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Traxxas 3.3 carb up grade

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Jacks9930

Jacks9930

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While playing with my revo last night I found it hard to keep it in tune. On tear down when I had some more light to see I noticed that the HSN was leaking at an idle. So obviously it was leaning out at full throttle. So I need to order parts to rebuild it but I was wondering is the there a better carb for the 3.3 I can use then the stock one?
 
This is a much debated topic. There are a lot of guys saying the losi carb is a decent upgrade over the stock 3.3 carb but if you goto the losi forums there are lots of guys there claiming the traxxas carb is an upgrade over the stock losi carb.

Overall there seem to be lots of opinions on different carb setups for the 3.3 but no solid evidence that I have seen. I would just put a fresh 3.3 carb on it and be sure to pull all of the needles and lube the orings up real well so nothing leaks on it and then use some RTV on the neck when you reinstall it.
 
I can tell you from experience the O.S. 11k carb is a nice but expense upgrade and a Ofna force .25 carb is a great upgrade. I have a friend that uses a Losi 3.4 carb and he swears by it. Personally I've never used it but have only heard good things about it.
 
jerzey10 said:
I can tell you from experience the O.S. 11k carb is a nice but expense upgrade and a Ofna force .25 carb is a great upgrade. I have a friend that uses a Losi 3.4 carb and he swears by it. Personally I've never used it but have only heard good things about it.
Click to expand...

What would make it an upgrade? How can it be better for performance than the stock carb?
 
At the end of the day u either need to port it for a decent amount of gain, or stick a big block in it. The 28's are a good upgrade :)
 
The trx carb is a turd compared to the 11k, but the 11k is 80 bucks. I already had one laying around so I tried it and it made the 3.3 run really nice.

If you were going to spend 80 bucks on a carb you'd be better off spending 220 on an os 21tm or else get a new trx carb.
 
Tm 523 is said to be the best personally I have a RB NOVa and a tm 523 I have yet to run the 523 but the 9mm throat on the RB nova changed the tune window and it's ability to hold a tune longer it also was a ton better of the line and higher rpm
Stock carb throat diameter (6mm)
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RB nova throat diameter (9mm)
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it's a tight fit in the revo but it's doable
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The only downside go the nova carb is I had to turn it down to get it to fit I think I had to take of like .75 or 1 mm to get it to fit
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The RB tm 523 carb is a direct fit u just have to cut off the white ring
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Am working on my 3.3 Revo with a new TRX carb. Been fine tuning to a good 250 degree head temp. Varying idle with low mixture and idle set very tempermental. Is there something that I may be overlooking? High setting runs strong!
 
Cleaned up old carb but never would pull fuel. New one works great.. Have a T Maxx 3.3 too, which ran great when I bought it used. Now not pulling fuel. Exhaust has loosened up but cannot pressurize up manually. Another carb issue?
 
There are tons of threads about the 2.5/2.5R/3.3 and the carb. For me, they have always been finicky at best. If I ran 3 tanks in a row without needing to adjust the tune, it was a rare day. I had an old tired OS18TM that had the same sized neck on it as the TRX carb, so I gave that a try. It didn't add any power, but it totally stabilized the engine to where it would hold a tune all day. So clearly, the carbs suck, or at least are far to fussy for a guy like me.

I wouldn't recommend spending $80 on a carb for a $100 engine. I only did it because I had the carb already.

If you seal the neck/cinch bolt, backplate and fuel inlet banjo fitting with RTV and it's still fussy, then all you can do is try a new carb or live with it.
 
Thanks for the input. Revo ok enough to play with. T Maxx next issue. Last time when running noticed seepage under head. Tightened up, but should disassemble, clean, and put back together. Old Revo carb has been cleaned and rebuilt. Maybe try that next on the Maxx..
 
I have a 3.4 in the mail Forbes my 3.3 t maxx. Hoping for a drop in install with no modifications needed. Weird that Losi forums say to use be 3.3 carb but whatever. Every video and no thing I read says the 3.4 makes the 3.3 much better with the off idle gurgle, inconsistent idle, and low-mid performance which is where mine gets annoying. WOT is always fine but it seems to be you’re either idling or full throttle, it’s almost shaky to drive it mid.
 

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