Go Back   EcoModder Forum > EcoModding > Success Stories
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 01-04-2016, 06:32 PM   #1 (permalink)
MPGuino Supporter
 
t vago's Avatar
 
Join Date: Oct 2010
Location: Cedar Rapids, IA
Posts: 1,766

The Karen-Mobile - '05 Dodge Magnum SXT
Team Dodge
90 day: 26.72 mpg (US)

Fiat Dakota - '00 Dodge Dakota SLT RWD Quad Cab
90 day: 16.67 mpg (US)

The Red Sled - '01 Dodge Durango SLT 4WD
90 day: 16.96 mpg (US)
Thanks: 799
Thanked 681 Times in 437 Posts
2005 Dodge Magnum SXT - Auto>Manual Conversion- 10.3% decrease in fuel consumption

This past March, my Dodge Magnum decided to shred apart its 4-speed automatic transmission. Shortly afterward, I decided to swap the 4-speed out for a 6-speed NSG370 transmission. I placed the Magnum back on the road with the new transmission this past October, and start gathering fuel consumption data for it in November.

2015 (with 6-speed NSG370)
DateOdometer (mi)Fuel (gal)FE (US)FE (L/100)
11/09/2015 19:56350.615.44322.710.4
11/20/2015 16:39353.614.45524.49.6
12/07/2015 08:04364.915.71923.210.1
12/17/2015 19:35380.115.47924.69.6
Total:1449.261.09623.79.9


2014 (with 4-speed 42RLE)
DateOdometer (mi)Fuel (gal)FE (US)FE (L/100)
11/10/2014 00:00342.215.12222.610.4
11/20/2014 18:48277.913.47020.611.4
12/05/2014 17:14284.014.15420.111.7
12/15/2014 18:26313.814.50121.610.9
Total:1217.957.24721.311.1


Note: I also changed the rear end from 3.636 to 2.87, in order to compensate for the top gear change from 0.69 (42RLE, 4th) to 0.84 (NSG370, 6th). However, the resultant decrease in engine speed from this swap (about 3.9%) cannot account for the 10.1% decrease in fuel consumption.

__________________
The Fiat Dakota


The Karen-mobile


The Red Sled

Last edited by t vago; 01-05-2016 at 09:14 AM..
  Reply With Quote
The Following 11 Users Say Thank You to t vago For This Useful Post:
Fat Charlie (01-06-2016), fusion210 (01-05-2016), JRMichler (01-06-2016), ksa8907 (01-04-2016), mcrews (01-06-2016), Piwoslaw (01-05-2016), rumdog (01-04-2016), RustyLugNut (01-07-2016), sendler (02-04-2016), UltArc (04-18-2016), Xist (02-04-2016)
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 01-04-2016, 08:21 PM   #2 (permalink)
Master EcoModder
 
Join Date: May 2012
Location: Indiana
Posts: 1,530

Volt, gas only - '12 Chevrolet Volt Premium
90 day: 38.02 mpg (US)

Volt, electric only - '12 Chevrolet Volt Premium
90 day: 132.26 mpg (US)

Yukon Denali Hybrid - '12 GMC Yukon Denali Hybrid
90 day: 21.48 mpg (US)
Thanks: 164
Thanked 333 Times in 232 Posts
I read the title and thought you started using MORE fuel, glad i was wrong! contrats! I'm a bit jealous, i always wanted to drive a chrysler 3.5 with a manual trans.

what are the rpms at 60?
__________________




  Reply With Quote
The Following User Says Thank You to ksa8907 For This Useful Post:
t vago (01-05-2016)
Old 01-05-2016, 12:31 AM   #3 (permalink)
MPGuino Supporter
 
t vago's Avatar
 
Join Date: Oct 2010
Location: Cedar Rapids, IA
Posts: 1,766

The Karen-Mobile - '05 Dodge Magnum SXT
Team Dodge
90 day: 26.72 mpg (US)

Fiat Dakota - '00 Dodge Dakota SLT RWD Quad Cab
90 day: 16.67 mpg (US)

The Red Sled - '01 Dodge Durango SLT 4WD
90 day: 16.96 mpg (US)
Thanks: 799
Thanked 681 Times in 437 Posts
Quote:
Originally Posted by ksa8907 View Post
I read the title and thought you started using MORE fuel, glad i was wrong! contrats! I'm a bit jealous, i always wanted to drive a chrysler 3.5 with a manual trans.
Thanks! These 3.5L engines do seem to like being harnessed to a manual very much. Automatic transmission really sap a lot of power.

Quote:
Originally Posted by ksa8907 View Post
what are the rpms at 60?
About 1780 RPM. I also had to change out the rear diff. It was a 3.64 ratio, now it's a 2.87 ratio.

