General Speed-Running
 

Doing speed runs with my cars is something I have enjoyed. It first started with my Rustler on 4s 6600mah 8C Lipo and a Feigao 540 12s and then a Mamba Max 4600. Those Lipos couldn't hold their voltage very well, so speed was limited. However, the Rustler did hit 57.5mph (GPS verified). Gearing was 26/87 with HPI Geolandar tires all around.
Soon the Rustler will be running the Mamba Max 4600 system on 4s2p A123 M1 cells. This battery setup can put out quite a bit more power than the Lipos I had been using, so I'm hoping to speeds easily in excess of 60mph.

Yesterday I finished up my HPI MT2 18SS brushless conversion. It's using 4s2p A123 M1 cells (same pack that will be used in my Rustler) with a Feigao 540 8L and a mamba Max ESC. The tires are the ones that come with the 18SS kit. With 4wd, this truck is QUICK. It accelerates very fast, with a lot of control. It's geared 20/49 (38/13 at the diffs). So far, the highest speed I've hit with it is 55.7mph. That's without the body, though. I tried running it with the body since if the truck flips over it'll have some protection, but it went a fair bit slower with the body on. I think it hit something like 50.9mph, almost 5mph slower than without the body.

With both trucks, one major limiting factor has been radio range. The Rustler's range was worse than with the MT2, but the MT2 still isn't getting as much range as I would like it to. The radio is a MX-3 FM 75mhz, a Novak XXL receiver, and "genuine" Airtronics crystals.

It seems at least for 1/10 stadium trucks bodies aren't good to use if you're after speed. Anyone else ever found this?

I used my old stock rustler body back when I had the 8s in it.. (both sold now) but I had great runs.. seems like alittle over 60 like 60.2 or some mph.. never tried it without though..was geared tall seems like I used a 30t pinion.
phil

30t piniuon holy crap! that would be for like ONLY top speed im guessing...

I was using the MX-3 + Airtronics RX and had terrible luck. I switched over to a Novak XXTra and WOW what a huge difference. I get incredible range on anything that I use that combo on. I can just about drive it clear out of sight. I pick mine up used on fleabay, and end up paying about $45. It's a great deal when you consider you don't have to buy any more RX crystals.

Sleebus

yeah what I used was strictly for 2-3 high speed passes.. never try to run gearing like that..LOL
phil

now you have me wanting another rusty just for speed runs..hey mm why not shoot for the fastest speed comp.
phil

Awesome on the MT2! I want to see some pics, as I have one too.

Here it is

Need a wedge body. I used to have some Dahms bodies on an old RC10T that were pretty wedge shaped, they were supposed to be aerodynamic. Haven't seen any in years.

I found the bandit body on the rustler is much better for speed runs. More arrow dynamic.

"arrow" dynamic huh?

Yea.... You know.... Shaped like and ''arrow'' :005:

I'll post up a thread some time. But earlier I accidentally drove the front left wheel into my foot at 5mph, and it broke the knuckle :mad:1. Fortunately I work at my LHS, so I should be able to get the part easily.

Not enough time, not enough money, not enough range (for now). If I ever get a radio setup that gives the range I need, I'll be set.

My rustler is about 95% non-stock. It would take a bit of work to get a bandit body on there (body post mounting). I suppose if I really get into speed running it might be something to look into.

I sideswiped a curb at about 5mph today and broke the rear hub on mine. Was only a few blocks from hobby shop at the time so I was able to get a new one right away. Time for some aluminum hubs.

I have a T4 that will flip out at 45 so i just scored a super RS4 electric to continue my speed quest, 4600 and 5s anyone??

Be careful! I'm rendering a video of my MT2 from earlier today, that shows it running 55.7mph. Hopefully it will be ready tomorrow morning.

Yea...speed runs are way fun - doing drag style passes with the Jato is a blast...even though its nitro

I've been wanting to get a FT TC4 to do some crazy high speed stuff. I've been trying to snag one up off ebay (especially since its out of production). I want the shaft drive...not the belt drive on the soon to be released TC5...

I am planning to put either a MM5700 and run it on 3S, or a Novak GTB3.5 on 2S. Its a big dilemma. I'd probably be happy with either system (I know the MM would smoke the 3.5 though) but its all a matter of cost. The GTB would cost me at least 50 bucks more than the MM, but with the MM I have to spend $100 per 3S Lipo pack...

As for the body, it probably is too high-profile and creates too much air resistance. If you can find a way to mount a Touring Car body on there, I'm sure it would be much better, and might even increase your speed.

Running no body creates drag because the air is moving across an uneven surface, but running with a body can create lots of resistance because more air must be displaced.

Depends on the body, a stadium truck may look like a barn door compared to a ferrari

Metalman, I probably won't try 5s on a 4600, but 4s and geared to the moon would be interesting

I should see about getting a 3s Lipo for my TC4 to try out with my 5700. First, I need some new tires ;).

RR has 27T pinions for a TC4 that are a direct fit LOL

That would be hilarious if the MM on 3S would beat that one guy's world record TC4 that was running a Neu on like 8S.

I have an interesting combo to try, lehner 1200XL and mgm 16024 esc. On 8s the motor will be running 35,520 rpm with outragous torque

now that could take some serious gearing there!! lol question how and what are you using to get the videos on the comp? I might sound stupid but I'm curious..

phil

Never done it myself, but you need a server to upload to, like photobucket or RCPics, then you can link. A lot of people use you tube and google video as well

I finally got my MT2 video up. Here's the link:
http://metalman.xoompages.com/mt2speed.zip
Right-click and click "Save Target As".

