R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Nitro Off-Road

Reply
 
Thread Tools Search this Thread
Old 04-04-2007, 07:32 PM   #2761
Tech Master
 
jkirkwood's Avatar
 
Join Date: Feb 2007
Posts: 1,231
Trader Rating: 8 (100%+)
Default

A drilled 55 piston vs a molded 55 piston.

The drilled piston will have more pack as the holes in the pistons are sharper at their edges which promotes turbulent flow of the fluid than the molded pistons would. The molded pistons have rounded edges which promotes laminar flow of the fluid.

In fluid dynamics turbulent flow occurs at high Reynolds numbers (greater than 3000) and lamiar flow occurs when Reynolds numbers are below low (less than 2100). The sharper edges of the piston hole edges simply help promote the high Reynolds numbers.
__________________
SMC Racing | AKA Products | SANWA
jkirkwood is offline   Reply With Quote
Old 04-04-2007, 08:21 PM   #2762
Tech Regular
 
SlobbaTech's Avatar
 
Join Date: Jun 2003
Posts: 423
Default

Everyone runs drilled 54 pistons in the front of the 8ight and 8ight-T cars. If they run 55's in the rear in buggy they run drilled pistons, if they run 56's in the rear of buggy it's a stock/molded piston, if they run 55's in the back of truggy I'm not sure if they run stock or molded pistons. A drilled piston will have slightly smaller holes (more pack/stiffer) than a stock/molded piston. To make a drilled 54 piston you need to take a piston with smaller holes (55 or 56) and use a #54 drill bit to drill all 6 holes to a 54 size. To make a drilled 55 piston you need a 56 piston, then drill it's holes out with a #56 bit to get a drilled 55 piston.
__________________
Hot Bodies, HPI, Novak Electronics, JR Propo, Lunsford, Skipgear.com, Planet R/C, Vinyl Graphics Unlimited, JConcepts, B-Mods Racing, CRCRC, King's R/C Raceway, Avid R/C, GMK Supply, & Pacific Coast Hobbies.
SlobbaTech is offline   Reply With Quote
Old 04-04-2007, 08:21 PM   #2763
Tech Champion
 
R40Victim's Avatar
 
Join Date: Jan 2005
Location: N.W. FL___L.A.___Lower Alabama
Posts: 7,822
Trader Rating: 1 (100%+)
Default

What are the direct effects of the Reynolds numbers on the performance of the shock's rebound?
R40Victim is offline   Reply With Quote
Old 04-04-2007, 08:36 PM   #2764
Tech Regular
 
Join Date: Oct 2003
Posts: 314
Trader Rating: 2 (100%+)
Default

So Slobba Tech, when on the Drake set up it says #54/40, what they are really running is drilled #54/37.5? And in the rear #55/32.5 but they really run drilled #55/30?
Dale.0 is offline   Reply With Quote
Old 04-04-2007, 08:43 PM   #2765
Tech Master
 
Join Date: Jan 2004
Location: Wisconsin
Posts: 1,605
Trader Rating: 17 (100%+)
Send a message via AIM to Kave
Default

Quote:
Originally Posted by SlobbaTech
Everyone runs drilled 54 pistons in the front of the 8ight and 8ight-T cars. If they run 55's in the rear in buggy they run drilled pistons, if they run 56's in the rear of buggy it's a stock/molded piston, if they run 55's in the back of truggy I'm not sure if they run stock or molded pistons. A drilled piston will have slightly smaller holes (more pack/stiffer) than a stock/molded piston. To make a drilled 54 piston you need to take a piston with smaller holes (55 or 56) and use a #54 drill bit to drill all 6 holes to a 54 size. To make a drilled 55 piston you need a 56 piston, then drill it's holes out with a #56 bit to get a drilled 55 piston.
Is there an oil thats preatty much standard also?
Kave is offline   Reply With Quote
Old 04-05-2007, 09:05 AM   #2766
Tech Regular
 
SlobbaTech's Avatar
 
Join Date: Jun 2003
Posts: 423
Default

Dale...yes. Reynolds number...I wouldn't try to get that precise with fluids, fluid stuff is very hard to figure out and you'll probably end up spending tons of time figuring it out just to get a ballpark figure. On the standard oil...no there isn't one viscosity shock oil that works the best in the front and rear of the 8ight/t cars. For the front of both cars you need 37.5-40wt, for the rear you need 25-32.5wt oil.
__________________
Hot Bodies, HPI, Novak Electronics, JR Propo, Lunsford, Skipgear.com, Planet R/C, Vinyl Graphics Unlimited, JConcepts, B-Mods Racing, CRCRC, King's R/C Raceway, Avid R/C, GMK Supply, & Pacific Coast Hobbies.
SlobbaTech is offline   Reply With Quote
Old 04-05-2007, 09:39 AM   #2767
Tech Regular
 
Join Date: Feb 2007
Location: Virginia
Posts: 302
Default

Quote:
Originally Posted by SlobbaTech
Dale...yes. Reynolds number...I wouldn't try to get that precise with fluids, fluid stuff is very hard to figure out and you'll probably end up spending tons of time figuring it out just to get a ballpark figure. On the standard oil...no there isn't one viscosity shock oil that works the best in the front and rear of the 8ight/t cars. For the front of both cars you need 37.5-40wt, for the rear you need 25-32.5wt oil.
Yep - I run 40 wt front with 54 pistons and 32.5 wt rear with 55 pistons and it works a lot better (for me) then the stock wt and pistons
gtsum is offline   Reply With Quote
Old 04-05-2007, 09:43 AM   #2768
Tech Regular
 
Hrdluck13's Avatar
 
Join Date: Apr 2006
Posts: 478
Trader Rating: 8 (90%+)
Default

Guys,
I just started driving an 8.
I had a Jammin and a Sp2 and most recently the Mugen truck..
I like the losi allot and am glad I changed..
The only problem I am having is
A. I run a Vspec and for some reason using the stock motor mount and clutch set up the screw that retains the clutch bell is "drilling" a hole into my gas tank.. Anyone having an issue with this?
B. I cant seem to get the rear end tame... I am running the Truhe set-up.. Any suggestions??


