R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Electric On-Road

Reply
 
Thread Tools Search this Thread
Old 06-19-2015, 09:16 PM   #1
Tech Apprentice
 
Join Date: Sep 2014
Posts: 74
Default TC4 Speed runs gearing help

Hello everyone I have a associated tc4 and I just bought the castle sidewinder3 5700kv, with a traxxas 25c 3300mah 2s lipo battery, and I am wondering if anyone can help me with gearing for speed runs? I have a friend who has a nitro tc3, and he is beating me pretty bad in drag racing! I am running the stock gears is there anything I can do to make this car go much faster? the guys at the hobby shop told me I would be able to take on nitro cars. thanks in advance.
NewXGen is offline   Reply With Quote
Old 06-20-2015, 05:13 AM   #2
Tech Addict
 
phildoggg's Avatar
 
Join Date: Feb 2009
Location: N.C.
Posts: 665
Trader Rating: 24 (100%+)
Default

Stock gearing is too low for speed. try going up a few teeth on the pinion and keep an eye on motor and esc temps. also this is not going to be gearing for repeated running. make 1-2 passes and let cool.
phildoggg is offline   Reply With Quote
Old 06-20-2015, 06:36 AM   #3
Tech Regular
 
longuylander's Avatar
 
Join Date: Jul 2014
Location: Long Island
Posts: 307
Trader Rating: 7 (100%+)
Default

You also may want to pick up a 3s battery. The sidewinder with the 5700kv can handle it for a short while (you'll definitely want to strap a fan onto the ESC), but as phil said, make a few passes then let it cool.
I have the same setup (except the sidewinder 2) in a TC4 geared at 66/27 running 3s and it was good for 60mph, though nearly uncontrollable acceleration, even on foams.
longuylander is offline   Reply With Quote
Old 06-20-2015, 08:14 AM   #4
Tech Master
 
Geezatec's Avatar
 
Join Date: Oct 2007
Posts: 1,460
Default

Smaller the pinion, off line the quicker. larger the pinion top speed. Too large, motor could cog(cogging), go 2 less teeth. When running 5700kv motor, can go 5000-6000KV lipos, 2 or 3 cells. Go to hotter motor as in the 7700kv only run 2C lipos. Use a RC Gear Calculator if you want, can be found on the web.

Electrics are quicker then nitro, will beat it offline, depending on your speed trap.
Geezatec is offline   Reply With Quote
Old 06-20-2015, 10:22 AM   #5
Tech Addict
 
Join Date: Sep 2014
Location: Bay Area, Cali
Posts: 589
Default

How fast do you want to go? I went 116 mph with a 5700kv motor
tc4basher is offline   Reply With Quote
Old 06-20-2015, 01:21 PM   #6
Tech Apprentice
 
Join Date: Sep 2014
Posts: 74
Default

Thanks everyone for the replies. I would be happy in the 70-80mph range just enough to edge out a nitro slightly modded nitro car. I changed the pinion to a 20 tooth and it got quicker off the line but it was spinning new rubber tires so I went and bought some foams and will try again when its not raining. Would a 3s lipo eat up the stock diff gears and cvds? Thanks for the replies .


/edit. I did forget to mention that I ran the 2s at 3.80v per cell so not full charged if that makes a big difference? New to lipo my first time I'm not sure how low to run it before I have to charge. I stop at the low 3.7 range ATM and charge up to 4.2. Thanks
NewXGen is offline   Reply With Quote
Old 06-20-2015, 02:50 PM   #7
Tech Regular
 
longuylander's Avatar
 
Join Date: Jul 2014
Location: Long Island
Posts: 307
Trader Rating: 7 (100%+)
Default

Yes, fully charging your battery will make a huge difference. 3.6-3.8V per cell is a good level to keep the batteries at for storage, but you don't want them to get below 3.0-3.2V or else they're dangerous paperweights.

As for 3S destroying the drive train... yeah, it kind of does. I had to rebuild the rear diff with steel outdrives because the original ones melted. The gears need to be meshed well or else they'll get eaten, but otherwise should hold up.
longuylander is offline   Reply With Quote
Old 06-20-2015, 04:29 PM   #8
Tech Addict
 
Join Date: Sep 2014
Location: Bay Area, Cali
Posts: 589
Default

Upgrade the stock plastics diffs to steel and cvds to aluminum or steel. They wont hold up long to 3s and up.
tc4basher is offline   Reply With Quote
Old 06-20-2015, 04:29 PM   #9
Tech Addict
 
phildoggg's Avatar
 
Join Date: Feb 2009
Location: N.C.
Posts: 665
Trader Rating: 24 (100%+)
Default

upgrade to the steel outdrives or a spool in front and diff in rear. I run spool front and rear in mine.
phildoggg is offline   Reply With Quote
Old 06-20-2015, 04:50 PM   #10
Tech Addict
 
Join Date: Jul 2008
Location: WEST COAST
Posts: 628
Trader Rating: 95 (100%+)
Default

straight line speed run with a 3.5 =rollout-3.70's set motor timing low and add the timing thru the esc- combo goes 120 plus with a 2 cell
__________________
T.M. Tires BOCA Bearings Pemberton Race Works EAM ORCA GFRP/HD Trinity Muddslide Motorsports Independent Racing Products Fantom Gravity R1WURKS
koz47 is offline   Reply With Quote
Old 06-20-2015, 07:03 PM   #11
Tech Apprentice
 
Join Date: Sep 2014
Posts: 74
Default

Went to the hobby shop and bought a 3s 25c 4000mah lipo and the castle ESC fan. Hopefully I can test tommorow if it doesn't rain.
NewXGen is offline   Reply With Quote
Old 06-20-2015, 08:40 PM   #12
Tech Addict
 
Join Date: Sep 2014
Location: Bay Area, Cali
Posts: 589
Default

Quote:
Originally Posted by NewXGen View Post
Went to the hobby shop and bought a 3s 25c 4000mah lipo and the castle ESC fan. Hopefully I can test tommorow if it doesn't rain.

Keep an eye on esc temps. Sidewinders get hot fast on 3s. Even with a fan. Mite want to try a Yeah Racing Tornado fan if the Castle fan does not do much which I dont think it will.

Keep in mind your motor will run cooler than your esc.
tc4basher is offline   Reply With Quote
Old 06-20-2015, 08:55 PM   #13
Tech Master
 
Geezatec's Avatar
 
Join Date: Oct 2007
Posts: 1,460
Default

Next thing to mess with, Pinion teeth then motor timing.
Geezatec is offline   Reply With Quote
Old 06-21-2015, 09:24 AM   #14
Tech Apprentice
 
Join Date: Sep 2014
Posts: 74
Default

Took the car out this morning and it didn't last but 3 passes on 3s with a 20 tooth pinion. Broke the diff out drive part that the CVD goes into... Gonna have to upgrade to steel I guess. Bummer.
NewXGen is offline   Reply With Quote
Old 06-21-2015, 09:51 AM   #15
Tech Addict
 
Join Date: Sep 2014
Location: Bay Area, Cali
Posts: 589
Default

Quote:
Originally Posted by NewXGen View Post
Took the car out this morning and it didn't last but 3 passes on 3s with a 20 tooth pinion. Broke the diff out drive part that the CVD goes into... Gonna have to upgrade to steel I guess. Bummer.
I called that one haha. Do yourself a favor and replace the plastic cvds while you're at it
tc4basher is offline   Reply With Quote
Reply



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 04:58 AM.


Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net