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Discussion Starter #1 (Edited)
Well we finally got the build done that my other half posted about some time back. Our 5.7l Commander spit a rod out of the side of the block for no apparent reason with 47,000 miles on the clock.

Blown engine pics in this thread:
http://www.jeepcommander.com/forums/showthread.php?t=17575


Not being one to settle on mediocrity we decided that if were spending money we might as well do what we always joked about and make a "srt" commander. I started making calls to junkyards and experts to get the scoop on the strength of the stock drivetrain and compatibility. Found out the swap is DAMN easy, with the exception of the fitment of the jeep srt8 mani's take a little work.

Found a motor at a salvage yard in texas, supposedly a stock SRT-8 Motor out of a wrecked charger.

Salvage yard sent us a supposedly stock motor, but after it came the aftermarket fuel rail, big injectors, and ARP main side bolts made it obvious it was not stock.

Wiseco 9.3:1 pistons, K1 H Beam Rods, ARP2000 Fasteners, Ported Heads, Stock 6.1 cam, and a keyed crank made the blower it used to have obvious. Looks brand new, I would wager someone got into it after spending a lot of money and lost it into a wall.

The jeep already has a janky fabbed up abs pipe intake, the srt8 exhuast manifolds were squeezed in there, the cats were ditched and a dual 2.5 inch Y to single 3" catback with a single 14" magnaflow muffler was used. A 180* thermostat was used as it gets HOT out here in AZ.

Rob Wetzel from Fit Fabrication who is almost unarguably one of the best new hemi tuners in the country and definately the best in the state worked his magic with diablosports CMR software through a diablosport predator and ran it through the gamit, fuel trims are dead nuts on and wot is 12.8:1 AFR's.

Thing runs and pulls hard. Rob has turbo kits that he has made for SRT8 GC's that will bolt right on so that is in the future, should be a solid 700hp setup.


imagejpeg_2_2 by bijanmaleki, on Flickr


imagejpeg_2 by bijanmaleki, on Flickr


imagejpeg_2_3 by bijanmaleki, on Flickr


IMAG0277 by bijanmaleki, on Flickr


imagejpeg_2_4 by bijanmaleki, on Flickr
 

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So when it's all said and done whats the ballpark how much it took?
 

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lol Im realistic Im saying if he can get a cheap mercedees to put in there that may be better in the long run. I will say your xk hauls butt though! ;)
I have a Mercedes mechanic in the family that has discussed a worked up G-wagon that would do beautiful four wheel burnouts. Keep in mind these things weigh over 6000 pounds and have lockers front and rear.

Long story short.... he eventually got rid of it because it was always having tranny and driveline issues.

I doubt Mercedes has a bigger tranny than would be used in a high powered G-wagon, so that may not be the best direction to head........
 

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Yes I was saying to just get the stock mercedees tranny thats in the grand cherokee srt8 because that can take the power of the 6.1
According to http://wkjeeps.com/wk_srt8_specs.htm, the SRT-8 uses the W5A580 tranny........

Which according to http://www.xkjeeps.com/xk_specs.htm, is the same one used in 3.7 xk's

My guess is this has to do with the lower, more aggressive gearing in the W5A580 as appose to the 545RFE used in the 5.7 commanders and nothing to do with strength.

The same lower gearing that helps make the 3.7 manageable in such a heavy vehicle also gives the SRT-8 that extra oomph for 0-60 and 1/4 mile times.
 

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So when it's all said and done whats the ballpark how much it took?
$8k


The trans is a possibility yeah. Until it goes though I'm not going to worry about it haha.
 

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Jealous!! Does the QD2 and everything else still work? Did you lose functionality on anything?
Yep, QD2 still works! I lost no functionality except for displacement on demand, which I wanted to lose anyway. I'm really happy with everything. Mander rolled over 50k yesterday, bittersweet moment. Owned it since brand new, replaced almost everything at this point except the transmission... If my Corvette pulled this kind of crap on me it would be sold, but Mander... never letting go! :roller:
 

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Discussion Starter #16
The 545rfe has proven itself in several high performance applications enough to the point where I might question the NAG1's strength in comparison. Regardless line pressure has been jacked and I have rarely seen on road failure of hard parts of the rfe, usually just burnt clutches and bands. When it goes, it will be built with all the good stuff as a NAG1 will not communicate with the commanders TCM and I am not aware of a way to make it work as of now with the transfer case although I am sure there is a way. My tuner said he has several 500whp trucks running around on the stock trans without issue.
 

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According to http://wkjeeps.com/wk_srt8_specs.htm, the SRT-8 uses the W5A580 tranny........

Which according to http://www.xkjeeps.com/xk_specs.htm, is the same one used in 3.7 xk's

My guess is this has to do with the lower, more aggressive gearing in the W5A580 as appose to the 545RFE used in the 5.7 commanders and nothing to do with strength.

The same lower gearing that helps make the 3.7 manageable in such a heavy vehicle also gives the SRT-8 that extra oomph for 0-60 and 1/4 mile times.
So, I'm in the running for a truck and ran across this thread. Basically, based on my research, i could purchase a v6 Commander with the W5A580 (NAG1) and drop in the 6.1 along with:
  • GC SRT8 wiring harness (is this actually needed??)
  • nv146 transfer case
  • nv146 transfer case control unit and corresponding wire harness
Is this correct, or am I missing something? If thats the case, a used v6 4x4 Commander runs about $7k + the SRT motor ~ $6k.

Or, I could just get the 5.7 Hemi and and throw heads, cam, and throttle body which adds ~ 100 hp. Which is better?
 

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So, I'm in the running for a truck and ran across this thread. Basically, based on my research, i could purchase a v6 Commander with the W5A580 (NAG1) and drop in the 6.1 along with:
  • GC SRT8 wiring harness (is this actually needed??)
  • nv146 transfer case
  • nv146 transfer case control unit and corresponding wire harness
Is this correct, or am I missing something? If thats the case, a used v6 4x4 Commander runs about $7k + the SRT motor ~ $6k.

Or, I could just get the 5.7 Hemi and and throw heads, cam, and throttle body which adds ~ 100 hp. Which is better?
The v6 and SRT 8 have a NV 140 Transfer case. Depending on what you plan on doing with it...id say just get a nice decked out hemi and do some work to the engine!
 

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The SRT8 has a NV146 is a clutch locking one speed transfercase.
 

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So I live in AZ much like yourself. I was considering doing some work to my 4.7L but not sure. Who's the guy you went to and how to find his shop? I am very impressed with the 6.1L mod! Nice work
 
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