Thanks for all the good info on this thread.. It has helped allot..
Hrdluck13 is offline   Reply With Quote
Old 04-05-2007, 10:01 AM   #2769
Tech Elite
 
Brian Miskolczi's Avatar
 
Join Date: Sep 2003
Location: Maryland
Posts: 3,531
Trader Rating: 154 (100%+)
Default

Slobbatech- So if i drill out the pistons, will i still be running 40wt front 32.5 wt rear. Or do I change the fluid also to 37.5 front and 30 rear once the pistoms are drilled? LMK thanks.
__________________
l TLR l OS SPEED l RADIOPOST l PROLINE l NITROTANE l HORIZON HOBBY l HOBBYWING/FALCON SEKIDO l VENOM l UPGRADE RC l SMC BATTERIES l PCDRC GRAFFIX l GMK SUPPLY l OGIO l 4C HOBBY SUPPLY l
Brian Miskolczi is offline   Reply With Quote
Old 04-05-2007, 10:34 AM   #2770
Tech Fanatic
 
sport10's Avatar
 
Join Date: Dec 2005
Location: Pensacola, FL
Posts: 964
Default

Quote:
Originally Posted by Hrdluck13
Guys,
I just started driving an 8.
I had a Jammin and a Sp2 and most recently the Mugen truck..
I like the losi allot and am glad I changed..
The only problem I am having is
A. I run a Vspec and for some reason using the stock motor mount and clutch set up the screw that retains the clutch bell is "drilling" a hole into my gas tank.. Anyone having an issue with this?
B. I cant seem to get the rear end tame... I am running the Truhe set-up.. Any suggestions??


Thanks for all the good info on this thread.. It has helped allot..
Use either Adam Drake's "the Dirt" or Mike Truhe's posted setup. I like "the Dirt" setup but with 30 weight oil instead of 32.5 weight oil. I am also running 3-5-1 diff fluid setup and like it.
__________________
Hot Bodies VE8 w/ RX8-1900 combo
Losi XXX-SCT CRC conversion MMP/hacker 13.5
Associated B44
Associated B6
Durango DESC410V2 Pro
sport10 is offline   Reply With Quote
Old 04-05-2007, 12:07 PM   #2771
Tech Adept
 
Join Date: Feb 2007
Posts: 157
Trader Rating: 1 (100%+)
Default

Quote:
Originally Posted by sport10
Use either Adam Drake's "the Dirt" or Mike Truhe's posted setup. I like "the Dirt" setup but with 30 weight oil instead of 32.5 weight oil. I am also running 3-5-1 diff fluid setup and like it.
Yeah like sport said above 3-5-1 is a great diff setup I am running that also. The only thing is with running 1 diff oil you have to maintain it a little bit more so that means you have to check on it a little bit more frequetley so the oil does not get cooked into the diff case it self.
losi8ight is offline   Reply With Quote
Old 04-05-2007, 12:09 PM   #2772
Tech Regular
 
Join Date: Oct 2003
Posts: 314
Trader Rating: 2 (100%+)
Default

Slobba, thanks. Any other little tricks we should know about?

Are you coming to the mod nats warm up race?
Dale.0 is offline   Reply With Quote
Old 04-05-2007, 01:33 PM   #2773
Tech Master
 
trebor's Avatar
 
Join Date: Nov 2006
Posts: 1,338
Trader Rating: 6 (100%+)
Default

Does anyone have any extra drilled pistons they would like to share? My LHS doesnt carry them. Ill even pay.Help. I am trying to get the right set-up so it will be nice.
trebor is offline   Reply With Quote
Old 04-05-2007, 01:35 PM   #2774
Tech Regular
 
Join Date: Sep 2005
Posts: 373
Trader Rating: 2 (100%+)
Default

Quote:
Originally Posted by sport10
Use either Adam Drake's "the Dirt" or Mike Truhe's posted setup. I like "the Dirt" setup but with 30 weight oil instead of 32.5 weight oil. I am also running 3-5-1 diff fluid setup and like it.

Where is Adam Drake's "The Dirt" setup posted?
*Topher* is offline   Reply With Quote
Old 04-05-2007, 01:37 PM   #2775
Tech Elite
 
Join Date: Nov 2003
Location: Covington, La.
Posts: 3,585
Trader Rating: 50 (98%+)
Send a message via AIM to micrors4guy
Default

trebor- you dont NEED the drilled pistions to have a good setup.
__________________
Rob Jensen
Thanks to the following companies for their support in 2017: Team Associated, Maclan, Fierce R/C Solutions
micrors4guy is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
Losi 8ight Clutch building Cvdiver Nitro Off-Road 3 05-21-2008 04:47 AM
Team Losi 8ight Buggy with Brushless Setup RcOneNitro R/C Items: For Sale/Trade 9 04-20-2008 06:04 PM
losi 8ight-t package f/t for brushless lipo setup ColeT R/C Items: For Sale/Trade 6 03-02-2008 11:17 AM
Losi 8ight-t setup F/s ColeT R/C Items: For Sale/Trade 15 02-11-2008 08:51 PM
OS .21 V-spec Cluth Setup on Losi 8ight? RcOneNitro Nitro Off-Road 6 09-03-2007 01:07 AM



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 03:42 AM.


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