Questions about Converting an Xray-XB808? Please Help! :)
 

Many of the RCM users have converted their XB808 buggies. I have just ordered the RCM-808 mounts from a fellow user here which I'm going to install in one of my XB808 buggies. I'm wondering if there are any important finding within the conversion to add to my list of "How to do it" ? I will also be using your information and help by sending it to my fellow TeamXray Canada Drivers (CanwestRC), as we are planning to have E-808 buggies added to the races we attend. Any information provided for the following questions would be greatly appreciated!!! :wink:

We're very interested in hearing about;

What motor/ESC combos work best? (please provide links)

Where and what pinion gears should we be using? OR are you guys using a clutch setup? (please provide links)

Where is the best positions to install the battery tray and ESC? (please show pics)

What choices of batteries are being 'raced' with on the tracks? (please provide links)

Is there any fine tunning we need to be aware of before we take it to the track?

Do we need mechanical braking setup or this the ESC braking sufficient enough without over heating?

I don't own an 808, but I'll do my best to answer some of your questions.

With the RC-Monster conversion, pinion gears are used. These are the best available on the market at the moment in my opinion:
http://www.rc-monster.com/proddetail...=5mmmod1pinion

The Tekin RX8 just came out and seems to be doing very well for most people. It is designed with racing in mind, so it will probably work for you the best. Just choose the KV depending on what voltage battery you run.
http://www.rc-monster.com/proddetail...=tekinrx8combo

The ESC will do perfectly fine without mechanical brakes. There really isn't a best place to put the ESC and battery. I mounted my battery/ESC like this to give you an idea:
http://s199.photobucket.com/albums/a...t=IMG_1104.jpg

Thanks for the information, nice setup you have there! Our 1/8 electric class hasn't been 100% developed, not enough of them in attendance yet. We are running them as 'exhibition' races for the 2009 season, but plan on having an offical points series in 2010.

Its good to hear that the ESC will be ok for braking on its own and the Tekin setup looks sweet but the cost is alittle higher compared to the MMM combos (which Ive heard is also a great setup) I noticed you are running the MMM, are you happy with its performance or will you perfer to have the Tekin? As for the batteries; what is the choice of the racers in your area using?

I am very happy with the MMM. I am using a Neu 1512/3D motor with it on 5s lipo. The main difference between the Tekin system and Mamba Monster is that the Tekin system is sensored on start ups, so it starts much smoother than a sensorless system, such as the MMM. Ideally, I think I'd prefer the Tekin RX8 system, but because I do not race very much, the Mamba Monster works great for me.

As for batteries, 4s, 5s, or 6s, will work great in a buggy as long as you choose the right KV motor. 6s and 5s is definitely more efficient than 4s, but is also more expensive. On 6s, look for a motor with KV between 1300 and 1700. On 5s, choose a KV between 1700 and 2000. On 4s, choose a KV between 1900 and 2500. Of course this is all relative, but ideally try to stay between 30,000 and 40,000 RPM. And a 25C or higher battery. I am using a NeuEnergy 25C 5s 4300mah lipo pack, and so far really like it.

This calculator by BrianG helps a lot in picking a motor, voltage, and gearing.
http://www.scriptasylum.com/rc_speed/_top_speed.html

Again, thanks for the help! :) Alot of great information here! I think you have covered what I need to know as far as ESC/motors and batteries and the calculator page is genius!

Last thing I need to know about will most likely have to come from RCM member owning E-808 buggies...

- What is a good starting point as per gearing with the above information!?
Stock 808 spur gear is 42t (but I also have 41t and 43t)

- What pinion gear would I need with a 5s 25-30C - 14.8v battery and a motor KV rating between 1700 and 2000?

Hey!

I am converting my 808 aswell and just waiting on different parts to complete my build... I think some shipments might have gotten lost on their way to me, so now they could be here in a month or 2 days, I'm bummed :neutral:

Here's my 2 cents on your questions, and I am sure jhautz will pop in here and help you out aswell. This forum has been a great source of info!

-I am also going for the Tekin RX8 combo. 1900KV buggy motor that I plan to use on 5S

-I also use RCM pinions, but since I plan on running the slipperential (46T) I will go for a 15T pinion that should give me about 35mph top speed.

-According to people that ran the 808 in electric the battery likes to be as far back as possible. Then you can try to mount the ESC on top of a tray over the rear driveshaft for exemple. I plan to try and mount my RX8 in the back behind the battery tray. Should be good weight wise and it could fit since the RX8 is a smaller footprint than the MMM.

Here's how TDC57 did it, others also tried having the ESC on the chassis but went back to having it over the rear drivetrain to be able to push the battery tray further back.

http://i264.photobucket.com/albums/i...7/IMG_2976.jpg

-I plan on using NeuEnergy 30C 5S 3300 mAh. This should give me just a little over 10 minutes of race time and will help keep the buggy weight down. Also RCM has a 2600mAh 6S lipo that has just enough juice to get you 11 minutes of race time, so no wasted energy at all. Lightest setup you can go for if you plan on running 6S (a 1500kv motor would be nice on 6S).

-Fine tuning would be using the Tekin Hotwire to adjust timing and whatnot, and upload the latest software. You need to shoot them an email with your application to get the right one.

-The only reason to run mechanical brakes is to be able to adjust rear brake bias. Downside is more weight and complicates the whole setup. I guess it will depend on your driving style but know that the ESC braking is very capable and efficient.

-Now as for gearing on 5S using the calculator jnev linked to, with the stock 42T spur a 14T pinion will give you 36mph top speed and 15T will be 39mph. So it will also depend on your track. Note that when using the calc the 808 has a 43/10 TRUGGY ratio ;)

Hope it helps :intello:

With the calculator listed above, you can add and change variables countless times to simulate different setups.

I am in the middle of a Revo conversion and have referenced that page countless times trying to decide on a motor, esc and batt. setup.

Best of luck!:mdr: