swapping a VG30E for a VG20ET (Z31)


  • swapping a VG30E for a VG20ET (Z31)


    hey folks,

    just wanted to pop the question since I have come across several complete motors and mine is in need of a rebuild.

    so.... here we are. well, yesterday while up in Dubai at the infamous Afghani scrap yards, I came across several JDM 200Z's imported from Japan with complete turbo engines among other parts and/or accessories. I have been wanting to do an NA2T on my 87 Z31 for some time now, and after seeing these VG20ET motors, I am thinking about swapping one in place of my worn NA. this seems to be a pretty rare, if ever done swap. research is telling me that although they look the same as the bigger 3 liters, the intake plenum is smaller, they are a bit smaller internally and the turbo is different from what I understand. not sure how different the exhaust manifold is.

    my current motor needs a rebuild as it has an internal misfire somewhere and burns up oil pretty quick (I have to add a liter every week) so I had planned to have it torn down and repaired and later converting NA2T. or I could try this VG20 swap instead or perhaps just take the required turbo parts from it.... hmmm.

    I did also find an RB20DET engine in its entirety sitting in what's left of a 200ZR.... hmmm.
    in addition, I now have access to at least 3 turbo cross-members so that should alleviate the issue with the non-turbo cross-member, unless there is a difference where it would not be compatible to swap into a Z31 kouki. my power steering rack just went out too… so, I guess now would be the time to get that fixed.

    please, what are your thoughts?

    thanks,

    Bonny

  • #2
    As they say there is not replacement for displacement with the exception of more efficient air flowing engine(Engine size to power output. So a VG20E would not be worth it. Unless I am wrong a RB is more efficient engine but I wouldn't be worth my effort for the 2 liter size. If I were you I would research to see if all the 200ZR RB20 accessories can bolt on to the RB26 which would make for a much easier swap.
    Own:
    1986 Z31 2+0 Turbo GLL ---- spearco IC ,3" exhaust, Poly everything with solid subframe and diff mounts, HX35/40 Holset Turbo, CLSD, Nistune with 1220cc FIC injectors on E85.
    1993 Jeep Cherokee 4X4
    Owned:
    1995 Z32 2+0 NA Black
    1985 Z31 2+0 turbo Black
    1986 Z31 2+0 NA Red
    1988 Z31 2+2 NA Auto
    1988 Z31 2+0 Turbo White ---- Stripped for all of its goodies.
    1984 Z31 2+0 turbo Brown
    1985 Z31 2+0 NA Black
    2003 Nissan frontier D22 supercharded vg33e 4x4

  • #3
    Nat2

    WTS,

    thanks for the reply. well, the motor in question is actually a VG20ET, not the E. but after reading this and doing some research it seems that maybe it might not be worth loosing the 3.0 displacement even with a turbo setup. but its hard to resist the offer… 300 bucks for a complete motor with all the turbo parts and accessories connected. kinda hard to beat. I might be able to talk the seller to let me pull the needed turbo parts off the engine instead. that having been said, the next issue is will those parts be compatible with the VG30… there isn't really a whole lot of info on the 2.0 liter VG20, so I am going to assume that it uses the same type of injectors as its Z31 cousin uses. I know the turbo used on it is different than a T3/T25 but I would think that the exhaust manifold would be the same or even the turbo crossmember. im not sure if the oil pan is the same… it might be smaller. do you know if these items might be smaller or configured differently? if all of these turbo components are the same as what the Z31 uses, then I pretty much have all the parts I would need for a turbo conversion.

    I could go the RB20DET route also. I didn't see an RB26 though.
    I wanted to ask you about your exhaust setup on your NA2T… did you go 3" from front to back or just from cat-back? I was thinking of getting with certified muffler and 2.5" back to the cat, and then 3" from there to the muffler, or just going 2.5" for the whole thing. that way I should be able to retain the stock Nissan heat shields. what do you think?

