Rebuild vs Swap need help

[raizor33193]

Heya guys,

I'm new to z cars, I'm a muscle guy. But I've always had a thing for nissan z cars and the other day I picked up a 85 NA z31 with ~140k miles for 700 bucks.

The transmission is in good shape the clutch is ok for now and the engine runs, but with what seems to be a bit of a misfire. and theres a terrible exhaust leak.

My question is, to make decent power would i be better off:

a. Rebuilding the VG30E and turboing it. or

b. Buying an RB25DET and swapping it in? (paying a shop to do swap since i'm pretty much lost in the world of imports lol)

any info on which is better for power, which is cheaper, or just prices in general would be helpful.

[reddzx]

Paying someone to do a RB25 swap plus buying all the components will be very expensive. I would just turbo it, add a intercooler and a boost controller and see how you like that.

[Pdfflyer]

There is a 3rd option to rebuilding with a Turbo addition, versus an RB25DET option,

and that being the use of an Infinity VH45DE V8 as used in the '90 to '96 Q45, or VH41DE as used in the '97 to 2006 Q45

which is now an obsolete Infinity rear wheel drive platform. This DOHC VVT engine makes 280 hp without any turbo

and a great deal more with the correct turbo installed.

There is considerable more discussion on www.nicoclub.com and www.VH45DET.com and a few conversion pics. Engine mounts are considerably different, and radiator cooling must be re-determined, and hood/ground clearances are a must do effort in this conversion.

ZMech has posted his VH45DE conversion pics on this HybridZ website. There are several VH45DE videos on Youtube as well.

 

Heya guys,

I'm new to z cars, I'm a muscle guy. But I've always had a thing for nissan z cars and the other day I picked up a 85 NA z31 with ~140k miles for 700 bucks.

The transmission is in good shape the clutch is ok for now and the engine runs, but with what seems to be a bit of a misfire. and theres a terrible exhaust leak.

My question is, to make decent power would i be better off:

a. Rebuilding the VG30E and turboing it. or

b. Buying an RB25DET and swapping it in? (paying a shop to do swap since i'm pretty much lost in the world of imports lol)

any info on which is better for power, which is cheaper, or just prices in general would be helpful.

[New 2 z]

RB's are stupid. just build the VG there have been people who have built them and produced 450hp on the STOCK bottom ends. and with the Z32 rods and pistons I've heard of 550 being easily obtainable.

 

RB's have more cons then pros, if something breaks you'll be waiting a 2 weeks - a month for a part from japan, you need forged pistons to make any decent power over 400hp, and when something breaks it really DOES break. you'll have to rebuild it even before you swap it because you don't know whats been done to it. (parts)

 

VG's are more forgiving motors, they are PLENTIFUL in junkyards, VG's lasted till 2004 so they have a lot of parts laying around. they cam in ALMOST every single nissan built. maxima, quest, pathfinder (old and new), villager, S12, xterra, nissan pick up 4x4, so shortage of parts is pretty slim.

 

you're main limiting factor will be you're 9.1 compression ratio, you're ideal compression ratio would be 7.8:1 or 8.3:1. anyway now would be a good time to open her up and make the tolerances tighter then spec (not too tight need some clearance remember things heat up and expand.)

 

if you want to get real crazy you can get a VG33E and bore it to a VG34ET I've heard of a VG35 but I'm not too sure about that. I think by then the sleeves on the walls would be very thin.