Here's a short vid, using Torque Pro and Track Recorder, shortly after I returned the Karen-mobile back to the road.

__________________
The Fiat Dakota


The Karen-mobile


The Red Sled
  Reply With Quote
Old 01-05-2016, 12:55 AM   #4 (permalink)
Master EcoModder
 
mcrews's Avatar
 
Join Date: Oct 2009
Location: Texas
Posts: 3,523

The Q Sold - '02 Infiniti Q45 Sport
90 day: 23.08 mpg (US)

blackie - '14 nissan altima sv
Thanks: 2,203
Thanked 659 Times in 474 Posts
....so h0w do you know it WASNT the rear gear change that improved the mileage.....and why not include that info in the first post......
__________________
MetroMPG: "Get the MPG gauge - it turns driving into a fuel & money saving game."

ECO MODS PERFORMED:
First: ScangaugeII
http://ecomodder.com/forum/showthrea...eii-23306.html

Second: Grille Block
http://ecomodder.com/forum/showthrea...e-10912-2.html

Third: Full underbelly pan
http://ecomodder.com/forum/showthrea...q45-11402.html

Fourth: rear skirts and 30.4mpg on trip!
http://ecomodder.com/forum/showthrea...tml#post247938
  Reply With Quote
Old 01-05-2016, 09:08 AM   #5 (permalink)
MPGuino Supporter
 
t vago's Avatar
 
Join Date: Oct 2010
Location: Cedar Rapids, IA
Posts: 1,766

The Karen-Mobile - '05 Dodge Magnum SXT
Team Dodge
90 day: 26.72 mpg (US)

Fiat Dakota - '00 Dodge Dakota SLT RWD Quad Cab
90 day: 16.67 mpg (US)

The Red Sled - '01 Dodge Durango SLT 4WD
90 day: 16.96 mpg (US)
Thanks: 799
Thanked 681 Times in 437 Posts
Quote:
Originally Posted by mcrews View Post
....so h0w do you know it WASNT the rear gear change that improved the mileage....
Fair question.

Top gear on the dead 42RLE had a ratio of 0.69. Top gear on the replacement NSG370 has a ratio of 0.84. This represents about a 21.7% increase in propshaft rotation speed, for a given vehicle speed. If I were to have left the original 3.636 rear end in place, that should have resulted in a definite increase in fuel consumption.

The FDR was 3.636, while it is now 2.87. This represents about a 21.1% decrease in required pinion input speed, for a given vehicle speed.

These two changes almost cancel each other out, and the net decrease in engine speed (about 3.9%) does not account for the 10.1% decrease in fuel consumption.

Put it another way - Engine speed at 60 MPH was about 1850. Now, it's about 1780. There is no way that this change in engine speed (~3.9%), by itself, would have resulted in the measured decrease in fuel consumption.

Quote:
Originally Posted by mcrews View Post
.and why not include that info in the first post......
Because I forgot? I only regarded the rear end swap as a necessary adjustment to counter the larger top gear ratio of the installed NSG370, nothing more. I figured that the 3.9% drop in engine speed that I calculated back in April of last year, would have given me a very modest 2% decrease in fuel consumption. This is based on the rule of thumb that a percent change in fuel consumption will be about half the percent change in the rear end ratio. The 2% change would have been rather hard to measure as it is just above noise.

You do bring up an interesting idea - What if I had left the original 3.636 rear end in place? Engine speed would have been about 2250 RPM at 60 MPH, which would have resulted in a net increase in engine speed of... 21.7% from when the 4-speed was still installed. I would have expected a 10.9% increase in fuel consumption just from swapping in the NSG370, if I were to have treated the engine speed increase as a result of swapping in a (nonexistent) 4.43 rear end.
__________________
The Fiat Dakota


The Karen-mobile


The Red Sled

Last edited by t vago; 01-05-2016 at 01:47 PM.. Reason: clarification
  Reply With Quote
The Following 3 Users Say Thank You to t vago For This Useful Post:
mcrews (01-06-2016), UltArc (04-18-2016), Xist (02-04-2016)
Old 01-05-2016, 10:44 AM   #6 (permalink)
Administrator
 
Daox's Avatar
 
Join Date: Dec 2007
Location: Germantown, WI
Posts: 11,035

CM400E - '81 Honda CM400E
90 day: 58.68 mpg (US)

Daox's Grey Prius - '04 Toyota Prius
Team Toyota
90 day: 49.53 mpg (US)

Daox's Insight - '00 Honda Insight
90 day: 64.33 mpg (US)

