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Trx 2.5 Vs Ofna .25

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Old 04-18-2003, 02:23 PM
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joe78586
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Default Trx 2.5 Vs Ofna .25

Some questions
Doese the .25 have alot more power than the 2.5?
How will the t-maxx react with the .25 on it?
Do I need to buy a new flywheel or will the the .25's cluchbell fit?
Also,
I have the 2.5 but broke the rod and the piston has a little crack at the very bottom. Do I need to replace the piston?
If someone has one that they can sell me I will buy. Or where can I buy just the piston without the sleeve?
thaks for your replies
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Old 04-18-2003, 02:59 PM
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Default Trx 2.5 Vs Ofna .25

With the light weight of the maxx and the 2.6hp rating and the super torque of the Force engine, I would say you will have a tough time keeping it on all four wheels. Just so you know, I dont think the 25 will drop in. You need the .21 conversion kit.
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Old 04-18-2003, 03:23 PM
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Default Trx 2.5 Vs Ofna .25

If you snapped a connecting rod and damaged the piston, you will need to replace the piston and sleeve as they are matched sets.
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Old 04-18-2003, 03:24 PM
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Default Trx 2.5 Vs Ofna .25

Sirio sells upgrade internals for the traxxas 2.5. If you decide to rebuild and wanted more power, that's an option.
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Old 04-18-2003, 08:51 PM
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Default Trx 2.5 Vs Ofna .25

Or you can go and buy a sirio .18 and sell me your broken 2.5. Just thought I would put that out there.
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Old 04-18-2003, 09:11 PM
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Default Trx 2.5 Vs Ofna .25

Well to be short there is no compairison to a small block and big block, but you should know that!! Your on the maxxtraxx forum correct? Anyways You must replace the piston and sleave, as well as the rod in your broken 2.5. There is no sence in running with a broke piston.

As for putting the .25 in your maxx you will need a .21 conversion, but the 2.5 clutch assembly with fit right on the engine, the only thing that will be needed in that place is a 1/8th clutch nut, do to the fact that the shaft is to big for the 2.5 clutch nut!!
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Old 04-19-2003, 01:19 AM
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Default Trx 2.5 Vs Ofna .25

How much would you give for the 2.5 rmiller?

I know I need to upgrade to a .21 conversion but I was planning on making my owen parts and just buy the engine and mabey the mount.
What cluch nut, do you mean the cluchbell?

i8tweety What you are saying is that with the sirio piston/sleeve I will have more power than the stock piston/sleeve?

Doese anyone have a piston/sleeve or a connecting rod sitting around that you can sell me.
thanks
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Old 04-19-2003, 01:52 AM
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Default Trx 2.5 Vs Ofna .25

The rebuild is around $80 or better I believe. You can buy sirio internals and put it in your 2.5 and get more power. But from what I am told it will not put out as much power as a sirio .18. Ohh and the sirio internals are over $100 because you have to get the crank, rod, piston, sleve. The sirio sells for $185- $200. i AM TOLD THAT IS THE WAY TO GO.
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Old 04-19-2003, 02:00 AM
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Default Trx 2.5 Vs Ofna .25

then what do you want a 2.5 for if you say the sirio is better?
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Old 04-19-2003, 02:02 AM
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Default Trx 2.5 Vs Ofna .25

the .25 is almost twice as big displacement wise as the 2.5 It should easily lift the front wheels, at pretty low throttle. You might want to get upgraded diffs and drive shafts though.
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Old 04-19-2003, 02:05 AM
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Default Trx 2.5 Vs Ofna .25

I just want to play with it. It's no big deal to me. You can keep it or sell it to someone else. I just figured You could get a little cash toward your new setup and I could tinker with something. The sirio is definately more powerful (from what I've read) I will most likely get one soon. I don't want to get into changing everything into an 1/8 scale truck. I myself cant wait to see the new associated truck. I might get one of them as well.

Let me know.
RYan
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Old 04-19-2003, 02:42 AM
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Default Trx 2.5 Vs Ofna .25

If I had the money I would buy it but right know I don't have any and I think I will just have to wait and see which one comes first.
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Old 04-19-2003, 01:37 PM
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Default Trx 2.5 Vs Ofna .25

Joe,
I found a NEW TRX 2.5 on ebay for $120. It has never been run. It is almost the same as the one that comes in your max but the crank sticks out a little longer. If you grind it down a little to the length of you 2.5 you will have a new engine.

Here is a rebuild kit for around $40
http://cgi.*********/ws/eBayISAPI.dl...category=34063

Here is the 2.5
http://cgi.*********/ws/eBayISAPI.dl...category=34062

hope you see these in time
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Old 04-19-2003, 02:17 PM
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Default Trx 2.5 Vs Ofna .25

Putting that .25 in your Maxx is way too much power. You won't be able to use it all. BTW, the Force .25 makes 2.39 hp, not 2.6. If you want to overpower your Maxx, you can do it by just dropping in a Sirio .18. It's a direct drop-in replacement for the 2.5. Installing a big block requires a whole bunch of other mods.
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Old 04-19-2003, 04:58 PM
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Default Trx 2.5 Vs Ofna .25

How about the Yokomo .18 RX engine?
How much power doese this one have?
If it is as much or more than the 2.5 I might get that one.
But I don't want an engine with less power than the 2.5.
Right now what I really want is to get my maxx running again.

If someone has a used sirio .18 or sale please post.
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Old 04-19-2003, 06:24 PM
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Default Trx 2.5 Vs Ofna .25

Originally posted by Joe78586

What cluch nut, do you mean the cluchbell?

thanks
No the clutch nut and clutch bell are 2 totaly different things. You will need a "1/8th CLUTCH NUT" to run the stock flywheel, clutch, and clutch bell on a .25 or any other big block engine!!

Stock clutch nut:


Ofna sg shaft clutch nut(1/8th)


Ofna Threaded shaft clutch nut(1/8th)
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Old 04-19-2003, 08:03 PM
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Default Trx 2.5 Vs Ofna .25

Oh I see.
And I guess I will also need the a new exhaust and header.
I think I am just going to go with a drop in.
What about the Yokomo .18 RX engine?
Is it a drop in?
I found one with less than 10 tanks on ebay that is currently for 49.00 and thought I could use that but I need to know if it is a drop in and if it has equal or more power than the 2.5. OH, and it has a carbon fiber boost bottle.
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Old 04-19-2003, 09:57 PM
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Default Trx 2.5 Vs Ofna .25

I've never even heard of that engine. I wouldn't even mess with it. Just get the Sirio. That thing is guaranteed to kick *****!
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