4th Gen Ram Tech 2009 - 2018 Rams and the 2019 Ram Classic: This section is for TECHNICAL discussions only, that involve the 2009 - 2018 Rams and the 2019 Ram Classic. For any non-tech discussions, please direct your attention to the "General discussion/NON-tech" sub sections.

How many RPM's at 70 w/ 4:10's and factory 20's?

Old May 28, 2009 | 09:49 PM
  #1  
dpracing57's Avatar
dpracing57
Thread Starter
|
Registered User
Joined: Mar 2009
Posts: 23
Likes: 0
Default How many RPM's at 70 w/ 4:10's and factory 20's?

Just curious............I just received my 4:10's gonna put em in soon.

Thanks!
 
Reply
Old May 28, 2009 | 09:51 PM
  #2  
switchblade906's Avatar
switchblade906
Record Breaker
Joined: Mar 2009
Posts: 1,250
Likes: 0
From: Apopka FL
Default

well when you put them in and get to cruse at 70 let me know cause im going to be getting them soon
 
Reply
Old May 28, 2009 | 09:54 PM
  #3  
dpracing57's Avatar
dpracing57
Thread Starter
|
Registered User
Joined: Mar 2009
Posts: 23
Likes: 0
Default

Originally Posted by switchblade906
well when you put them in and get to cruse at 70 let me know cause im going to be getting them soon
You got it!

But hopefully someone will chime in, forgot his name but he has 4:10's w/ factory 20's.
 
Reply
Old May 28, 2009 | 09:56 PM
  #4  
switchblade906's Avatar
switchblade906
Record Breaker
Joined: Mar 2009
Posts: 1,250
Likes: 0
From: Apopka FL
Default

it was bountyhunter but he was recently banned, no more info or pictures from him (thank god)
 
Reply
Old May 29, 2009 | 12:23 AM
  #5  
72combo's Avatar
72combo
Champion
Joined: Dec 2007
Posts: 3,563
Likes: 0
From: Ontario, Canada
Default

This is not what you are asking but my 3 55's put me around a hair under 1500 at 60mph
 
Reply
Old May 29, 2009 | 01:07 AM
  #6  
bigred3297's Avatar
bigred3297
Record Breaker
Joined: Jan 2009
Posts: 1,149
Likes: 1
From: Hawaii
Default

Originally Posted by dpracing57
Just curious............I just received my 4:10's gonna put em in soon.

Thanks!

http://www.4wheelparts.com/aux_incl/gear_ratio.html
 
Reply
Old May 29, 2009 | 07:51 AM
  #7  
switchblade906's Avatar
switchblade906
Record Breaker
Joined: Mar 2009
Posts: 1,250
Likes: 0
From: Apopka FL
Default

ok so i was doing the math to figure this out for you.

in my truck with 3.55's doing 65 MPH the chart says i would be doing 2349 RPM obviously thats not the case so if you minus that by 32% it will give you the right rpm's

2349 - 32% = 1597.32 RPM

so then if you move to the 4.11's it says you will be running 2720 RPM so again minus that by 32 %

2720 - 32% = 1849.6 RPM

so thats about what you should be running at 65 MPH
 
Reply
Old May 29, 2009 | 08:48 AM
  #8  
blue2050's Avatar
blue2050
Veteran
Joined: Dec 2006
Posts: 253
Likes: 1
Default

(5)45RFE
1 3.0:1
2 1.67:1
2P 1.5:1
3 1.0:1
4 0.75:1
5 0.67:1 (545RFE only)
R 3.0:1

There are the numbers for the tranny.
Here is another calculator.
http://www.angelfire.com/fl/procrastination/rear.html
Calculates mine to 1800. In the real world my truck with 3:92's turns 2000 or so..analog... at 70 mph.
I will aslo say I am taking mine in soon for a tranny check. 3:55 I drove had much more get up than this 3:92.
I wish Dodge has not dropped the Getrag 238 6 speed auto that was initially planned for the 2009.
 

Last edited by blue2050; May 29, 2009 at 09:23 AM.
Reply
Old May 29, 2009 | 03:28 PM
  #9  
turk1270's Avatar
turk1270
Veteran
Joined: Mar 2009
Posts: 265
Likes: 0
From: new jersey
Default

4.10s should put you around 2000-2100 rpm @ 70mph with the factory 20s
 
Reply
Old May 29, 2009 | 03:55 PM
  #10  
Mopar21277's Avatar
Mopar21277
Rookie
Joined: Mar 2009
Posts: 69
Likes: 0
From: Upstate NY
Default

Originally Posted by blue2050
(5)45RFE
1 3.0:1
2 1.67:1
2P 1.5:1
3 1.0:1
4 0.75:1
5 0.67:1 (545RFE only)
R 3.0:1

There are the numbers for the tranny.
Here is another calculator.
http://www.angelfire.com/fl/procrastination/rear.html
Calculates mine to 1800. In the real world my truck with 3:92's turns 2000 or so..analog... at 70 mph.
I will aslo say I am taking mine in soon for a tranny check. 3:55 I drove had much more get up than this 3:92.
I wish Dodge has not dropped the Getrag 238 6 speed auto that was initially planned for the 2009.

Wasn't the Getrag 238 a 6 speed manual that was on the 4.7's pre '09? A friend has that setup and it is sweet; boy do I miss my old handshaker in a Dakota...

Speaking of 6 speed autos, this is where Dodge is really lacking IMO. The Ford 6 speed ala F150 is one sweet piece; it is really nice having that extra gear before your double O/D. After putting 2500 miles on a Rental Expedition in the Rockies with the 6 speed, I'm seriously considering the F150
 
Reply

Thread Tools
Search this Thread

All times are GMT -4. The time now is 10:08 AM.