Greetings everyone, been a long time lurker and definitely learned a lot from this forum. I'm finally getting a 2009 Lexus IS250 as a project car. My initial plan is to either turbo or supercharge the 4GR-FSE, but a new opportunity arises. A friend who works in a salvage yard recently received a totaled LS460 with extensive rear damage (heard the owner spun and hit a tree but thankfully no serious injuries). The front half however is mostly intact, I have an opportunity to buy the entire front half (the LS is literally cut in half now) including the engine 1UR-FSE, 8 speed AA80E transmission, all the auxiliary (alternator, AC compressor etc), the ECU and all the harness.

I'm really tempted by this opportunity to build a poor man's IS-F.
Following are some of my thoughts and doubts :
- IS-F has a 2UR and 8 speed trans, I'd assume the engine bay and trans tunnel should have enough space to fit 1UR and its trans?
- modifications needed for engine and trans mount?
- need any modifications to the subframe? or maybe steering rack?
- IS250 rear diff probably can't survive the torque long term?
- IS350 rear diff is the easiest swap? noticed its a popular mod for LS460 guys
- do IS350 and LS460 share the same driveshaft flange?
- fueling system upgrade? high flow in-tank pump?

My biggest question
- does any of the LS460 harness works / compatible with IS250?
- for example the gear shifter? the instrument cluster? A/C systems?
- I'd try to avoid splicing and messing with the original harness (either of the car or the engine side) unless absolutely necessary.

I noticed 1UR isn't nearly as popular swap for IS250 as UZ swaps, mostly because of the electronics and the 1UR being a lot more sophisticated. So do you guys think its a possible swap? Would the complete harness and electronics from the donor car help? Or should I just stick to the 4GR? Thanks in advance, cheers!

 

What you're thinking of doing is a rich mans build it will cost you 3x more to do it than simply buying a car with a 1UR. I've been involved in a few 1UZ swaps into Nissan's that is a highly challenging project and the wiring is not near as complex. You won't be dragging the LS harness into your car intact you'll need to break down multiple harnesses and wire up custom.

 

Well, the whole front half of the LS460 is only costing me roughly US$2,000, the engine still starts, even the satnav radio system is still working (turn on at least). So I'm wondering if the harness is compatible with IS250. The 1UR, the trans, ECU, TCU, all the auxiliary is getting transplanted into the IS250. My thoughts is incase this wiring loom wouldn't work. I don't mind frankensteining the interior with LS460's center console / shifter. But that would be undesired as I rather keep the interior stock.

 

For more context, this is what I meant by I have the opportunity to buy the front half of the car. It literally is front half of the car, engine, transmission, interior, suspension, brakes. This is why it is such a tempting project for me. All these for roughly US$2000

 

You seemed convinced this is possible so go for it.

 

I'm not convinced, hence my questions and doubts above. Would definitely love to hear some more input from people with more experience with IS platform. I understand your reasoning, especially when I intend to keep most of the creature comfort. Appreciate your input, but would definitely like to hear more than "its a rich man build", I mean isn't being a car guy an expensive hobby anyway?

 

I'm not sure you're gonna get any better feedback here in the 1st gen IS300 (2001-2005) section. Good luck though!

 

You are in the wrong forum, but a 1UR + AA80e has already been swapped into an IS250, seems pretty straightforward and not much modification is needed if you have everything for the swap. https://www.clublexus.com/forums/gs-...wrong-way.html

IS350 diff is way to aggressive for the 8 speed, you'll end up with major traction issues.

You'll only need to upgrade fuel pump if you want to run E85.