1515 1y/f & Quark 125b... What to build?
 

So I got the brushless bug and decided on a whim to buy a 1515 1y/f I found and a Quark 125 ESC. Now I just need to buy a car for the system! I am some what new to RC, so I am still trying to decide what 1/8 to get. I have been going back and forth between a 1/8 buggy and 1/8 truggy and even Revo.

I currently have a VXL that I love for street runs more than anything. The new car is going to be primarily used for flying at high speeds across baseball fields and track usage with occassional parking lot speed runs.

First, should I got with a buggy or truggy and what brand? Second, which brand is recommened for these conversions?

If it is mostly for speed, I would go with a buggy, they handle better at high speed. Just about any brand can be done, the RC-Monster store has mounts for most. I like to pick a brand that you can get parts for at the local hobby shop.

I'd definitely suggest a buggy. They're less expensive to start off, less expensive to maintain, go faster, handle better and are notably lighter. The benifet of a truggy would be the more suspension and wider tires for heavy off-roading.

Some say the 1515 sized motor is "too much" for a buggy, though I've got a pal locally here who's pretty happy with his. I'd take one in a heartbeat if I could afford it.

Personally I'd suggest a Losi 8ight or Associated RC8 buggies. They're a little more expensive than some (Ofna, etc) but it shows. Especially when racing. If you're not racing or it's out of your budget - you could same some $$$ and go for a more primitive buggy such as an Ofna such as a Hyper 7 where you can find a used roller on eBay for about $100. They're great buggies and they make great conversions for play-use.

Mike offers motor mounts for all 3 buggies mentioned as well as several other cars (revo, xray, Ofna CRT, Ofna CR Buggy, Mugen, etc).

-Jeff

My vote is for buggy as well. More specific a Kyosho....:lol: I am loving mine....:whistle:

Ok... buggy it is. I think I am going with an rc8. I ordered an rc8 mount, tray, heat sink, and motor covers from Mike. What else do I need to make this conversion work? What 5mm pinion do I need? What kind of plugs are needed for the battery, motor, and ESC? Are people using Deans or Powerpoles? What amp size do I need?

you need an rc8 kit too lol:lol:

You can use deans or traxxas connectors for the battery to esc. I usually direct solder the wires from the motor to the esc, as I have had issues with the bulet connectors. People use 5mm and larger connectors and report success, so you may try that.

I like deans for the battery to ESC connection. I have also had good success with 5.5mm bullet connectors between the motor and ESC.

I think I will go with the Traxxas connectors since I already have balancer set up with those. How do you connect the bullet connectors for the ESC and Motor? I am assuming I just need to solder them on?

Anyone know what 5mm pinion sizes I need to get from rc-monster?

That is correct, you just solder them on. The first one may be a little challenging, but you get the hang of it pretty quickly.

So I think I have everything for my project. So far I have:

1515 1y/f
Quark 125b
Quark Heatsink
2x 40mm Fans
RC Monster rc8 Mount
14 & 15 tooth mod-1 5mm pinions

I am going to purchase the rc8 from my LHS this weekend and order the 4s 6000 Lipo. Is there anything else I am missing? Do I need an external BEC with the Quark?

I also need to pick up the bullet connectors as well for motor and ESC. Will the Traxxas connectors handle 4s or do I need another type of connector for the battery to the ESC?

God knows I can't afford this car, but this stuff is like crack.

Running an external bec will help the qaurk stay cooler. The ccbec is great and for 20 bucks it is a great deal. The traxxas connectors should be good for higher voltage, less current will be going through them than the vxl can pull.

Enjoy the crack, just clean yourself up before you go back to work.

You do need a external bec for anything over 10 cells nimh with the quark.
You don't need to buy any bullet connectors. The quark should come with a set 5.5mm plugs, which are the ones I've been using for the last year without issues.

I appreciate all the feedback. I am getting excited and hopefully will have a functioning Electric RC8 by next weekend!

However, I am having buyer's remorse about the Quark. It might be unfounded. I guess since I am new at this I just want to make sure I am getting the right stuff. Some seem to say it runs great and is the smoothest ESC and excellent customer servive, but others point out it has some serious heat issues (and others haven't had heat problems). Given that after the heatsink, fans, and potentially having to use an external BEC, I am already at the cost of just getting one of the high dollar MGMs with way more capacity than I could ever need which people say barely get warm.

Should I stick with the Quark or swap it out for an MGM? What are the downsides to getting MGM instead?

