Considering G2 (Carbon Fiber) Upgrade

<-- forum n00b


Howdy,

Got an e-maxx back in December...now I'm going through the upgrade process (don't we all). The goal I've set for my e-maxx is to run 50mph (long straight only) on the off-road track where I run/practice (and now race, as of last Saturday...racing wasn't in the plan, yet...totally different Oprah). DNF'd, btw...refer to the aforementioned Oprah remark.


Part of the acceleration formula is the mass of the vehicle. After all, what's 50mph if it takes the entire straight to get there?
As I begin to lighten my maxx to improve acceleration I believe the chassis is a great place to lose a few ounces and gain a lower CG for stability. The CG is a no-brainer, but losing weight and maintaining strength are important. I've noticed the chassis doesn't seem to take a beating similar to all the flanges that hang out (and break)...like the suspension arms and body posts. The flanges absorb most of the energy...so I'll probably leave them stock and continue to purchase extra parts everytime I'm at the hobby store.

My requirement is to drop weight, gain stability, and be able to finish a race. So will the carbon fiber G2 x-brace chassis get me closer to my goal w/o creating a large and expensive break point?

It (the G2-CF) seems to meet the weight requirement. The lower CG for the batteries and motor(s)/tranny have great appeal. What about the x-brace (aluminum) backbone? Will it handle a large jump if you land (slam!) the peak of the last jump on a triple? Am I at risk of ruining matched gp3300's by setting them closer to the ground on a carbon fiber platform?

Finally, when I go to LiPo, is there enough platform space to keep LiPo packs safe? Is there a link to G2 dimensions?


thx!

[Serum]

Welcome on this forum!

No wrong intentions, but have you driven a truck at 50 mph? I can tell you; that is FAST for such a large thing! (TWICE as fast as stock!)(once you drove it on such a high speed, you’ll be hooked though..)

The CF gmaxx frame is in one word superb, It is very rigid, can take serious abuse, and to gain stability it's cg is ultimate low (buggy style, it could be called truggyconversionframe as well.. ;) )but if you want to push your truck to or thru the 50mph barrier, you might consider on beefing up the drivetrain as well.

It could be managed on 12 cells though. I read a thread from one of our forummembers, Promod, he managed running 50mph on 12 cells. (lehner XL3100) with a stock drivetrain. Don't count on it to last forever though, but it is doable! And rather cheap too! And that motor COULD take 14 cells too!! But i would not gear it down a bit if you did.

Be sure to use topnotch cells if you want to push it that far!

If you want to make a lightweight truck that can go 50mph and can run it without to many servicehours, i would strongly suggest on beefing up the drivetrain. (diffs/cvd's) if you want to loose some weight, Lipoly is an excellent choice!

Rather expensive, but excellent..


To build a lightweight truck i would suggest to use;

-Stock or bigbore traxxas shocks (4 pcs instead of 8)
-gmaxx CF frame
-in the very near future the 1 speed conversion from Gmaxx! (you could drop the shifting servo and a few gears from the gearbox (including the weak idlers)
-MUCH weight can be saved with using other tires as well (1LBS on the truck with ease!)

[Sylvester]

I like the CF chassis, i have them, they are lighter than stock, look nicer, and are more durable! i say go for it, i got CF instead of aluminum beacause its lighter and it looks better for me.

Thanks for the replies.

I'm considering every piece of the truck and its impact to weight and performance. I've already lightened it a bit.

In fact, w/ the stock motors and promatch 3300's (1.17) I had to gear up my truck considerably to keep it from wheelie-ing during 2nd gear starts. Its an extremely fast truck w/ the few changes I've made to it, and the runtime from these batteries is awesome...both statements though are unmeasured and based on experiences pre and post upgrades. btw, the stock motors were warmer than "normal", but not by much.

Anywho, the CVD's will be replaced when or if they're twisted. If the mass (weight) may be reduced enough such that I can use a brushless system and stock shafts, that'd be peachy...we'll see. W/ regards to weight, CVD's, and brushless motors I should be able to use a rev happy motor rather than a torque monster, maybe the stock CVD's will suffice. Maybe not.

With regards to top speed, its the acceleration and keeping things firmly planted during acceleration which seem to be the issue. I need to work on my lead finger. ;-)

Seems most people "bash" around their house, my preference is to "bash" at the track. And it's definately bashing, w/ the speed and frequency of bumps and jumps racing is no less harsh on my truck. Out of a dozen trucks in the 30 minute main two of them finished it. So durability is a very important piece, even for the race truck. I've heard good things about the carbon fiber chassis (nothing disparaging) but I've not read many (more than a few) reviews from racers or bashers on the durability. So confirmation that a G2-CF chassis is a suitable chassis for the conditions to which my truck are exposed will help me make my decision.

thx!

[supermaxx4190]

Yes, go with the CF gmaxx. my friend just bought one and loves it. he has giving it a good beating and it held up great. you also may want to concider the extention to keep wheelies under control.

[Smurfy]

Im not sure 50MPH offroad is very practical.
High 30's feels fast, 40+ is insanely fast and uncontrollable on anythign other than a smooth surface.

If this is a one time thing 50 would be doable, if however its for a race maxx its so much more speed than is actually helpfull, id doubt most buggys would ever hit 50 down the straights.

Still sounds like a nice project, definatly get yourself a light tire setup and try and get a setup where you can drop 4 shocks.

teh stock drivechain isnt 2 bad as logn as you dont put huge shock loads.
I belive promod infact had his fastest run of 70+MPH on a stock drivechain which is very impressive.

If you could shim the diffs that would extend there life signifficantly

Originally posted by Smurfy
Im not sure 50MPH offroad is very practical.
High 30's feels fast, 40+ is insanely fast and uncontrollable on anythign other than a smooth surface.

If this is a one time thing 50 would be doable, if however its for a race maxx its so much more speed than is actually helpfull, id doubt most buggys would ever hit 50 down the straights.

Agreed. Not sure how practical 50 mph is...but I wanna push the envelope a bit. If I can get the truck to do 50 I'll need the right setup (suspension, ride height, weight, CG, etc.). I guess I'm really looking for an engineering goal and task. ;-)

'sides, ripping past people down a straight is simply fun.

Originally posted by Smurfy

Still sounds like a nice project, definatly get yourself a light tire setup and try and get a setup where you can drop 4 shocks.

teh stock drivechain isnt 2 bad as logn as you dont put huge shock loads.
I belive promod infact had his fastest run of 70+MPH on a stock drivechain which is very impressive.

If you could shim the diffs that would extend there life signifficantly

I've done the first two things you suggest. Brushless and LiPo's come after the chassis.

I figure, with all the weight reductions I'm going through (for my truck, that is) I should be able to utilize the stock drivetrain parts. The reduced weight in conjunction w/ a less torque-ie motor should be manageable.

By shimming the diffs, is the goal to decrease the play?

thx!

[Serum]

One hopup i advise to you is the g-maxx single speed conversion (weightsaver too) And an aluminum diffcup and diffhousing. When these are shimmed right, they are very tough. (stock gears)

The older stock gears are not as tough as the new traxxas gears.

And indeed, shimming is done to reduce play to a minimum. The goal is to let the gears touch eachother as much as possible without binding.. (that's the art of proper shimming)

And with the plastic cups there is just too much flex possible, so the gears can create their own play.. And when the play is created, the contact is needed the most.. (under large stress)