Go Back   Jeep Garage - Jeep Forum > Jeep Platform Discussion > Grand Cherokee SRT - WK2

Join Jeep Garage Today
Reply
 
Thread Tools Display Modes
 
  #1  
Old 12-26-2013, 04:34 PM
SRTgeek's Avatar
SRTgeek
My Jeep: 2014 6.4L SRT8 WK2
 
Join Date: Dec 2012
Posts: 690
Thanks: 460
Thanked 78 Times in 64 Posts
Rep Power: 2548556
SRTgeek has a reputation beyond reputeSRTgeek has a reputation beyond reputeSRTgeek has a reputation beyond reputeSRTgeek has a reputation beyond reputeSRTgeek has a reputation beyond reputeSRTgeek has a reputation beyond reputeSRTgeek has a reputation beyond reputeSRTgeek has a reputation beyond reputeSRTgeek has a reputation beyond reputeSRTgeek has a reputation beyond reputeSRTgeek has a reputation beyond repute
Garage
Dyno Questions

Hey Guys! Hope you all had a great Christmas!

With the SRT's putting power to all the wheels, ideally I am assuming an AWD Dyno is best. I have seen Dyno photos though of SRT's with the front tied down, just the rear being dyno'd.

umm... how does that work? Where I live there are no AWD dynos so I am wondering if there is another way to Dyno that works?

I'm somewhat ignorant on dyno technology
__________________

__________________
--------------------------------------
2014 Jeep Grand Cherokee SRT Bright White Clear Coat
2015 Dodge Challenger Hellcat (inbound)


GT Haus Meisterschaft catback exhaust | fastman 87mm throttlebody | bwoody 4" true ram air cai | bwoody sway bar links | billet tech catch can
20x10 SRT WK1 Replicas mounted on 295/45/20 BFG KDW's
Reply With Quote
  #2  
Old 12-26-2013, 06:19 PM
jim383's Avatar
Member
My Jeep: 2014 3.2L KL
 
Join Date: Mar 2013
Location: THOUSAND OAKS CA
Posts: 208
Thanks: 0
Thanked 27 Times in 25 Posts
Rep Power: 842
jim383 is on a distinguished road
Re: Dyno Questions

Quote:
Originally Posted by JDR8 View Post
Hey Guys! Hope you all had a great Christmas!

With the SRT's putting power to all the wheels, ideally I am assuming an AWD Dyno is best. I have seen Dyno photos though of SRT's with the front tied down, just the rear being dyno'd.

umm... how does that work? Where I live there are no AWD dynos so I am wondering if there is another way to Dyno that works?

I'm somewhat ignorant on dyno technology
On the 2w dynos they take out the T/CASE motor(4 bolts) and unplug it and that keeps the front wheels from turning. As far as hp i think on the 2w dyno you may put out more hp BUT i have heard guys say they put out the same BUT i have to think not turning the front wheels you would put out more hp. Go here and read this by builder bill who builds the racing t/cases. Below is a post by builder bill who builds the RACING T/CASES ON THE 5 SPEEDS BUT IT WILL GIVE YOU THE OPERATIONS OF THE TRANSFERCASE.

Ok here is our SRT Transfer case.
Many thanks to Resume Speed for helping with links etc. on this thread!
Thanks also to Blown7 for the help on loading all the photos.

Below link is a basic parts list for our Transfer case:
http://www.wkjeeps.com/misc/Tcase_2008_Parts.pdf

Below is a write up from my Shop Manual:
The NV146 transfer case provides Full-Time Active Four-Wheel Drive for optimum traction in a wide range of conditions
and is used in the Grand Cherokee SRT8 vehicles. The transfer case center differential distributes torque 48
percent to the front axle and 52 percent to the rear axle along with an electronically controlled clutch pack that is
coupled to the center differential for torque biasing. The NV146 electronics provide an active system because it can
anticipate and prevent slip. The transfer case can redistribute 100 percent of torque to the front or rear axle,
depending on need.
The NV146 single-speed transfer case provides the following benefits:
No shift lever or driver interaction required.
Full-time four-wheel drive provides smooth operation and vehicle stability under all conditions because torque
is constantly being transferred.
Even torque distribution provides traction to maintain forward motion under most conditions.
The Brake Traction Control System (BTCS) works in tandem with full-time four-wheel drive. BTCS provides
resistance to any wheel that is slipping to allow additional torque transfer to wheels with traction.
Robust design and improved sealing enhance reliability.
No maintenance required.

