sirio .27 tmaxx engine

[wcdfmt510]

I just bout the sirrio .27tx drop in big block for my tmaxx. i love the motor. i have not even barely broken in. its got massived amounts of torque... can't keep the front wheels on the ground....i've twisted all of the stock driveshafts.. replacing with MIP spline CVD's...now my question is about the trottle linkage.... i cannot get it to open up completely...I've done everything i cud think of.....What can i do to either modify or buy new parts to make it work...

 

[frickenjoey]

Have you tried shortening the linkage from the bellcrank to the ball cup that attaches to the carb? That would be my first thing to check. If you have the option check your servo end points on your radio.

 

[LBSinGTX]

I have the S27 in my Revo with the same issues. I rotated my carb, drilled a new hole in the throttle mixing arm and changed to a softer throttle return spring. Mine is about 95% open now. I know it's a Revo not a TMaxx, but hope that helps.
Just curious, does your CB/Spur gear line up okay?

 

[wcdfmt510]

thanks.... i got it fixed... what i did was take the longest part of the throttle linkage and moved it so that it was at the end, and i made a small turn buckle with ball cups... it works perfect.. alot more smooth and no binding... the pics arent the best but you can tell what i did..... i cannot seem to get it to run rite... it seems to bog down. should i try putting it back to the factory settings? and do you know what those seetings arefor the low? the high is 5 turns out rite? and what would be the best clutch to run with it. its got a robinson reacing steel spur gear and clutch bell with the stock clutch and spring?

 

[surgemaster1970]

I have both the T Maxx and Revo with Sirio .27 conversions running Integy 3 shoe aluminum clutches,Robinson Spur gear and hardened clutch bell.My stock settings were 4 1/2 turns out on the HSN and I'm tuning it between 4 turns out and about 3 3/4 on different days.The way I fixed my throttle problem on the T maxx was lengthen the smaller rod with ball cup 1/4" longer and stick the Traxxas controller throttle split switch to 70/30,readjusted the rod stop with spring and my throttle opens up fully......Good job on getting it done your way.....Now go have some fun....I stuck the stock rims and tires from my MGT 8.0 on my T Maxx to get it planted to the ground better and the homemade handle/rollbar was much needed on my basher....Insane wheelies and power compared to the 3.3;- it climbs in and out of 30- 45 ft high pits with ease..Just as a curiosity..........How did you others with Sirio BB conversions break-in your new powerplants?

 

[wcdfmt510]

i broke mine in using o-donnell 30% race mix.. i have been running an O.S. #8 plug, and it fouled out after about 4 1/2 tanks.. it dones run to hot....i can't seem to get it tuned rite. i get it to the point where it got lots of low end torque,but slugish top end? what would be a better plug to run? colder? and i was thinking about buying the turbo plug button,and what kind of plug should i run with that?

What is a good pipe to run? waht are all you guys running? whats your set up's?

 

[surgemaster1970]

I have the T maxx 4908 extended version.It came with the 3.3 and race tuned resonator pipe....All I did was add Integy 3 shoe aluminum clutch setup,Robinson 22t hardened clutch bell and 58t hardened spur gear and drilled the exhaust exit port larger.....So far the combo hasnt let me down.....

I also have a .27 Sirio in my Revo and it runs killer too.My brother has a Revo also with .27 Sirio and he broke his in differently than both mine and his runs quirky...

The way I broke mine in was I turned in my carb settings and counted the turns, then I set them 1/4 turn richer on both needles than what was set by Sirio.......I pre-lubed the engine with CRC engine fogging oil then filled the tank with Trinity 20%,started it and let it idle through two tankfuls of fuel with full cooldown with a fan between runs.....It ran straight through both tanks without stalling and it left a heck of an oil puddle on the bench and the cooling head was only warm to the touch through both tankfuls also....At third tank I replaced the airfilter and leaned the carb settings almost back to Sirios stock settings,1/8 richer and ran the truck slow and rich through two tankfuls.....On 5th tank I leaned the lowspeed needle 1/8 turn and the high speed 1/8 back to Sirios stock settings and ran it up to half throttle for 2 tankfuls,,,,after that I gave it another filter change and tweaked the carb an 1/8 turn more leaner on lsn and 1/4 on the hsn and gave it a high speed pass to see how it was gonna shift with the midblock and it took off nicely and when it hit second the front end came off the ground for 60ft on the wheely bar before I let off with a bigazz smile....;-Then I stuck the other Sirio combo in the Revo and performed the same break-in procedures and both run about the same............can't say that for my bro...He broke it on Sirios settings and did it his way on 20% also and his runs good one start-up and on the next tankful its running alot differently;-sometimes lean and sometimes rich......I checked for airleaks and the install of the easystarter and all was good..All I'm doing is adjustments in the increments of 1/8-1/4 turn if needed and hes going almost 1/2 in either direction every tankful just about and its also running way hot.Kind of the way my 3.3 ran when I broke it in wrong and not the way traxxas recommended...I broke it in on the HPI method and the engine never ran right so I killed it in a week and a day and went big;-lol................