| Author |
Message |
mandraks
Samba Member
Joined: November 28, 2004
Posts: 7050
Location: Lawrenceville, Ga
|
 Posted: Wed Oct 23, 2013 11:22 am Post subject: |
 |
|
| Clara wrote: |
| srfndoc wrote: |
| Mountain gearing? |
There was a mountain geared big nut 1 ton RGB with 1.39 gearing.
I have never seen one in the USA, but evidently they were sold in Italy (alpine gearing)
You can take out the RGB fill plug, mark a tooth with a sharpie, and slowly turn the drum and count teeth. Then compare to this chart:
Double check your numbers. |
back home in germany we see these quite a bit, from the swiss army busses. they are seriously slow, though, recommended speed is something like 60km/h which is less than 40mph  they did also come with a locking differential, the old ball style 100% locker, very noisy when it engages
_________________
regards
Uli
----------------------------------------
'53 3-Fold Oval, L35 Metallic Blue, looking for a narrow hatch panel |
|
| Back to top |
|
 |
Culito
11010101
Joined: December 07, 2006
Posts: 5866
Location: Columbia Missourah
|
| Posted: Thu Oct 24, 2013 2:59 pm Post subject: |
|
|
So I had time to do some quick experimentation with the transaxle today.
RGB = 19 teeth top, and I figured a 1.26 reduction so they are indeed 63-on big nut boxes.
Then I jacked one rear wheel up (keeping the other stationary) and rotated the engine.
2nd gear: engine almost 5 3/4 (5.7?) rotations per one axle rotation
4th gear: engine almost 1 1/2 rotations (1.4?) rotations per one axle rotation.
Now I'm off to see if I can find out exactly what that means.
_________________
Copyright CJ Industries, Inc.
'64 standard w/2.0L type 4
'62 bug
| johnnypan wrote: |
| ...dont pay no attention to Culito,he's a cornhole.. |
|
|
| Back to top |
|
|
Wayland
Samba Member
Joined: December 29, 2005
Posts: 498
Location: Lasqueti Island B.C.
|
| Posted: Thu Oct 24, 2013 6:29 pm Post subject: |
|
|
| If you're only jacking up one wheel you need to let it rotate exactly twice while counting the engine revolutions. |
|
| Back to top |
|
|
Culito
11010101
Joined: December 07, 2006
Posts: 5866
Location: Columbia Missourah
|
| Posted: Thu Oct 24, 2013 8:44 pm Post subject: |
|
|
| Wayland wrote: |
| If you're only jacking up one wheel you need to let it rotate exactly twice while counting the engine revolutions. |
Ok...and then?
I guess I'm not really sure how the diff affects the gear ratios. Does it double the output if you block one wheel?
_________________
Copyright CJ Industries, Inc.
'64 standard w/2.0L type 4
'62 bug
| johnnypan wrote: |
| ...dont pay no attention to Culito,he's a cornhole.. |
|
|
| Back to top |
|
|
Wayland
Samba Member
Joined: December 29, 2005
Posts: 498
Location: Lasqueti Island B.C.
|
| Posted: Fri Oct 25, 2013 10:45 am Post subject: |
|
|
| If you block one wheel the other wheel turns twice as fast, so two revs of the jacked up wheel = one rev of the ring gear. |
|
| Back to top |
|
|
quartermilecamel
Samba Member
Joined: April 16, 2008
Posts: 3929
Location: ohio
|
| Posted: Sat Nov 02, 2013 12:41 pm Post subject: |
|
|
I thought the 4:37 r and p was stock for a bus to 67. My bus does 65mph at 4 grand. 205/75/15 tires, 1:26 big nut boxes. Still need to calculate the 1st through 4th gears but that link is down that e and b posted a while back. Im contemplating putting in the 4:12 as suggested to bring the rpms down a bit to 3800 at 65.
_________________
Waiting for santa to drop off funky green. I can wish can't I???? |
|
| Back to top |
|
|
AlteWagen
Troll
Joined: February 23, 2007
Posts: 8503
Location: PNW
|
|
| Back to top |
|
|
quartermilecamel
Samba Member
Joined: April 16, 2008
Posts: 3929
Location: ohio
|
| Posted: Sat Nov 02, 2013 1:00 pm Post subject: |
|
|
I tried to open it after I saved it. Says windows cant open the file. Aparently I need whatever program the calculator uses.