Controls for the NV146 transfer case active clutch (torque biasing device) are located in the Final Drive Control
Module (FDCM) and communicated on the CAN C bus. The FDCM monitors wheel speeds at the front and rear
axles to detect wheel slippage. A complete vehicle dynamics model calculates slip at each tire for given vehicleoperating
conditions. The clutch pack in the transfer case is engaged to minimize the speed difference between the
front and rear axle, resulting in torque transfer to the axle with higher traction. The electronically controlled wet clutch pack uses an electric motor to actuate a sector plate. The sector plate actuates a clutch lever that applies
normal force to the multi-disc wet clutch pack bridging the differential. The clutch discs are alternately splined to the
front and rear driveshafts. When normal force is applied to this clutch pack, torque is transferred to equalize speed
differences between front and rear axles.

Unfortunately, the shop manual just copied the text and illustrations from a similar transfer case so I was on my own as far as the dismantling and re-assembly of some components.

Basic operation as I see it:
The shift motor (which some of us unplug from time to time) rotates the shaft that has a cam attached to it. It appears that it can rotate clockwise and counter clockwise. I can see NO harm in unplugging it for the dyno etc. as the shift arm will not engage the clutch pack for the forward output shaft.
The clutch pack is engaged when the cam is rotated...could be partially engaged or fully engaged, therefore increasing the torque to the front wheels. I did note that the clutches in this transfer case which had approximately 6,000 miles (per the junk yard) looked perfect. I did notice a shiny area on the output shaft where the clutches engage though.
The chain and gears look substantial...time will tell!
The one piece output shaft also looks substantial.
One thing that I was surprised at was with the 1 piece output shaft, the torque may be distributed to the front tires (again through the clutch pack) when the rear tires spin, HOWEVER, the rear wheels will still spin the same. This does not take into account the ABS system that will apply the brakes to the spinning wheel(s).

All in all, a pretty straight forward design.
__________________

__________________
2014 JEEP CHEROKEE TRAILHAWK
Reply With Quote
The Following User Says Thank You to jim383 For This Useful Post:
  #3  
Old 12-26-2013, 06:20 PM
august77's Avatar
SRT@Brunei
My Jeep: 2014 6.4L WK2
 
Join Date: Jun 2013
Posts: 197
Thanks: 26
Thanked 17 Times in 14 Posts
Rep Power: 757
august77 is on a distinguished road
Send a message via MSN to august77 Send a message via Yahoo to august77
Re: Dyno Questions

They could have removed the front drive shafts/transfer case, to prevent the front wheels from turning.. by doing that, the Jeep will be running in RWD. You might need to set it to track mod to get the most power to the rear.
__________________
2014 (Deep Cherry Red) Jeep Grand Cherokee SRT

Mods: tchrist30 Domed Decals, BT Catch Can, Injen CAI, Black Ops CF Front Splitter..

Facebook- Augustus77,
Instagram- augustus_wong
Reply With Quote
The Following User Says Thank You to august77 For This Useful Post:
  #4  
Old 12-26-2013, 07:49 PM
august77's Avatar
SRT@Brunei
My Jeep: 2014 6.4L WK2
 
Join Date: Jun 2013
Posts: 197
Thanks: 26
Thanked 17 Times in 14 Posts
Rep Power: 757
august77 is on a distinguished road
Send a message via MSN to august77 Send a message via Yahoo to august77
Re: Dyno Questions

Something i found while googling for Jeep SRT Dyno...

SOUTHERN HOTROD JEEP Grand Cherokee SRT-8 2WD dyno instructions - Dodge SRT Forum - SRTConnection
__________________
2014 (Deep Cherry Red) Jeep Grand Cherokee SRT

Mods: tchrist30 Domed Decals, BT Catch Can, Injen CAI, Black Ops CF Front Splitter..

Facebook- Augustus77,
Instagram- augustus_wong
Reply With Quote
Reply

Thread Tools
Display Modes

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 On
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Dyno numbers avsfan13%5 Engine Performance/Intake/Exhaust 10 03-27-2013 02:59 PM
Dyno Time SweetWilliam Engine Performance/Intake/Exhaust 4 03-10-2013 09:50 PM
Dyno'd the D Newman 2011+ Dodge Durango-WD 2 08-05-2012 08:59 PM
Sleepy4.7 on the dyno again....... FlyinRyan Performance Modifications 20 05-20-2010 08:22 AM
Sleepy4.7 ON THE DYNO!!!!! FlyinRyan Performance Modifications 7 10-26-2009 06:00 PM

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 07:42 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Copyright 2012 - JeepGarage.Org
The Jeep Grand Cherokee Owners Community

JeepGarage.org is in no way associated with or endorsed by Chrysler Group LLC.