Traxxas 4-Tec Conversion - Page 2 - RC-Monster Forums

Unsullied_Spy · 01.26.2009, 12:19 PM

Quote:

Originally Posted by lincpimp

At least they sell decent chargers... but those are overpriced too

Their chargers minus the 20% discount is about what you'd pay to buy the same thing from mike

myndseye · 02.05.2009, 09:03 AM

Screw savings, they offer some with 40C discharge.

http://www.trakpower.com/

lincpimp · 03.11.2009, 03:17 PM

Hey BG, any more shots of the rest of the chassis? Wondering how you did the servo and front belt mounts...

BrianG · 03.11.2009, 03:24 PM

It's funny, everytime I finish a little project, I pull the 4tec back out and do some more pondering about how things are gonna lay out. After a while, I get discouraged and shelf it again. But just the other day, I had an epiphany!

The problem I had was that I needed a really short lipo. Somewhat easy enough to solve, but I would MUCH rather use regular size lipos (in the 6 NiMH cell size range). But, that stupid side belt!!! Well, this might not be the best way for side to side balance, but here is the plan (and I've already done some of it):

- Move the steering bellcrank to the other side. DONE
- Relocate the steering servo to the middle of the chassis as far right as possible, and extend the steering link. DONE
- Add supports to the front belt mount area. DONE

This will allow plenty of room for the battery on the left side of the chassis. I figure if I mount everything else possible towards the right, it should offset the battery weight. Some preliminary layout experiments look favorable. But, I need a motor where the leads come out the side (hence my email to medusa).

I don't have any fresh pics right now, but I suppose I could snap a couple tonight...

lincpimp · 03.11.2009, 06:16 PM

I just finished modding the 2 speed to lock it up. Drilled and tapped a few holes, seems to run true. I am having the same issue as you with battery mounting. However I plan to run 5s, so I may just use some maxamps 2100 cells that I have laying around... A 5s 2100 20c (maybe) lipo will have around the power of a trakpower pack, so hopefully it will work. A 15l may be overkill, but hopefully it will stay cool... Same think with the 9920...

I managed to get the old rcm revo mount to fit the 4-tec chassis... Might even try the tekno mount, although I would like to have some adjustability for gearing. I plan to try a 20/45 to start. Should do around 60 with that. I will get some pics in a thread later...

BrianG · 03.11.2009, 08:00 PM

Here is a snapshot of the chassis layout showing the plans. I tried to get a shot of the ruler to show how much room there is for the motor, but there was too much of a glare.

Sorry about the picture quality, it was taken via my cell...

lincpimp · 03.11.2009, 08:33 PM

Looks good Brian. I like how you re-mounted the servo. Must be tight for the linkage going under the front upper deck.

I got the motor mount in and put the center belt back on on mine. Looks like I have enough room to run 6s 2100 maxamps lipos, and I have that many "matched" cells (or at least what maxamps calls matched) so I may have to swap in a quark and give it a try. I will stick to a 5s pack at the moment, and see how it does. 5s and 20/41 gearing give me around 65mph, so we will see how this turd holds up to that.

BrianG · 03.14.2009, 07:53 PM

A little more progress. Made a top plate. Functions as a place to mount receiver, ESC, steering servo and as a chassis brace. Yes, that tan flat piece labeled "MM ESC" is the new MM Pro ESC; very very thin and is wireless!

Showing how the steering servo is mounted.

This one shows where the UBEC is gonna go. I removed the middle section from a servo case and screwed the bottom plate directly to the top part. Should be perfect for a DimensionEngineering ParkBEC (little one). The enlarged hole is for cooling.

This is turning out to be a "kit bash", lol:

- Wing stay from a Mugen MBX5 serves as a standoff for the brace.
- Turnbuckle from a Jato serves as the brace itself.
- Steering link and servo mounts from an XRay XT8 serving as intended.

Next up is the battery tray, which I'm still doing some thinking on...

JERRY2KONE · **Fun -** 03.14.2009, 08:23 PM

Looks like your both having some fun with this. I have been thinking about picking up a 4tech for a while now. I would love to fun something on road, but the nitro stuff really stinks if you ask me to. The conversion looks to be quite a challenge though. How is it going now? I am looking forward to seeing your finished projects and some videos on how well they run for you. Good luck with that.

lincpimp · 03.14.2009, 08:29 PM

Looking good Brian. I am not sure if i will bother to brace the top of the chassis or not... Considering my batt tray is in the center it might be difficult to add any sort of brace. Hopefully the chassis is strong enough with the bent sides...

I do like the wireless esc, it was about time someone did something with all of those wires. I made a cordless toaster once, wanted it to be bathroom safe, just in case it fell in the tub.

BrianG · 03.14.2009, 08:44 PM

Jerry: This isn't the best platform for conversions to be sure, but it is fun doing something challenging. And judging my Linc's and my conversion, we are going about it totally differently.

Linc: I also wasn't gonna worry much about bracing the chassis until I saw how much it flexed just by pushing down on the middle belt (to check tension). With the way I have it, there is VERY little flex. Probably wouldn't be needed since it is onroad, but I like to over-engineer stuff. Call it a weakness.

I am in the process of making the battery tray now. I'm just gonna use the same design as I used on my CRT.5 (v2). Seems to work well, and is pretty easy to make.

FYI: these progress pics are not the final product! I'm still going to paint stuff, trim protruding screws, etc. It's gotta be pretty!

magman · 03.14.2009, 11:23 PM

Ok who is setting up a drag race between you to...may be hard to do, however, you both could find someone who has a radar gun and post results to see who has bragging rites!

BrianG · 03.14.2009, 11:42 PM

Linc would probably win in a race as I'm only shooting for ~55-60mph. Just for playing around at the house on some deserted streets.

lincpimp · 03.14.2009, 11:46 PM

I am going to push mine and see what happens. Just had a drift session on the shop floor and after about 20mins of goofing off the motor was at 130, esc at 110 and batt at 100. I have a feeling I will be able to gear it up a bit. Also fixed the poor startup, upped the expo on the throttle channel to 50% forwards and reverse. Nice startup now, very little glitching. Pity the old bk does not have a lvc... I do have a li-saver, do they work on 5s?

lincpimp · 03.14.2009, 11:49 PM

Quote:

Originally Posted by BrianG

Linc: I also wasn't gonna worry much about bracing the chassis until I saw how much it flexed just by pushing down on the middle belt (to check tension). With the way I have it, there is VERY little flex. Probably wouldn't be needed since it is onroad, but I like to over-engineer stuff. Call it a weakness.

I may be able to run a longer turnbuckle from the front to rear on both sides of the battery tray. That should add some rigidity.

I do have a radar gun, and plan to post results. I kinda think it is funny having a tc with a l can motor in it. Should be even funnier if the 1512 makes its way in there on 6s...