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VG34 Defined.


SleeperZ31

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Okay from what i've been told the VG33 used in later Nissans could be upped to 3.4 liters (now correct me if im wrong) vh45 rods and pistons, correct?

 

Im looking for a way to make a little over 200hp without the use of forced induction or NoS, and i've been informed that with the right amount of head and cam work i could be up to the 250hp range which would be outstanding, BUT...

 

Would this be a direct swap into a z31? I know a few of the differences on the late VG-E series v6s are w-code heads, along with a non-interfacing design AND they also used a serpentine system rather than the v-belt used on my '87 300zx. I heard alot of talk about intake fitment issues but i figured i could just use the stock z31 top-end and just bolt it to the VG34, would this be possible? Or would i have to use the VG33's accessories?

 

Also, how would i maximize the potential of this mill? Im assuming i cant just bolt it up and hope the stock z31 ECU could compensate for the change in displacement, so would i need the MAF sensor and ECU from the VG33 or could i send my ECU to Jim Wolf tech and have it re-mapped? Would i be able to use the VG33's injectors also? Or should i just try and find some VG30et injectors and use them?

 

I know i should have searched elsewhere in this forum but most of the VG33-34 discussions have been for turbo use and i have no interest in such matters, and i was hoping to get a more direct answer from some of the HybridZ elders or anyone with experience building the forementioned motor. I just need a step-by-step description of what would be involved in building and swapping a VG34 into a '87 300zx.

 

Thanks...

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From what I've read so far... this would be the route you take:

 

VG33E bored out to 93 mm (about .060 over... closer to .059, either way, get your Q45 pistons and take them to the machinist before boring so that they can bore each cylinder to each piston for correct clearances, easiest and safest way to do it)

 

Cams and maybe some other head mods like porting, cams are the most important though considering the stock ones are more designed for torque being a truck engine and all

 

VH45DE pistons - from pictures I've seen, you'll probably want to have some valve reliefs cut into the piston as it is a flat top and has valve reliefs cut for a DOHC head. Bring a VG33 piston along and the machinist can likely figure out how deep and such, especially if you're getting cams

 

VG33 rods - no need for different ones, just get a custom bushing in the small end for the Q45's wrist pin (from what I've seen, it is 1mm larger in diameter). If for some reason you want stronger rods the VG30DETT rods are slightly bigger... but just remember you aren't going for a whole lot of power and a lighter rotating assembly would be of more benefit when NA

 

Since its going into a Z31, the easiest route would be to use a Z31 crank along with the Z31 oil pump, timing belt gears, crank pulley, oil pickup tube, oil pan, accessory brackets, and accessories. This should allow a direct swap from what I've seen. I'd also go ahead and swap all of the needed electronics and use the Z31 computer system to make it easier... I would probably use the turbo stuff with turbo injectors considering the turbo Z produced 205 hp stock and you're looking at 250. You should be quite safe with the turbo fuel system, especially considering NA's tend to do a little better with a leaner mixture. If you aren't planning on going with any boost down the road and want this to be your final setup... I'd personally just probably get a piggy back fuel controller along with the turbo Z stuff. That should give you the fine tuning needed to get a decent air/fuel ratio.

 

This should get you the final setup of a 3.4 liter VG with a ~9.7:1 compression ratio from what I've seen.

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Thanx! Im just looking for something with a good,even mix of power and torque as simply as possible, considering the amount of custom work needed i might skip the vh45 piston route and either see if i can just get bigger rings for the vg33 pistons or just stay at the 3.3l displacement and work from there. The turbo ECU was a good thought, didnt think of it myself and probably would be the cheapest route but if alls well with my tax rebate i might just have my current ECU mapped eventually pending the installation of the motor, when i get around to building it..

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  • 3 weeks later...
Thanx! Im just looking for something with a good,even mix of power and torque as simply as possible, considering the amount of custom work needed i might skip the vh45 piston route and either see if i can just get bigger rings for the vg33 pistons or just stay at the 3.3l displacement and work from there. The turbo ECU was a good thought, didnt think of it myself and probably would be the cheapest route but if alls well with my tax rebate i might just have my current ECU mapped eventually pending the installation of the motor, when i get around to building it..

 

 

The turbo ecu and injectors in an NA car is a bad idea. The fuel and timing maps in the turbo cars ecu are far too rich and far too retarded to make good power in a non-turbo application. Your best bet is to use the turbo injectors, and a programmable ecu via nistune. You can take your existing ecu and put a nistune board in it for about 400 bucks. It doesnt matter if you have an NA ecu because it will now be fully programmable with nistune. In fact, you will have a much easier time using your existing ecu because there will be no O2 sensor and idle control wiring issues to change. All you would have to do is change a few values (most notably injector K value and null time) in the NA ecu's program to make it work properly with turbo injectors. By far, this is the best and most cost effective solution. I think its a really bad idea to have someone "map" your ecu without having a running car to work off of. Nistune is only 400 bucks which is less than most places will charge to reprogram an ecu. After this initial investment you have a fully programmable ecu that you can change however you want. At that point, if you dont feel like making the changes yourself, you can drive the car to a dyno and have a program written based on feedback from your cars performance, not some generic off the shelf tune. If you go this route let me know. Ill be able to help you get the basics setup.

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Thanks! I had seen something awhile ago on this forum about the difference between the N/A and turbo 02 sensors and the injector issues in a N/A to turbo thread, the nistune and megasquirt systems are mentioned quite a bit and i had thought of those also...i still really have my heart set on dropping the supercharged vg33e® instead of a turbo or N/A build and after i save up $$$ whilst in boot camp i might just wait and try that instead...

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That's the best thing to do... if you have a project idea planned, like the VG33ER swap, I wouldn't bother with doing anything that is essentially the opposite of that goal. I've made that mistake way too many times and still have a bad habit of doing it. Its best to just save your money for you ultimate goal so that it gets done and gets done right the first time. You definitely will not regret doing it that way. :D

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