LS Swap Driveshaft Lengths

[cdsurf]

Question to all the guys who've done "LS" swaps or to any of the other xj savants:


I have a 4L80e, NP231J, and JB Conversions Shorty SYE on my XJ. It's an '01 which originally had the AW4 and 8.25.



The length I'm measuring for the rear driveshaft is kinda tripping an alarm in my head. Everything I've read would imply that the new one would be shorter and angles would be steeper, yet my two yokes almost look like they're pointing at each other and the yoke to yoke distance is significantly longer than I expected at 34.75".



I'm trying to think if it was the old tailhousing that was so long but between the longer trans, the novak adapter, and JB Conversions SYE (~ +1", +2", -4" respectively) I don't understand how I'm getting almost 7" more. The only thing I can think of is the LS' shorter length to the 4.0 means the trans might be further forward naturally, but it's a little too late to measure that. :roflmao:


Any help/sanity check would be welcomed. Thanks.

 

[RCP Phx]

I don't find that length odd at all. The 4.0 is longer, the AW4 shorter and with the std hd sye I run a 33 1/2" inch drive shaft.

 

[cdsurf]

I don't find that length odd at all. The 4.0 is longer, the AW4 shorter and with the std hd sye I run a 33 1/2" inch drive shaft.

Sweet. I just wanted to know that I wasn't losing it. Thank you.


Now just to call Adams or Tattons tomorrow morning and place my order.

 

[KarmaKannon]

Sweet. I just wanted to know that I wasn't losing it. Thank you.


Now just to call Adams or Tattons tomorrow morning and place my order.

Do you have a build thread? I'd love the motivation.

 

[Skruffy]

I did an ls swap with a 6L80e and a different suspension, but the effect was similar. My rear shaft needed to be longer by a couple inches and the front shaft needed to be shorter.
Details can be seen on the build thread. Search “skruffy supercharged LS3 Crammed in an XJ “ if your interested.

That LS is way shorter, even with the six speed and a transmission to transfer case adapter (Novak) everything was still forward a couple inches.

Have fun with all that engine man. You won’t regret it.

 

[cdsurf]

Do you have a build thread? I'd love the motivation.

No build thread. . .yet. I was hoping to be completely done before doing one but I've been documenting it in the mean time.

 

[cdsurf]

I did an ls swap with a 6L80e and a different suspension, but the effect was similar. My rear shaft needed to be longer by a couple inches and the front shaft needed to be shorter.
Details can be seen on the build thread. Search “skruffy supercharged LS3 Crammed in an XJ “ if your interested.

That LS is way shorter, even with the six speed and a transmission to transfer case adapter (Novak) everything was still forward a couple inches.

Have fun with all that engine man. You won’t regret it.

Oh I def went through your thread (and everyone else's) to get an idea of the hellish parts of this swap. For example, I regret not following Clydefrog's lead on wiring because figuring out the Jeep's harness and what to cut/keep was a pain and it would have saved me time to just rewire everything.

The big thing hanging over my head is currently the exhaust. I'm ordering a kit from Summit or Jegs and hopefully I'll be able to get that ready for welding over the next week or so. The difference between mine and yours is that it looks like the driver's side will be easy on mine and the passengers side will be TIGHT. Why Novak went flange instead of v-band in such a tight package, I'll never know.

 

[Skruffy]

If your not concerned with emissions that will simplify the exhaust. If you need pass CA emissions, and actually do it, you are a real champ and inspiration for the rest of us.
Did you retain your AC? What about your gauges? Do they all work? That was the hard part for me.

 

[cdsurf]

If your not concerned with emissions that will simplify the exhaust. If you need pass CA emissions, and actually do it, you are a real champ and inspiration for the rest of us.
Did you retain your AC? What about your gauges? Do they all work? That was the hard part for me.

The emissions is a complicsted one. I have to retain some stuff but my state isn't anywhere near as bad as Cali so not all things and cats for example don't have to be in stock location.

For gauges, I'm undecided between Autometer Invision, Dakota Digital HDX, or going the cheaper and easier to integrate route with Intelliteonix. I'm going to roll with some cheapo OBD2 display in the meantime while I decide because even my harness is temporary. I bought something cheap to just get me going because the lead times at all the top places were ungodly long (2-6 months depending on the company). I'll be able to use it as a template after to give build instructions to whoever I go with (leaning towards either BP Automotive or PSI).

 

[cdsurf]

Tapatalk won't let me edit. For AC, I'm going to just run my own system using Vintage Air's dryer with trinary switch. I can't do PCM controlled unfortunately because of the capabilities of my pcm.

 

[Skruffy]

The gauge integration was a bear for sure. I kept the XJ cluster and made it work but there has to be an easier option.
Hard wiring the ac is probably a good call since almost everybody ends up doing that anyway.
What engine did you get? The LS3 is overkill for sure. Fun, but unnecessary.

 

[cdsurf]

The gauge integration was a bear for sure. I kept the XJ cluster and made it work but there has to be an easier option.
Hard wiring the ac is probably a good call since almost everybody ends up doing that anyway.
What engine did you get? The LS3 is overkill for sure. Fun, but unnecessary.

Seeing people go nuts with the gauge integration was a massive turn off for me. I had two options, go Novak but have to keep the Jeep PCM + pay like $800 for them to do the harness or get rid of all of it and buy something like the Autometer LCD dash at the same price. I'm just waiting until my next few days off so that I can 3D print a test dummy for fitting. I like the Dakota Digital for the greater integration (really wish they did an LCD cluster) but for the price the Autometer seems to be the goldilocks option. I'll decide after I'm able to daily it for a bit. The longer it's not running, the longer my summer activities are on pause so I'm in a "get it running now, we'll make things pretty later" mindset.




I have an LQ4 from the junkyard. I rebuilt it, put in a mild cam, LS6 intake, and mated it to a 4L80e. I'd have liked to go LS3 but those are worth more than gold where I am. If I was starting over I'd probably go L83/86 with a 6L80. The prices are actually not bad on those and I'd just skip the rebuild. It would cost a bit more but you can't escape the Aluminum tax. In terms of practicality ANYTHING with some grunt will do in the Jeep so outside of just being a fun exercise, it ultimately doesn't matter.




For the AC, if I had a year earlier PCM it would have possible.





One thing I'm a fan of is your pedal mounting. I might actually try to find another truck pedal and give your idea a go.




How many miles have you put on your swap btw?

 

[Skruffy]

I was under the impression that I had to use the pedal from the donor car or the throttle percentages would be all over the place since the ecu and pedal are calibrated to each other. The camaro pedal has a better weight to it anyway.


I only have about 500 miles in the swap. Just about the time it was safe in the highway (sway bar repaired) I left for an overseas deployment. I haven’t driven it since March! My wife took the kids to school in it once and scared herself so now she won’t go near it. Overall an intensely satisfying project.