_________________
Waiting for santa to drop off funky green. I can wish can't I???? |
|
| Back to top |
|
|
AlteWagen
Troll
Joined: February 23, 2007
Posts: 8503
Location: PNW
|
|
| Back to top |
|
|
quartermilecamel
Samba Member
Joined: April 16, 2008
Posts: 3929
Location: ohio
|
| Posted: Sat Nov 02, 2013 1:32 pm Post subject: |
|
|
excel installed. Now I just need the excel mental idiot instruction download 
_________________
Waiting for santa to drop off funky green. I can wish can't I???? |
|
| Back to top |
|
|
Brokenbus
Samba Member
Joined: May 04, 2005
Posts: 272
Location: Balibago
|
| Posted: Fri Oct 24, 2014 6:12 am Post subject: |
|
|
Can anyone tell me what RPM's a stock 1600 DP motor should spin at (50 mph, 60 mph and 70 mph RPM's?)with a stock non modified bus 1967 big nut transmission with stock RGB's? I know the DP is not stock but I have asked a local re-builder build my big nut trans to stock 1967 specs. I am going to hook up a tachometer for the test drive and would really like to know if it was built right. My tire are General grabbers 27X8.5X14lt.
If you know what the 1600 engine RPM's should be, roughly, for 4.375, 4.12 and 3.88 R&P using the same size tires and stock RGB's I would extremely grateful if you could post it here. BTW I GPS'd the speedo with the grabbers and its within +1 mph so speedo is acurate.
Thanks |
|
| Back to top |
|
|
srfndoc
Samba Member
Joined: August 21, 2010
Posts: 3275
Location: SoCal
|
| Posted: Fri Oct 24, 2014 6:43 am Post subject: |
|
|
| Brokenbus wrote: |
Can anyone tell me what RPM's a stock 1600 DP motor should spin at (50 mph, 60 mph and 70 mph RPM's?)with a stock non modified bus 1967 big nut transmission with stock RGB's? I know the DP is not stock but I have asked a local re-builder build my big nut trans to stock 1967 specs. I am going to hook up a tachometer for the test drive and would really like to know if it was built right. My tire are General grabbers 27X8.5X14lt.
If you know what the 1600 engine RPM's should be, roughly, for 4.375, 4.12 and 3.88 R&P using the same size tires and stock RGB's I would extremely grateful if you could post it here. BTW I GPS'd the speedo with the grabbers and its within +1 mph so speedo is acurate.
Thanks |
It's easy to do on your own with the right formula:
RPM=(MPH*336* (R&P*4th*1.26))/Tire Diameter in inches
Stock 1967 Big nut uses a 4.375 R&P and a .82 4th. With your tires:
50mph - 2833rpm
60mph - 3400rpm
70mph - 3966rpm
Just change the value for the R&P to get the other values.
_________________
RPM=(MPH*336* (R&P*4th*1.26))/Tire Diameter in inches |
|
| Back to top |
|
|
Brokenbus
Samba Member
Joined: May 04, 2005
Posts: 272
Location: Balibago
|
| Posted: Fri Oct 24, 2014 7:23 am Post subject: |
|
|
| srfndoc wrote: |
| Brokenbus wrote: |
Can anyone tell me what RPM's a stock 1600 DP motor should spin at (50 mph, 60 mph and 70 mph RPM's?)with a stock non modified bus 1967 big nut transmission with stock RGB's? I know the DP is not stock but I have asked a local re-builder build my big nut trans to stock 1967 specs. I am going to hook up a tachometer for the test drive and would really like to know if it was built right. My tire are General grabbers 27X8.5X14lt.
If you know what the 1600 engine RPM's should be, roughly, for 4.375, 4.12 and 3.88 R&P using the same size tires and stock RGB's I would extremely grateful if you could post it here. BTW I GPS'd the speedo with the grabbers and its within +1 mph so speedo is acurate.
Thanks |
It's easy to do on your own with the right formula:
RPM=(MPH*336* (R&P*4th*1.26))/Tire Diameter in inches
Stock 1967 Big nut uses a 4.375 R&P and a .82 4th. With your tires:
50mph - 2833rpm
60mph - 3400rpm
70mph - 3966rpm
Just change the value for the R&P to get the other values. |
Thanks for the quick reply but could you clarify what the * is and the 336 or*336*? In other words could you spell out what math functions are used and when? (I get the / is divided by and I am assuming my tire diameter is 27. |
|
| Back to top |
|
|
srfndoc
Samba Member
Joined: August 21, 2010
Posts: 3275
Location: SoCal
|
| Posted: Fri Oct 24, 2014 7:34 am Post subject: |
|
|
The * means to multiply so:
RPM=(MPH x 336 x (R&P x 4th x 1.26))/Tire Diameter in inches
Simplified this would be:
50mph x 336 x (4.375 x .82 x 1.26) / 26.8"
or
50 x 336 x (4.520) / 26.8 = 2833rpm
_________________
RPM=(MPH*336* (R&P*4th*1.26))/Tire Diameter in inches |
|
| Back to top |
|
|
Brokenbus
Samba Member
Joined: May 04, 2005
Posts: 272
Location: Balibago
|
| Posted: Fri Oct 24, 2014 7:38 am Post subject: |
|
|
I think I got it. Is it
RPM=(MPH*336* (R&P*4th*1.26))/Tire Diameter in inches
50 x 336 x (4.375 x .82 x 1.26) / 27 ?