It's one fast mt2!

Are you the person holding the transmitter sky-high!? LOL.. not good... It's glitching like crazy! i think it might went a bit faster, the GPS is kind of slow to get to the real speed. How hot does the 8L get? and how much does the entire car weight? i would say fair light, since the nitro version weights next to nothing.

Looks like it runs sweet on that setup. Except for the glitching. Thats some pretty impresive speed for on a 13.2V system. You might try putting a little weight on the front of that thing next time you go for speed runs. A couple of old AA baateries zip tied to the front bumper makes a huge differance in keeping the front end down.

You need a ladder for a drivers stand.:005: Dude, get youself a 2.4ghz tx/rx before doing any more upgrades. What good is a fast setup if you cant get the range to let it run.

Too late I guess. Bandwidth limit has been reached! :(

Yeah, that's me holding it up high. And to think 6' 2" tall isn't tall enough :005:.
The 8L hasn't been running too hot, maybe 150 deg. F tops. The Mamba Max ESC seems like it will thermal before the motor hits 180 deg.
Not sure on the weight, or the weight compared to stock. Some time I will have to weigh my Revo as well.

At first I did have a 5cell receiver pack on the front deck, but I removed it since I'm running a low enough voltage to use the internal BEC.

Yeah, I do need a radio system that won't glitch. However, the antenna on the receiver I'm using did get shortened about 1/4" since it was repaired after it ripped.
I think I want to wait for the Airtonics MX-3FHSS, Airtronics' first attempt at 2.4ghz. It's supposed to be out in March. Tower shows it for $165 for the TX/RX, which is a pretty good deal. And then I can get it cheaper through the LHS I work at. I've also emailed Airtronics to see if they could just convert one of my two MX-3 transmitters to 2.4ghz. They are pretty local (~25mins away) so I could just bring it to them if they were to offer that service.

You are in luck. I have a second page where it can be downloaded from (:)):
http://metalmanx.xoompages.com/mt2speed.zip

Damn...that thing is pretty fast...

Hopefully I'll get to see it run...I saw it today in person (dropped by the LHS where MetalMan works and he showed me).

That was one LOOONG skid...that explains why the body mount mosts were completely flat - no more little knobs for the body clips anymore lol.

MX-3 + Novak XXTra = :043:

I had glitchies, after the XXTra, there were gone.

OnEdit: Oh and another thing, you may have done these or not, but here goes! Braid your ESC/Motor wires to cut EMI. Also, putting a ferrite bead on your wires going to the RX will help cut interference. I had my RX really close to my motor, and that made it act pretty wonky. Moving it farther away (and the antenna too) helped a lot.

I've also noticed that as my packs get low, the motor will glitch regardless. With running the 5700, it just shuts off, but with the 10L it'll keep running for a while, the hard cutoff doesn't seem to want to engage, either that or the extra load of the motor bounces around the cutoff voltage. I'm running a 10L, which is a lot less draw than the 8L you are running, so you might be more sensitive to low voltage.

Sleeb

Thats fast MM! Looks good!

After work I drove it in the alley, and within 20secs. the leftr rear wheel nut came off :010:. Left-side wheel nuts are not friendly to me.

Motor wires were braided. The receiver was sitting on top of the servo at the front of the truck, about 3" away from the motor. I don't have a ferrite ring to try out, and I really don't know where to get one.

This glitching is throughout the entire discharge of the battery. A123 cells hold their voltage pretty darn well, so I'm not sure that would be a problem.
I was using the Mamba Max's internal BEC, so I can try using the receiver pack again.

Thanks :).

maybe the servo motor is causing glitching????

pinolelst

I sure hope not. The only place on the truck besides the servo to mount the receiver on is the front deck, but it's not the best surface to mount to (it's got a buch of holes). Some time I might try a Novak XXtra and see if that will eliminate the glitching I'm getting (I get those on discount too :).

Hmmmm. Well, looks like you are doing all you can to minimize RFI. I agree, it's unlikely the batts are the problem. I might have a ferrite ring around here somewhere. If I can find it, I'll send it to ya. I don't remember if you are running the airtronics RX (or maybe you said it was a XXL?) I don't know the performance differences between the XXL and XXT, all I know is that mine is smooth as silk after I got one. If you can get your hands on one to test, it might be worth it.

I think a RX pack is a logical next step to debug the problem. Oh! one last thing...do you have your antenna located away from the motor? I've got mine up front with the servo. Looks funky but works great.

Sleeb

It has a Novak XXL with "genuine" Airtronics crystals. The receiver antenna was shortened 1/4-1/2", so that could very possibly be the problem.

The antenna is mounted to the aluminum upper plate over the slipper clutch (about 2" from the motor). The antenna isn't touching the aluminum at all. I can also try making a raised mount that keeps the antenna closer to the receiver and further from the motor.

Also, the Mamba Max ESC is as far away from the receiver as possible (in the rear, the RX is at the front).

I suppose it would help for me to take a picture of the layout so you can see what exactly I'm talking about.

NICE!!! now i want to convert this LOL

and a nitro mt was my first real rc car! but i gave it to one of my real good friends