Flyojumper

I've had an Evader BX Pro buggy for about a month now and I bought a cheap Venom Fireball 13t (double wound) to tide me over until my original motor was fixed (long story).
I know it's a cheap motor but it's still 13 turns and I was expecting my car to reach in the high 20s low 30s but I timed it on several occasions and it's only doing 23mph (on a 130ft straight on pavement).
I've made a google search on the Fireball 13t and I've found a post of someone using it who was getting his car to 36mph, but he didn't specify the type of car (touring maybe?).
Originally on factory timing it was running at 20mph on pretty much every pinion/spur combination between 18/88 and 25/88. I recently advanced the timing to the max mark on the can and I got it to run at 22mph on 21/88 and 23mph on 23/88.
The car's internal ratio is 2.66, regular 3.5" tires.
My battery is a Team Orion 3000mAH sports pack.
I know my battery is not tip-top but I have heard from other people that even on sports pack 30mph is relatively easy to reach.
I cleaned the motor, all bearings on the car, inspected the brushes, etc and didn't find a problem as far as I knew.
Unfortunately I don't have a way to borrow a motor or battery from anyone to test them out.
Is that low speed normal for a cheap 13t? Does my setup has a problem? Any way I could diagnose it?
If that speed is normal and to be expected with my current setup, what's the cheapest way for me to get into the low 30s mph?

SkrapIron

You have 2 problems with your approach. Your speed depends entirely on the quality of the equipment used.

1, the Venom fireball is a very slow motor, even though it is 13 turns. At best it's going to peak at about 33,000 rpm.
2, the speed of your motor is going to depend very heavily on the quality of the battery used. The team Orion cells are, in a word, cheap.

What can you do? First, put some deans connectors on the battery and the ESC. Then replace the bullet connectors on the leads between the ESC and motor. Reducing the resistance in those two coneections will help alot.

Second, drop the 88t spur gear. The buggy weighs less than the ST, so it doesn't require the sam etorque to acccelerate. Go to an 85, or even an 81t spur. With the 85t spur, try a 21t pinion. With the 81t spur, go with a 22t pinion.

Third, get some better batteries. You really don't realize what a difference that will make, until you get better cells. Even a cheap GP3300 pack from Radioshack is going to be an improvement over the Orion pack.

Fourth, Get a better motor. Most 13t motors should turn about 40,000 rpm. That willgive you mid to upper 30's in speed. Just remeber, that you do get what you pay for. Spend $15.00 on a motor, don't expect much by way of performance. Any Trinity, Reedy, or even a team Checkpoint motor is going to really wake up your performance dramatically.

I'm sorry to tell you, but there is no magic $20.00 add on that can help you. It's going to take a combination of better equipment, and better setup to get you where you want to go.

Good Luck!

-Skrap

lcnet

i beleive I have the the team orion super duty plus 3000, are those of poor quality too ?
maybe we need to have a "chart" with high quality to lower quality for the battery pack. that will help everybody to decide which pack they want to go for versus their budget..

jakjr

My Feedback: (18)

Better batteries and good connectors (if you don't already have them) should wake up the fireball a bit. My Evader ST use to do around 30mph with it. Well, that's what the VSM said anyways, I didn't have a radar gun at the time and never thought about putting a GPS on it.

David236

I will agree with Skrap that the batteries are your biggest problem. I have found over the years that a cheap motor with great batteries can outperform a great motor with cheap batteries almost every time. In fact believe it or not my son's Stampede with the Stock Stinger running one of my matched packs actually blew the doors off my friends sons truck running a Quad Mag and a Venom pack......And those Radio Shack GP 3300 are really pretty good packs especially for the 19.99 price tag.

Flyojumper

Alright, thanks guys. I was actually planning to put some Deans on there ASAP but I have a little hesitation for two reasons: first I'm afraid it'll cancel the warrantee on my ESC (I really like keeping my warrantee for peace of mind) and second I'm afraid it'll hurt the potential resale value since many bashers are still on Tamiya I think (and when I sell my batteries the low budget bashers will most likely be my main target market).

