Very interesting. Now I'll have to find out about bore spacing, main journal diameters, etc. Thanks for the link!

 

The main journals on the VQ30 and the VQ35 are 60mm. The VQ20, VQ25 and VQ23 should all be the same. Only the VQ40 has larger main journals @ 70mm .

The VQ30 has 48mm rod journals and the VQ35 has 55mm rod journals. It really wouldn't matter which journal size the VQ23 has because you would either use it's matching rod set or get custom rods. That combo would also have a very high rod ratio at 2.18:1 which means you would have to spin the crap out of it anyway.


The bore spacing is the same on all VQ engines.

 

Superb info, thanks SR20. This is getting better and better. Now the only thing I would need is 2.15mm longer rods to get the pistons back "up" in the cylinders, assuming I stick with stock VQ35 pistons. Any OEM rods I might look at?

Then I need to do cams, valvetrain, and intake manifold to get it to breathe up top, which a stock VQ35 doesn't seem to do to well.

 

That is why I was saying custom rods will probably be needed. I doubt the VQ23 uses 150.2mm rods. The VQ35 pistons do have a shorter pin height compared to the VQ30.

The rod difference would have to be the difference of the stroke radii which is 6.2mm.

 

Oops, you're right - I was was comparing the VQ23 to the VQ30 (69 vs. 73.3) which is where I got the (incorrect) 2.15mm.

Starting to think out a phased approach-
Phase 1: get a stock VQ35 dry sumped, in the car, and working
Phase 2: get a VQ23 crank and custom rods, get that running
Phase 3: headers, head work, etc.

 

Then you'll need engine management. Even the 2003+ 350Z ECUs might not even go past 8k. If you can budget it, I would recommend the Motec M600 or M800. Those are the only standalones in the world that can control DBW systems and control the Nissan CVTC and BMW Vanos.

 

I thought the exhaust manifolds are the same setup for the VQ30 and VQ35. So couldn't a RWD VQ30 use the same headers as the 350Z or G35?

 

Probably, I guess all he has to worry about is not hitting a motor mount

 

Yup, they work fine. However, custom mounting brackets for the motor mounts must be made.

 

Larrio, you gotta give us a hint. What is Andy dropping that thing into?

 

Something RWD of course.
That's all I'll say for now, since it's not complete, and the mods here don't like to hear about our crazy projects without dyno's/pics/explanations.

 

Just so you know, Nismo did just release their Nismo 3.5 head which has the VQ30 CC... which on a 3.5 would bring the CR up to 12:1 on a stock internal setup. That'd probably save you some time when it comes to headwork. And then there's also the hard to find HKS .272 cam with a .433 lift. Mmm... lift.

Edit: Screw what I said. This is what you want to look at. This contains the different stage cylinder heads, as well as multiple cam sets (which make me want to drool,) as well as a couple of different pathways, whether it be money or what suits your particular pathway. What it seems is you do have a lot of money to put into this car, or just a lot of knowhow and time. But there are some serious toys to be bought on this website.

 

jzr, your solution is in simplicity of design, the VQ30DE Turboers look for DE-T internals to make their turbo engines more reliable, there should be no reason that you couldn't take a RWD VQ30DET, strip it bare and use standard VQ30DE internals, that would bring it up to standard compression, you would basically be left with a RWD VQ30DE.