That gave me 2812 for RPM.
Thanks again I was typing my reply as you did yours. i appreciate it! |
|
| Back to top |
|
|
Eric&Barb
Samba Member
Joined: September 19, 2004
Posts: 24764
Location: Olympia Wash Rinse & Repeat
|
| Posted: Fri Oct 24, 2014 7:59 am Post subject: |
|
|
Did you find any paper work on which gears were installed?
Did you try the gearing calculator we Pmailed you last night?
| Quote: |
Here is a post about stock 14" bus tire size:
http://www.thesamba.com/vw/forum/viewtopic.php?t=129570&highlight=tire+diameter
Here is great gearing calculator:
http://weddleindustries.com/gear-calculator
Fill out all 1st thru 4th gear ratios, R&P, tire height, up shift RPM, and scroll down. Just edited this last sentence to be more accurate
Then any result for both MPH @ what RPM you want to run, you divide it by 1.26 which is the RGB gearing reduction to get final road speed result.
EG for us running 3.875 R&P @ 3,000 upshift RPM results in 75.8 MPH without RGBs. With 1964-67 standard 1.26 RGBs road speed is 60 MPH. |
Great thing about that gearing calculator is you get results listed by every 100 RPM ranging from 1,000 thru 9,500 RPM for all four forward gears. So you can easily pick a low RPM to shift into the next upper gear.
Once was offered a rebuilt transaxle that by the paperwork would have had to get up to about 5,000 RPM in third just to get into the bottom of fourth gear at 1,500 RPM which with stock bus R&Ps is as low as one should go or risk lugging the engine.
Found out that using the stock Beetle 3.88 R&P, with .82 fourth gear, and 1.26 RGBs, that below 2,000 RPM due to the higher gearing it feels like it is lugging the engine.
Plus once you have all the gearing and tire height in there, all you have to do is change the R&P ratio to see the changes.
_________________
In Stereo, Where Available! |
|
| Back to top |
|
|
srfndoc
Samba Member
Joined: August 21, 2010
Posts: 3275
Location: SoCal
|
| Posted: Fri Oct 24, 2014 8:18 am Post subject: |
|
|
| Brokenbus wrote: |
I think I got it. Is it
RPM=(MPH*336* (R&P*4th*1.26))/Tire Diameter in inches
50 x 336 x (4.375 x .82 x 1.26) / 27 ?
That gave me 2812 for RPM.
Thanks again I was typing my reply as you did yours. i appreciate it! |
No problem. FYI, your tires are actually 26.8" according to the specs. The calc EB posted is nice as well as you can change one value and see the effect (as EB mentioned).
_________________
RPM=(MPH*336* (R&P*4th*1.26))/Tire Diameter in inches |
|
| Back to top |
|
|
2type2
Samba Member
Joined: June 02, 2002
Posts: 978
Location: SW Colorado
|
| Posted: Sat Oct 25, 2014 1:56 pm Post subject: |
|
|
Hey there! FWIW I took my 66 Westy out for a 60 mile coastal cruise today and got 68 mph at 4000 on the flat. I'm running a 2017 ,215/75/15 Kumhos,stock big nut, and 3.88 FF tans. I about worried and overanalyzed it to illness when I was deciding the combo for the build, but there's a wide variety of results reported and who the hell wants to go 70 alot in a bus? $.02
_________________
"A life of peace and happiness depends on your own gratefulness" |
|
| Back to top |
|
|
GDOG57
Samba Member
Joined: March 19, 2006
Posts: 1065
Location: Gilbert,Arizona
|
| Posted: Tue Dec 09, 2014 10:38 pm Post subject: |
|
|
That speed and that rpm sounds like like you have 4.12 not 3.88 gears. I have 4.12 w/126 big nuts and my rpm's are 3800 at 65mph w/205/75/15 tires. The 3.88 should drop rpm's by about 400. So 3400 rpm's at 65mph.
_________________
'57 oval window deluxe,Agave green(L240) 2276cc w/51.5 IDA's
'57 type 2 panel ( L31 dove blue) project daily driver,Singleport 1955cc
'69 Squareback (L30A Royal Red) |
|
| Back to top |
|
|
|
