N-4-Speeed

Im thinking about getting a picco .21 or maybe sirio .18 later this week for my b-day and i am going to put in CVD's, but do i need to get new primary gears and everything too or will the stock gearbox handle it?

N-4-Speeed

Does anyone know if the sirio .18 will accept the stock exhaust system?

sweetmaxx

It will except the stock system but from my understanding it greatly reduces power, thats how it was on my fantom too. There is a lot of debate on wether to use the stock or after market pipe for break. I went with the stock for breakin then switched to the sirio bigbore.

With the .18 ur tranny should be fine and with the .21 it should hold up for the most part but u might strip or blow a couple of drivetrain parts here or there...I think it would be worth it.

Acs_guitars

My Feedback: (3)

Yes it will use the stock exhaust, but you might look into getting a tuned pipe, trust me, you'll be happier. About the trany... I wouldn't do it, I have heard of too many stripped gear. YOu would have to upgrade to metal gears, CVD's, and metal diff cases.

binaryterror

Yeah the .21 big block conversion kits are eating out stock trannies and sliders like nothing. Now most .21 conversion kits include the metal CVD's.

N-4-Speeed

Yeah i know i need CVD's, but im trying to decide whether i need the whole gearbox metal. I guess i could just not get it metal and if it stripped upgrade it.

packerfan3001

My Feedback: (1)

i have a os rg-x (p), on stock sportmaxx tranny. Rear diff blew, so i upgraded it

redheat8

Which Maxx do you have? First off the .15pro well take the Sirio.18TX-PTR and if you have the 2.5 Maxx the Sirio TX-.18 well work. And as far as the tranny holding up to the extra hp you should be just fine. RED

Asmodi

I upgraded mine to a Sirio .18 and have blown, twisted, stripped, and destroyed every gear and shaft in my tranny and Diffs. I now run, RPR Diffs with maximizer cups and a 4 spider conversion, look in the most recent RC Driver on how to do this for the savage, for the T-maxx you can use the same shafts just cut them down a bit, but use T-maxx spiders, I have the UE Super6 FOC kit and RPR Steel pinion and Spur, also the MIP Shiny CVDs all around and under. This has cured all the problems thus far, however I just installed the Sirio .23 and wait to see what this bad boy will destroy.

Also I broke my Sirio .18 in with the Stock pipe (drilled) and then put the Sirio BB Pipe on, because at the time they were Back Ordered for months.

truggybasher

Yeah , you definenetly want a metal tranny for a 21 or more. I payed that price a little while back. but if your smart you will want to do it right the first time. and save a lot of headaecs. I would go with the robinson gears either allum, or steel it dont matter. I used alumm. It does great with my 26. If you do all that it sounds like your truck will rip for good. I hope it all goes well for ya man.

redheat8

Do you think that the 2.5 would have done the same amount of damage ? The hp is about 2.hp in the .18, compared to the 2.5@ 1.33hp. I wouldnt think that that small of a gain would make that big of a mess of things . RED

Asmodi

Neither would I, but I think that just the increase in HP coupled with the increase of Torque was the deciding factor as the .18 has alot more torque then the 2.5, also it has a much sharper and quicker throttle response.

redheat8

Interesting, maybe by gearing up a couple of teeth on the pinion would bring the stress level down on the drive train, RED

Deandome

My Feedback: (1)

You certainly DO NOT need to get a metal tranny case!! They add a LOT of weight & unlike diff cases, the extra rigidity brings nothing to the table as the gears do not stress the case in the same way.

UE does NOT make/offer/suggest aluminum tranny cases, but they DO sell a modified Traxxas case for use w/their tranny gears:

http://www.unlimitedengineering.com/...sxZCHViJ&open=

As for gears, well I haven't heard of many problems related to .21 upgrades. The stock tranny seems to hold up pretty darn well! Now .26-.28....that might be another story, but there is NO need to rush out & upgrade your tranny for a .21...you might need to at SOME point, but it certainly isn't a given that it's gonna crap out right away!!

Diffs.....CVDs......slipper clutch...THESE are the things you probby DO need to address sooner rather than later, so save your money for those & leave the tranny alone (unlike Danny Bonaduce ).

Dean

truggybasher

Like heck you don't! you are better off getting metal gears because a 21 will eat them up like crazy , I did that myself, it is worth it you will feel a lot better about it if you do .... Trust me!

Asmodi

I run the Sirio .23 and so far the tranny is holdin nicely, I do have the Super6 FOC from UE in it and replaced all the bearings with the Ceramic Nitride ones from Acer, I have yet to have a problem with the tranny, although I have been babieing the truck, this will change soon, however I still retain the plastic tranny case and diff cases, although the diff cups are alum, and 3mm conversion

truggybasher

They are not going to blow out right away anyhow.. you can try avoid the prob for a while. but it will getcha. you dont have to baby nothin with a metal tranny. cause I know that .23 of yours has some guts at full performance. either way your decision should be metal. they just take more abuse.

truggybasher

They are not going to blow out right away anyhow.. you can try avoid the prob for a while. but it will getcha. you dont have to baby nothin with a metal tranny. cause I know that .23 of yours has some guts at full performance. either way your decision should be metal. they just take more abuse.