, Ive been reading up on other four stroke conversion, and some day they have had to cut the the mian shaft to make it fit , so that it wont hit the tranny.

Did you hav to do any cutin o much more modding , after the .21 conversion, to get the .40 to fit?