Ok, besides the Deans I'm pretty sold on the idea of getting a good pack. I want to skip the Radioshack GP3300 for 25$ and go with better batteries that will later be able to handle ANYTHING I throw at them, including a possible BL setup in my future (leaning towards 4.5/5.5 Novak atm). What's a still reasonably priced good performance battery that will handle the high current of BL setups? Preferably under 45$-50$ shipped. I'm still hesitating between 6 and 7 cells, 7 cells would do wonder on my current setup (Intellispeed 12t modified can handle 7 cells according to docs) but I'm afraid that the 7 cells will become worthless or require me to tamper with it (which I'd rather avoid) if I go with the Novak BL system in the future since it only allows 6 cells.
I've heard zapped batteries usually give higher voltage but I read some racers say that it drastically reduce the life of the battery. Is it true?
I don't plan to be a serious racer so matched is not necessary, just a high performance yet still affordable battery that will be able to handle good BL setups.
Thanks again guys!

Flyojumper

Oops, forgot to comment on SkrapIron's point on spur/pinion.
85/21= 4.04
81/22= 3.68
Why would I do either of those instead of say 88/22 (same ratio than 85/21) or 88/24 (same ratio than 81/22)?
I heard that the higher the spur you can use with your gear cover the better (since given the same ratio the setup with the larger spur would be less taxing on the spur/pinion at high speed since less rotations needed) and that you should play on the pinion to affect the ratio.
So why do you recommend to decrease the spur to play with the ratio instead of varying the pinion?

SkrapIron

Ok, I'll try to be brief:

Your buggy has 48p gears to drive the transmission. 48p is the standard measurement of the gear. it means that you will have 48 teeth, on a 1" diameter gear. Knowing this, we can determine the circumference of the gear itself.

88/48= 1.8333" diameter. Multiplying that by Pi (3.141592) give you circumference. In this case, it is 5.7595"

Same thing with the pinion gear: 24/48 = 1.5707"

This gives you an over all reduction of: 5.7595/1.5707= 3.668:1 revolutions

Now, check the actual reduction ratio of the other two gear sets:

85/48*pi=5.5632", 21/48*pi=1.3744". Giving you an overall reduction of: 5.5632/1.3744= 4.047:1 revolutions
81/48*pi=5.3014", 22/48*pi=1.4398". This gives you an overall reduction of: 5.3014/1.4398=3.682:1 revolutions.

Now, even though 88/24 and 81/22 give you the same overall gear ratio, you can see that the actual revolution ratio of the gears are different. 3.668:1 for the 88/24 and 3.662:1 for the 81/22.

What does this mean? Translated, it means the motor will require slightly less power to get the 88/24 ratio moving, but the 81/22 ratio will achieve a slightly higher velocity ( And travel farther per revolution of the motor )

CustomTamiyas4Life

My Feedback: (34)

Hey i just learned something new........actually, half the stuff i read from skrap is new to me.

Flyojumper

SkrapIron, thanks a lot for the time you took to write this, but this particular analysis is flawed.
The overall "reduction ratio" of (spur circumference/pinion circumference) is EXACTLY equal to the "gear ratio" of (spur # of teeth/pinion # of teeth). The former ratio is just the latter ratio where both the numerator and denominator have been multiplied by the same number: Pi/48.

88/24=(5.759586/1.570796)
and
85/21=(5.563237/1.374447)
and
81/22=(5.301438/1.439897)

When you say "even though 88/24 ad 81/22 give you the same overall gear ratio" you consider 88/24 to be = to 81/22 but later in that sentence you declare 3.662 and 3.668 to be sufficiently different when in fact they are as different as 88/24 and 81/22 (in fact, with no rounding at all in the consecutive calculations, they both represent the same EXACT number as shown above).
However, I did learn a valuable bit of info: "48p= 48 teeth on a 1" diameter gear".

The Stig

There's your problem. Not all 13t motors are created equal. Just like you can buy a V8 from Ford and a V8 from Ferrari - and have totally different behaving engines.

Flyojumper

Yes, I was aware of that variance in performance between same turns motors of different quality, but even though a cheap 15t could be matched by say a high quality spec 19t, we are talking about a 13t that produces the speed and performance of a good 27t stock motor for pete's sake! (23mph on a good 27t stock is definitely doable from what I've read). As a matter of fact I have yet to read a single post by anyone on any forum I visit about a 13t of ANY brand doing only 23mph on a buggy. I've read people getting 25-27mph out of the stock Evader RTR (not pro, so with the reportedly crappy photon 20t motor) with a sport pack.
It seems it's a combination of battery/motor/plugs in my case but I was still expecting 27ish-30mph out of my current setup.