I can't really see myself having to use 6s very much if at all given I will be running at 50,000 rpms. I don't even wanna know how fast that would push the car on the street with a big 1515 in it - but I may have to see!

I primarily plan to drive the snot out of the car on a RC track on 4s which gives me 32,000 rpm and should embarrass any nitro. I don't race (yet), but will probably start. Every now and then I might do some street runs or drive across an open field, but my Rusty is really for that. I am not the sharpest tool in the shed with the electric RC stuff yet, so I really don't want to get into having to do a whole lot of modifications and ghetto rigging of stuff to make it work properly either.

Help!

Buyer's remorse is understandable when you plunk down serious cash for such a small thing. The Quarks are VERY VERY smooth and run just about everything out there. I love both of mine. Also, warranty is fast and easy from all reports. But, yes, they have heat issues, which can be rectified with a little additional heatsinking. And yes, they don't run at anything over 5s well. So, if these concerns are important enough, then maybe you should go to an MGM.

Thanks. I just don't want to blow $300 and then it not work so hot when I could have spent $375 and been done with it from the start. So is the BEC mod optional? What type of temps are you seeing on your Hyper with 4s? Also, what kind of run time do you get?

I am sure I could figure out how to do it... I just get nervous having to cut wires, etc on these things. Is it easy to do?

BEC mod? Do you mean adding heatsink to the ESC? My temps are really good, usually 20*F above ambient. I've never run the packs totally down and have run for about 20-25 minutes nonstop. Can't remember what mAh I put back into the packs, but I would estimate between 30-40 minutes of total runtime.

I meant adding the external BEC and disabling the internal BEC on the Quark. I am definitely going to use the heatsink. You seem to be having good success with those temps. I am going to have the RC-monster heat sink for the Quark and 2x 40 mm fans, so I woudl be surprised if it goes thermal. Just given all the talk about heat, I want to make sure my car and $300 bucks doesn't go nuclear.

You will have to use an external bec and disable the internal one, it's not really on option on 4s.
It doesn't involve any cutting though.
The bec input wires just get soldered to the esc input wires. And the output plug goes in the battery slot of the receiver.
And to disable the internal one there is a small three wire lead (black wire, red wire, yellow wire) that goes from the esc and gets plugged into the receiver. To disable the bec all you have to do is go to the plug at the end of the lead, get a small pointy object and lift up the tab on the plug that's inline with the red wire. You can then just slide the red wire out. Tape or heatshrink it back out of the way and it's done. Once you get the stuff and have a look at it, it will seem really easy.

I like my quark. I did burnt out 2 of them early last year when I was using a 7xl on 14 cells nimh in the middle of summer, but both were replaced under warranty. My third one has been mainly used with a 1515 2.5D (1700kv) in a truggy and e-maxx on 5s for racing and some high speed bashing. I also use it on 6s sometimes as well for bashing and about 15 minutes of practice laps on the track. I'd like to know how many people have actually used quarks on 6s and how many worked and how many didn't, because this one has never even blinked when I've used it of 6s.
About a week ago I used it for 10 minutes or so on 6s geared for around 55mph no problems. It's summer here now and it's been used on some 40C+ days (104f), but I haven't thermalled this quark.
I've always used them with the rcm heatsink and 1 40mm fan, but I think the neu has helped a lot to keep this one working for the last 7 months. I haven't done the internal mod or put extra caps on it.
If you don't go crazy on the gearing I think yours should be ok with the neu, heatsink, and 2 fans in a buggy, but if it's not, they'll replace it.

Look what I snuck past the wife yesteday evening...

http://i240.photobucket.com/albums/f...o/P1250967.jpg

Oh, what is this? Some type of antiquated nitro technology? I didn't know they still made this stuff... with it being so slow and noisy.

http://i240.photobucket.com/albums/f...P1250968-1.jpg

Almost done... I just need to solder up the wires, the BEC, pinion, and some kind of battery tray. Also waiting on my 2x 4s batteries. In the mean time, I am going to see how the VXL holds up in it on 3s.

http://i240.photobucket.com/albums/f...o/P1250969.jpg

looks great!!!
a quick question for you. how do you glue your tires without getting glue on the edge of the tire (where it is visible)

I didn't glue them yet. :lol: I am going to dye the rims black.

I am still trying to figure out how to mount the Quark though. I guess I have to wait on the heat sink and fans so I can see how that is going to work. I think I am just going to use an aluminum L bracket next to the motor.