I have a 2003 g35 vq35de automatic. I just recently got my hands on a manual vq35HR motor with trans and ecu, with only 15k miles. i was looking to build the vq35hr motor befor i put it in the g35. I wanted to know will the vq35hr motor fit in my g35, and will it be able to connect to an automatic transmission? What will i need for this swap and will the vq35hr manual work with a vq35de automatic? i need some advice 
Former G35driver Vendor
It would bolt up - HOWEVER....
The biggest issue will be wiring. You will spend $5000-10,000 just to wire the vehicle up correctly for functionality. Not worth the headache. Just sell those and build your stock motor or sell the car and buy a newer model with the HR to begin with.
The biggest issue will be wiring. You will spend $5000-10,000 just to wire the vehicle up correctly for functionality. Not worth the headache. Just sell those and build your stock motor or sell the car and buy a newer model with the HR to begin with.
Registered User
^This. It's not the 70s anymore where you can through a Rat motor into your dad's old Chevelle. There is way too much electrical wizardy going on with these cars including the ECU, drive-by-wire throttle, automatic TCM, body control module (BCM), stability control components, etc, etc. You'll be lucky to get this thing to run. You'll need the entire VQ35HR wiring harness, BCM, TCM, 07+ tranny, etc.
I'd love to see how a 350lb lighter VQ35HR equipped 03 sedan would perform, but you'd have to be a rich man to do it. It would be FAR cheaper just to add a tiny turbo and call it a day.
I'd love to see how a 350lb lighter VQ35HR equipped 03 sedan would perform, but you'd have to be a rich man to do it. It would be FAR cheaper just to add a tiny turbo and call it a day.