I've learned recently that the 1GZ-FE's crossmember is the same as the 1UZ's and got the idea to try to swap a 1GZ to my 1998 LS400. I'm wondering if anyone has any ideas on what the problems are that i may run into, so i can get ahead of them, i've put about a month and a half of research in so far, but i'm just trying to hit all the bases before i start to minimize complications lol, Thanks all.

 

well i'm very interested to see what happens with this! sadly i can't be of any help, nor have i ever seen this done so i'm not sure who could be of help lol

the only other 1GZ swap i know of was of course done my my all time favorite tuner Smokey Nagata, and that was into a MK IV Supra, and that worked well considering the GZ is basically just two JZs on a common crankshaft... the LS was never designed to accommodate an inline-6 since the 1UZ was the only engine ever considered, i feel like this project might be easier with a GS or an IS, and i'd check lextreme.com if you haven't already

 

interested as well, but this is uncharted territory (for the most part to an LS400). there are a slew of considerations i can think of that need to be covered:​​​​​​
- mounting: sure the subframe is the same, but is the tunnel the same? nothing a little hammering can't fix? what about the transmission mount?
- driveline: will the 1UZ trans mate to the 1GZ? sounds like it might! if not then will the 1GZ trans fit? then you have the driveshaft.
- wiring: likely will need some re-mapping and ECU conversion, hopefully the engine set will come with the ECU and associated harness but it won't be plug and play since the 1UZ is mainly for RHD.
- misc: intake, exhaust, power steering, hvac, etc...all minor in the grand scheme of things but just a consideration if you want them to function.

it's not an impossible task, and sounds fun to figure out, but my time is better spent just buying a toyota century with the v12 already in place.

 

All of you raise really important, creative and descriptive objections

But...

Independent throttle bodies


This put in in a Soobie, mated it to a dual clutch and twin snails (this is unbelievable)

 

i've seen that ITB video before but never this subaru! that's an awesome build! a subaru with a toyota engine and BMW transmission lol

but if i got my hands on a 1GZ i'd be most interested in fitting it with a custom exhaust by Mr. Sasaki of Brilliant Exhaust

 

Ahhhhhhhh yes the W140 treatment

(W140 is a v12 S-class, and the engine which goes in... answer on your postcard... that's right! It goes in the Zonda. And so people like to straight pipe those old Merc's just like that video you posted)

 

I’ve made a post there too, about to check it, and I chose the LS because I don’t want to have to change up tooo much to mount it and it’s already got the same mounting points. I’m definitely going to update here when the project gets going.

 

Best part of the deal for me with this is that I have someone ready to sell me engine, along with the trans, ECUs, and power steering pump all from the 1GZ. It’s mostly the problem of getting all to fit, the drivetrain and the wiring like you mentioned that I have to sort out, I also have a nice shop to work in with my buddies, but none of us are experienced in tuning so we’re going to have to outsource that lol.

 

that M120 V12 is probably the last hurrah of the proper old school benz over-engineering, basically everything after is a product of jurgen schrempp's MBA style mercedes lol... the previous CEO edzard reuter is a genuine mathematician/physicist and you can tell from what mercedes was doing in the 80s to early 90s that building the best possible car was still the top priority

also just straight piping the engine won't make Zonda sounds, the key to everything is using special 6 to 1 equal-length headers!



i can't exactly explain why but before combining into one, the length between all 6 exhaust ports and the main piping just after the manifold needs to be the same, otherwise no F1 scream... maybe something to do with the harmonics all merging into a single frequency

the GZ in that century also has special equal length headers fitted

 

I’ve been planning this swap since February of 2022. I’ll be sure to share updates and issues I run into as well