    Thanks,

    Bon

  • #4
    All the turbo parts and cross member works perfectly.

  • #5
    parts

    that's great. I just need to see if the seller will part the motor as it is still complete intact and still in the car… or half a car I should say.
    I'm debating on whether or not to go stock T25 or T3 on the turbo. since the piping and lines are a bit different. the smaller turbo might be perfect for my stock n/a compression application, however it seems that most guys go with the slightly bigger T3 and don't seem to have problems running the engine with stock psi up to around 10. need to decide before i start gathering parts.

    thanks!

    Bon

  • #6
    from what I have gathered, the 30, and 20 parts are different in general sizes, like manifolds, ports, and possibly head size I believe. if you have the possibility, getting a junkyard VG33E, and doing that, with VG30ET turbo parts (the VG33 head castings are the best available for these engines, plus the larger cyl. diameter!) T3 is the ideal choice of turbo in any regard on a VG single turbo.
    Damn dirty angels....these cars!

    Current Daily Driver - 86 Turbo.
    Under the cover - THE BANANA… that needs to be re-energized.
    sigpic

  • #7
    Doesn't really solve his immediate goal of slapping a turbo on the vg… but the middle east does have plenty of vg models, I'm sure vg33er isn't hard to find?

  • #8
    Originally posted by Axel kain View Post
    from what I have gathered, the 30, and 20 parts are different in general sizes, like manifolds, ports, and possibly head size I believe. if you have the possibility, getting a junkyard VG33E, and doing that, with VG30ET turbo parts (the VG33 head castings are the best available for these engines, plus the larger cyl. diameter!) T3 is the ideal choice of turbo in any regard on a VG single turbo.
    yeah, I think the sizes very also. but when looking directly at the VG20, its hard to tell a difference other than the plenum cover. I didn't see any VG33s at the yards, but there were so many engines I didn't have the time to look at everything. lots of various JDM engines. I need to go and look again. as far as turbos go, dude I found a warehouse with a 20' high pile of nothing but turbos. I asked the guy if he had a T-25 and he handed me two. still, I think T3 is the choice also. haven't decided on whether to get a used one from the yard and have it rebuilt, or just getting a new one from turbonetics or other reputable company. thanks for your input, Sir! Cheers.

    Bonny

  • #9
    Originally posted by G-E
    Doesn't really solve his immediate goal of slapping a turbo on the vg… but the middle east does have plenty of vg models, I'm sure vg33er isn't hard to find?
    well, there are plenty of cars and motors out here, especially up in Kuwait. if you want a Z.... that is the place to look because they're all there. there are a lot of options. I still want to go turbo though, but I haven't found a vg33 yet or vg30et. still a lot of searching to do while the weather is nice. if all else, I could take the turbo parts of those vg20et engines I found. options, options, options....

    thanks,

    Bon

  • #10
    IMHO, The RB20DET would be a bit more expensive but a In-Line Motor will always be very strong reliable power. Even today people will always talk about how great In-Line motors are. I have a 87ET but i wouldn't underestimaste the RB Motor's. The RB20 has Dual Cam instead of single cams, and will be alot quicker response than a single cam IMO. If you not looking to push more than 500hp, i would go with the RB20DET hands down. Plus you'll have the cool factor of having something Very Rare setup. Only thing making the VG better is displacement as he mentioned it, but the RB is a better choice for cheap reliable power 400rwhp on stock internals and the sound of the RB OMG. Plus the VG motor is a big hassel compared to the RB, everything on it has to be custom made and hard to find parts. Eventhough i love my VG motor because it still a great design and hasnt fail me yet. (Knock on wood), but the RB has something special about it. Everthing you do will be much easier to work with, weather it IC, Turbo upgrades, Rails, etc etc the list goes on and on. If i had a chance to buy RB20DET, i would jump on that chance if the price is right like you said. Plus you can always work on your VG on the back burner or either way. It all comes down if you going on big power or not, Drifing/racing around 300-400sih is still alot of fun and the RBmotor will take alot of beating with eas because of the design In-Line. This is just my own opinion like i said… ( so everyone knows lol)

  • #11
    not this argument again, if you go I6, do it right and go RB25 or 26, make it a worthwhile upgrade. if you really want an upgrade, go VG30/33 turbo, or if you really want to have some fun, do a VG30DETT swap…
    Damn dirty angels....these cars!