Swarthy - '14 Mitsubishi Mirage DE
Mitsubishi
90 day: 56.69 mpg (US)
Thanks: 2,368
Thanked 2,432 Times in 1,468 Posts
Nice mod. I bet its a lot more fun to drive now too.
__________________
Current project: Adding regenerative braking to the Mirage
  Reply With Quote
The Following User Says Thank You to Daox For This Useful Post:
t vago (01-06-2016)
Old 01-05-2016, 01:54 PM   #7 (permalink)
MPGuino Supporter
 
t vago's Avatar
 
Join Date: Oct 2010
Location: Cedar Rapids, IA
Posts: 1,766

The Karen-Mobile - '05 Dodge Magnum SXT
Team Dodge
90 day: 26.72 mpg (US)

Fiat Dakota - '00 Dodge Dakota SLT RWD Quad Cab
90 day: 16.67 mpg (US)

The Red Sled - '01 Dodge Durango SLT 4WD
90 day: 16.96 mpg (US)
Thanks: 799
Thanked 681 Times in 437 Posts
Quote:
Originally Posted by Daox View Post
Nice mod. I bet its a lot more fun to drive now too.
Oh, yah! I like to think that the Karen-mobile now has performance that approaches the available 5.7L V8, while having fuel economy that approaches the available 2.7L V6.

Shortly after I placed the Karen-mobile back on the road, I accidentally gave too much gas when starting in 1st from a dead stop. I left a nice, pretty black tire stripe for about 20 feet on dry pavement. Obviously, not good for either tire life or fuel economy. I shudder to think what would have happened, had I left that 3.636 diff in.
__________________
The Fiat Dakota


The Karen-mobile


The Red Sled
  Reply With Quote
Old 01-05-2016, 10:36 PM   #8 (permalink)
It's all about Diesel
 
cRiPpLe_rOoStEr's Avatar
 
Join Date: Oct 2012
Location: Porto Alegre, Rio Grande do Sul, Brazil
Posts: 7,456
Thanks: 0
Thanked 767 Times in 677 Posts
The lower weight of a manual transmission and the absence of the torque converter slip should be taken into account for the final results, but what about the gear spread of the 4-speed automatic and this 6-speed manual? Is it the same transmission used in the Wrangler and the Sprinter, right?
  Reply With Quote
Old 01-06-2016, 12:01 AM   #9 (permalink)
Master EcoModder
 
Join Date: May 2012
Location: Indiana
Posts: 1,530

Volt, gas only - '12 Chevrolet Volt Premium
90 day: 38.02 mpg (US)

Volt, electric only - '12 Chevrolet Volt Premium
90 day: 132.26 mpg (US)

Yukon Denali Hybrid - '12 GMC Yukon Denali Hybrid
90 day: 21.48 mpg (US)
Thanks: 164
Thanked 333 Times in 232 Posts
The 42le and 42rle were really just a modern take on much older transmission design. The increase is probably a result of no converter slip when accelerating, no pumping fliud, etc. Plus now you're essentially doing mini pulse and glides whule shifting.
__________________




  Reply With Quote
Old 01-06-2016, 02:01 AM   #10 (permalink)
MPGuino Supporter
 
t vago's Avatar
 
Join Date: Oct 2010
Location: Cedar Rapids, IA
Posts: 1,766

The Karen-Mobile - '05 Dodge Magnum SXT
Team Dodge
90 day: 26.72 mpg (US)

Fiat Dakota - '00 Dodge Dakota SLT RWD Quad Cab
90 day: 16.67 mpg (US)

The Red Sled - '01 Dodge Durango SLT 4WD
90 day: 16.96 mpg (US)
Thanks: 799
Thanked 681 Times in 437 Posts
Quote:
Originally Posted by cRiPpLe_rOoStEr View Post
The lower weight of a manual transmission and the absence of the torque converter slip should be taken into account for the final results, but what about the gear spread of the 4-speed automatic and this 6-speed manual? Is it the same transmission used in the Wrangler and the Sprinter, right?
The Jeep Wrangler used this transmission on the 3.8L V6 engine (which was what made this swap possible - the 3.5L and the 3.8L V6 bellhousing bolt patterns are nearly identical). The Chrysler Crossfire also used this transmission, but with a radically different bellhousing bolt pattern.

42RLE gears
1st2.80
2nd1.55
3rd1.00
4th0.69


NSG370 gears
1st4.46
2nd2.61
3rd1.72
4th1.25
5th1.00
6th0.84


The gearing appears to be more closely spaced together on the 6-speed. That would help with fuel economy during acceleration, particularly with city driving.

I think that the two largest power drains were torque converter slippage and pumping losses through the transmission oil pump.

Not sure if transmission weight itself would have played much of a part. I lost maybe 50 lbs or so from the swap.

Quote:
Originally Posted by ksa8907 View Post
Plus now you're essentially doing mini pulse and glides whule shifting.
Heh, that's true, too.

__________________
The Fiat Dakota


The Karen-mobile


The Red Sled
  Reply With Quote
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com