bradjones

Hi so i got to tune in my tmaxx 3.3 4907 extended chassis this afternoon and had the speedometer app on my iphone,

i gave it a tune from factory setting and had the Judder or a lean top end on wot so backed it off 1/8 turn after leaning and that was running fine

then I did the LsN in hour increments till it was good acceleration not spot on no wheelies but fast enough May lean it more next time I'm out

but my question is this what is the actual top speed stock cause when I was doing speed runs I only manages to get 36.6mph on the app, when on the box it shows 45+mph?

i got the truck as a roller and the clutch bell spur gear is standard size 22/58t I think that's standard anyway, the shift point between 1st and 2nd I think May have been adjusted, could this be why I'm not getting 45mph as the tune is pretty good.

im thinking that if I lean the LsN little by little that I will get wheels off the ground from a stand still and maybe if I was to make the shifting point a little more longer that I would get better rpm meaning better top end? Would just like to get 40+ out of it

thanks a lot brad

bradjones

Also the engine is not overheating at all spit test is fine smoke all the way to top end, lots of smoke on acceleration and when it's at a stand still there is unburnt fuel spitting out of the exhaust. Here's a pic of it just to show how it's setup

bradjones

COMMON TRAXXAS GUYS help me out

is there a rule of thumb with top speed and stock gearing?

22/58 combo = 37mph stock?

will putting on a 54spur gear give better top end, or at least the 45mph mark which traxxas say you can do.

any advice appreciated

collector1231

My Feedback: (1)

Smaller spur=more speed.
Bigger pinion=more speed.

The stuff thats coming out the pipe is just fuel byproduct; nothing to be worried about. Also, did you happen to break it in?

bradjones

Yes broke it in to traxxas manual got quite hot at factory so was 4 1/2 turns for most part of break in, was going to get a 54t sg to try get more top end racing against a mta4 and revo so bit more top end would be nice

Maj_Overdrive

My Feedback: (11)

First, go through all the settings of the app to make sure it's set correctly. The things like gearing, tire size, etc all factor into the speed displayed and making sure it's as accurate as possible.

If raw fuel was spitting out of the exhaust that means the mixture is a bit too rich. It won't effect top speed but quicker acceleration means you'll get there faster. The high speed mixture will effect top speed though. With a strong smoke trail it sounds like you are on the safe side tune wise, possibly a little too safe and not getting all the rpm that's possible while still being safe. If you're comfortable experimenting a little, try leaning out the HSN (High Speed Needle) until performance drops or the engine starts cutting out from being too lean. You can note the temperature as you go but the sound and performance will tell you if the engine is too lean or not.

The 54t spur will make give the truck a higher top speed. The transmission also has 3 available ratios, make sure the wide ratio is installed for the highest top speed. I'm pretty sure the Tmaxx came with either the standard or wide ratio installed from the factory.

bradjones

Ok I think I'm pretty near the top tune on Hsn but will try to get abit more out of it and maybe a longer run, will get some more speed runs after a tune and see what I get, also I'll get a small spur and see what difference it makes.

im sure there are people out there with tmaxx's who have tested the stock speed and gearing anyone?

thanks and I'll try get the maxx rolling abit faster

Maj_Overdrive

My Feedback: (11)

Well if Traxxas' 45mph claim is truthful I'm sure it's with a tune that's right on the edge. Still I'd think 40mph would be easily achievable while being safe. When you say you're using an app on your phone, do you mean a gps speed app with the phone strapped to the truck or the Traxxas app with a TQi radio?

bradjones

Sorry ye it's the speedometer app on my iphone not the traxxas app, I have a pretty good tune if I went say 1/8-1-4 turn on Hsn I'll be too lean and get stalling conditions so not sure if I would get any more rpm top end out of her.

just thought 36.6mph was a long shot off the 45+mph they quote I'd do, wasn't sure if I'd need different gears for it too achieve them speeds or if it was on my end doing something wrong

ps it's the stock gears so 22/58 for the 4907

Curriejoseph

I have a tmaxx 3.3 I know the factory carb settings are 4 turns out hsn and the motor is broke in properly I have the hsn turned out 3.5 but what is the best lsn setting and what is the best setting for the hsn anyone that can help me I would appreciate it p.s. trying to get more run time out of it I do both on road and off road traveling

1QwkSport2.5r

The proper setting will differ from person to person in different climates. Set the high speed so it runs the fastest without the rpm sagging at WOT. Once you hear it say or cut out, open the main needle 1/8-1/4 turn. It should still run smooth at WOT albeit a tiny bit slower than totally peaked.

Set the low speed so it will idle nice and low for 15 seconds and throttle up without a hiccup. At the 20-25 second mark, it should be a little loaded up and burble a little when you punch it. The idle gap is critical for getting proper settings. The gap should be in the 0.5-0.7mm range. If you adjust the idle gap, you will need to reset the low speed mixture.