I wanted to poll the "audience". For those who have upgraded their Traxxas 2.5 to the Sirio (?), how much more reliable is it? After proper break in does it have similar stalling issues? Is it a must to go to a metal spur, if so what else should I do after a possible engine upgrade?

Thanks in advance.

Mike

I am in the process of breaking mine in now. I will let you know as soon as I am done. I am on tank 3. In the meantime, if anyone else has experience with this engine, let us know.

I also have one that will be going in a zero hours T maxx with the maxx engine going (one more time) into a production race truck. This will be the third time I've tried to make a traxxas engine last in a race truck and I'm hoping i have it lined out. In my light production truck the 2.5 with an OS carb is the perfect race engine, if it would only last long enough to be worth it. I have zero problems with it in a stock maxx, but when pushed to race performance the sleeve goes away so fast it's a joke.
Sorry about the OT rant, back on track.
This is my very first Sirio engine of any kind and I'm hoping it's every bit the powerhouse it's touted to be.

Just finished break in, and man this motor is sick! I haven't even dialed it in all the way because it's dark, snowing, cold and my cul de sac has too many puddles (an accident waiting to happen). Just bashing around and running some sprints, this blows the 2.5 away! I put about 3 tanks through it with no break. Starting and stopping - hot or cold - was a breeze (i kept all the ez start gear and am still using the stock exhaust).

The only problem I had was making sure my gear mesh was perfect. At first I had it too tight and the Sirio had it buzzing, so I quickly adjusted it. Other than that, I wish this motor came out early this past summer!

I was doing stand still doughnuts and steering out of them into wheelies on wet ground!

If anyone is thinking about getting this motor, I can vouch for it.

Of course now I have to change my whole setup to accomodate this new powerplant. But, that's half the fun.

I have a sirio 18 with just over a gallon through it. I have a motor saver filter, thrust mac's pipe (I'm thinking of getting a sirio bb pipe), mip cvd's, steel spur, alum. tranny gears, and big joes. This engine will idle through an entire tank and has never stalled out on me, that's right, never. It always starts, and runs consistantly. But I don't experience the same wheelie poppin power that others post about. Maybe the increased rotational mass of my other hop-ups drags it down a bit, hopefully the sirio pipe helps. Right now my buddy's stock tmaxx is every bit as fast as mine. They say that it gets faster and faster as you run up to 1-1/2 gallons through it. Mine hasn't got much faster yet. But when I spin the flywheel, the "pinch" is still incredible, if I'm not careful the piston will still get stuck at TDC. Maybe even after a gallon it's still not broken-in. All in all, the reliability is awesome, but I'm somewhat disappointed in the performance.

Remember, I put this engine in my Sportmaxx. No Reverse, no 4wd, no aluminum. So my power to weight ratio is probably better than the T-Maxx. But, he's right. The reliability is worth it alone.

I've noticed that a bunch of people are putting in all the steel gearing. I'm not so sure about that. I mean if something goes wrong, I'd rather have something like the $8 Robinson Racing spur gear get stripped out than have my brand new $190 engine get totally screwed. But anyways, I have a totally stock 2.5 T-Maxx and I just can't handle the engine; it never stays running, but when it does, it has definately got some power. I need wheelies though! But yeah, post your experiences with this engine in your T-Maxx.[sm=RAINFRO.gif]

I too am looking for a good replacment motor for my hard to tune 2.5 (incredible power when it does run)but I am afraid to spend big money on a motor that I dont Know ! Is it tuner friendly for somone who doesnt Know tuning that well ?

Thats why I got the sirio, I was tired of messin with my 2.5. I spent more time tuning it and checking for air leaks then I did driving it. That engine took alot of the fun out of my truck.

As far as steel and alum gears, I just replaced the stockers with them every time I stripped one. It's not like all my stock gears stripped at the same time, I just don't like fixing the same thing more than once if I can help it. If something were to go wrong in the tranny with steel/alum gears, then your clutch would burn out, not your engine.

Tuning the sirio has been a dream compared to the 2.5. As long as you know the basics of what you are trying to do, it's very tuner-friendly. The reason being, IT RUNS all the time, even if it is rich or lean IT STAYS RUNNING! You can't very well tune an engine that stalls all the time. Since it stays running, you can take your time to fine tune it and make it run even better! The only problem I've had with it was at break-in. The piston/sleeve fit is so tight that the e-z start has a hard time turning it over. That problem cleared up after break-in.

Wow guys.. Excellent posts!! Ha Ha because you are telling me everything i want to here!! I've been looking into the sirio with "reliability" questions.. but it seems you guys are having good experiences. My piston/sleeve on my trx 2.5 wore out and i just couldnt stomach fixing up the engine that pissed me off so much. Who woulda thought that a sleeve could wear out just sitting there with me *****ing at it!! But keep them Sirio posts rolling!!! I just might order one today. Oh... just gotta add.. The XTM 24.7 is beautiful. maybe put about 10 or so tanks through it in (in my Xterminator) Engine NEVER stalled ever! If the sirio can do that and still have balls its going on my orderform.

Thanks

-scott

What about fuel for the Sirio? I run 30% in all my buggy engines and that's all i keep on hand. Anyone running 30% in their TX 18?

The Sirio is hands down one of the best engines I have ever seen. The quality of the parts and machining is excellent and its a dream to break in and tune. It runs very stable and holds a tune forever. After you install it you will see what a complete nightmare piece of crap the TRX 2.5 is and you'll kick yourself in the ass for not getting it sooner.

I didn't have the same problems with my 2.5 that others have had, but I love the Sirio. It makes gobs of power and you dont have to run quite so high of temps to make the power. I just tune it in the morning of raceday and dont have to fool with it all day. The 2.5 I usually tuned durung the break between the heats and the mains, because it was usually cooling down (ambient temps) but none of that is needed anymore. The Sirio adds piece of mind, that makes it worth it to me.

fhm101, I run 25% in mine. I would think that a head shim would be required for the 30%. Contact Trinity and ask them.

Are any of you guys running the turbo plug set up in your Sirio?? I was wondering if it is really worth it to change over.

I ran the turbo plug for a little while, then went back to the standard. In my experience, it didn't run as consistantly with the turbo plug, and I didn't really notice any power/speed increase. But that was shortly after break-in, and maybe I didn't have the right plug.

I dont know. I have had people tell me they make more power and are more fuel efficient. The main reason I ask is for fuel effiency, 25% Trinity doesnt come cheap. If it runs effecient enough I might make it through a 10 main without pitting.

Ya, there supposed to be. Like I said, I only tried the one plug. They cost twice as much, and I didn't feel like spending that much to experiment. The standard worked fine, so I stuck with it.

I have the Serio for about 6 months now with a gallon and a quarter through it. This engine has to run trrough a gallon of juice AFTER break to develop maxium power. It's in the manual. A number of guys were *****ing and complaining after breaking in that the engine was a waste, after I told them to burn a gallon of juice through it, they went crazy over it. Some poor guys sell it of of ebay after break in not knowing this. I am running mine with skis on, dual rear wheels and it flies http://www.torkndork.com Unlimited wheelies as long as you can keep up I am working on a gadget right now to get off the starting line a sec faster. Hope this idea will not be stolen too LOL