    Current Daily Driver - 86 Turbo.
    Under the cover - THE BANANA… that needs to be re-energized.
    sigpic

  • #12
    Rb20det -- vg30e na2t

    thanks guys for your info. I thought about doing the RB20DET but after doing some research, it seems that the cost would out way the worth of doing the swap, compared to staying with the VG. now, keep in mind Gentlemen, that I do have access to a complete RB motor sitting in a stock 200zr with everything just staring at me in the face (except for the half of the car that is missing… its only complete from the floor pans forward). so, doing this might actually be worth it since everything I need can come right out of that 200zr. but even with the cross member and the mounts, I think so is a lot more that needs to be done, fabrication-wise and electrical-wise in order for it work in my Z31. that being said, and from what I read, its more logical and money-wise to stick with the VG. plus I don't know how it would work with a/c (unknown to me if the 200zr came with a/c) but in this climate, you cannot drive around during the summer time without a/c and be comfortable.
    so, if you guys had access to an RB in a 200zr, would you consider doing the swap, or not? just like to get your opinion.

    thank you again for your responses.

    bonny

  • #13
    Things to ask yourself:
    What's my price range?
    How good are my Wrench Skill's?
    What's my goal on HP?
    If I do, what I am looking at in the future in regards to modifications, will it be possible?
    Price has a big role, if you get it for cheap ($500 or less). A RB20DET sell for over 1k in good working condition. Do as much resreached as much as possible so you see what is predicted ahead of time. The VGDETT a super tight fit and will throw off the balance of the car IMO, plus it will be hard to work on in the future if something breakdown since little space. In-Line easier IMO to work with, but I'm not sure about the AC Fitment. But either way you will be pulling out the motor and will have access to it (Fab).
    RB has my Vote

  • #14
    Maybe this will help you buddy
    https://youtu.be/i-UnCHvL3HE

  • #15
    RB



    Dragon,

    thanks for the info and the video link.


    price range: I've got about a $3000.00 budget to work with currently.
    How good are my Wrench Skill's? : I'm an aircraft mechanic by trade, however do to my location, job, and limited space, a performance shop will be doing the work. (been taking my Z31 there to the same Phillippino mechanic for years)
    What's my goal on HP?: Honestly, I'm not looking for big horsepower. Just a bit more zip. I was set on a stock turbo setup… (then came up this RB engine)
    If I do, what I am looking at in the future in regards to modifications, will it be possible?: that's what I'm afraid of. again, looking at staying quite stock.


    after taking a look at the video, I found it to be quite informative, lot of good info regarding the swap. however, I think it would be easier for me since the RB that I am looking at, as it is, is already sitting in a 300zr. so all the parts I need SHOULD be there to swap into the Z31. the guy in the video makes it sound like his motor came out of a different car, maybe a skyline, or whatever. but I'm sure even in my case, there will be modifications to be done. as far as the price of the motor, a got a price of 2000 UAE dirhams (roughly $500 USD) and that's not bad… and only about 250 bucks for the complete VG20ET that I saw.

    what I am concerned over is being able to have a/c. I don't recall that 300zr having a/c when I looked at it… overall I think it would nice to have an RB, but it just seems more convenient and logical to stick with the VG. though I prefer inline 6 series, I think the VG is very capable and dependable, even though they are a pain to work on and get access to things… hehe, the 280zx guys know what I'm talking about.... (I can have the spark plugs out in 5 minutes with ease.... not so on the Z31's VG30E)

    thank you Red Dragon for you input, Sir!

    Bonny