Car-Tune

Were those LiPo batteries you have? How old are the batteries? Have you changed your gearing? Does your Car run smoothly?

tilbarr

Hello All……..New to this thread…….but not to the hobby, have been into RC for a long time and Just purchased a Sprint 2 Sport about a month or so ago and have been having a blast with it. I usually run off road buggies and trucks, (for land vehicles) but wanted a car for a while and the hpi looked nice. Had some issues with the rear belt but reading through the thread came across “drc35ca� s post on his tensioner arm setup mod and it fixed me up nicely (By the way thanks again for the post and help). But all in all a nice vehicle not into racing mostly bashing. When I get a chance will post a couple picks of my cars bodies……..see ya in the forums……….

Quattromanta

Hi,cheers for your comments. 

t9dragon

My Feedback: (11)

Where does Castle recommend that the cutoff for running lipos be set at 6v?

If you set the LVC at AUTO-LIPO you will get longer runtimes and you will not damage your lipos. I have been running all of my Castle ESC's at AUTO-LIPO for about 4-5 years now and have never had a lipo go bad.

Here is what Castle says when using the AUTO-LIPO cutoff.
This setting automatically detects the number of LiPo cells you have plugged in. It will
automatically set the cut-off to 3.2 volts per cell. It will beep the number of cells in your
Lipo pack between the initialization tones and the arming tones on initial power up the
controller

Quattromanta

Hi T9dragon, hopefully I've got to the bottom of my Sprint prolems. I found out that I was using a very old version of the Castle software, I updated it and applied default settings and sure enough the car ran fine and cut off when expected. When I put my second battery in the car lost power after a few mins so I think the battery is faulty.

Thanks for your help.

t9dragon

My Feedback: (11)

Kool..

Do you have a way of checking the voltage of each cell in the "bad" lipo?

WindyCitySquirrel

http://www.youtube.com/watch?v=nwjSw...eature=related

digitalsmithy

hey yo y'all

I'm currently running a Venom 5000 2s lipo but it's a little bloated so it's time for a new one. I was happy with its performance but i'm wondering if there's a certain brand or other type of battery that is better/faster? Any reccomondations are appreciated.

thanks!

bonus pic of my recently finished trueno

MF-DK

^ Good looking car  

I wonder what people like of shocks nowadays? I need a replacement, all HPI's seem to be discontinued...

digitalsmithy

thanks

they are still selling comp shocks


http://www.hpiracing.com/products/en/75194/

drc35ca

I like his ideas except the rear tensioner should under the belt not on top, in this manner it still can allow the belt to touch the backside of a hot motor and it cause the belt to stress instead of picking up the slack and preventing bouncing and skipping on the pulley! It also can make the aluminum weaker with the long slot!

WindyCitySquirrel

What aluminum? The motor mount - - - ?

I suppose someone could design some kind of system that is mounted to the chassis proper to push up, but then you'd have to drill an extra hole in the chassis and counter sink the hole & (no disresperct intened) the extra hole would weaken the chassis.

I'm guessing that If the tensioner was mounted underneath it would remove the slack coming off of the pulley going into the rear dif instead of keeping the belt tighterbetween the pulley and the difas it feeds forward.

The pulley is pulling the belt which pulls the rear dif - - -

If the tensioner was underneath then most all of the slack would be on top before the pulley and rear dif - - -

With the slack between the pulley and reardifthere's more of a chance for the belt to skip and get chewed up because the pulley is meshing with less belt lugs.

Thewayit is mounted it appears that there is virtuallyno slack on the top.

I suppose that it may possibly stress the plastic mainshaft eccentric and on the extreme the main shaft bearing if it was set too tight - - - But loose plastic eccentrics is a built in design flaw(?) with all of the Sprints and the bearings are not the best either.


JMO & Ts

WindyCitySquirrel

smithy, you have a PM

digitalsmithy

thanks bro, i tried to reply but it said you didn't accept pm's or something, but anyways i'll be ordering those asap, thanks again!

Car-Tune

Is this squirrel from you tube?

narwalrus

My Feedback: (4)

Digitalsmithy - Are those traxxas rally tires? How do they slide on a touring size car?

digitalsmithy

They are traxxas rally rims and tires, they're pretty awesome. You can drift and speed around so it's a nice mix of both worlds, alhough i had to mod 'em quite a bit for them not to rub on everything, i think they would be considered a negative offset when put onto a sprint.


i painted in where the backside of the "spoke" was, had to cut off and sand/dremel about 3/4 of an inch for clearance.

WindyCitySquirrel

get yourself a sett of these - www.amainhobbies.com/product_info.php/cPath/1_24_149/products_id/154790/n/RPM-6mm-Wide-Hex-Adapters-4 -

RPM 6mm Wide Hex Adapters (4) [RPM80202]they should compensate for some of the offset in those rims you use.

digitalsmithy

aw dang i have those and it didn't even cross my mind (i am a noob afterall)

thanks!

drc35ca

Under power the belt is tight on top anyway,adding a tenioner in a small area just forces the belt to run against the bearings harder,under it picks up the slack and the belt follows more of the top pully to almost 3/4 circumfrerence!

I take the same principle from a bycycle derailer. I have been able to get 4 x the life off of a belt and it also wont jump when reversed hard as most of the top pully is used instead of the belt just sitting on the top pully.

My tensioner only uses a tiny amout of swing in the tensioner to add just the right amout of tension with only one hole to hold everything.

Using a aluminum top pully helps a lot also,good investment.

WindyCitySquirrel

Ok, I found your original post (#1251) with the picture. So it'sa littleeasier for me to grasp what you're saying about a bicycle derailleur.

If you have only one hole, thenthe tensioner just acts as a stationary idler pulley on a 1:1, because there is no spring tension like in a bicycle derailleur right?

Are you still having belt wear issues?

Are you still having rounded plastic pulley issues?- Or did you upgrade to the aluminum pulleys?

drc35ca

the pully is able to swing back and forth and that way can add or release tension and stop bouncing and jumping on pulleys. I place it closer to the top gear to keep the belt away from the motor and it uses more of the top pulley! I only stripped one plastic top gear but it was because of a runaway at WOT hitting the wall and by the time i could pick it up the belt and pully were both toothless! I have changed to aluminim as it is just plain better and it dosent attract dirt.


I can get up to three times the life of a belt but hpi belts do come off the assembly line better than others and had a few break within seconds so these were defective,running outside i would only use a tough racing belt(much better quality) real rubber and kevlar! HPI belts seem to use a rubber vinyl??

Keeping the belts and pulleys clean go a long way! had 1 guy run his sprint from oct-march and it still has the same belt but he is meticulous on maintenence.or just plain lucky?

WindyCitySquirrel

Thanks

Car-Tune

This really sucks. I just got the HPI plastic pulley. Installed it on the flux and 10 min run and it was all stripped.

Can't wait fit the aluminum

digitalsmithy

jeez that's pretty hardcore, i've driven mine about 30-40 times and the orig's are still solid, one very minor chip, AND i've only drivenitin parking lots so i dunno what's with that.