FWD vs RWD VQ35 Differences (Lengthy)

[pmohr]

To try to cut down on the 'can I use a 350z motor in my car', or 'why can't I use a G35 or FX35 or (etc) motor for my swap?' type of questions.

Recently started as a tech at a local Nissan performance shop (AAM), so I had the opportunity to snap some pics (and hopefully be more helpful around here). The following pictures all have the blocks aligned in basically the same exact way for ease of comparison).

RWD Block (350z, FX35, G35, any RWD VQ35DE platform)


FWD Block (Maxima, Altima, Quest [IIRC], any FWD VQ35DE platform)


Mounting Comparison

• RWD:
  • Large bolt pattern, maybe 8"x5" (from memory, definitely not accurate)
  • Mount cast positioned towards the timing cover
• FWD:
  • Small bolt pattern, maybe 4" square (from memory, definitely not accurate)
  • Mount cast positioned towards the end of the block

Accessory/Manifold comparison

• RWD:
  • Exhaust manifolds/headers curve backwards, away from the motor mounts
  • Accessory mounting points are located vertically along the front edge of the block (these are for the AC compressor, IIRC)
• FWD:
  • Exhaust manifolds/headers head straight down, motor mount is offset and doesn't get in the way
  • Accessory mounting points are located horizontally along the lower edge of the block

Here's two side-by-side pics (blocks are aligned in the same position, however the FWD block has torque plates 'installed'):

Left side


Right side (crappy pic, but you get the point)






Basically, you can definitely use the RWD block in a FWD design, it would just require re-engineering of a lot of things. Not even minor things, but motor mounts, headers/exhaust manifolds, etc.

To use a RWD block in a FWD chassis

• Custom motor mounts that extended towards the trans to utilize the center crossmember. Would most likely be weaker than the stock FWD mounts (on the FWD block) unless you braced the hell out of them.
• Custom headers made to stretch around the custom motor mounts made above - as you can see the RWD mounts are just plain in the way of any sort of manifold that comes straight down.
• Custom mounting brackets for all of the accessories, or try to customize the RWD accessories/mounting rails to work

Benefits of using a RWD block in a FWD chassis (assuming it will ever be done, not likely)

• Turbo manifolds could go directly over to the driver's side without the typical FWD mount interference
• Engines may be easier to find
• Possible ability to use the revup engine (with all associated electronics of course)

Long I know, but trying to get the point across. If anyone has any questions, please post them here and I'll try to address them for you.

[pmohr]

Originally Posted by mastercoryd

quick question, i know their mounted differently and may gain horse power from different headers, but why is the vq35 in a 350z have more horsepower is it just cuz of its boltons or is the vq35 in a rwd better? also whats a vq35hr just a rwd version of it or what?

The RWD VQ35 has different intake and exhaust manifolds, as well as different overall tuning and CVTC maps. Between all of those, you end up with more power.

The HR is a redesigned version of the VQ35DE; more power, stronger internals, CVTC on both intake and exhaust (like the revup), etc.

[mtrai760]

Thread cleaned up, stickied, and closed. If anyone has anything RELEVANT to add, send me a PM.